3rd Year

1st Semester

1st Assignment

The Ways of Forgetting and the Ways of Improving Memory

PSY 203-Cognitive Psychology

Name:D.K.D.MadhubhashiniReg no:A/BBA/09/068Lecturer:Mrs.M.Gunasekara

Acknowledgement

I consider it is a great privilege to thank all those people who helped me to complete this assignment

I express my sincere thanks to Main lecturer Mrs.M.Gunasekara and Assistant Lecturer Miss.Kokila

Subhashinifor giving me this opportunity to commence the project work and guidance do so.

At for last not for least like to thank my parents who gave me a great deal of helping hand to make

this assignment a success.

D.K.D.Madhubhashini

Content

Acknowledgement..................................................................................................................................1

Content...................................................................................................................................................2

Table of Figures.....................................................................................................................................3

Introduction............................................................................................................................................4

Literature Review...................................................................................................................................5

Cognitive Psychology........................................................................................................................5

History of Cognitive Psychology...................................................................................................5

Memory and Forgetting..........................................................................................................................9

Memory..............................................................................................................................................9

Main Processors of Memory........................................................................................................10

Storage..............................................................................................................................................13

Special Situations in Recalling memeory.............................................................................................20

Hyperthymesia.................................................................................................................................20

Rebirth and Past life memory...........................................................................................................20

Forgetting.........................................................................................................................................21

Why We Forget?..................................................................................................................................22

Elizabeth Loftus’s key explanations for why forgetting occurs.......................................................22

1. Retrieval Failure.......................................................................................................................22

The Ebbinghaus Forgetting Curve...............................................................................................22

2. Interferance...............................................................................................................................23

3. Failure to Store.........................................................................................................................24

4. Motivated Forgetting................................................................................................................24

Memory Disorders...........................................................................................................................25

Alzheimer's Disease.....................................................................................................................25

Dementia......................................................................................................................................26

Age Associated.............................................................................................................................27

Alcohol.........................................................................................................................................29

Amnesia........................................................................................................................................30

Autism..........................................................................................................................................32

Huntington's Disease....................................................................................................................33

Korsakoff's Syndrome..................................................................................................................34

OCD.............................................................................................................................................35

Parkinson's Disease......................................................................................................................36

Schizophrenia...............................................................................................................................37

Tourette Syndrome.......................................................................................................................38

WAYS OF ENHANCING MEMORY................................................................................................38

Organization.....................................................................................................................................39

Concentration...................................................................................................................................39

Chunking Memory...........................................................................................................................39

Recoding:.........................................................................................................................................40

Use of schema..................................................................................................................................40

Mnemonic Strategies........................................................................................................................40

Method of loci..............................................................................................................................40

SQ3R method...................................................................................................................................41

SURVEY......................................................................................................................................41

QUESTION..................................................................................................................................41

READ...........................................................................................................................................42

RECITE........................................................................................................................................42

REVIEW......................................................................................................................................42

Table of Figures

Figure 1 Memory and Brain.................................................................................................................11

Figure 2 Schematic Model of The Human Information Processing System........................................15

Figure 3 Ebbinghaus Forgetting Curve................................................................................................22

Figure 4 Aging.....................................................................................................................................26

Figure 5- Alcoholism...........................................................................................................................28

Figure 6 Source of amnesia..................................................................................................................30

Figure 7 OCD.......................................................................................................................................33

Figure 8 memory palace.......................................................................................................................38

Introduction

The chapters in this collection all reference causes of forgetting. But the variety of possible causes is

outstanding. Here we examine insights into trace decay, interference, and consolidation that have

emerged from recent computational and mathematical models of memory.

Two key theoretical issues support the contemporary discussion. The first of these concerns the

reputed distinction between two memory systems that are dedicated to the storage of information

over the short and the long term (STS and LTS respectively), and the second concerns the

importance of consolidation failure as a cause of forgetting. STS vs. LTS. Although the usefulness of

a theoretical distinction between STS and LTS has often been questioned (Crowder, 1989; Melton,

1963) only recently have specific models emerged that claim to account for both short-term and

long-term memory phenomena within a united framework.

There is no evidence that time based decay is the sole or even primary cause of forgetting over the

short term, thus undermining one piece of evidence from forgetting for the traditional distinction.

Other arguments that are consistent with our perspective can be found somewhere else.

In particular, we note that interference-based models such as those of Lewandowsky and others

(Lewandowsky & Farrell, 2008; Oberauer & Lewandowsky, 2008) and Brown (2007) can reason for

forgetting data that have previously been expected to connect a STS and LTS disunion, and that

experimental evidence that has been taken in support of temporal decay can be understood.

Consolidation is the second theoretical topic addressed that of consolidation as a primary factor

underpinning memory and forgetting.

Consolidation refers to the idea that memories continue to strengthen after they have been formed,

and that they thus become hardier to forgetting over time. As Wixted (2004b, 2005) notes,

“consolidation has featured prominently in theorizing on forgetting in the neurosciences for several

decades, whereas most cognitive approaches have relied exclusively on alternative notions such as

interference or decay”. Indeed, not a single recent formal model of memory within a cognitive

tradition assigns an important role to consolidation.

Conversely, models of memory that do emphasize consolidation (McClelland, McNaughton, &

O'Reilly, 1995; Meeter & Murre, 2005; Norman & O'Reilly, 2003) handle the data implicating

consolidation, but they typically do not address the rich data sets that are traditionally taken as the

path for cognitive models of memory.

Literature Review

Cognitive Psychology

Cognitive psychology is the scientific investigation of human cognition, that is, all our mental

abilities the way people think, perceive, remember and learn. As part of the larger field of cognitive

science, this is narrowly related to artificial intelligence, computer science, philosophy,

anthropology, linguistics, biology, physics, and neuroscience.

The fundamental concentration of cognitive psychology is on how people acquire, process and store

information. There are numerous practical applications for cognitive research, such as enlightening

memory, increasing decision-making accuracy etc.

History of Cognitive Psychology

Cognitive psychology in its contemporary practice includes a extraordinary set of new technologies

in psychological science. Although published inquiries of human cognition can be traced back to

Aristotle’s ‘’De Memoria’’ (Hothersall, 1984), the intellectual origins of cognitive psychology began

with cognitive approaches to psychological problems at the end of the 1800s and early 1900s in the

works of Wundt, Cattell, and William James (Boring, 1950).

Behaviorism school of thought

“Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and

I'll guarantee to take any one at random and train him to become any type of specialist I might select

-- doctor, lawyer, artist, merchant-chief and, yes, even beggar-man and thief, regardless of his

talents, penchants, tendencies, abilities, vocations, and race of his ancestors.”

John Watson, Behaviorism, 1930

Till the year 1950 was the leading school of thought in psychology (Watson, 1913; Boring, 1950;

Skinner, 1950). Wilhelm Wundt's Influence The creation of a psychology lab established psychology

as a separate field of study with its own methods and questions. Wilhelm Wundt's support of

experimental psychology these issue led to the decline of behaviorism as the dominant branch of

scientific psychology and to the “Cognitive Revolution”. Cognitive psychology declined in the first

half of the 20th century with the rise of “behaviorism" the study of laws relating. It is a theory of

learning based upon the idea that all behaviors are acquired through conditioning. Conditioning

ensues through interaction with the environment. Behaviorists believe that our responses to

environmental stimuli forms our behaviors. There are two major types of conditioning:

Classical conditioning is a technique used in behavioral training in which a naturally occurring

stimulus is paired with a response.

Operant conditioning Operant conditioning /instrumental conditioning is a method of learning that

occurs through rewards and punishments for behavior.

Cognitive Revolution

The Cognitive Revolution began in the mid-1950s when researchers in couple of fields originated to

develop theories of mind based on compound representations and computational procedures (Miller,

1956; Broadbent, 1958; Chomsky, 1959; Newell, Shaw, & Simon, 1958). Cognitive psychology

became main theory in the use1960s (Tulving, 1962; Sperling, 1960). Unlike behaviorism, which

focuses only on observable behaviors, cognitive psychology is concerned with internal mental states.

The term "cognitive psychology" was first used in 1967 by the publication of Ulric Neisser’s book,

‘’Cognitive Psychology’’, in 1967. According to Neisser, cognition involves

"All processes by which the sensory input is transformed, reduced, elaborated, stored, recovered,

and used. It is concerned with these processes even when they operate in the absence of relevant

stimulation, as in images and hallucinations... Given such a sweeping definition, it is apparent that

cognition is involved in everything a human being might possibly do; that every psychological

phenomenon is a cognitive phenomenon."

