Recognition Memory decisions
- presented with word, have to remember whether it is old or new
- how do we decide?
- single vs dual
Response classification to recognition memory decision paradigm
- hit: old, say old
- miss: old, say new
- false alarm: new, say old
- correct rejection: new, say new
Unitary memory signal
-decision based on assessment of memory strength
-signal detection
-past experience with stimulus leads to greater evidence
-set criterion for strength in order to classify as old
(the overlap is where we get FA and misses)
Decision bias
- where we place our criterion determines our decision bias
- ranges from liberal to conservative
- liberal = more false alarms
- conservative = more misses
witnesses and line up (sequential or simultaneous)
-in sequential, witnesses are much more conservative
Discriminability
- d-prime
- how far apart the target and lure distributions are
- if they are farther apart then they have greater differences in strength and you are less likely to have FA or misses
using bias to see how good your memory is
-bias is independent of how good your memory is
Dual Processes
recollection and familiarity
Recollection
- retrieval of event-specific information
- depends on conjunctive memory trace
- requires attention during encoding
- more controlled operation
- relatively slow
Familiarity
- undifferentiated feeling of having recently encountered item
- less dependent on attention during encoding
- more automatic operation
- relatively fast
- absence of pattern completion
- doesn’t identify a particular event
How do familiarity and recollection work together?
-both lead us to the same decision (that you have seen it before)
“Becoming famous overnight”
-Jacoby, 1989
Study:
-read non-famous names (full or divided attention)
Test:
- fame judgment
- new famous = familiar
- new not famous = not familiar or recollected
- old not famous:
- remember study event = recollected
- if didn’t remember study event = familiar/ more likely to label as famous
fMRI Activity during Recollection at retrieval
Study
Test
-old or new
- if old, do you remember study event?
- or is it just familiar?
-correct recollection: increased activity in left and right hippocampus
-no difference in hippocampal activity for familiarity vs miss
What does fMRI data imply about single vs dual processes?
- if single, you would have to have more activity in the misses (increased activity of hippocampus is associated with reinstatement, which is like recollection)
MTL activity during decision (is it old or new? )
- perirhinal activity predicts item remembered
- Hippocampal activity predicts item + context remembered
Repetition suppression and item familiarity
- more activity for first occurrence
- suppressed response to repeated (this might become the subjective sense of familiarity)
Role of MTL in repetition suppression
- perirhinal cortex: shows repetition suppression
- (about 25% of neurons)
- Hippocampus: repetition suppression (about 1% of neurons)
- stimulus-context conjunction
Familiarity
shown face (is it old or new?) Measure: -signal change -confidence of familiar vs not -decrease in hippocampal activity when it is more familiar
Functional distinction of Perirhinal cortex
- items
- what
- item memories:
- familiarity and item recognition
functional distinction of parahippocampal cortex
- context
- where
- item memories:
- familiarity, item recognition
functional distinction of hippocampus
- binding items and contexts
- conjunctive memories:
- recollection
- cortical reinstatement
