Current Research: Hierarchy Theory & Emotion (continued)
... It seems clear that the causal arrow must run downward, from emotion to thought and behavior. Introspection tells us that thoughts and behaviors are driven by values and preferences -- that we think and act because we want or prefer some outcome. Indeed, as David Hume argued two centuries ago (A Treatise of Human Nature), values and preferences can only arise from emotion. The only other factor that has ever been proposed as a cause of thought and behavior is reason, but reason (in the sense of pure rationality) is value-neutral and utterly incapable of motivating anything. As Hume put it, "Reason is and ought to be the slave of the passions and can never pretend to any other office than to serve and obey them. So how does emotion cause thought and behavior? I argue that it is a form of downward causation, of a sort that is familiar in many simpler hierarchical systems. Consider a balloon filled with gas. If the balloon as a whole is moved -- say 2 inches to the left -- this large-scale movement causes all of the gas molecules within it (as well as the molecules in the plastic skin of the balloon) to move, on average, 2 inches to the left. A similar sort of top-down causation occurs, it seems, in the emotion-behavior and emotion-thought relationship. Consistent with this, these relationships seem to follow certain key principles of hierarchy theory.
1. Rates. Lower levels move quickly relative to the higher level. The gas molecules in a balloon typically move quickly relative to the balloon as a whole. Likewise, thought and behavior are fast relative to change in emotional state.
2. Causal asymmetry. Lower-level units cannot, as individuals, much affect the higher level. A single gas molecule cannot much affect a whole balloon. Likewise, individual thoughts and behaviors ordinarily do not much affect an emotion. Rather, an emotion hovers more or less unchanging, in the background, while thoughts and behaviors aimed at satisfying that emotion play out.
3. Vagueness. Lower-level units do not directly interact with higher levels and therefore "perceive" them only "vaguely." Consistent with this, thoughts and behaviors are clear and distinct, but we perceive our emotions only vaguely.
4. Downward causation. Higher levels exert their causal influence on lower-level units via boundary conditions, and therefore higher-level control is not precise, with the result that lower-level units have considerable freedom. Consistent with this, in two similar higher-level systems, the sequence of behaviors of lower-level units could be very different. The movements of individual gas molecules in two very similar balloons will be very different. Likewise, the same emotion, the same motivation, in two different people is consistent with their thinking and behaving very differently. (Although presumably some very general similarities can be found. To the extent that the two share the same emotion, the goals they are pursuing are similar. Analogously, the movements of the gas molecules in the balloon share a general similarity, in that they all move two inches to the left on average.)