Investigating MemoryInvestigating MemoryExperimental designExperimental design

Jonathan Stirk & Jasper Jonathan Stirk & Jasper RobinsonRobinson

E-mail: E-mail: jas@psychology.nottingham.ac.ukjwr@psychology.nottingham.ac.uk

IntroductionIntroductionIntroductionIntroduction

AimsAims To design your own experimentTo design your own experiment To support the memory component of the first year To support the memory component of the first year

cognitive coursecognitive course To give experience in using a between groups t-testTo give experience in using a between groups t-test

ObjectivesObjectives You are going to choose a research topic which can You are going to choose a research topic which can

either be conducted on computer or otherwiseeither be conducted on computer or otherwise You will design the experiment and the stimuli (to a You will design the experiment and the stimuli (to a

certain extent) run the experiment and analyse the datacertain extent) run the experiment and analyse the data

IntroductionIntroductionIntroductionIntroduction

Timetable:Timetable: TodayToday

You will work in groups to design your experiment and You will work in groups to design your experiment and prepare your stimuli. Before the end of the session your prepare your stimuli. Before the end of the session your design should be agreed with the lecturer or one of the design should be agreed with the lecturer or one of the demonstratorsdemonstrators

Between practical sessionsBetween practical sessions You should pilot your experiment, make necessary You should pilot your experiment, make necessary

changes, and try to run all your subjectschanges, and try to run all your subjects At the next practicalAt the next practical

This session will focus on entering data and running the This session will focus on entering data and running the appropriate analysis. We will be doing the analysis by appropriate analysis. We will be doing the analysis by hand as well as in SPSS, so will show you how to do this hand as well as in SPSS, so will show you how to do this and revisit concepts such as variance and standard and revisit concepts such as variance and standard error. We will finish off with tips on what to include in the error. We will finish off with tips on what to include in the write upwrite up

The Experimental MethodThe Experimental MethodThe Experimental MethodThe Experimental Method

An experiment is a method of research in which the researcher deliberately intervenes in order to introduce changes into a situation, with the intention of observing the effects of those changes on the processes being studied.

The aim of the experimental method is to identify causal relationships between variables.

Experimental VariablesExperimental VariablesExperimental VariablesExperimental Variables

The independent variable (IV) Identified, from theory or elsewhere, as a possible cause of the

phenomenon under investigation. During an experiment the value (or level) of the IV is changed by the experimenter in order to observe whether any consequent changes occur to the dependent variable

The dependent variable (DV) Is the variable that is thought to be causally linked to the IV, and

which is therefore expected to change its value in response to any changes induced in the IV. During the experiment the DV’s value is measured in order to detect any such changes due to the experimental manipulation (= experimental data)

Extraneous VariablesExtraneous VariablesExtraneous VariablesExtraneous Variables

Independent variables which are undesirable and may Independent variables which are undesirable and may influence the DV in a random or systematic way which we influence the DV in a random or systematic way which we must try and control. Without some control of these they must try and control. Without some control of these they may add ERROR to the experiment. Systematic may add ERROR to the experiment. Systematic extraneous variables (counfounds) are a big problem!extraneous variables (counfounds) are a big problem!

1.1. Subject variablesSubject variables (e.g. Gender, age, IQ, handedness, etc.) (e.g. Gender, age, IQ, handedness, etc.)2.2. Task variablesTask variables – arise from the procedures which the – arise from the procedures which the

subjects are required to perform in an experiment (e.g. Time subjects are required to perform in an experiment (e.g. Time allowed, task difficulty etc.)allowed, task difficulty etc.)

3.3. Situational variablesSituational variables – all variables found in the environment – all variables found in the environment in which the experiment takes place (e.g. Lighting, in which the experiment takes place (e.g. Lighting, temperature, time of day, experimenter’s mood, etc.)temperature, time of day, experimenter’s mood, etc.)

Controlling Extraneous VariablesControlling Extraneous VariablesControlling Extraneous VariablesControlling Extraneous Variables

Unless extraneous variables are controlled they may influence the outcome of the experiment. Without control it is impossible to be sure that the DV was affected by the IV – the extraneous variables may have become confounded with the effects of the IV

Control strategies: Design – select the design that minimises possible effects Standardisation – hold conditions constant Randomisation – distribute probable effects of a variable at

random though the experiment Counterbalancing – to remove order effects

Choosing A Basic Design (2 Condition Choosing A Basic Design (2 Condition Experiment)Experiment)

Choosing A Basic Design (2 Condition Choosing A Basic Design (2 Condition Experiment)Experiment)

Independent (between subjects) design Each participant is assigned to one of the conditions

(but not both) Repeated measures (within subjects) design

Each subject is tested twice, once in each condition. Conditions must be counterbalanced

