(And re: previous post – no, I’m not horribly depressed, nor am I working full-time again. I’m doing things I enjoy in order to get better, and emotion theory happens to be one of them.)
Reading Tooby & Cosmides (2005), Conceptual Foundations of Evolutionary Psychology, as a part of refamiliarizing myself with basics of evopsych. It is a very good description of a lot of basic ideas behind evopsych, having mostly familiar stuff and surprisingly little stuff I disagree with, but the new part I had not run into before was the idea of recalibrational emotion programs.
The core idea is that unlike many other emotions*, emotions such as guilt, grief, shame, gratitude, and depression, have not evolved for producing any immediate behavior change. Instead, drawing from the computational approach to psychology, the idea is that behavior generally is dependent on a lot of (nonconscious) regulatory variables that track the relatively stable circumstances of one’s life. This way the brain does not have to calculate things like the estimate of social support, evaluation of a particular person’s likelihood of reciprocating kindness (or aggression), or present health and energy of own body, on the fly when already in a situation. But these variables need to be updated constantly, and sometimes the act of updating a variable itself should cause changes in other evaluations, in default modes of behavior in related situations, and so on. The authors use guilt as an example (p. 59):
Imagine a mechanism that evolved to allocate food according to Hamilton’s rule, situated, for example, in a hunter-gatherer woman. The mechanism in the woman has been using the best information available to her to weight the relative values of
the meat to herself and her sister, perhaps reassuring her that it is safe to be away from her sister for a short time. The sudden discovery that her sister, since she was last contacted, has been starving and has become sick functions as an information-dense situation allowing the recalibration of the algorithms that weighted the relative values of the meat to self and sister. The sister’s sickness functions as a cue that the previous allocation weighting was in error and that the variables need to be reweighted—including all of the weightings embedded in habitual action sequences. Guilt functions as an emotion mode specialized for recalibration of regulatory variables that control trade-offs in welfare between self and others […] Previous courses of action are brought to mind (“I could have helped then; why didn’t I think to?”), with the effect of resetting choice points in decision rules.
The authors briefly mention depression as well: “Former actions that seemed pleasurable in the past, but which ultimately turned out to lead to bad outcomes, are reexperienced in imagination with a new affective coloration, so that in the future entirely different weightings are called up during choices.”
I have always considered the functional explanations of depression (or sadness) suspect, because they have typically only briefly mentioned “deattachment” or something similar as the function, and that has sounded… not right. Why would depression have such a horrible feeling if it was simply aimed at deattaching or realigning goals or something? An adaptation that seems to make you passive, drive you to ruin your relationships, and ultimately kill yourself does not seem very adaptive**.
The idea of recalibration makes this so much more understandable! It is not that depression is an adaptation in itself. Instead, (I now hypothesize,) it is the result of the recalibration program accidentally recalibrating all the core motivations at the same time to zero. Normally, the recalibration operates on one core motivation at the time – it gets set to zero, but other motivations are still running, so the behavior is directed more adaptively. But in a case where you only happen to have a couple of core motivations, and they all get set to zero due to some recalibration (that is not maybe based on the most objective of evaluations if the preceding states are already biased), you end up in the state where you have no core motivations left: depression. The program signals that you should not be doing these things, do the other things, but there are no other things left to do.
*) The authors strongly subscribe to a discrete emotion view, but their arguments can be read as somewhat inconsistent with the basic emotion theories.
**) Yes, yes, suicide can be adaptive from the gene’s point of view. But depression does not seem a reliable result of situations where suicide would actually be adaptive.