Major Topics in Cognitive Psychology

Cognitive psychology comprises human perception, attention, learning, memory, concept

formation, reasoning, judgment and decision-making, problem solving, and language

processing. For some, social and cultural factors, emotion, consciousness, animal cognition,

evolutionary approaches have also become part of cognitive psychology.

Perception

Learning perception pursue to recognize how we build subjective interpretations of proximal

information from the environment.

Cognitive psychologists have studied these properties empirically with psychophysical methods and

brain imaging. Perceptual systems are composed of separate senses like visual, auditory,

somatosensory and processing modules according to Livingston & Hubel, (1988)Ungerleider &

Mishkin, (1982)Julesz, (1971) “form, motion” and sub-modules as for Lu & Sperling, 1995 that

symbolize unlike aspects of the stimulus information.

Contemporary research also focuses on how these separate demonstrations and modules cooperate

and are integrated into intelligible percepts. As per findings of Grossberg & Mingolla (1985) Marr

(1982) Wandell (1995) Computational models, grounded on physiological principles, have been

established for many perceptual systems.

Attention

As defined by Broadbent, (1957) Posner, (1980) and Treisman, (1969) Attention solves the problem

of information overload in cognitive processing systems by picking some information for additional

processing, or by handling resources useful to several sources of information same time.

The theoretical analysis of attention has taken several major methods to categorize the mechanisms

of attention

1. The signal-detection approach by Lu & Dosher, (1998)

2. Similarity-choice approach byBundesen, (1990), Logan, (2004)

Experimental investigation conducted by Posner (1980) Weichselgartner & Sperling, (1987) Chun

& Potter,(1995) and Pashler, (1999) on attention has focused on how and why attention improves

performance, or how the lack of attention hinders performance. “Brain imaging studies” by

Kanwisher & Wojciulik in 2000 have documented effects of attention on activation in early visual

cortices, and have investigated the networks for attention control.

Learning

“Learning is never a matter of passive of passive absorbsion or registration but rather a complex of

activities which depend partly on what is being learned and partly on accomplishments brought by

the individual o the learning.” (Hunter I.M.L, 1964).and also says Learning improves the response

of the organism to the environment. Kandel’s, (1976) Estes’s, (1969) and Thompson’s, (1986)studies

argue that The study of learning begins with an analysis of learning phenomena in animals

instrumental, contingency, habituation, conditioning, and, and

Studies of conceptual learning emphasize the nature of the processing of incoming information, the

role of elaboration, and the nature of the encoded representation (Craik, 2002). Those using

computational approaches have investigated the nature of concepts that can be more easily learned,

and the rules and algorithms for learning systems (Holland, Holyoak, Nisbett, & Thagard, 1986).

Those using lesion and imaging studies investigate the role of specific brain systems (e.g., temporal

lobe systems)

Memory

Memory study focuses on how memories are encored, stored, and retrieved. The study of human

memory is one of the most developed aspects of cognitive psychology. Memory domains have been

functionally divided into memory for facts, for procedures or skills, and working and short-term

memory capacity.

Anderson, (1996) Shiffrin & Steyvers, (1997) describe memory in Computational approaches as

“propositional networks, or as holographic or composite representations and retrieval processes.”

The experimental approaches have recognized dissociable memory types or capacity limited

processing systems such as short-term or working memory (Cowan, 1995; Dosher, 1999).

Concept Formation

The response to a precise stimulus is determined not by the precise occurrence but by classification

into the category and by association of knowledge with that category (Medin & Ross, 1992).

Concept or category creation rise to the ability to organize the perception and arrangement of

experiences by the construction of functionally relevant categories.

Definite concepts essentially reflect comparison of structures, but others may reflect function, or

conceptual theories of use (Medin, 1989). Computational models have been developed based on

aggregation of instance representations, similarity structures and general recognition models, and by

conceptual theories (Barsalou, 2003). Cognitive neuroscience has identified important brain

structures for aspects or distinct forms of category formation (Ashby, Alfonso-Reese, Turken, and

Waldron, 1998).

Judgment and decision

As for von Neumann & Morgenstern (1944 )and Luce, (1959)”The historic foundations of choice are

based in normative or rational models and optimality rules, beginning with expected utility theory”.

Extensive analysis identified failures of rational models due to differential assessment of risks and

rewards, the distorted assessment of probabilities. The limitations in human information processing

New computational approaches rely on dynamic systems analyses of judgment and choice

(Busemeyer & Johnson, 2004), and Bayesian belief networks that make choices based on multiple

criteria (Fenton & Neil, 2001) for more complex situations.

Problem Solving

This is the study of how humans follow goal directed behavior. Solving a problem is conceived as

finding operations to move from the initial state to a goal state in a problem space using either

algorithmic or heuristic solutions. The problem representation is critical in finding solutions (Zhang,

1997).

The computational state space analysis and computer simulation of problem solving of Newell and

Simon (1972) and the empirical and experiential analysis of Wickelgren (1974) together have set the

cognitive psychological approach to problem solving.

Language Processing

Psycholinguistics has studied encoding and verbal access of words, sentence level procedures of

describing and representation, and general representations of concepts, meaning, inference, and

semantic assumptions. While linguistic approaches focus on the formal structures of languages and

language use (Chomsky, 1965), Kintsch (1974)Pinker (1994) and Levelt, (1989) suggest cognitive

psychology has focused on language acquisition, language comprehension, language production, and

the psychology of reading The neuroscience of language has a long history in the analysis of grazes.

Computational models have been developed for all of these levels, including lexical systems, parsing

systems, semantic representation systems, and reading aloud.

Memory and Forgetting

Memory

According to Hunter I.M.L (1964) “Memory is an abstraction, a shorthand way of referring to

certain kind of activities.” Memory is a remarkable mental process and a mental system which

receives information from external or internal stimuli, recalls it and makes it obtainable on future

events. Though we talk about memory as a tangible it really is intangible and hypothetical store

house. It delivers continuity to our experiences across different time points. A moment’s reflection

will tell you how difficult it will be if you do not have undamaged memory function. You would

perhaps lose your identity or the sense of what you are and will always remain a new learner because

the past learning experience will have no value or significance to you.

Whatever we experience now influenced by what we experience in past and our memory system

does perform this more dynamically and multipurpose like a tape recorder. It gives value by enabling

him to adjust to the present circumstances in the light of past events. But human memory differs

from a tape recorder in many important ways. For instance, we remember happen through various

forms, not only verbal material but visual experiences, tangible impressions, feelings of pain and

joy, motor skills, events, activities and so on. Second, retrieval of information can be exactly in

the same way or in a different form. Third, the reception of new information depends a lot on

what information we already have. Fourth, we neither receive nor retain all the information

presented to us because there is great deal of selectivity in receiving the information . Fifth, all

tape recorders have some limitation non recording but human memory can retain extremely

large amounts of information.

Finally, our memory system is an active system. It works on the information received. It may

mingle, enlarge, adapt, neglect or reorganize the information. It is not passive like a tape recorder

which reproduces the information in its original form significance to you.

Main Processors of Memory

Encoding

It is the vital first step to creating a new memory. It permits the perceived article of attention to be

converted into a concept that can be stored within the brain, and then recalled later from short-term

or long-term memory. Encoding is a biological event beginning with perception through the senses.

The process of placing a memory originates with attention regulated by the thalamus and the

frontal lobe, in which a memorable event causes neurons to fire more frequently, making the

experience more intense and repetition the probability that the incident is encoded as a memory.

Emotion tends to increase attention, and the emotional element of an event is processed on an

unconscious pathway in the brain leading to the amygdala. Only then are the actual sensations

derived from an event processed.

The perceived sensations are decoded in the various sensory areas of the cortex, and then combined

in the brain’s hippocampus into one single experience. The hippocampus is then responsible for

analyzing these inputs and finally determining if they will be committed to long-term memory which

performances as likely of cataloging centre where the novel sensations are compared and associated

with previously recorded ones. The different threads of information are then stored in different parts

of the brain, although the exact way in which these pieces are identified and recalled later remains

mostly unknown. The key role that the hippocampus plays in memory encoding has been highlighted.

Ex: Individuals who have had their hippocampus damaged or removed and can no longer create new

memories (Anterograde Amnesia).

It is also one of the few areas of the brain where completely new neurons can grow. Human memory

is fundamentally associative, meaning that a new piece of information is remembered better if it can

be associated with previously acquired knowledge that is already firmly anchored in memory.

.

Figure 1 Memory and Brain

Different levels of Encoding occurs

Being the formation of short-term memory from the ultra-short term sensory memory,

followed by the conversion to a long-term memory by a process of memory consolidation.