Matched subjects design Each subject is given a pre-test and then matched

with another subject on the basis of their scores. One member of the pair is then randomly assigned to condition 1 while the second subject is assigned to condition 2

The Research AreaThe Research AreaThe Research AreaThe Research Area

Your experiments will be taken from one of three hypotheses taken from the memory literature. Only the first is designed to be run on E-prime. If you choose the second or third you will either have to program the experiment yourself, or not use the computers (both of which are acceptable). The three areas are:

Lorayne’s imagery mnemonic (E-Prime) Tulving’s encoding specificity principle The role of organisation in memory

Lorayne’s Imagery Technique: Putting Lorayne’s Imagery Technique: Putting Names To FacesNames To Faces

Lorayne’s Imagery Technique: Putting Lorayne’s Imagery Technique: Putting Names To FacesNames To Faces

Cohen (1980) believes that names are particularly hard to remember because there is no semantic relation between name and face

Lorayne (1958) suggested that an imagery mnemonic device may help. This has two stages:

1. Make the name more concrete2. Link the concrete version of the name with the

persons face E.G. You want to recall ex-prime minister Tony Blair’s name

when you see his face Change his name to blain (a pustule, blister or sore) Envision our ex-prime minister with a large blemish on the

end of his nose

Lorayne’s Imagery Technique: Putting Lorayne’s Imagery Technique: Putting Names To FacesNames To Faces

Lorayne’s Imagery Technique: Putting Lorayne’s Imagery Technique: Putting Names To FacesNames To Faces

Your task is to devise a particular strategy based on Lorayne’s imagery mnemonic and test it out. E.G. Group A are shown the twenty faces stored on

E-prime. They are instructed in how to use your mnemonic device. They are later shown the faces again and asked to remember the names.

Group B are treated exactly the same but they are not given any advice on how to encode the names.

Alt. hyp? Subjects that have been told how to use a mnemonic

device will remember more names that the control group.

Tulving’s Encoding Specificity PrincipleTulving’s Encoding Specificity PrincipleTulving’s Encoding Specificity PrincipleTulving’s Encoding Specificity Principle

“The probability of successful retrieval of the target is a monotonically increasing function of informational overlap between the information present at retrieval and the information stored in memory.” – Tulving, 1979, p408.

Divers who recalled a list of words underwater, performed better when the words were initially learned under water rather than dry land. When the place/mood/context is consistent in both the encoding and the recall, subjects perform better. –Godden and Baddeley, 1975. E.G. Would you recognise your dentist at Sainsburys?

Tulving’s Encoding Specificity PrincipleTulving’s Encoding Specificity PrincipleTulving’s Encoding Specificity PrincipleTulving’s Encoding Specificity Principle

What about light levels? Temperature? Inside vs. outside? Loud music vs. silence?

The design should involve two conditions: a consistent context (between learning and retrieval) and an inconsistent context. E.g. Group A learn a list of words while in a boat on the campus

lake. They are later tested again while out on the lake. Group B learn a list of words while in Mooch and are then taken out in a boat to recall them.

Alt. hyp: the subjects with the consistent context across encoding and recall will recall the most words.

Implications: should you revise in the actual exam room?

The Role Of Organisation In MemoryThe Role Of Organisation In MemoryThe Role Of Organisation In MemoryThe Role Of Organisation In Memory

Which is easiest to learn?

List A:

List B:Car

Wheel Seat Metal

Round Spare

Comfort Recline

Shiny Hard

Comfort Shiny Wheel Recline Metal

Round Car Spare Hard Seat

Bower’s (1969) original hierarchyBower’s (1969) original hierarchy

Bower had subjects learn these words in a structured hierarchy or in an unstructured random list

The Role Of Organisation In MemoryThe Role Of Organisation In MemoryThe Role Of Organisation In MemoryThe Role Of Organisation In Memory

Bower et al. (1969) found evidence in favour of list B. You will replicate the findings of Bower et al. Using your

own stimuli. E.G. Group A is given a list of words in a random order without

any structure. Later they are asked to recall those words. Group B are given the same words in a semantic hierarchy, and

are asked to recall them at a later point in time.

Alt. hyp: the group that is given the overt structure will remember more words than the control group.

Implications: should your revision notes be structured hierarchically?

Assessment CriteriaAssessment CriteriaAssessment CriteriaAssessment Criteria

The markers will be looking specifically for: Evidence of wide reading – there are a lot of primary

sources available Design – have you controlled for all extraneous

variables? Those you haven’t you should mention in your discussion (e.g.. Word frequency, word length etc.)

Results – no raw data. t-test result (standard format). Table OR graph

Discussion – implications to the real world Appendices – instructions, examples of stimuli, SPSS

print out AND t-test workings by hand, raw data