Classical Conditioning – Ch. 5 September 16, 2005 Class #11

Stimulus-Substitution Theory  Pavlov’s early idea that the tone was the substitute for food

Preparatory-Response Theory  The purpose of CR is to prepare organism for the UCS The dog salivates to the tone so as to get ready for the presentation of the food The rat freezes in response to the light so it is ready for the painful shock

Compensatory-Response Model of Classical Conditioning  The compensatory after-reactions to a UCS may come to elicit the CS Conflict with Pavlov’s early theory  See next slide

Pavlov’s Early Classical Conditioning Experiments  UCS  UCR (shock) (HR increase)  NS  NO RESPONSE (tone)  NS + UCS  UCR (tone) (shock) (HR increase) * This is repeated several times…  CS  CR (tone) (HR increase)

But with further pairings…  UCS  UCR (shock) (HR increase)  NS  NO RESPONSE (tone)  NS + UCS  UCR (tone) (shock) (HR increase) * This is repeated several times…  CS  CR (tone) (HR increase)  NS + UCS  UCR (tone) (shock) (HR increase) * This is repeated several more times…  CS  CR (tone) (HR decrease) What other theory does this remind you of???

Classical Conditioning: Drug Tolerance Example  Drug Tolerance Drugs have less of an effect when taken repeatedly (less of a high) Drug users crave more of the drug despite its lessening effects It appears that certain drugs trigger our body to call upon its defenses against the effects of the drug

Drug Tolerance  Siegel et al. (1982) Demonstrated that classical conditioning principles might be in effect during drug- injecting episodes… Possible reason for overdoses???

Siegel’s theory…  UCS  UCR (drug) (anti-drug defenses)  NS  NO RESPONSE (injection ritual) (no defenses)  NS + UCS  UCR (injection ritual) + (drug) (anti-drug defenses) * Repeated several times  CS  CR (injection ritual) (anti-drug defenses)

Siegel’s theory…  Familiar setting  anti-drug defenses (usual time, place, etc) (body reacts)  New setting  no defenses (place, time are different) (body doesn't react)  The same dosage now becomes an overdose – they get too high as their bodies have been fooled by the new procedure

Siegel’s Model Initial Exposure Sight of needle, taste of beer, etc. Neutral Stimuli Effects of drug on neurons UCS Compensatory reaction opposing drug effects UCR Later Effects Sight of drug- associated stimuli CS Compensatory reactions. Resemble withdrawal effects in the absence of the drug. CR

Siegel, Hinson, Krank, & McCully (1982)  In this experiment laboratory rats were preconditioned to a tolerance of large doses of heroin… Procedure:  Lab rats given daily intravenous injections for 30 days  Placebo or heroin given either in “animal colony” or alone in “white noise” room on alternate days  Counterbalance of treatment: For some rats: heroin in WN; placebo in AC For others: heroin in AC; placebo in WN Control group received only placebo in different rooms on alternate days

So this then gives us 3 main Groups:  Group 1: Received heroin in the Colony room (their normal living quarters) and placebo in the Noisy room the next day  Group 2: Received placebo in the Colony room (their normal living quarters) and heroin in the Noisy room the next day  Group 3: Received placebo in the Colony room (their normal living quarters) and placebo in the Noisy room the next day  All rats were then injected with a large dose of heroin (15 mg/kg)

But does it depend on the room???  But the room in which this potentially lethal dose of heroin was administered was varied between subgroups of rats… Group 1A were injected with heroin in the Colony room - where they had received all their previous injections of heroin Group 1B were injected with heroin in the Noisy room - where they had never received any previous injections of heroin Group 2A were injected with heroin in the Noisy room - where they had received all their previous injections of heroin Group 2B were injected with heroin in the Colony room - where they had never received any previous injections of heroin Group 3A were injected with heroin in the Colony room - they had no previous injections of heroin Group 3B were injected with heroin in the Noisy room - they had no previous injections of heroin

Results: Death Rate  Group 3 showed substantial mortality (96%)  A group with prior exposure in the same cage showed tolerance (only 32% died)  A group with the same history of exposure, but tested in an environment not previously associated with heroin showed higher mortality (64%)

Results: Death Rate  Results: 50% increase in death rate in new room Rats show "room-specific" tolerance

McCusker and Brown (1990)  In a study analyzing alcohol's effects on the performance of an eye-hand coordination task, a group of men classified as social drinkers received alcohol either in an office or in a room resembling a bar  Most subjects performed the task better (i.e., were more tolerant) when drinking in the barlike environment Results suggest:  This suggests that for many people, a bar contains cues that are associated with alcohol consumption and promote environment-dependent tolerance  Environment-dependent tolerance develops even in "social" drinkers in response to alcohol-associated cues

Conditioned Taste Aversion  Doesn't fit exactly within all the rules of classical conditioning… Occurs reliably after only a single trial (one pairing) Timing doesn't seem to be much of a factor – strong learning is taking place despite delays of minutes or hours or more

Garcia and Koelling (1966)  Rats drink flavored water from tubes that flashed light and made noise when the tubes were licked… Group 1:  Rats were given electric shocks to their feet two seconds after beginning to drink Group 2:  Rats were exposed to X rays (which made them sick) while they drank  Later, both groups were tested with a tube of flavored water producing lights and noise and a tube of unflavored water that was not producing lights and noise… so rats are basically given a choice between these two tubes to drink from

Garcia and Koelling (1966)  Group 1 (rats that had been shocked) avoided the tube producing the lights and noise while Group 2 (rats that had been made sick) avoided only the flavored water  Conclusion: Evidently, rats (and other species) have a built-in predisposition to associate illness mostly with what they have eaten or drunk (Group 2 rats) and to associate skin pain mostly with what they have seen or heard (Group 1 rats) This is another example of preparedness – organisms are "biologically prepared" or "genetically tuned" to develop certain conditioned associations  Note: In literature, this is sometimes referred to as biopreparedness

Valentine (1930): Extends “Little Albert” experiments  Another example of preparedness… This researcher actually blows loud whistle whenever his infant touched certain objects Interesting (although ethically-troublesome) results:  When she touched a pair of glasses there was no response  When she touched a caterpillar she began to cry  Other participants also showed similar reactions to dogs, etc.

Websites you can check for additional information:  Information contained on slides #12-16 taken from following website: drugtolerance.htm drugtolerance.htm  Slide #11 prepared by Keith Clements and taken from his website: