Physiology and behavioral causation

Sorry for the delay, aside from gallivanting around more than usual (Tony Chemero invited me out to teach a class and give a department seminar at Franklin and Marshall), I have been trying to take a bit of a mental break since the Holt book finally came out. To try to get started again, I want to write at least a little bit about the potential difficulties in talking about physiological causation (including neural causation) of behavioral phenomenon.

To give a bit of a framework, in the classic field of Ethology and the modern field of Animal Behavior, one of the most of important papers was written by Niko Tinbergen, in which he laid out the goals of animal behavior studies as answering four "why" questions about behavior. Tinbergen explains that the researcher is interested in understanding the mechanism of a behavior, the development of that mechanism over the life of the organism, the evolutionary function of the behavior in the context of the current organism, and the ways similar behaviors have functioned in the evolutionary past. There have been attempts to further frame these questions in the years since (the whole proximate vs. ultimate thing from Marr), and attempts to refine and alter the questions (by Don Dewsbury and other people worth listening to). That said, the four questions have been fairly stable, and still serve their original function: Tinbergen wrote the paper to make it clear that these different types of explanations did not contradict each other, and that a full understanding of a behavior required knowledge of mechanism, development, function, and history. The idea was to end silly fights, and to help researchers contextualize their own research with respect to other people's research.

So, at this point there has been much research about the role of physiology (including neural activity) in the behavior of many organisms (including humans). Good stuff, overall. This research is commonly seen as giving one type of explanation for behavior. Much credence is lent to this in the animal behavior community by the understanding of Tinbergen's questions, but this would have been an intuitive way of thinking for laymen regardless. Tinbergen's four questions are not that far from Aristotle's "four causes", and mechanisms are commonly accepted as explanations in everyday conversation.

[breaking third wall] I'm struggling to find a good transition so, please just pretend that there is one right about.... here. [end break]

But typically when we ask questions about behaviors, the physiological happenings are entailed in the description we give, and therefore they cannot also be part of the explanation. For example, if I ask "why did that student raised their hand in class" I have already told you that it is the student who raised their own hand. If you reply with an explanation in terms of motor neurons that released neurotransmitters against the surface of muscles in the shoulder, we get no where. To "raise your hand" entails that your shoulder muscles activated. If I ask "why did that student raise their hand in response to my question" I have explicitly included in the description that the hand was raised in response to my question. Thus, no amount of details regarding the physiology of hearing, the semiotic, symbolic, or information "processing" of the question in the brain, nor the "decision" to raise the hand, nor the physiology of the hand movements themselves will explain anything. At best such details just flesh out the question itself. At best, it simply provides a more detailed description of the thing to be explained.

Let me try to provide a good metaphor:

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Episode 1

We both see a building get demolished.

You ask: Why did the building fall?

I reply: Because the parts that were up very high are now on the ground.

After an awkward pause, you insist: Yes, but why did the building fall?

I reply: Because the parts that were near the bottom went to the ground, and then the parts above them moved further down in sequence.

After another awkward pause, you regroup and insist: Yes, but that is what I want an explanation for! Why? I want to know why!

I reply: Well, a series of event were initiated and the result was that the building ended up on the ground.

You: YES, I KNOW THAT. I know that the building fell, and all you keep doing is re-describing "falling". That is bull shit, and you are not explaining anything. I want to know WHY!

I reply: Oh, well the city hired a demolitions team because they want to build a shopping mall there.

You: By God, Finally! Why couldn't you have just said that in the first place.

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Episode 2

We both see a man run to a moving train and jump onto the back of it.

You ask: Why was he chasing the train?

I reply: Because his legs were propelling him along the path of the train's movement, at a slightly faster clip than the train's speed.

After an awkward pause, you insist: Yes, but why was he chasing the train?

I reply: Because his brain was active in such a way that he oriented to the train, then his brain sent signals to his limbs so that he moved in the direction of the train, and then the brain sent signals so that he grabbed on to it when he was close enough. 

After another awkward pause, you regroup and insist: Yes, but that is what I want an explanation for! Why? I want to know why!

I reply: Well, most people like to start with the stimulation of the retinal surface, which sets off a cascade of neural processing, eventually resulting in a "mental model" of the train-relative-to-the-runner. From that model the brain can "calculate" a trajectory to intercept the train and then send out motor commands accordingly. Frankly though, I prefer to say that the runner was attuned to information that reliably indicates the actions necessary to achieve the affordance of train-interception.

You: YES, I KNOW THAT. I know that he was running to intercept the train, and all you keep doing is re-describing "running to intercept the train". That is bull shit, and you are not explaining anything. I want to know WHY!

I reply: Oh, well I overheard a conversation he was having earlier, and he has to get to Chicago. There will not be another train going there for two days, so he was probably worried he wouldn't make the conference unless he caught that train. 

You: By God, Finally! Why couldn't you have just said that in the first place.

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So, given the questions we typically ask about behavior --- "we" being either psychologists or laymen --- the fact of physiological happenings is typically implicit in the description that starts the question rolling. Though we might not know the details of the physiology, and we might find those details interesting on a personal level, they do nothing to help answer the questions we are asking. Thus, relative to the concerns of the psychologist, physiological facts should rarely be accepted as explanations.