The process begins with the creation of a memory trace or engram (or memory trace) in

response to the external stimuli. An engram is a hypothetical biophysical or biochemical

change in the neurons of the brain, hypothetical in the respect that no-one has ever actually

seen, or even proved the existence of, such a construct.

An organ called the hippocampus, deep within the medial temporal lobe of the brain,

receives connections from the primary sensory areas of the cortex, as well as from

associative areas and the rhinal and entorhinal cortexes.

While these anterograde connections join at the hippocampus, other retrograde pathways

arise from it, returning to the primary cortexes. A neural network of cortical synapses

effectively records the various associations which are linked to the individual memory.

Main types of encoding

1. Acoustic encoding is the processing and encoding of sound, words and other auditory input

for storage and later retrieval. This is assisted by the concept of the phonological loop, which

permits input within our echoic memory to be sub-vocally rehearsed in order to facilitate

remembering.

2. Visual encoding is the process of encoding images and visual sensory information. Visual

sensory information is temporarily stored within the iconic memory before being encoded

into long-term storage.

The amygdala fulfills an important role in visual encoding, as it admits visual input in

addition to input from other systems and encodes the positive or negative values of

conditioned stimuli.

3. Tactile encoding is the encoding of how something feels, generally through the sense of

touch. Physiologically, neurons in the primary somatosensory cortex of the brain react to

vibrotactile stimuli caused by the feel of an object.

4. Semantic encoding is the process of encoding sensory input that has precise meaning or can

be applied to a precise context, rather than originating from a precise sense.

Ways to Enrich Encording

As of the associative nature of memory, encoding can be upgraded by a strategy of

organization of memory called elaboration, in which new pieces of information are

associated with other information already recorded in long-term memory, thus integrating

them into a wider, rational narrative which is already familiar. W

When we use mnemonic devices while enording, (Mnemonic devices are techniques a

person can use to help them improve their ability to remember something. In other words, it’s

a memory technique to help your brain better encode and recall important information. It’s a

simple shortcut that helps us associate the information we want to remember with an image, a

sentence, or a word)we are effectively passing facts through the hippocampus several times,

so that it can keep strengthening the relations, and therefore increase the probability of

subsequent memory recall.

Storage

Storage is the more or less passive process of retaining information in the brain, whether in the

sensory memory, the short-term memory or the more permanent long-term memory. Each of these

diverse stages of human memory function as a sort of filter that helps to guard us from the flood of

information that meet us on a daily basis, avoiding an overload of information and helping to keep us

sane.

The more the information is repeated or used, the more likely it is to be retained in long-term

memory ex: studying helps people to perform better on tests.

Since the early neurological work of Karl Lashley and Wilder Penfield in the 1950s and 1960s, it has

become clear that long-term memories are not stored in just one part of the brain, but are widely

distributed throughout the cortex. After consolidation, long-term memories are stored throughout the

brain as clusters of neurons that are primed to fire together in the same design that created the

original experience, and each element of a memory is stored in the brain area that originated.

Certainly, it seems that they may even be encoded unnecessarily, several times, in various parts of

the cortex, so that, if one engram (or memory trace) is wiped out, there are duplicates, or alternative

pathways, in another place, through which the memory may still be retrieved.

Hence, opposing to the common concept, memories are not stored in our brains alike books on

library shelves, but necessity to be actively reconstructed from elements dispersed all over various

areas of the brain by the encoding process. Memory storage is therefore an ongoing process of

reclassification resulting from continuous changes in our neural pathways, and parallel processing of

information in our brains.

Richard Schiffrin and others have claimed, “ALL memories are stored somewhere in the brain,

and that it is only in the retrieval process that irrelevant details are “fast-forwarded” over or

expurgated”. It seems more likely that the memories which are stored are in some way edited and

sorted, and that some of the more peripheral details are never stored.

In the absence of disorders due to trauma or neurological disease, the human brain has the capability

to store almost unlimited amounts of information indefinitely. Forgetting, therefore, is more likely to

be result from incorrectly or incompletely encoded memories, and/or problems with the

recall/retrieval process. It is a mutual experience that we may try to remember something one time

and fail, but then remember that same item later. The information is therefore clearly still there in

storage, but there may have been some kind of a gap between retrieval cues and the original

encoding of the information. “Lost” memories recalled with the aid of psychotherapy or hypnosis

are other examples supporting this idea, although it is difficult to be sure that such memories are

real and not implanted by the treatment.

Key Aspects of Memory Storage

The stage model of memory is often used to explain the basic structure and function of memory that

also called “Information Processing Approach of Memory” , originally proposed in 1968 by

Atkinson and Shiffrin, this theory outlines three separate stages of memory, sensory memory, short-

term memory and long-term memory.

Sensory Memory

Sensory memory is the earliest stage of memory. During this stage, sensory information from

the environment is stored for a very brief period of time, generally for no longer than a half-

second for visual information and 3 or 4 seconds for auditory information. We attend to only

certain aspects of this sensory memory, allowing some of this information to pass into the next stage

- short-term memory.

Short-Term Memory (STM)

Short-term memory, also known as active memory, is the information we are currently aware

of or thinking about. In Freudian psychology, this memory would be referred to as the conscious

mind. Paying attention to sensory memories generates the information in short-term memory. Most

of the information stored in active memory will be kept for approximately 20 to 30 seconds. While

many of our short-term memories are quickly forgotten, attending to this information allows it to

continue on the next stage long-term memory.

Long-Term Memory (LTM)

Long-term memory refers to the continuing storage of information. In Freudian psychology,

long-term memory would be call the preconscious and unconscious. This information is largely

outside of our awareness, but can be called into working memory to be used when needed. Some

of this information is fairly easy to recall, while other memories are much more difficult to

access.

, 1968

Figure 2 Schematic Model of The Human Information Processing System.

ADAPTED FROM ATKINSON & SHIFFRIN

Memory Recall/Retrieval

Recall or retrieval of memory refers to the subsequent re-accessing of events or information

from the past, which have been previously encoded and stored in the brain. In common jargon,

it is known as remembering. During recall, the brain "replays" a pattern of neural activity that was

originally generated in response to a particular event, echoing the brain's perception of the real event.

In fact, there is no real firm difference between the act of remembering and the act of thinking.

These replays are not quite identical to the original otherwise we would not know the difference

between the genuine experience and the memory, but are mixed with an awareness of the present

situation. One consequence of this is that memories are not frozen in time, and new information and

suggestions may become incorporated into old memories over time. Thus, remembering can be

thought of as an act of creative re-imagination.

Since of the way memories are encoded and stored, memory recall is effectively rebuilding of

elements spread throughout many areas of our brains. Memories are not stored in our brains like

books on library shelves, or even as a collection of self-contained recordings or pictures or video

clips, but may be better thought of as a kind of collage or a jigsaw puzzle, involving different

elements stored in disparate parts of the brain linked together by associations and neural networks.

Memory retrieval therefore requires return to the nerve pathways the brain formed when encoding

the memory and the strength of those pathways controls how quickly the memory can be recalled.

Recall effectively returns a memory from long-term storage to short-term or working memory, where

it can be retrieved, in a kind of reflection of the encoding process. It is then restored in long-term

memory, thus re-amalgamating and solidification it.

The efficiency of human memory recall is astonishing. Most of what we remember is by direct

retrieval, where items of information are linked directly a question or cue, rather than by the kind of

in sequence scan. Other memories are retrieved quickly and efficiently by hierarchical implication,

where a specific question is linked to a class or subgroup of information about which certain facts are

known.

Also, the brain is usually able to determine in advance whether there is any point in searching

memory for a particular fact.

The evidence suggests that memory retrieval is a more or less automatic process. Thus, although

distraction or divided attention at the time of recall tends to slow down the retrieval process to some

extent, it typically has little to no effect on the accuracy of retrieved memories. Distraction at the

time of encoding, on the other hand, can severely impair subsequent retrieval success.

It is also possible that false or wrongly interpreted memories may be created during recall, and

carried forward thereafter. One can also, up to a point, choose to forget, by blocking out unwanted

memories during recall (a process achieved by frontal lobe activity, which inhibits the laying down

or re-consolidation of a memory

Main Methods of Accessing Memory

Recognition is the association of an event or physical object with one previously

experienced or encountered, and involves a process of comparison of information

with memory, e.g. recognizing a known face, true/false or multiple choice questions,

etc.

– Recognition is a largely unconscious process, and the brain even has a

dedicated face recognition area, which passes information directly through the

limbic areas (in brain) to generate a sense of familiarity, before linking up

with the cortical path, where data about the person's movements and

intentions are processed..

