Conditional learning Charlotte Bonardi C82NAB Neuroscience and Behaviour Conditional learning Charlotte Bonardi

A red light means....

A red light means....

JAM!!

JAM!!

newspaper

newspaper journal

periódico shinbun

Conditional control of associations The same stimulus can be associated with two different outcomes. Which association is retrieved is conditional on the context in which the stimulus is presented. This allows the associations to represent knowledge in a versatile way. The context appears to control access to the CS-->US association. spanish “periódico” “newspaper” english

Conditional control of associations Standard associative theories can't explain this -- the association forms and that’s it. ... maybe associative theory cannot explain all animal learning? Questions: Is conditional control really independent of associative learning? If so, how does it work?

Conditional learning in animals Feature-positive discrimination: light+tone ---> food tone --> nothing

Conditional learning in animals Feature-positive discrimination: light+tone ---> food tone --> nothing Associative theory predicts that the light is strongly associated with food ... and that the tone is not On reinforced trials the light and the tone both acquire some strength; on nonreinforced trials the tone loses it again. As there is only limited associative strength available, eventually the light gets it all, and the tone is left with nothing.

Conditional learning in animals Feature-positive discrimination: light+tone ---> food tone --> nothing Associative theory predicts that the light is strongly associated with food ... and that the tone is not On reinforced trials the light and the tone both acquire some strength; on nonreinforced trials the tone loses it again. As there is only limited associative strength available, eventually the light gets it all, and the tone is left with nothing. But how do you know this is what is happening?

Ross and Holland 1981 Used the fact that auditory and visual stimuli elicit different behaviours in the rat: auditory: "headjerk" visual: "rearing" They examined responding in two groups of animals: 1 light + tone --> food tone --> nothing 2 light + tone --> food light --> nothing

Ross and Holland 1981 Used the fact that auditory and visual stimuli elicit different behaviours in the rat: auditory: "headjerk" visual: "rearing" They examined responding in two groups of animals: 1 light* + tone --> food tone --> nothing 2 light + tone*--> food light --> nothing

The rats learned exactly according to the Rescorla Wagner model: light* + tone --> food tone --> nothing rearing to light light + tone* --> food light --> nothing headjerking to tone But if you don't have the light and the tone simultaneous something else happens...

Ross and Holland, 1981 simultaneous

Ross and Holland, 1981 simultaneous

Ross and Holland, 1981 simultaneous serial

Ross and Holland, 1981 simultaneous rear serial

Ross and Holland, 1981 simultaneous rear serial headjerk headjerk In serial case hard for light to associate with food – so tone can

headjerk headjerk Headjerk response suggests responding is based on the tonefoood association.... and it seems to be stronger after the light! tone food so is the light acting as a switch??? light

headjerk headjerk ...or is it just associated with food too?? tone food Although the light is not closely followed by food, it is always followed by food delivery Maybe the rats headjerk more to the tone when the light has been on because they are already expecting food, and this boosts the headjerk CR elicited by the tone. light

grub up!

grub up!

tone food light We can test this by extinguishing the light-->food association. Will the rats headjerk to the tone when it is followed by the light? If they do, we cannot explain the results in terms of associative learning.

Holland, 1989 Two groups of animals: Group FP: Lighttonefood, tone no food Group PP: Lighttonefood, tone no food...

Holland, 1989 Two groups of animals: Group FP: Lighttonefood, tone no food Group PP: Lighttonefood, tone no food, light no food

Holland, 1989 Two groups of animals: Group FP: Lighttonefood, tone no food Group PP: Lighttonefood, tone no food, light no food If the light-->food association is responsible for discrimination in Group FP, then Group PP should not show any discrimination. This type of discrimination is called a positive patterning (PP) discrimination.

The light is still controlling responding to the tone, despite the fact that it’s not associated with anything. In these cases standard associative theory cannot explain how the light is controlling responding. The light may be called a conditional cue, a modulator, or an occasion setter. Can get negative occasion setting too – turn OFF an association

SIM light & tone  nothing tone  shock noise shock SER lighttone  nothing tone  shock noise shock A normal Pavlovian inhibitor will suppress responding to the noise – a summation test will this also happen in the serial case? Holland & Lamarre, 1984

tone shock so is the light acting as a negative switch??? light tone food or is the light just a Pavlovian inhibitor? light if you can explain the discrimination in terms of regular classically conditioned associations, associative theory can explain it – don’t need any other theory but if associative theory can’t explain result, need something else -- then light is an occasion setter

suppression ratio

Rescorla’s modulation theory (Rescorla, 1985) tone food light Whenever a CS is presented, it must activate the US representation to get a conditioned response. If the light is a positive occasion setter, it lowers its activation threshold -- making it easier for the CS to activate.

Holland’s and-gate theory (1983) tone food light The light acts as an and-gate, allowing activation to flow from the CS to the US, and so elicit a conditioned response.

