1. Models of Memory
Psychology 3717

2. Introduction Really there are two types of models
Models that look at specific phenomena
ACT*/ACT-R or TLC for example
Models that look at general organization
Atkinson and Shiffrin for example

3. But why model? Models organize data Models make explicit predictions
Models can lead to application
When you think about it, the first two are what science is all about, so models help us get beyond simple description

4. SAM Search of Associative memory Grew out of Atkinson-Shiffrin
Math model
Basically looking at list learning results
So study list
Then recognition or recall

5. Assumptions
Target items are viewed in relation to the memory representations of all other items learned
This includes the words, the context etc
To be learned items are associated with the context
When words are presented they are rehearsed
Words have a familiarity value
Old v new decisions are based on familiarity vale
Basically a signal detection approach

6. Memory strength Based on rehearsal during encoding
Association between the stimulus and the representation of the word itself
Association between the stimulus and the context
Item retrieval based on prompt by the experimenter

7. Retrieval
Retrieval depends on the joint contribution of the context, of all other items and the item itself
So the strength is, basically, the sum of all the associative strengths in the list
This explains why recognition is easier than recall

9. Explains a lot Longer presentations, better memory
RI effects (context changes subtly)
Serial position
Encoding specificity
Recognition failure of recall

10. Nice eh! Yeah, but…. Makes a lot of assumptions
Why aren’t all items recognized when one is?

11. Levels of Processing Craik and Lockhart
Memory is NOT just this passive thing
It is the result of encoding
Perceptual analysis
Pattern recognition
Semantic elaboration

12. LOP is A OK
Semantic processing produces better memory than perceptual processing
Conceptually driven vs. Data driven
Only true with explicit memory (though see Challis and Brodbeck, 1992)
Deeper semantic processing, better memory
Read – generate effect

13. Levels Depth seems sort of vague though
Hmm, when do you get better memory?
Well when you have deeper processing
How do you know you have deeper processing?
Err umm cuz you have better memory…
Transfer appropriate processing may be a bit of a better concept

14. Memory systems approaches
Tulving and episodic / semantic distinction
One is explicit, one is implicit
There is physiological evidence of a sort
Tulving maintains that only humans have episodic memory
For him, it involves consciousness because it must be self referential
I don’t agree really…

15. Why would there be multiple systems?
Sherry and Schacter, 1987
When a problem shows up that cannot be solved with the present system a new one will be selected for
So, our memory for facts could not deal with autobiographical stuff
Or, birdsong cannot be remembered with simple CS US associations

16. Conclusions Models are cool
They can be tested because they will make explicit predictions
They organize data
They cannot have too many assumptions, the fewer the better