– Recognition is usually considered to be “superior” to recall (in the sense of

being more effective), in that it requires just a single process rather than two

processes. Recognition requires only a simple familiarity decision amd

recognition only requires a relatively simple decision as to whether one thing

among others has been encountered before. Sometimes, however, even if a

part of an object initially activates only a part of the neural network concerned,

recognition may then suffice to activate the entire network.

Recall involves remembering a fact, event or object that is not currently physically

present (in the sense of retrieving a representation, mental image or concept), and

requires the straight exposure of information from memory, e.g. remembering the

name of a recognized person, fill in the blank questions, etc .

– A full recall of an item from memory requires a two-stage process (indeed,

this is often referred to as the two-stage theory of memory) in which the search

and retrieval of candidate items from memory is followed by a familiarity

decision where the correct information is chosen from the candidates

retrieved. Thus, recall involves actively reconstructing the information and

requires the activation of all the neurons involved in the memory in question,

Alternative theory to two-stage process by Endel Tulving.

This theory states that memory utilizes information both from the specific memory trace as well as

from the environment in which it is retrieved. Because of its focus on the retrieval environment or

state, encoding specificity takes into account context cues, and it also has some advantages over

the two-stage theory as it accounts for the fact that, in practice, recognition is not actually always

superior to recall.

Typically, recall is better when the environments are similar in both the learning (encoding) and

recall phases, suggesting that context cues are important. In the same way, emotional material is

remembered more reliably in moods that match the emotional content of these memories (e.g. happy

people will remember more happy than sad information, whereas sad people will better remember

sad than happy information).

Alternative theory to two-stage process by Fergus Craik and Robert Lockhart

This theory suggest that memory recall of stimuli is also a function of the depth of mental

processing, which is in turn determined by connections with pre-existing memory, time spent

processing the stimulus, cognitive effort and sensory input mode.

Thus, shallow processing as, naturally, that based on sound or writing leads to a relatively fragile

memory trace that is vulnerable to rapid decay, whereas deep processing as that based on semantics

and meanings results in a more durable memory trace.

This theory suggests, then, that memory strength is continuously variable, as opposed to the earlier

Atkinson-Shiffrin, or multi-store, memory model, which just involves a sequence of three discrete

stages, from sensory to short-term to long-term memory.

Main Types of Recall

1. Free recall is the process in which a person is given a list of items to remember and then is

asked to recall them in any order. This type of recall often displays evidence of either the

primacy effect of “Early Vs Late Selection” when the person recalls items presented at the

beginning of the list earlier and more often or when the person recalls items presented at the

end of the list earlier and more often, and also of “the contiguity effect”; the marked

tendency for items from neighboring positions in the list to be recalled successively.

Testing helps protect against "proactive interference" the familiar feeling of being

overwhelmed by too much information, and the studies suggest that a quick test is much more

effective than en extra hour of study or re-reading.

2. Cued recall is the process in which a person is given a list of items to remember and is then

tested with the use of cues or guides. When cues are provided to a person, they tend to

remember items on the list that they did not originally recall without a cue, and which were

thought to be lost to memory. This can also take the form of stimulus-response recall, as

when words, pictures and numbers are presented together in a pair, and the resulting

associations between the two items cues the recall of the second item in the pair.

3. Serial recall refers to our ability to recall items or events in the order in which they occurred,

whether chronological events in our autobiographical memories, or the order of the different

parts of a sentence in order to make sense of them. Serial recall in long-term memory appears

to differ from serial recall in short-term memory, in that a sequence in long-term memory is

represented in memory as a whole, rather than as a series of separate items.

Testing of serial recall by psychologists have yielded several general rules

– more recent events are more easily remembered in order;recall decreases as

the length of the list or sequence increases

– there is a tendency to remember the correct items, but in the wrong order;

where errors are made, there is a tendency to respond with an item that

resembles the original item in some way (e.g. “dog” instead of “fog”, or

perhaps an item physically close to the original item)

– repetition errors do occur, but they are relatively rare; if an item is recalled

earlier in the list than it should be, the missed item tends to be inserted

immediately after it; If an item from a previous trial is recalled in a current

trial, it is likely to be recalled at its position from the original trial.

Special Situations in Recalling memeory

Hyperthymesia

Rare condition called “Hyperthymesia” (also known as hypermnesia or superior autobiographical

memory) in which a few people show an extraordinary capacity to recall detailed specific events

from a person’s personal past, without relying on practised mnemonic strategies.

Although only a handful of cases of hyperthymesia have ever been definitively confirmed, some of

these cases are quite startling, such

As a California woman who could recall every day in complete detail from the age of 14

onwards, a young English girl with an IQ of 191 who had a perfect photographic memory

spanning almost 18 years

Russian man known simply as "S." who was only able to forget anything by a deliberate act

of will.

One of the most famous cases, known as “A.J.”, described it as a burden rather than a gift,

but others seem to be able to organize and compartmentalize their prodigious memories and

do not appear to feel that their brains are "cluttered" with excess information.

Rebirth and Past life memory

According to Buddhist psychology “Rebirth, or samsara” mirror interest fat on memory in the

principle of rebirth has been greatly stimulated by the publicity given to several cases of people who

have remembered previous lives. . Cases of this kind have from time to time appeared in the popular

press, particularly in Asia, mostly with sensational accounts of how the child's claims were verified.

Psychologists-and scholars in general-have paid al- most no attention to these rare cases, with the

exception of Ian Stevenson, a psychiatrist at the University of Virginia. Stevenson (1 974, 1975,

1977a,

1977b, 1980, 1983, 1987, Stevenson and Samararatne, 1988) has studied cases of this kind for over

30 years and published numerous reports of his thorough and detailed investigations of individual

cases in various countries, most of them in Asia. Story (1975), a scholar of Theravada Buddhism,

has also investigated some cases in Sri Lanka as well as in India, Burma, and Thailand. The present

study can be considered an attempt to replicate Stevenson's (1977a) work in Sri Lanka. They have

ranged from chance coincidence, paramnesia, extrasensory perception by the child of life events of

a deceased person, to the theory of reincarnation, which is generally accepted by the Buddhists and

the Hindus of Sri Lanka.

For a long time past it has been known that under deep hypnosis events in very early infancy, outside

the normal range of memory could be recovered and this technique has been increasingly employed

for the treatment of personality disorders. It cannot be used with success on all patients because of

the involuntary resistance some subjects show to hypnotic suggestion, which in birth the cooperation

necessary to obtain deep trance. But where it can be applied, it has definite advantages over the usual

methods of deep psychoanalysis, one of them being the speed with which results are obtained.

The technique is to induce a state of hypnosis and then carry the subject back in time to a particular

point in childhood or infancy at which it is suspected that some event of importance in the psychic

life may have occurred. In this state, known as hypermnesia the subject becomes in effect once more

the child he was, and re-lives experiences that have long been buried in the unconscious. Memories

of earliest infancy, and in some cases prenatal memories, have been brought to the surface in this

way

Cases relevant to this will be further explained in Annexes 01

Forgetting

Forgetting is temporary or permanent inability to retrieve a piece of information or a memory that

had previously been recorded in the brain. Forgetting normally follows a logarithmic curve, so that

information loss is quite hasty at the start, but becomes slower as time goes on. In particular,

information that has been learned very well will usually be very resistant to forgetting, especially

after the first three years.

Unlike amnesia, forgetting is usually regarded as a usual phenomenon involving specific pieces of

content, rather than relatively broad categories of memories or even entire segments of memory.

From forgetting where you left your keys to forgetting to return a phone call, memory failures are an

almost daily occurrence. Forgetting is so common that we typically rely on numerous methods to

help us remember important information such as jotting down notes in a daily planner or scheduling

important events on your phone's calendar.

As you are frantically searching for your missing car keys, it may seem that that the information

about where you left them is permanently gone from your memory. However, forgetting is generally

not about actually losing or erasing this information from your long-term memory. Forgetting

typically involves a failure in memory retrieval. While the information is somewhere in your long-

term memory, you are not able to actually retrieve and remember it.

Why We Forget?

Of course, many factors can help contribute to forgetting. Sometimes you might be distracted when

you learn new information, which might mean that you never truly retain the information long

enough to remember it later. Well-known memory researcher

Elizabeth Loftus’s key explanations for why forgetting occurs.

1. Retrieval Failure

Have you ever felt like a piece of information has just vanished from memory? Or maybe you know

that it's there, you just can't seem to find it. The inability to retrieve a memory is one of the most

common causes of forgetting.

