Archive for March 2nd, 2010

Posted on March 2, 2010 - by David

‘Analytical Rumination’:Depression as an Adaptive Response?

I read an article last week in the New York Times Magazine by Jonah Lehrer called Depression’s Upside, exploring the possibility that depression is an adaptive, evolved response which helps people focus cognitive resources on solving complex problems. The idea comes from a paper by Paul W. Andrews and J. Anderson Thomson, Jr. published in July of 2009 in the Psychological Review, titled The Bright Side of Being Blue: Depression as an Adaptation for Analyzing Complex Problems.  Lehrer’s clever lede uses a description of Darwin’s own mental anguish to slide into yet another evolutionary explanation for the workings of the mind. The following paragraph describes the theoretical view from which the work springs:

In the late 1990s, Thomson became interested in evolutionary psychology, which tries to explain the features of the human mind in terms of natural selection. The starting premise of the field is that the brain has a vast evolutionary history, and that this history shapes human nature. We are not a blank slate but a byproduct of imperfect adaptations, stuck with a mind that was designed to meet the needs of Pleistocene hunter-gatherers on the African savanna. While the specifics of evolutionary psychology remain controversial — it’s never easy proving theories about the distant past — its underlying assumption is largely accepted by mainstream scientists. There is no longer much debate over whether evolution sculptured the fleshy machine inside our head. Instead, researchers have moved on to new questions like when and how this sculpturing happened and which of our mental traits are adaptations and which are accidents.

As Lehrer points out earlier in his article, the prevalence of depression poses a problem for those who are “trying to explain the features of the human mind in terms of natural selection.” The only solution for them seems to be to demonstrate that depression actually has evolutionary benefits. Meanwhile a disorder like schizophrenia is rare enough, and a case for its adaptive benefits would be so difficult to make, that I guess it’s easier for them to chalk it up to a kind of glitch in the system.

My first problem is that this point of view fundamentally disregards the symbolic reality of culture. Once again, I’ll quote from Liah Greenfeld’s essay, Nationalism and the Mind, to give background on the view of culture as an emergent phenomenon:

On the most general level, culture is the process of transmission of historical ways of life and forms of human association across generations and distances… In distinction to other animal species, such transmission of ways of life and social organization, in the case of humanity, is not genetic, but symbolic. Humans are the only biological species, the continuation of whose existence is dependent on symbolic transmission.

The products of this cultural process are stored in the environment within which our biological life takes place, but the process itself goes on inside us. In other words, culture exists dynamically, develops, regenerates, transforms only by means of our minds – which makes culture a mental process. Let me reiterate: culture is a symbolic and a mental process. The fact that it is a mental process means that it occurs by means of the mechanisms of the brain. The fact that it is a symbolic process means that its logic cannot be reduced to the logic of the brain mechanisms, that it is an emergent phenomenon and a reality sui generis. In other words: the neural processes by means of which the cultural process occurs serve only as boundary conditions outside of which it cannot occur, but are powerless to shape the nature and direction of the cultural process. In contrast, culture itself consistently directs the brain, by means of which it occurs, forcing brain mechanisms into patterns of organization and operation which (though, obviously, not impossible) are most improbable given all that we may know of the biological functioning of the brain. (15-16)

The idea of culture as an emergent phenomenon leads to a view of the human mind as the individualized process of culture,  and this obviously clashes with the argument made by Andrews and Thomson which seeks to explain the human mind as a product of biological evolution. Nevertheless, their argument is based upon an implicit acceptance of the idea that problems in the cultural environment affect the function of the brain.

I think it’s best now to look at the paper itself. On page 6, they describe the theory one claim at a time:

“In summary, we hypothesize that depression is a stress response mechanism: (1) that is triggered by analytically difficult problems that influence important fitness-related goals; (2) that coordinates changes in body systems to promote sustained analysis of the triggering problem, otherwise known as depressive rumination; (3) that helps people generate and evaluate potential solutions to the triggering problem; and (4) that makes tradeoffs with other goals in order to promote analysis of the triggering problem, including reduced accuracy on laboratory tasks. Collectively, we refer to this suite of claims as the analytical rumination (AR) hypothesis.”

By calling depression “a stress response mechanism,” they make it analogous to any animal’s response to a problem (such as the presence of predator) in the physical environment. On page 4, they write that “negative emotions are stress response mechanisms – they are involuntary response to environmental challenges with important fitness consequences, and they evolved to coordinate changes in physiology, immune function, attention and cognition, physical activity and other body systems to meet those challenges.” This view both cuts out the cultural (therefore symbolic) aspect of emotion and fails to acknowledge that “environmental challenges” are cultural challenges – for humans, the most important and challenging terrain that must be navigated is not the physical but the cultural world. When they write that “different environmental stressors trigger different emotions…” the only way to make sense of this is to read “environmental stressors” as “cultural stressors. The “stressor” may be present in the physical environment – a boss, an ex-wife, a place of work – but it is the cultural significance attached to these things which can “trigger different emotions.” I think we can safely assume that the “stress response” of a rabbit exposed to a wolf has never been based on symbolic reality and has probably been consistent over thousands of years. But for humans, both what constitutes a complex problem, and responses to such complex problems, has not been consistent over time and between places.

