1. Experimental Psychology PSY 433
Chapter 10
Memory

2. Vote Tomorrow
Where to vote (if you are registered):

3. Ebbinghaus’s Techniques
Nonsense syllables – controls for prior experience and knowledge of meanings.
Trials to criterion – keep practicing until the words are perfectly learned, count trials needed.
Savings score – percentage of trials saved in relearning a list, relative to original trials needed.
Example: 10 – 5 / 10 x 100% = 50%
10 original learning (OL), 5 relearning (RL)

4. Ebbinghaus Forgetting Curve

5. Varieties of Memory Short-term vs long-term memory
Atkinson & Shiffrin’s 3-stage model
Procedural vs declarative (semantic)
Memory for doing things vs knowledge of facts
Explicit (episodic & semantic) vs implicit memory
Squire’s idea that consciousness makes a difference.
Implicit includes procedural memory but also priming

6. Atkinson & Shiffrin’s Model

7. Squire’s Model

8. Name the Seven Dwarfs

9. Is it easier with the picture?

10. A Recognition Task
Which of the following are names of the Seven Dwarfs?
Goofy Bashful
Sleepy Meanie
Smarty Doc
Scaredy Happy
Dopey Angry
Grumpy Sneezy
Wheezy Crazy

11. Dependent Variables Recall -- % or proportion remembered
Serial recall
Free recall
Paired-associates recall
Recognition -- % or proportion remembered
Yes/No
Forced choice (multiple choice)
Primed recognition– e.g., stem completion

12. Independent Variables
The kind of material to be remembered:
Letters, digits, nonsense syllables, words, phrases, sentences, paragraphs, passages of prose.
Retention interval – how fast does forgetting occur?
Modality of presentation – visual vs verbal.
Encoding strategies
Type of test – recall vs recognition.

13. Control Variables Amount and type of material presented.
Concreteness vs abstractness of words.
Rate of presentation.
Modality of presentation – eyes, ears.
Each of these could also be an IV – but do not vary everything in the same experiment.
Whatever is varied, the other aspects should be controlled.

14. Scale Attenuation Effects
Memory experiments are especially sensitive to difficulty of the task:
Ceiling effects occur when the task is too easy and everything gets nearly 100% correct.
Floor effects occur when the task is too difficult and few people get any questions correct.
Aim for 80% correct in the control group.
Test your items before manipulating the IV.

15. Scarborough’s Experiment
Used the Brown-Peterson technique to measure short-term memory:
A trigram is followed by distractor task after a certain number of seconds.
Percentage correct is measured
Proactive interference makes the task difficult:
trigrams seen on previous tasks interfere with remembering subsequent trigrams.

16. Scarborough’s Design
Do we remember info better if we see it or hear it – does modality of presentation matter?
IV 1 – Presentation modality:
Visual Only group saw the trigrams
Auditory Only group heard the trigrams read aloud
Both group saw and heard the trigrams.
IV 2 – Retention interval: 0, 3, 6, 9, 12, 18 sec
DV – Proportion correctly recalled.

17. Which condition did better?

18. Scarborough’s Results
Subjects who only saw the trigrams did as well as subjects who both saw and heard the trigrams.
Subjects who only heard the trigrams did worse than those who saw or both saw and heard them.
Seeing produces better retention than hearing.

19. Different Rates of Forgetting?
Decline in retention appears steeper for those who only heard the trigrams.
Does this mean auditory presentation results in faster forgetting?
A ceiling effect complicates this interpretation.
All three modalities are at 100% at 0 sec.
With a higher ceiling, the decline for visual modality might have shown the same slope as for auditory.

20. Weight Loss Example
Two men make a bet about who can lose the most weight.
They weigh themselves on a scale that tops out at 300 lbs.
Both weigh 300 lbs on the scale, although one actually weighs 350 while the other truly weighs 300.
Both lose 100 lbs, so one now weighs 200 while the other weighs 250. Who won the bet?

21. Pilot Studies are Important!
Avoid extremes of performance (high or low) by testing materials on pilot subjects.
Make the task more difficult by increasing the amount of material to be remembered, presenting it faster, testing after a longer time interval, etc.
Make the task easier by decreasing material, slowing down presentation rate, etc.