Mar 24, 2015

Rank Theory and The Evolutionary Cause of Depression

Some time ago I became fascinated with the physical ravages of depression on the mind and the body which, in addition to the more popularly understood psychological trauma caused, will often leave the depressed in a state of perpetual illness, thoroughly fatigued, and – as recent research has found – even smaller brained!

Depression doesn't play the helpful evolutionary role it once did!
Despite the extraordinary resources marshaled at every level of society to combat depression, it still left me questioning why do we get depressed to begin with?

More specifically, what role, if any, has depression played in human evolutionary development?  Is depression the psychological equivalent of the appendix, or could it possibly serve a defensible evolutionary purpose?

It's against that basic backdrop of curiosity that I came to learn of a fascinating body of work developed recently by Anthony Stevens and John Price, known as "Rank Theory".  Rank Theory proposes that there is in fact an evolutionary role for depression in humans.  In fact, they argue that depression is an involuntary and adaptive response to defeat (and loss of social rank) which has played a vital role in maintaining social order and helping insure survival.

The mechanics of Rank Theory state that in the aftermath of human conflict, the defeated are often subject to an automatic internal inhibitory response that set off a cascade of maladies.  Those include general fatigue, feelings of helplessness, disturbed sleep, and loss of confidence (among myriad other ailments); all typical characteristics of depression. 

Often called the "yielding subroutine", this inhibitory response has its uses: among them is in physically and psychologically discouraging the loser in a status conflict from re-challenging their opponent and suffering further injury, losing additional resources, being extricated from their group, or even losing their lives.

It could be said then that depression has played a key role in helping preserve the stability and competitive efficiency of human society in general.  A good thing to be sure.

One of the major advantages to a human living amongst his or her fellow humans is the safety the group confers from predators, which includes protection from other homo sapiens. Therefore living within a group became essential to humans for their very survival, as well as for access to resources, co-operative hunting of big game, and for reproductive success. 

A feeling of "belonging" has therefore become absolutely crucial to the physical and psychological well-being of an individual.  To become well-liked and to maintain a high rank within an organization or group are both exceptionally desirable states of being.  Alternatively, to see oneself as unpopular and without social desirability will unfailingly sponsor anxiety and unhappiness, and rejection altogether by ones group typically has devastating psychological (and eventual physical) consequences. 

It's with regard to these variables and by studying the correlation between ones relative psychological well-being and their social standing that grief and happiness, mania and depression, satisfaction and anxiety can be most cleanly recognized and understood.  And in taking that into consideration perhaps the implications of contemporary "defeat" (in its manifold forms) ought to be considered even more seriously and with greater concern for their potentially significant long-term implications on both our psychological and physical well-being.  After all, the conflicts we have today, while perhaps more frequent, are dramatically less significant in their impact and ultimate consequence to the health and longevity of the defeated.  Yet, it would seem, our brains, blocked perhaps by countless generations of social adaptation, have yet to get the memo. 

Rank Theory, if proven accurate, suggests to me a stronger and more pronounced interdiction at the earliest evidence of onset-depression to combat our antiquated physiological response to defeat.


Be well,

Christian Hunter
Austin, TX

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