The authors focus on social dilemmas as the classic example of a complex problem that triggers depression. But you can’t talk about social dilemmas just in terms of evolution, cutting out the symbolic process of culture. Otherwise, each culture and its particularities must represent a separate human evolution. They use sexual infidelity as an example of an evolutionary fitness-related social dilemma, but it doesn’t take an anthropologist or an historian to figure out that such a situation differs widely over time and from culture to culture. It’s like they’re moving between descriptions of humans as just another species of animals and humans as cultural beings without ever acknowledging the difference.  On the one hand they write “if his wife gets pregnant…” and then they mention “access to mates.” So are we cultural beings with institutions like marriage or just animals who need mates? They are speculating about the social dilemmas of hunter-gatherer groups and trying to relate this to the depression of modern people who live in a radically different cultural environment, but they don’t seem to see the disconnect.

The core of their theory is the claim that depression can be seen as adaptive rather than a disorder, because the analytical rumination characteristic of depression actually leads people to solutions for their complex problems. I’d like to consider this view in relation to the view of Allan Horwitz and Jerome Wakefield as described in the Loss of Sadness. Horwitz and Wakefield believe that certain symptoms of depression are normal reactions to difficult life events, and can even lead to personal growth of some kind, but they don’t consider these reactions to be true cases of depression. They consider true depression to have no apparent cause or context, or to last longer and have more severe symptoms than “normal sorrow.” Andrews and Thomson, on the other hand, see no qualitative difference between major depression and subclinical depression, claiming that “…depressive symptoms are better characterized on a single continuum of severity, duration, and liability” (7).  While there may be good reasons for the continuum view, I believe this allows Andrews and Thomson to make their adaptive response argument for depression on the basis of evidence drawn mostly from subclinical cases and even from subjects in which “depressed affect” was induced by sad music or film clips. I don’t doubt that for some people, rumination may lead to a better understanding of their problems which could in turn lead to resolution or avoidance of future problems, but critics are quick to point out that this is probably not the way it works for severely depressed people. Lehrer quotes Peter Kramer, Brown University professor of psychiatry and human behavior and author of Listening to Prozac, who wrote, “this study says nothing about chronic depression and the sort of self-hating, paralyzing, hopeless, circular rumination it inspires.”

Andrews and Thomson are clearly interested in proposing new methods of treatment for depression, and believe that therapies which facilitate the process of rumination may be effective in dealing with the underlying problems causing depression. They describe a method which involves “having patients write about their strongest thoughts and feelings about their depressive episode in a journal (25). Journal entries were later examined and coded for “avoidance and processing.” The study found that:

“…the peak in processing was also associated with a spike in depressive symptomatology. Thus, the authors viewed the temporary spike in depression as a positive sign of growth and insight during treatment. This suggests that depression may enhance processing that promotes growth and insight into problems and may facilitate the resolution of the episode. “ (26)

I simply don’t see what leads them to conclude that “depression may enhance processing,” except that this view fits with their hypothesis. It would seem more logical to me to conclude that the increase in processing of negative thoughts and emotions caused the “temporary spike in depression.” They also fail to acknowledge the huge difference between depressive rumination in isolation, and carefully facilitated processing which occurs in the context of therapy. “Analytical rumination” may very well be a common feature of depression, but there is no reason this has to be seen as an evolutionary adaptation, and I doubt that it often leads to the resolution of complex problems without some form of outside help that can orient this rumination towards action.

As their paper draws to a close, Andrews and Thomson restate their claims and review the evidence they’ve used to try to demonstrate that “depression evolved by natural selection, probably because it helped people analyze and solve the problems they were ruminating about.” (41) I have to say, I was extremely frustrated by the number of times that “social dilemmas” and “complex problems” were mentioned, without any real examination of what this means for a depressed person today, or any apparent consideration of differences between cultures and over time. Then, I read this little paragraph:

A design analysis does not require depressive rumination to be currently adaptive because modern and evolutionary environments may differ in important ways (Thornhill 1990, 1997). All that is required is that, on average, depressive rumination helped people analyze and solve the problems they were ruminating about in ancestral environments. Still, strong, replicable evidence that depression rumination currently helps people analyze and solve the problems they ruminate about would support the evolutionary argument, and more research is needed here. (41)

Wow. Now they say something about this? So how do these environments differ, and why? They move between their ideas of the evolutionary past and today without blinking an eye, implying continuity and giving the appearance that they are in fact arguing that depressive rumination is “currently adaptive,” and then with only a few pages left to go in the paper they throw this in? So what has the point of all this been?

In looking at ‘now and then,’ so to speak, they suggest that today, compared to the “ancestral environment,” there are more ways to distract oneself from depression and the “complex problems” which trigger it, meaning that we are robbed of the potential benefit of depressive rumination. However, nowhere do they consider the obvious possibility- that the problems that individuals in modern societies face are of a much different nature than those of the “evolutionary past.” In the end, they seem to be saying the same thing Horwitz and Wakefield say, only they take a much more circuitous and frustrating path to arrive at their final statement:

Depression is the primary emotional condition for which people seek help. The current therapeutic emphasis on antidepressant medications taps into the evolved desire to find quick fixes for pain. But learning how to endure and utilize emotional pain may be part of the evolutionary heritage of depression, which may explain venerable philosophical traditions that view emotional pain as the impetus for growth and insight into oneself and the problems of life. (43-44)

I guess by this point, I shouldn’t be surprised when our “venerable philosophical traditions” get reduced to byproducts of evolution, but it still leaves me shaking my head.