Associative Learning

Psychology 3906

Introduction

• Every species tested seems to show some form of associative learning

• There are many possible responses• Are they all served by some

overarching ‘associative learning system?’

Constraints

• Early on (meaning the 1960s….) people looked at so called constraints

• Taste aversions• “Misbeahviour”• The whole notion of adaptive

specializations of learning• Not really a clear research program

More recently..

• The modular view has helped out here• Intelligence is modular• Memory, for example, has many

subsystems, we accept that easily• Same with perception• So learning may as well

What is learning?

• Some event at time 1 affects behaviour at time 2

• Probably the best definition out there, though there are others

• Bob Rescorla

What are we interested in?

• Conditions for learning• Contents of learning• Effects on behaviour

Conditions for learning

• Contingency• The “Rescorla control” vs conditioned

inhibition• Compounding• Features and blocking• Surprisingness

The Model:

• ΔVi – Si(Aj-Vsum)• i = CS• j = US• S = Salience• A = Value of the US• V = amount of conditioning• These quantities are, of course, hypothetical

An example

• OK, say a food pellet = 100• Say salience of a light CS = .2• Vsum = 0 (at the start of the experiment,

there is no conditioning yet

OK, now for the numbers

• Trial 1• ΔVi – Si(Aj-Vsum)

=.2(100 – 0)=20

• Trial 2ΔVi = .2(100-20)

=16

Continued….

• Trial 3ΔVi = Si(Aj-Vsum)ΔVi = .2(100-36)12.8

• And so on….• Less and less conditioning as time goes

by• Cool eh

More on conditions

• Gallistel’s model is more to do with duration of events and number of pairings

• Events have to “go together”– Preparedness– Belongingness– No model deals with that well at all

I just want to belong to something….

• Spatial and temporal contiguity can be considered types of belongingness

• Think about backwards conditioning, it never works

• When you look at these two types of contiguity from a functional viewpoint it makes a great deal fo sense

Prior learning affects new learning

Group Phase 1

Phase 2

Test Result

Control Nothing LT+ T CR

Blocking L+ LT+ T No CR

The contents of learning

• Is it an association between stimuli?• Is it an association between a stimulus

and a response?• It seems to depend on the preparation• How in the hell could you tell?• As usual, Bob Rescorla figured this

out…

S-S and S-R

US

CS

UR

If we could just get rid of that US – UR bond…..

US

CS

UR

Rescrola (1973)

• So, how do you get rid of a response that is hard wired to a stimulus?

• Well, if you use CER, then your response is startle right?

• How do you get rid of a startle reflex?• Habituation!!• (Bob is a smart man)

Design

Group Phase 1 Phase 2 Test

Habituation

L -> N Noise Light

Control L -> N Nothing Light

Results

• Less suppression in Habituation group• (In other words, more responding)• Therefore, the connection MUST be S –

S• WOW!

But, after all of that….

• Need it be a connection?• Gallistel says that it is contingency itself

that is learned• Different features of the CS and US are

learned• Holland’s experiment

Effects on Behaviour

• Learning vs. performance• The Behaviour system approach• Are Pavlovian and Instrumental learning

different?• Operationally of course yes• But, what about occasion setting and

within event learning

In sum

• It may simply be that most types of what we call associative learning use many of the same modules

• Cause effect realationships• Patterns• Predicting the future is pretty adaptive