After Rescorla-Wagner

Transcription

1 After Rescorla-Wagner W. Jeffrey Wilson March 6, 2013

2 RW Problems STM-LTM & Learning SOP Model Configural vs Elemental Nodes

3 Problems with Rescorla-Wagner Model Extinction: No Spontaneous Recovery or Rapid Reacquisition Extinction of CI Latent Inhibition

4 Mackintosh Model If SALIENCE of CS is allowed to change, some problems go away. Mackintosh & Turner (1971) Phase 1 Phase 2 Phase 3 Test N shock LN SHOCK L CR N shock LN shock LN SHOCK L cr Something happened to L in Phase 2... Salience of best predictor goes up; salience of others goes down.

5 Pearce-Hall Model Model If SALIENCE of CS is allowed to change, some problems go away. Hall-Pearce Negative transfer (1979) Phase 1 Phase 2 Test T shock T SHOCK T cr L shock T SHOCK T CR CS that was perviously learned about produces worse learning in Phase 2... Salience of uncertain stimulus goes up; salience of stimulus that one knows about goes down. Kaye & Pearce (1984) illustrates this. Rats continue to attend to a light that predicts food 50% of the time.

6 Short-Term Memory & Learning STM LTM Priming puts something into your STM Self-generated priming Retrieval-generated priming. Relate Priming to Surprise (per R-W)

7 Priming, Surprise, & Learning Best et al. (1979): Taste aversion Grp 1: Vinegar Illness Grp 2: Vinegar 4 hrs before Vinegar Illness Grp 3: Vinegar then Vanilla 4 hrs before Vinegar Illness

8 Wagner s SOP Model Stimuli are represented in the mind by nodes. Each node is made of of many elements. Nodes can be in one of three states Inactive A 1 A 2

9 Wagner s SOP Model Nodes are normally Inactive. Nodes driven into A 1 by presentation of a stimulus. Nodes driven into A 2 by thought (memory) of stimulus. From A 1 nodes decay quickly into A 2. From A 2 nodes return slowly to Inactive state. Elements decay at different rates.

10 Wagner s SOP Model Learning rules: CS and US both in A 1 excitatory association. CS can then drive US into A 2. Associations form between the elements of nodes. CS in A 1 and US in A 2 inhibitory association.

11 Excitatory Conditioning

12 Backward Conditioning

13 AESOP

14 R-W and Wagner s SOP are Elemental These theories treat stimuli as individual, separate things. If two stimuli are presented on a given trial, the expectation is the sum of the predicitions of the two: A CR B CR AB CR and A CR B nothing AB CR

15 But... External Inhibition If a stimulus with no meaning occurs unexpectedly along with the CS, the CR is typically smaller. A CR B nothing AB CR

16 And... Negative Patterning Two stimuli that alone reliably signal the US can signal its absent if they are presented together: A CR B CR AB nothing R-W, Wagner SOP cannot explain this.

17 Pearce s Configural Theory Stimuli are not simply elements to be added together; instead if they are combined they become a new stimulus. The new stimulus is similar to the two original to the extent that it has feature in common, but it is treated by the animal as a different stimulus.

18 Wagner s Replaced Elements Theory Nodes are made of many elements. The same stimulus might be represented by a different subset of elements when it is presented alone vs with another stimulus. It is the elements that are associated, not the node as a whole. THis allows different elements representing the same stimulus to have different meanings.

19 Test of Pearce vs Wagner Train Test Pearce Wagner A US ABC US CR CR ABC US A US CR CR Wagner Replaced Elements is right.