A TRUE STORY OF A MAN EATING CHICKEN
Man Eating Chicken Illustration Used By Barnum & Bailey Following Photographer's Tragic Death
I would like to begin this piece by expressing my sincere, tremendous gratitude regarding my selection as an official beBee Brand Ambassador; I realize that in much of my writing I attempt to "inject" elements of humor, deliberately (and carefully) placed non-sequiturs, provocative (to varying degrees) statements cloaked in the guise of ideological challenges etc.
I am dead serious at this time however; as grateful and honored as I am --and as anxious as I am to focus on the diplomacy related activity expected of an Ambassador...I really, really would beg to be allowed a few hours to finish a long form post that I am currently working on.
In this post, I am trying to show how developments in the field of Psychology led to the building of a "circular bridge"; a way to link the freewill of William James' initial form of Scientific Psychology (from my previous post on the subject) -->to a deterministic/fractal/ complex mechanistic/mathematical Approach--->which finally was able to (like a dog chasing) capture its own tail and reconcile the original vision of William James in the form of "Cognitive Psychology" (the scientific foundation for Artificial Intelligence [AI]) --however...
... I'm finding that doing this in a coherent/readable fashion requires many revisions and tremendous concentration.
I beg, I plead for a little bit of time--that I may (at least to some degree) pull this off.
As of now, the only portion I have (which in and of itself is most unreadable to all but fairly well versed cognitive psychologists is a partial summary of the inception of what has come to be known as the "Rescorla-Wagner Model" of Cognitive Elements in Pavlovian Conditioning...this will NOT DO!
I must complete this:
Herewithin is a very basic review of the Rescorla/Wagner reinterpretation of Pavlovian conditioning as Cognitive Neuroscience in the Information Processing tradition: According to Rescorla and Kamin, associations are only learned when a surprising event accompanies a CS. In a normal simple conditioning experiment the US is surprising the first few times it is experienced so it is associated with salient stimuli which immediately precede it. In a blocking experiment once the association between the CS (CS1) presented in the first phase of the procedure and the US has been made the US is no longer surprising (since it is predicted by CS1). In the second phase, where both CS1 and CS2 are experienced, as the US is no longer surprising it does not induce any further learning and so no association is made between the US and CS2. This explanation was presented by Rescorla and Wagner (1972) as a formal model of conditioning which expresses the capacity a CS has to become associated with a US at any given time. This associative strength of the US to the CS is referred to by the letter V and the change in this strength which occurs on each trial of conditioning is called dV. The more a CS is associated with a US the less additional association the US can induce. This informal explanation of the role of US surprise and of CS (and US) salience in the process of conditioning can be stated as follows:
dV = ab(L - V)
where a is the salience (intensity) of the US, b is the salience (intensity) of the CS and L is the amount of processing given to a completely unpredicted US. In words: when the US is first encountered the CS has no association to it so V is zero. On the first trial the CS gains a strength of abL in its association with the US which is proportional to the saliences of the CS and the US and to the initial amount of processing given to the US. As we start trial two the associative strength is V is abL so the change in strength that occurs with the second pairing of the CS and US is ab(L - abL). It is smaller than the amount learned on the first trial and this reduction in amount that is learned reflects the fact that the CS now has some association with the US, so the US is less surprising (cute...very cute--oops I'm not supposed to impose my opinions). As more trials ensue, the equation predicts a gradually decreasing rate of learning which reaches an asymptote at L.
However, this is not what is seen when the development CS-US associations is measured over time. Instead the learning curve is sigmoidal. Rescorla has argued that the equation is consistent with observed behavior if one assumes that very small changes in associative strength are undetectable and that there is a limit to the amount of effect that very large changes can have on behavior.
There are other respects, however, where the model performs better in predicting experimental outcomes. It can also be applied to a number of CSs each of which contributes to an overall associative strength V of the US in the right hand side of the equation. It is reasonably clear that the presence of the CS salience term b in the equation lets it account for overshadowing. The meaning of the equation is clearest if the specific dVs on the left hand side are seen as referring to the increments in association between specific CSs while V on the right hand side is referring to the predictability of the US and so is the sum of all the different CS-US associations. If the conditioning strength accrued to CS1 is denoted by dV1 and that to CS2 by dV2 then our equations are:
dV1 = ab1(L - V)
dV2 = ab2(L - V)
and both dV1 and dV2 accrue to V on each trial. The amount of association directed to each CS is proportional to their salience.
The equation also models blocking well. During the initial phase of a blocking experiment the associative strength of the US is increased so later, when a second CS is presented the amount of associative strength it can gain has been reduced.
The critical question is, however, does the model predict experimental outcomes it was not explicitly devised for, i.e. can it be generalized? In one example the model predicts the effects of pairing two previously learned CSs on learning about a third new stimulus. If on separate occasions (not as compound stimuli) two CSs of equal salience have both been completely associated with a US then V=L for both stimuli and dV on subsequent trials is zero for both. Now a third CS in conjunction with the original pair is presented so three CSs are presented together whereas only two of them were presented singly in the past. The overall associative strength of the US is now 2L, a contribution of L from both of the original CSs. The equation predicts that there will be a negative change in associative strength on this trial proportional to the salience of the CSs:
dV = ab(L - 2L)
dV = -abL
Conducting the experiment shows: the third stimulus becomes a conditioned inhibitor of the US - it provokes a CR of the opposite quality to that produced by the other two CSs.
It was obviously only a matter of time before The elegant science of behaviorism began to be co-opted by the "cognitive neuroscience" movement, AI, Neural Networking, Holographic models of Neuronal connections... etc.
Thank you in advance for letting me turn this into something coherent in my next longform post.
© Gerald Hecht, 2016. Unauthorized use and/or duplication of this material without express and written permission from this author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Gerald Hecht with appropriate and specific direction to the original content.