So why are we often unable to retrieve information from memory? One possible explanation retrieval

failure is known as decay theory. Decay occurs when the passage of time causes us to forget.These

theories are popular because they appear to fit with common-sense views of the way memory works.

However, evidence suggests that they may not give a complete picture of how forgetting occurs.

They are also limited in terms of practical implications. According to this theory, a memory trace is

created every time a new theory is formed. Decay theory suggests that over time, these memory

traces begin to fade and disappear. If information is not retrieved and rehearsed, it will eventually be

lost. As mentioned in ‘The Ebbinghaus Forgetting Curve’

The Ebbinghaus Forgetting Curve

Psychologist Hermann Ebbinghaus was one of the first to scientifically study forgetting. In

experiments where is used himself as the subject, Ebbinghaus tested his memory using three-letter

nonsense syllables. He relied on such nonsense words because relying on previously known words

would have made use of his existing knowledge and associations in his memory.

In order to test for new information, Ebbinghaus tested his memory for periods of time ranging from

20 minutes to 31 days. He then published his findings in 1885 in Memory: A Contribution to

Experimental Psychology.

His results, plotted in what is known as the Ebbinghaus forgetting curve, revealed a relationship

between forgetting and time. Initially, information is often lost very quickly after it is learned.

Factors such as how the information was learned and how frequently it was rehearsed play a role in

how quickly these memories are lost.

The forgetting curve also showed that forgetting does not continue to decline until all of the

information is lost. At a certain point, the amount of forgetting levels off. What exactly does this

mean? It indicates that information stored in long-term memory is surprisingly stable.

Figure 3 Ebbinghaus Forgetting Curve

2. Interferance

Another theory known as interference theory suggests that some memories compete and interfere

with other memories. When information is very similar to other information that was previously

stored in memory, interference is more likely to occur. When such influences are adverse we call

them interference. It has been noted that more the similarity between two sets of materials to be

learned, the greater will be the degree of interference between them.

Basic Types of Interference:

1. Proactive interference is when an old memory makes it more difficult or impossible to

remember a new memory.

2. Retroactive interference occurs when new information interferes with your ability to

remember previously learned information.

3. Failure to Store

Sometimes, losing information has less to do with forgetting and more to do with the fact that it

never made it into long-term memory in the first place. Encoding failures sometimes prevent

information from entering long-term memory.

In one well-known experiment, researchers asked participants to identify the correct U .S. penny out

of a group of incorrect pennies (Nickerson & Adams). Try doing this experiment yourself by

attempting to draw a penny from memory, and then compare your results to an actual penny.

How well did you do? Chances are that you were able to remember the shape and color, but you

probably forgot other minor details. The reason for this is that only details necessary for

distinguishing pennies from other coins were encoded into your long-term memory.

4. Motivated Forgetting

Sometimes, we may actively work to forget memories, especially those of traumatic or disturbing

events or experiences. According to Freud, forgetting takes place because the event is unpleasant.

We forget because we do not want to remember something. We may exclude memories or push them

out of consciousness if we do not like them. Freud called this process repression. It’s a common

experience that we usually remember pleasant events more often than unpleasant ones. Also, we find

a strong tendency to remember incomplete tasks more than completed tasks. This has been termed as

“Zeigarnik effect”. The role of mood in human memory suggests that affective aspects of our lives

do shape our memory in significant ways.

Basic Forms of Motivated Forgetting

Suppression, a conscious form of forgetting and

Repression, an unconscious form of forgetting.

However, the concept of repressed memories is not universally accepted by all psychologists. One of

the problems with repressed memories is that it is difficult, if not impossible, to scientifically study

whether or not a memory has been repressed. Also note that mental activities such as rehearsal and

remembering are important ways of strengthening a memory, and memories of painful or traumatic

life events are far less likely to be remembered, discussed or rehearsed.

One problem with this theory, however, is that research has demonstrated that even memories

which have not been rehearsed or remembered are remarkably stable in long-term memory.

Theorists disagree over exactly what becomes of material that is forgotten.

Some hold that long-term memories do actually decay and disappear completely over

time;

others hold that the memory trace remains intact as long as we live, but the bonds or

cues that allow us to retrieve the trace become broken, due to changes in the

organization of the neural network, new experiences, likewise. In the same way as a

misplaced book in a library is “lost” even though it still exists somewhere in the

library.

It seems not to be probable to intentionally delete memories at will, which can have negative

consequences.

ex: we experience traumatic events we would actually prefer to forget.

In fact, such memories tend to be imprinted even more strongly than normal due to their emotional

content, although recent research involving the use of beta blockers (such as propanonol) suggests

that it may be possible to tone down the emotional aspects of such memories, even if the

memories themselves cannot be erased. The way this works is that the act of recalling stored

memories makes them "malleable" once more, as they were during the initial encoding phase, and

their re-storage can then be blocked by drugs which inhibit the proteins that enable the emotional

memory to be re-saved.

Memory Disorders

Alzheimer's Disease

Alzheimer's disease (also known as just Alzheimer's or AD) is a progressive, degenerative and

ultimately fatal brain disease, in which cell to cell connections in the brain are lost. It is the most

common form of dementia, and is generally (though not exclusively) diagnosed in patients over the

age of about 65.

The disease was first identified by Alois Alzheimer as early as 1906, although up until the 1960s

it was usually referred to as "senile dementia" and considered a normal part of ageing. Scientific

interest in Alzheimer's was only re-awakened in the 1960s and 1970s as the consequences of an

ageing society began to be examined, and it was during the 1980s that research first focused on the

toxic proteins amyloid in plaques and tau in tangles.

The most commonly recognized symptom of AD is an inability to acquire new memories and

difficulty in recalling recently observed facts, but it is by no means the only symptom. As the disease

advances, symptoms include confusion, irritability and aggression, mood swings, language

breakdown, long-term memory loss, and ultimately a gradual loss of bodily functions and death

A number of non-invasive life-style habits, such as mental stimulation, physical exercise and a

balanced diet, have been suggested for the prevention or delayed onset of Alzheimer's disease, but no

effective treatments to delay or halt the progression of the disease are as yet available.

Alzheimer's does not affect all memory capacities equally. Episodic memory (memory of

autobiographical events) is the first to go; next comes short-term memory (the ability of hold

information in mind in an active, readily-available state for a short period of time); then semantic

memory (memory of the meanings of words and facts about the world), and finally procedural

memory (how to perform tasks and skills). However, as the disease advances, parts of memory which

were previously intact also become impaired, and eventually all reasoning, attention, and language

abilities are disrupted.

AD patients tend to display a loss of knowledge of the specific characteristics of semantic categories.

Initially, they lose the ability to distinguish fine categories, such as species of animals or types of

objects, but, over time, this lack of discrimination extends to broader, more general categories. Thus,

at first, an AD patient may see a spaniel and say, “that is a dog”; later, they may just say, “that is an

animal”

Dementia

Dementia is a general term for a large class of disorders characterized by the progressive

deterioration of thinking ability and memory as the brain becomes damaged. Essentially, when

memory loss is so severe that it interferes with normal daily functioning, it is called dementia. Less

severe memory loss is usually referred to as mild cognitive impairment.

It is sometimes estimated that dementia doubles in frequency about every 5 years from the age of 65,

which suggests that around 5% of those age 65 have dementia, and over 50% for those in the 85 to

90 year range.

Dementia is usually characterized by severe memory loss in conjunction with one or more of aphasia

(loss of the ability to produce or understand language), apraxia (the inability to make certain

movements, despite a healthy body), agnosia (problems recognizing familiar persons and objects,

even though the senses are functioning) or executive dysfunction (inability to plan, organize or

reason). Sufferers exhibit serious loss of cognitive ability, beyond what might be expected from

normal ageing, and particularly in the areas of memory, attention, language and problem solving.

The best known and most common type of dementia is Alzheimer’s disease, which accounts for 50-

75% of all dementias. The second most common type, accounting for up to 20% of dementia cases,

is vascular dementia, which has symptoms similar to Alzheimer’s but usually results from damage

done to the brain by a blood clot or a hemorrhage cutting off the brain's blood supply due to a stroke

or succession of strokes. Other types of dementia include Lowy body dementia, front temporal

dementia, Huntington's disease and Creutzfeldt-Jakob disease. Some types of dementia are

reversible (such as those caused by thyroid disease), while some (such as Alzheimer's disease) are

irreversible.

Dementia may be caused by specific events such as traumatic brain injury or stroke, or it may

develop gradually as a result of neurodegenerative disease affecting the neurons of the brain (thereby

causing gradual but irreversible loss of function of these cells) or as a secondary symptom of other

disorders like Parkinson’s disease.