These theories make different predictions about transfer Suppose you also pair a clicker with food; would you expect the light to elevate responding to the clicker as well? click tone food

click tone food Rescorla’s theory says YES. The light is altering the activation threshold of the food, and will boost responding to any stimulus that is associated with it. light

click tone food Holland’s theory says NO The light is acting as an and-gate for the tone-->food association -- not the click-->food association light

Hundreds of experiments later... Occasion setters do sometimes transfer their effects to other CSs paired with the same US (ii) But this transfer effect is seldom as big as with the original CS Many people have done this experiment (e.g., Holland, 1986; Rescorla, 1985). Here is one example, using rats:

TRAIN light.....tone-->food tone--> no food click-->food

TRAIN light.....tone-->food tone--> no food click-->food TEST light.....tone? tone? light.....click? click?

Holland might say... the animals could confuse (“generalise between”) the two CSs (the tone and the click). This might give a false and weak) transfer effect click light food tone food light

Rescorla might say... animals are “upset” by experiencing novel CS combinations (such as the click and the light) -- this could disrupt responding, and transfer to a different CS. click light food tone food light

So get some transfer to the click (supporting Rescorla) but less effect than with the tone (supporting Holland) results are not conclusive...

a complication! (iii) Transfer is better if the transfer CS has its own occasion setter click tone food light

a complication! (iii) Transfer is better if the transfer CS has its own occasion setter click dark tone food light

light.....tone-->food, tone--> no food dark....click-->food click-->no food

light.....tone? tone? dark...click? click? SAME light.....tone-->food, tone--> no food dark....click-->food click-->no food

light.....tone? tone? dark...click? click? light.....click? dark...tone? SAME light.....tone-->food, tone--> no food dark....click-->food click-->no food DIFFERENT

Again, many people have done this experiment (e.g., Holland, 1986, Rescorla, 1985). This is one example (it actually used pigeons).

Conclusions: Everyone (including Rescorla!) agrees Rescorla’s theory is too simple; occasion setters specific to training CS Holland’s theory a possibility -- but why better transfer to a CS from another conditional discrimination? So Holland (1989) suggested an occasion setter will transfer perfectly to a CS that has its own occasion setter – not to a CS that hasn’t. Circular...!!

Bouton & Nelson (1998): occasion setters form best when tone can acquire strength more easily than feature... light  tone  food tone  nothing but tone always losing strength too.. both excitatory and inhibitory links with US: tone food light maybe light inhibits the inhibitory link!

Bouton & Nelson (1998): problem: can get occasion setting even without tonenothing trials light  tone  food tone  nothing tone food maybe light inhibits the inhibitory link! light

Bouton & Nelson (1998): problem: can get occasion setting even without tonenothing trials light  tone  food tone food ? no inhibitory link to inhibit! light

An alternative account ... configural learning although they are given this.... they actually experience something like this... tone after light

..when the tone and the light are presented together, the animal experiences a “configural” blend of the stimuli that is different from either This tone/light configure is associated with food in the normal way -- and that is what produces discrimination performance. (and extinction of the light doesn’t affect discrimination – it’s a different stimulus!)

It is difficult to discriminate between the and-gate and configural accounts of occasion setting -- but it seems the configural account is not enough to explain all occasion-setting effects. Occasion setters can be contexts (places) smells drug states (state dependence) maybe even apply to tasks like Stroop: red red green green blue blue task is occasion setter telling you which association to use – the one linked with the name of the word, or that linked with the colour

General references Bouton, M.E. (2007). Learning and Behavior. Sinauer Associates. Domjan, M. The principles of learning and behaviour. (1998). Brooks/Cole. Advanced: Swartzentruber, D. (1995). Modulatory mechanisms in Pavlovian conditioning. Animal Learning and Behavior, 23, 123-143. Specific references Bouton, M.E., & Nelson, J.B. (1998). Mechanisms of feature-positive and feature-negative discrimination learning in an appetitive conditioning paradigm. In P.C. Holland and N.A. Schmajuk (Eds.) Associative learning and cognition in animals: Occasion setting. APA, Washington, D.C. Holland, P.C. (1983). Occasion-setting in Pavlovian feature positive discriminations. In M.L. Commons, R.J. Herrnstein, & A.R. Wagner (Eds.), Quantitative analyses of behavior (Vol. 4, pp. 183-206). New York: Ballinger. Holland, P.C. (1986) Transfer after serial feature-positive occasion setting. Learning and Motivation, 17, 243-268. Holland, P.C. (1989b). Feature extinction enhances transfer of occasion setting. Animal Learning and Behavior, 17, 269-279. Holland, P.C., & Lamarre, J. (1984). Transfer after serial and simultaneous feature negative discrimination training. Learning and Motivation, 15, 219-243. Rescorla, R.A. (1985). Conditioned inhibition and facilitation. In R.R. Miller & N.E. Spear (Eds.), Information processing in animals: Conditioned Inhibition.(pp. 299-326). Ross, R.T., & Holland, P.C. (1981). Conditioning of simultaneous and serial feature-positive discriminations. Animal Learning and Behavior, 9, 293-303.