PSYCHOLOGICAL VS. BIOLOGICAL EXPLANATIONS OF BEHAVIOR

Behavior and Philosophy, 2004 by Dretske, Fred

ABSTRACT: Causal explanations of behavior must distinguish two kinds of cause. There are (what I call) triggering causes, the events or conditions that come before the effect and are followed regularly by the effect, and (what I call) structuring causes, events that cause a triggering cause to produce its effect. Moving the mouse is the triggering cause of cursor movement; hardware and programming conditions are the structuring causes of cursor movement. I use this distinction to show how representational facts (how an animal represents the world) can be structuring causes of behavior even though biological (i.e., electrical-chemical) events trigger the behavior.

Key words: triggering cause, structuring cause, biological explanations, psychological explanations, behavior

Causal explanations are context-sensitive. What we pick out as the cause of E depends on our interests, our purposes, and our prior knowledge. Almost any event, E, depends on a great variety of other events in such a way that makes any one of them eligible, given the right context, for selection as the cause in a causal explanation of E. The multiplicity of conditions on which the effect depends has both a synchronie and a diachronic dimension. At any given time there are a variety of synchronous events and conditions without which E would not occur. Any one of these can be singled out as the cause of E. Furthermore, because any cause of a cause of E is also a cause of E, a more remote cause, there is a diachronic aspect to this multiple dependency. Temporal chaining of causes gives rise to proximal as opposed to ultimate (or more distal) causes, and, once again, any one of these events can be featured in a causal explanation of E. There is no privileged vantage point, no such thing as the causal explanation of E.

I think these facts are reasonably well understood. When the event being explained is a piece of animal behavior, no one thinks that there is only one correct causal explanation of it. Functional explanations, the sort we get from evolutionary biology, are surely consistent with the more proximal explanations of neurophysiology. Both can be correct, and both reveal part of the truth. They do not compete with but complement one another. They merely deal with different sets of causally relevant factors.

Nonetheless, there seems to be a widespread feeling that such harmonious coexistence is not possible between neurophysiological and commonsense psychological explanations of behavior (in speaking of "psychological" explanations of behavior I will always mean commonsense psychological explanations of behavior-those that appeal to what the subject believes, desires, fears, expects, etc). Here, it seems, there is a tension, perhaps even a conflict arising from the fact that both explanations appear to describe proximal events and conditions. Beliefs, desires, expectations, and fears-the sorts of factors mentioned in commonsense psychological explanations of behavior-operate alongside and are concurrent with the neuronal activities featured in biological explanations of bodily movement and change. Hence, the apparent competition between these explanations cannot be relieved, as it is in other cases, by appealing to a proximalremote difference. Nor is it much help to think of psychological explanations as describing causally relevant conditions that are synchronous with the biological processes controlling muscles and glands but that can be ignored in neuroscientific explanations of behavior, because if the psychological factors are causally relevant they cannot be ignored with impunity. If they are relevant, qua psychological, then the explanatory resources of physics, chemistry, and biology must be essentially incomplete. Dualists may welcome that conclusion, but it is not likely to gain much favor in the naturalistic framework of contemporary cognitive science.

My purpose in this paper is to describe a difference between two types of causes-triggering and structuring causes-that I think is useful for understanding the difference between biological and psychological explanations of behavior. The difference might, at first, appear to be an instance of the familiar distinction between a proximal and a remote cause, merely a difference in the temporal location of the causal factors featured in the explanation, but the differences, I think, run much deeper. They run deeply enough to show promise of reconciling, within a naturalistic framework, the apparent conflict between explanations of behavior that invoke and those that ignore an agent's beliefs and desires. My ultimate purpose is to show that psychological and neuroscientific explanations of behavior are not only compatible but complementary.

Triggering and Structuring Causes

An operator moves the cursor on a screen by pressing a key on the keyboard. Pressure on this key causes or (as we sometimes say) makes the cursor move. Though other events can make the cursor move, pressure on this key causes the cursor to move if, given existing conditions, the cursor would not have moved without the key press.1 It is this kind of causal relationship that allows us to speak of the operator as moving the cursor by pressing the key, and I shall speak of such causes as triggering causes of their effect.