Lab 7/8: Investigating memory 1

Aims  Design your experiment  Experience use of t-test  Support the memory component of C81COG Objectives  Choose research topic (PC-based/paper based)  Design, run and analyse  Plan your report

Timetable: ◦ Today (22 Feb 2007)  Work in threes:  Design experiment  Prepare stimuli.  Check with demonstrators that design & stimuli look good. ◦ Between practical sessions  Pilot your experiment,  Can you think of any changes to improve?  Try to run all your participants. ◦ At the next practical (8 March 2007)  Part I: Test remainder of participants  Part II: Analysis  Part III: Tips for your report (Submission Date: 15 March, <Noon)

In an experiment, one intervenes  possible changes Implication: the change caused the outcome. Saline Study faces  Recognition Test (79 % correct) Scopolamine: Study faces  Recognition Test (23 % correct)

The independent variable (IV) CAUSE ◦ Variable that experimenter manipulates  E.g., activity of the cholinergic system The dependent variable (DV) EFFECT ◦ Variable that experimenter records  E.g., recognition accuracy

1. Subject variables (“match” Participants) Gender age IQ 2. Treatment variables (“counterbalance” allocation) Biased participant allocation – e.g., first 10 participants run in Experimental condition, 2 nd 10 run in control condition (maybe time of day  DV difference…or poorer motivation in lazy 2 nd group…?) 3. Situational variables (don’t allow to co-vary with IV) Lighting Temperature Different experimenters

Between Participants (a.k.a. independent) Within Participants (a.k.a.Repeated measures) Matched subjects design

Between Participants (independent) ◦ Participants assigned to one group only (either scopolamine or saline)  Match participants to avoid Subject Variables  Randomly assign to avoid Treatment Variables

Within Participants (Repeated measures) ◦ Participants tested twice (under scopolamine AND saline) ◦ Participants are already matched! ◦ Counterbalance order (i.e., ½ get saline then scopolamine; the other ½ scopolamine then ½ saline) ◦ Will repeat testing affect results?  Yes – participants may perform better on 2 nd test, irrespective of drug.  Solution: use TWO word lists.  But what if one list is just easier than the other?  Solution: Counterbalance the word lists

Three memory principles ◦ Lorayne’s imagery mnemonic (E-Prime) ◦ Tulving’s encoding specificity principle (Paper & pencil) ◦ The role of organisation in memory (Paper & pencil)

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 concrete 2.Link the concrete version of the name with the persons face  Peter Underwood  Peter Underpants

Devise & test strategy based on Lorayne’s imagery technique 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.

“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, ◦ E.G. Would you recognise your dentist at Sainsburys?

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 the Buttery 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?

Which is easiest to learn? List A: List B: Car WheelSeatMetal RoundSpare ComfortRecline Shiny Hard ComfortShinyWheelReclineMetal RoundCarSpareHardSeat

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?

The markers will be looking specifically for: ◦ Evidence of wide reading – there are a lot of primary sources available (ISI Web of Science) ◦ 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 – Table/graph (not both)  Description of results  Discussion – implications for other theories & real world ◦ Appendices – Stimulus examples; SPSS print out AND t-test workings by hand, raw data.