Human

MEMORY

Let’s define memory…

•is an ability to store, retain, and recall information and experiences.

•is our ability to encode, store, retainand subsequently recall information and past experiences in the human brain.

TYPES OF MEMORY

• Memory actually takes many

• different forms. We know that

• when we store a memory,

• we are storing information. But,

• what that information is and

• how long we retain it determines

• what type of memory it is.

• The biggest categories of memory

• are short-term memory (or working memory) and long-term memory, based on the amount of time the memory is stored.

Storage: Retaining Information

Storage is at the heart of memory. Three stores of memory are shown below:

SensoryMemory

WorkingMemory

Long-termMemory

Encoding

RetrievalEncoding

Events

Retrieval

*Sensory Memory

-is the shortest-term element of memory.

-The ability to look at an item for a second and

then remember what it looked like.

-It is processed approximately 200-500

milliseconds after an item is perceived.

Sensory Memories

Iconic0.5 sec. long

Echoic3-4 sec. long

Hepatic< 1 sec. long

The duration of sensory memory varies for the different senses.

Sensory Memory

SensoryMemory

WorkingMemory

Long-termMemory

Encoding

RetrievalEncoding

Events

Retrieval

*Short-term Memory (Working

Memory)

• Short-term or working memory is the brief time of keeping something in mind before dismissing it or pushing it into long-term memory. The hippocampus and subiculum store short-term memories.

Chunking

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The capacity of the working memory may be increased by “chunking.”

FBI TWA CIA IBM

4 chunks

Duration

Peterson and Peterson (1959) measured the duration of working memory by manipulating

rehearsal.

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The duration of the working memory is about 20 sec.

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Working Memory

SensoryMemory

WorkingMemory

Long-termMemory

Encoding

RetrievalEncoding

Events

Retrieval

*Long-Term Memory

-Is the ability to store more information for long periods of time (life times) like phone numbers, names and address’ from when we were kids.

-long-term memory can store much larger quantities of information for potentially unlimited duration (sometimes a whole life span). Its capacity is

immeasurably large.

- Long-term memory is often divided into two further main types: explicit (or declarative) memory and

implicit (or procedural) memory.

Explicit (declarative) memory (facts): factual knowledge

& personal experiences

Types:

> episodic memory

>semantic memory

Implicit (procedural) Memory (skills): Long-term

memories of conditioned responses and learned skills, e.g.,

driving

Types of Long-Term Memory

1. Declarative/explicit memory (“knowing what”)

refers to those memories that can be consciously

recalled.

>It is sometimes called explicit memory, since it

consists of information that is explicitly stored and

retrieved, although it is more properly a subset of

explicit memory.

>Declarative memory can be further sub-divided into

episodic memory and semantic memory.

1.1 Episodic Memory

> represents our memory of experiences and

specific events in time in a serial form, from which

we can reconstruct the actual events.

Personal experiences linked with specific times

and places

serial memory of events

1.2 Semantic Memory

>on the other hand, is a more structured record

of facts, meanings, concepts and knowledge about

the external world that can be described and

applied..

Impersonal facts and everyday knowledge

– structured memory of facts, concepts, skills

2. Procedural memory (“knowing how”)

>is the unconscious memory of skills and how to do

things, particularly the use of objects or movements

of the body, such as playing a guitar or riding a bike.

Procedural memory is sometimes referred to as

implicit memory, because previous experiences and

conscious awareness of these previous experiences,

Long-Term Memory

SensoryMemory

WorkingMemory

Long-termMemory

Encoding

RetrievalEncoding

Events

Retrieval

Memory Retrieval

Once information has been encoded and stored in

memory, it must be retrieved in order to be used.

There are four basic ways in which information can

be pulled from long-term memory

• Recall• Recollection• Recognition• Relearning

Memory Recall/Retrieval

*Retrieval, recall or recollection (calling back

the stored information in response to some cue

for use in a process or activity)

previously encoded and stored in the brain.

*During recall, the brain "replays" a pattern of

neural activity that was originally generated in

response to a particular event,

Why Do We Forget? Five Key Theories

• Decay

• Interference

• Motivated Forgetting

• Encoding Failure

• Retrieval Failure

Five Theories of Forgetting (Continued)

1. Decay Theory:

memory degrades with time

2. Interference Theory: one memory

competes (interferes) with another

–Retroactive Interference (new information interferes with old)

–Proactive Interference (old information interferes with new)

3. Motivated Forgetting: motivation to forget unpleasant, painful, threatening, or embarrassing memories

4. Encoding Failure: information in STM is not encoded in LTM

5. Retrieval Failure: memories stored in LTM are momentarily inaccessible (tip-of-the-tongue phenomenon)

Five Theories of Forgetting (Continued)

Forgetting: Memory Failure

• prospective memory– remembering to do something in the future

content – remembering what to do

timing – remembering when to do it

– absentmindedness

• amnesia– anterograde amnesia

inability to store new information and events

– retrograde amnesiainability to retrieve past information and events

>age factor

>brain injury etc…

THE END