Rick writes: I could see how taking a pill could, through repeated pairings, become associated with a particular effect. However, with the placebo effect, it would seem that there are two additional concerns. 1) If a person has taken a number of pills over the years for various conditions, and the pills had various effects, wouldn't this dilute the placebo effect in the case of any particular effect? On the other hand, if every pill you ever took had analgesic effects, it would seem that a pill could come to elicit a conditioned response. But that leads us to 2) Would the placebo response be congruent with or opposite of the original effect? For example, if a stimulatory effect is predicted by the delivery of a CS, the CR can often be the opposite of the UR (a depressant effect) allowing the organism to maintain homeostasis. In that case, the placebo effect would be the opposite of the effect of the drug.
Both great questions. As to the different effects of types of drugs that we've had experience with, this would be an example of discriminative conditioning. It's not hard to classically condition different responses to the same CS, using different USs in different contexts. Thus, the context (including perhaps cognitive expectations) could play a role in determining which effect we see. As to whether the CR should be the same as the UR, opposite or unrelated; as I'm sure you know, classical conditioning can produce all three patterns. in Domjan's text, he suggests that the CR is affected by the CS, US, timing between them and the context. Often the rule seems to be that the CR that is exhibited is the one that best prepares the animal for the anticipated occurrence of the US. Thus, I would guess the direction of the placebo effect would depend upon the nature of the drug and the speed of its onset of action. Mike --- You are currently subscribed to tips as: [email protected]. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=7654 or send a blank email to leave-7654-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