Age Associated

Figure 4 Aging

Age associated memory impairment is a label for the general degradation of memory which results

from ageing. It is a natural process, seen in many animals as well as humans, which often begins in

our 20s and tends to get noticeably worse as we reach our 50s. While some specific abilities do

decline with age, though, overall memory generally remains strong for most people through their

70s.

Episodic memory ; our memory of experiences and specific events in time in particular is impaired in

normal ageing. On the other hand, in the absence of specific neurological disorders, implicit or

procedural memory typically shows little or no decline with age, short-term memory shows only a

little decline, and semantic knowledge, such as vocabulary, actually tends to improve somewhat with

age.

Normal ageing is not responsible for causing memory disorders as such, but it is associated with a

general decline in cognitive and neural systems, including memory. As people age, the likelihood of

cholinergic dysfunction, beta-amyloid deposits, hippocampal neurofibrillary tangles or neuritic

plaques in the cortex of the brain increases, so that memory connections can become blocked,

memory functions decrease and the likelihood of memory disorders like dementia and Alzheimer’s

disease increases. Ageing is the single greatest risk factor for neurodegenerative diseases in general.

Recent research has identified a transitional state between the cognitive changes of normal ageing

and Alzheimer's disease, known as mild cognitive impairment, where some memory loss occurs, but

is not so severe that it interferes with normal daily functioning.

More severe memory loss is defined as dementia, of which Alzheimer's is just one common variant.

Those who experience mild cognitive impairment are at a significantly higher risk of developing

Alzheimer’s disease or other types of dementia, especially after events like strokes. Although the

brain does not change its overall structure or grow whole new batches of neurons over time, the

connections between them change during the normal process of learning, as synapses are reinforced

and neural cells make more and stronger connections with each other. As we begin to age, however,

these connections begin to falter and weaken, in the same way as other biological processes

deteriorate and become more fragmented over time, and this begins to affect how easily we can

retrieve memories.

In particular, as the brain ages, the white matter which links together different parts of the brain,

begins to die off, largely because the blood flow supplied to the brain is not as healthy as in the

young, which causes memory to become impaired. Also, the production of the chemical messengers

(neurotransmitters) used to carry signals through the brain is also reduced, perhaps by as much as

50% between young adulthood and old age, which impairs our ability to think and perform memory

tasks.The decline theory of forgetting is illustrated by the order in which words tend to be forgotten

in old age: proper nouns, which are typically used less often, are usually the first words to go,

followed by common nouns, then adjectives, verbs and, lastly, exclamations and interjections

One theory for why this happens, at the cellular level, is that ageing cause’s major cell loss in a tiny

region at the front of the brain that leads to a drop in the production of a neurotransmitter called

acetylcholine, which is vital to learning and memory. In addition, the brain itself shrinks in size to

some extent, and becomes less efficient as we age. In particular, the hippocampus, which is essential

to the proper functioning of the processes of memory, loses about 5% of its nerve cells with each

passing decade, up to a total loss of 20% by the age of about 80.

There are, however, several other environmental factors which may combine to speed up memory

decline, including the inheritance of unhealthy genes, exposure to toxins and poisons, or lifestyle

choices like smoking, drinking or bad diet. Physical exercise and mental stimulation can improve

mental function in general, and therefore help to slow memory decline, although there is no "magic

bullet" solution as some might claim

Alcohol

Alcohol, and the effects of alcohol on memory and general cognitive functioning, has been the

subject of much research over the years.

Alcohol acts as a general central nervous system depressant, but it affects some areas of the brain

more than others. Specifically, it leads to distraction and inattention and significantly inhibits

neuronal activity in the hippocampus, which impairs memory encoding since the hippocampus plays

an important role in the formation of new declarative memories. Because procedural memory

functions more or less automatically, retrieval of procedural memory (“remembering how”) is not as

severely impaired by alcohol as retrieval of declarative memory (“remembering what”).

Alcohol particularly impairs the encoding of episodic memory (that part of declarative memory that

relates to our personal experiences and specific events in time), especially for certain types of recall,

such as cued recall, the recognition of completed word fragments and free recall. A "blackout" is an

example of a difficulty in the encoding of episodic memories due to high doses of alcohol. It is

caused by a rapid increase in blood alcohol concentration, which in turn distorts the activity of

neurons in the hippocampus, thus impairing person's ability to form new episodic memories.

Alcohol also impairs short-term (working) memory, although mainly by affecting certain mnemonic

strategies and executive processes rather than by shrinking the basic holding capacity of working

memory or by physically altering the structure of the those parts of the brain which are critical for

working memory function. Although light to moderate drinking does not appear to impair long-term

cognitive functioning significantly (and according to some studies, may actually decrease the risk of

cognitive decline), heavy drinking and chronic alcoholism is associated with long-term impairment

in sustained attention and working memory function, especially visual working memory.

Serious over-consumption of alcohol, especially in comparison with the intake of other foods, can

cause a thiamine deficiency, leading to a much more serious form of amnesia known as Korsakoff’s

syndrome.

Figure 5- Alcoholism

Amnesia

Amnesi Amnesia is the general term for a condition in which memory (either stored memories or

the process of committing something to memory) is disturbed or lost, to a greater extent than simple

everyday forgetting or absent-mindedness. Amnesia may result either from organic or neurological

causes (damage to the brain through physical injury, neurological disease or the use of certain drugs),

or from functional or psychogenic causes (psychological factors, such as mental disorder, post-

traumatic stress or psychological defence mechanisms).

Types of Amnesia

Anterograde amnesia (where the ability to memorize new things is impaired or lost because data

does not transfer successfully from the conscious short-term memory into permanent long-term

memory) Anterograde amnesia is the more common of the two.

Retrograde amnesia (where a person's pre-existing memories are lost to conscious recollection,

beyond an ordinary degree of forgetfulness, even though they may be able to memorize new things

that occur after the onset of amnesia).

Sometimes both these types of amnesia may occur together, sometimes called total or global

amnesia. Another type of amnesia is post-traumatic amnesia, a state of confusion and memory loss

that occurs after a traumatic brain injury. Amnesia which occurs due to psychological factors is

usually referred to as psychogenic amnesia.

Many kinds of amnesia are associated with damage to the hippocampus and related areas of the

brain which are used in the encoding, storage and retrieval of memories. If there is a blockage in the

pathways along which information travels during the processes of memory encoding or retrieval, or

if whole regions of the brain are missing or damaged, then the brain may not be able to form new

memories or retrieve some old ones.

The usual causes of amnesia are lesions to the brain from an accident or neurological disease, but

intense stress, alcohol abuse, loss of oxygen or blood flow to the brain such and such, can all also

cause amnesia, as sometimes can treatments such as electro-convulsive therapy.

ex: Intense stress can cause the sympathetic nervous system to activate the adrenal glands, which

then secrete certain hormones into the bloodstream which can significantly affect the plasticity of the

brain’s neurons, especially those in the hippocampus.

In most cases, amnesia is a temporary condition, lasting from a few seconds to a few hours, but the

duration can be longer depending on the severity of the disease or trauma, up to a few weeks or even

months.

Although it is very rare for anyone to experience total (permanent) amnesia, one well-known case of

long-lasting and acute total (retrograde and anterograde) amnesia, perhaps the worst case of amnesia

ever recorded, is that of the British musician Clive Wearing, who suffered damage to his brain as a

result of an encephalitis virus in 1985. Because the damage was to an area of his brain required to

transfer memories from working memory to long-term memory, he is completely unable to form

lasting new long-term memories, and his memory is therefore limited to a short-term memory of

between 7 and 30 seconds, to the extent that he will greet his wife like a long-lost friend even if she

only left to go into the kitchen 30 seconds ago. However, Wearing still recalls how to play the piano

and conduct a choir, despite having no recollection of having received a musical education, because

his procedural memory was not damaged by the virus.

In general, memories of habits (procedural memory) are usually better preserved than memories of

facts and events (declarative memory), and the most distant long-term memories, such as those of

childhood, are more likely to be preserved. When memories return, older memories are usually

recalled first, and then more recent memories, until almost all memory is recovered.

Figure 6 Source of amnesia

Autism

Autism is a disorder of neural development, characterized by impaired social interaction and

communication and by restricted and repetitive behavior, which usually begins in childhood.

Autism spectrum disorders may range from individuals with severe impairments (who may be silent,

mentally disabled, and locked into hand flapping and rocking behaviors) to high-functioning

individuals who may have active but distinctly odd social approaches, narrowly-focused interests and

verbose or pedantic communication. Some individuals with autism spectrum disorder may even show

superior skills in perception and attention, relative to the general population. No cure is known.

In recent years, it has become increasingly apparent that autism affects the functioning of virtually

the entire brain, not just those brain areas involved with social interactions, communication

behaviors and reasoning abilities, as had been previously thought. It has been discovered that people

with autism have difficulty in many other areas, including balance, movement, memory and visual

perception skills, complex tasks which involve different areas of the brain working together. It is

perhaps better seen, then, as a disorder in which the various parts of the brain have difficulty working

together to accomplish complex (as distinct from basic) tasks.

Autism affects information processing in the brain by altering how nerve cells and their synapses

develop, connect and organize, although exactly how this occurs is not well understood, and there

does not appear to be a clear unifying mechanism at either the molecular, cellular or systems level. It

appears to result from developmental factors that affect many or all functional brain systems, and to

disturb the timing of brain development.

One popular theory, known as executive dysfunction, hypothesizes that autistic behavior results, at

least in part, from deficits in working memory, planning, inhibition and other forms of executive

function. Certainly, poor short-term memory (as opposed to long-term memory, which may actually

be normal or better than normal) is a common complaint among autism sufferers, although to what

extent this result from attention deficits is not clear.

Some studies have suggested that there may be selective damage to the limbic-prefrontal episodic

memory system in some people with autism, especially in the self-conscious memory of personally

experienced events.

Huntington's Disease

Huntington’s disease is an inherited progressive neurodegenerative disorder, which affects muscle

coordination and leads to general cognitive decline. If a parent carries the gene, there is a 50%

chance of the child inheriting it.

Early symptoms include a general lack of coordination and an unsteady gait, which develops into

involuntary and uncoordinated, jerky body movements (chorea) and a decline in mental abilities and

behavioral and psychiatric problems, and a gradual decline of mental abilities into dementia. The

memory decline symptoms, especially those affecting short-term memory, typically appear before

any motor function symptoms.

It typically becomes noticeable in middle age, affecting about 1 in every 10,000-20,000 people.

It results from a mutation of Htt proteins which is toxic to certain types of cells, particularly in the

brain. The mutation of specific gene codes leads to gradual damage to specific areas of the brain,

particularly the basal ganglia, although exactly how is not yet fully understood.

As the disease progresses, memory deficits tend to appear, ranging from short-term to long-term

memory difficulties, including deficits in episodic, procedural and working memory, ultimately

leading to dementia. Memory is affected by damage to the important brain pathways that help the

inner subcortical and prefrontal cortex parts of the brain to communicate. This damage occurs mainly

in the striatum, but other areas of the brain are also significantly affected as the disease progresses.

Korsakoff's Syndrome

Korsakoff's syndrome, or Wernicke-Korsakoff syndrome, is a brain disorder caused by extensive

thiamine deficiency, a form of malnutrition which can be precipitated by over-consumption of

alcohol and alcoholic beverages compared to other foods.

It main symptoms are anterograde amnesia (inability to form new memories and to learn new

information or tasks) and retrograde amnesia (severe loss of existing memories), confabulation

(invented memories, which are then taken as true due to gaps in memory), meagre content in

conversation, lack of insight and apathy.

Individual Korsakoff's sufferers may exhibit wildly differing symptoms. In some cases, a patient

may just continue "living in the past", convinced that their life and the world around them is

unchanged since the onset of the condition (which may have been twenty or thirty years before).

Others may adopt a constant, almost frenzied, fever of confabulation (see box at right), constantly

inventing a series of new identities, often with detailed and convincing back-stories, in order to

replace the reality which has been forgotten and lost.

Much about the disorder has been gleaned from a sufferer known as “Patient X”, who wrote an

autobiography in 1979 and then developed the disease a short time later. Thus, his post-

Korsakoff memories could be directly compared with the details in his written autobiography.

Korsakoff’s syndrome is caused by a deficiency of thiamine (vitamin B1), which is thought to cause

damage to the thalamus and to the mammillary bodies of the hypothalamus (which receives many

neural connections from the hippocampus), as well as generalized cerebral atrophy, neuronal loss

and damage to neurons.

Classically, the retrograde amnesia of Korsakoff’s syndrome follows a distinct temporal curve: the

more remote the event in the past, the better it is preserved and the sharper the recollection of it. This

suggests that the more recent memories are not fully consolidated and therefore more vulnerable to

loss, indicating that the process of consolidation may continue for much longer than initially thought,

perhaps for many years

OCD

Obsessive-compulsive disorder (OCD) is a mental disorder characterized by intrusive thoughts that

produce anxiety (obsessions) and repetitive behaviours aimed at reducing the anxiety (compulsions).

Symptoms may include repetitive hand-washing, a generalized fear of contamination, extensive

hoarding, preoccupation with sexual or aggressive impulses or with particular religious beliefs,

aversion to odd numbers, and nervous habits such as repeated opening and closing of doors, constant

organizing of objects in certain ways, obsessive counting of events, etc.

OCD may be seen as a result of an imbalance between long-term memory and short-term memory

processes. A sufferer may be stuck in a mental loop where long-term memory is in control of the

subject's brain to such an extent that their reactions are solely based on memory without the

influence of the input (other than as a trigger for the memory).

Neuroimaging studies show, however, that OCD patients perform considerably better on procedural

memory tasks (memory of skills and how to do things) due to over-activation of the striatum brain

structures, specifically the front striatal circuit. Thus, the procedural memory in OCD patients may

actually be improved in its early learning stages.

Although there is no scientific evidence to suggest that people with OCD have any problems with

verbal memory (remembering information that has been stored verbally or in the form of words), it

has been consistently found that people with OCD show deficits in non-verbal, visual or special

memory. Also, people with OCD (particularly those whose symptoms involve compulsive

checking) tend to have less confidence in their memory than those without OCD, even if this level of

confidence is not actually related to their actual performance on memory tasks, and the worse the

OCD symptoms are, the worse this confidence in memory seems to be. This may explain to some

extent the repetitive nature of many OCD symptoms.

OCD has been linked to abnormalities with the neurotransmitter serotonin, and to miscommunication

between the different parts of the brain involved in problem solving. In normal usage, when a

problem or task is identified in the orbitofrontal cortex at the front of the brain, it is dealt with in the

cingulate cortex, and the caudate nucleus is then responsible for marking the problem as resolved and

removing any worry over it. In OCD sufferers, it is thought that the caudate nucleus may be

dysfunctional and so this resolution never occurs, leading to increased worry and a recurring and

ever-intensifying loop in behavior.

Recent improvements in the understanding of the neuroplasticity of the brain may lead to a potential

cure for the disorder.

Figure 7 OCD

Parkinson's Disease

Parkinson's disease is a chronic and progressive degenerative disorder of the central nervous

system that impairs motor skills, speech and other functions. It is usually characterized by muscle

rigidity, tremor, postural instability, and a slowing or loss of physical movement.

Ageing is an important risk factor, and the incidence of Parkinson's increases with age, although

about 4% are diagnosed before the age of 50. An estimated 7-10 million people worldwide (roughly

1 in 1,000 of the total population) are thought to be living with Parkinson's.

A high proportion of sufferers also experience mild cognitive impairment as the disease advances,

including executive dysfunction (impaired problem solving, fluctuations in attention, such and such),

slowed cognitive speed and memory problems, particularly with working memory, episodic memory

and with recalling learned information. In many cases (about 25-30% of cases), this eventually

develops into full-blown dementia, although memory problems in Parkinson's are typically milder

than in Alzheimer's disease. Non-motor symptoms such as memory loss remain the most under-

addressed area for research into Parkinson's disease.

Parkinson's disease is the result of decreased stimulation of the motor cortex by the basal ganglia,

usually due to the insufficient formation and action of the neurotransmitter dopamine in the neurons

in an area of the brain called the substantia nigra. When cells that normally produce dopamine die

off, the symptoms of Parkinson’s often appear. Its main cause is thought to be genetic, although the

exact mechanism is still unclear.

Schizophrenia

Schizophrenia is a mental disorder mainly characterized by abnormalities in the perception or

expression of reality, usually manifesting itself in hallucinations, "voices", paranoid delusions or

disorganized speech and thinking, often with significant social or occupational dysfunction. It does

not necessarily imply the "split mind" of dissociative identity disorder (also known as multiple

personality disorder or split personality), but schizophrenia sufferers can experience severe

difficulty in distinguishing what is real from what is not. “Noise” in the brains of schizophrenics also

results in cognitive impairment, memory loss and attention deficits, resulting in difficulties in day to

day functioning and learning.

Both schizophrenia and multiple personality disorder chiefly affect biographical or episodic

memory, leaving semantic and procedural memory largely accessible (to all of the person’s

identities). The disorder is believed to develop as a defense mechanism against childhood deprivation

or abuse or some other kind of psychic trauma. Elderly schizophrenia patients often also suffer from

Alzheimer’s disease, or some other form of dementia, in varying levels of severity.

Schizophrenics often have difficulty encoding, storing and recalling words, although recent advances

in the understanding of neuroplasticity have led to some promising new treatments. It has been

shown that schizophrenic symptoms can be improved by stimulation, particularly through the regular

repetition of some simple (although progressively more challenging) auditory and visual exercises.

As brains change physically through neuroplasticity, many of the abnormal patterns in the brain

which characterize schizophrenia are removed. In addition, levels of the protein BDNF (brain-

derived neurotropic factor), which is lower than normal in schizophrenics, are also increased to near

normal levels. Similar treatments may even be used to prevent the onset of schizophrenia in people

exhibiting early warning signs of the disorder.

Studies have shown that schizophrenic patients not currently taking related medication have a

smaller putamen (part of the striatum that plays a very important role in procedural memory), as

well as improper communication from the basal ganglia part of the brain. Although it is thought that

functional problems in the striatum of schizophrenic patients are not significant enough to seriously

impair procedural memory, the impairment may be significant enough to cause problems in the

improvement of performance on a task between practice intervals.

Tourette Syndrome

Tourette syndrome, also known as Gilles De La Tourette Syndrome or simply Tourette’s, is an

inherited neuropsychiatric disorder of the central nervous system with onset in childhood,

characterized by physical and vocal tics, which often wax and wane, and, less commonly but more

publicized, the spontaneous utterance of socially objectionable or taboo words or phrases, or the

repetition of others’ words. It has been described, by both patients and neurologists, as a lack of stop

signs in the brain. Obsessive-compulsive disorder (OCD) and attention-deficit hyperactivity disorder

(ADHD) are often (but not necessarily) associated with Tourette’s.

Tourette's appears to be related to the skill-acquisition process that ties stimuli to responses during

the learning part of procedural memory (memory of skills and how things work). Physiologically, it

involves changes in the sub-cortical brain area known as the striatum, and its interaction with the

basal ganglia due to abnormalities in the way that hormones and neurotransmitters mediate

communication between nerve cells in the brain.

Although aspects of procedural memory may be abnormal in Tourette’s, declarative memory

(memory of facts and events) remains largely spared. For example, “rule-governed” knowledge (used

in language, for example, to combine parts of words together according to the grammatical rules of

the language), which involves the procedural memory system, is affected, whereas “idiosyncratic”

knowledge (which allows us to learn that a word is linked to an object), which depends on

declarative memory and is learned and processed in the hippocampus and other temporal lobe areas

in the brain, is not. Indeed, children with Tourette’s are sometimes faster and better than typically

developing children at certain aspects of language.

WAYS OF ENHANCING MEMORY

It is a common experience that forgetting is usually a source of trouble for people. Everyday

conversation, class room participation, performance in examination, interview, presentation and

communication in meetings often put demands on us to remember information. Failure in doing so

has negative consequences which all of us experience to different degrees in our lives. As a result

most of us are interested in improving our memory. The study of memory aids and related techniques

is called mnemonics. Some of the techniques used in improving memory are listed

Organization

While preparing for learning a learner needs to organize the material in some form. Such an

organization may help by creating a natural context and provide relevant cues while retrieving the

learned material. If the material lacks natural organization, an artificial organization may be created

by the learner.

Concentration

One of the main reasons of forgetting is inadequate allocation attention resources to the material

while processing the same. As a result the material is not stored and we fail to recall when we need

it. Thus by focusing attention on the material while processing we can increase the probability of

storage and recall.

Chunking Memory

Chunking involves creating something more meaningful and therefore memorable from seemingly

random bits of information. One example is if you need to remember a list of things such as buying

figs, lettuce, oranges, apples, and tomatoes you can create a word out of the first letters (e.g.,

"FLOAT"), which is easier to remember than the individual items. If you've ever tried to remember a

phone number by making a word (or words) out of the letters on the phone's dial pad, you've used

chunking.

The Atlantic recently highlighted the value of chunking based on the ideas in the book The Ravenous

Brain by neuroscientist Daniel Bor. In one study, an undergraduate volunteer went from being able

to remember a 7-digit sequence to remembering an 80-digit sequence after 20 months of practice,

using chunking. The volunteer had been a track runner, so he grouped numbers as running times:

3492, for example, became 3 minutes and 49.2 seconds.

Assigning meaning to hard-to-remember things like numbers and letters is also what's at play behind

the strategies used by memory champions

Recoding: While dealing with non-meaningful material one may recode the items to be

remembered in a more meaningful manner. Recoding may take many forms. For example people

may use the first letter of all the items and make a sentence. This kind of narrative structure works as

a cue. Acronyms (e.g., U.N.O., TV, CBI, WHO) are also used for the purpose in which all the first

letters are used. Using elaboration one may add more information which makes the material

distinctive. Chunking is a good example of recoding. If a large serial of numbers is presented it

becomes difficult to remember. The same, however, may be divided in two or three chunks in some

meaningful way using ingenuity. Using elaborative coding one may put many items in astory form

and recall the same easily

Use of schema

The efficiency of memory recall can be increased to some extent by making inferences from our

personal stockpile of world knowledge, and by schemata.. A schema is an organized mental

structure or framework of pre-conceived ideas about the world and how it works, which we can

use to make realistic inferences and assumptions about how to interpret and process information.

Thus, our everyday communication consists not just of words and their meanings, but also of what is

left out and mutually understood. Such schemata are also applied to recalled memories, so that we

can often flesh out details of a memory from just a skeleton memory of a central event or object.

However, the use of schemata may also lead to memory errors as assumed or expected associated

events are added that did not actually occur.

Mnemonic Strategies

In the same way, associating words with visual imaginary is another commonly used mnemonic

device providing two alternative methods of remembering, and creating additional associations in the

mind. Taking this to a higher level, another method of improving memory encoding and

consolidation is the use of a so-called memory palace (also known as the method mention above as

of loci), a mnemonic techniques that relies on memorized spatial relationships to establish, order

and recollect other memories. Many top memorizers today use the memory palace method to a

greater or lesser degree. Similar techniques involve placing the items at different landmarks on a

favorite hike or trip (known as the journey method), or weaving them into a story.

Method of loci/memory palace

As the name implies, this technique uses associations with place or task. The visualization of the

same provides cues for recalling the task. By choosing any action properly one can use memory at

any point in the day. Use of such mnemonic codes allows one to have vivid and distinctive

associations between new information and prior knowledge. Being related to context the cues

become very effective. For instance one may have a clear visual image of a building, its rooms,

furniture and other details. These may be linked to different ideas and using these linkages, memory

of those ideas can be enhanced.

Figure 8 memory palace

SQ3R method

SURVEY

Glance over the heading in the chapter to see the fee major points which will be developed.

This survey should not take more than a minute and will show the three to six central ideas

within the chapter. This survey helps you to organize the ideas as you read them later.

QUESTION

Now begin to work. Turn the first heading into a question. This will arouse your curiosity

and increase comprehension. It will help bring to mind information already known and help

you to understand the section more quickly. The question will make important points stand

out from the explanatory detail. Turning the heading into a question can be done the instant

you read it, but it demands a conscious effort on the part of the reader.

READ

Read to answer that question. Read to the end of the first section, not by passively plowing

along, but by conducting an active search for the answer to your question.

RECITE

After reading the first section, look away from the book and try to briefly recite the answer to

your question. Use your own words and cite an example. If you can do this, you know what

is in the book; if you can't, glance over the section again. An excellent way to do this reciting

is to jot down very brief cue phrases in outline form on a sheet of paper.

Now repeat steps 2, 3, and 4 for each heading in the section. That is, turn the next heading

into a question, and recite the answer by jotting down cue phrases in your outline. Read in

this way until you have completed the entire lesson.

REVIEW

When you have completed the assignment in the manner described above, look over your

notes to get a bird's-eye view of the points and their relationships. Then check your memory

for content by reciting the major sub points under each heading. An excellent way to check

your memory is to cover your notes and try to recall the main points. Then uncover each

major point and try to recall the sub points listed under it.

Robert Kurzban (2007) Evolutionary psychology. Scholarpedia, 2(8):3161