Depression: Nature’s Most Unlikely Tool
Anthropologically, clinical depression is considered to be “a behaviour pattern that is pan-human and confers a reproductive disadvantage now and in the archaic past,” (Young, 2003). To any normal person suffering from depression, this is a very worrisome statement, but there’s good news too - depression is believed by anthropologists to be an evolutionarily developed tool that was used to cope with complex problems by minimizing the disruption of deep thought to allow for longer, more in-depth analysis of said problems (Andrews & Thomson, 2009). This paper will analyze the evolution of depression, describe the evolutionary advantages to it, as well as lay out a cost-benefit analysis of depression’s presence in modern humanity.
Baboons are the key to our current understanding of the origins of depression. Early humans lived in small social groups run by strict dominance hierarchies that required aggressive competition very similar to baboons today (Young, 2003). Through these hierarchies people developed a sense of “irritability towards inferiors, anxiety towards superiors, elation on going up the hierarchy and depression on going down,” (Young, 2003). This depression, caused by a falling in the social hierarchy, is described by Young as a “yielding mechanism.” The person’s sense of superiority plummets along with their appetite and libido essentially eliminating their desire to fight the new alpha to regain positioning in the hierarchy. This protects the weaker person from incurring further, potentially life-threatening physical harm by replacing it with the mental stress of depression therefore keeping them alive longer. It is theorized also that depression is less prevalent in groups with an unquestioned leader and a common enemy because this causes a collective outward projection of the aggression normally used to battle within the hierarchy (Young, 2003). Finally, Young compares the increase in confidence of depressed people who are seeing medical professionals to deal with the illness to that of baboons suppressing the feeling of insecurity by trusting in a leader that is strong, capable, confident, and yet deeply concerned with their interests. Baboons, and in theory humans as well, use depression as a placeholder for what is recognized by their biology as being a larger threat to their existence. Since its inception, humans have developed out of these small, hierarchical social groups and into much larger, less organized civilizations. Now, instead of a drop in hierarchy causing depressive episodes, they are more commonly caused by more general, acute life changes, or as Young (2003) describes them, “life crises.” The examples he uses are loss of a job or divorce but some other common crises could be a sudden relocation, loss of a loved one, or even a traumatic event. At these points in life, people benefit from avoiding quick, imprudent decisions so depression comes in as a catalyst for uninterrupted rumination by diminishing excess stimuli. In this case: pleasure (Young, 2003). This may seem counterproductive but ultimately it’s a short-term sacrifice for a long-term gain.
When one reads “long-term gain,” in reference to depression, it very difficult to imagine how that might come about. As previously stated, depression developed to allow for extended and uninterrupted thought surrounding complex issues but who’s to say it’s beneficial in the end? Andrews and Thomson (2009) describe a 2003 study that had participants analyze a chart depicting 3 years of daily closing prices of Deutsche Marks and Swiss Francs on the Dow Jones. With careful consideration, participants could make good predictions about the general movement of the prices. Success was measured by accuracy, through buying or selling the correct currency each round, as well as profit, based on how much was invested and how much was returned. The participants’ moods were manipulated through falsifying the feedback of just the first round, thereby creating a happy subset (who made a high profit), a sad subset (who took a significant loss), and a neutral subset (who broke even). After this, the mood was maintained through playing happy, sad, or no music respectively. They go on to explain how the happy subset had the worst returns in both accuracy and profit, the neutral subset wasn’t very accurate but made a profit because they invested more, and the sad subset did the best with the highest accuracy and more conservative investments (Andrews & Thomson, 2009). Sad participants, while more unsure about their original decision making, exercised caution in order to make the best decisions. The financial frivolousness of the happy and neutral subsets juxtaposed with the caution exercised by the sad subset shows us how sadness allows us to focus in on a problem to better understand it and more successfully resolve it.
For those readers who are depressed and are now feeling very confident that they could go into their next economics exam and have a huge leg-up on the rest the class: it’s not that simple. Though depression is a tool that the human brain uses for processing intricate dilemmas, it can without a doubt be extremely disadvantageous as well. According to Watson and Andrews (2002), the current medical perspective is that “depression is maladaptive.” In other words, the costs of the trait outweigh the benefits. They do suggest that perhaps at one point in time depression did have benefits that outweighed the costs, such as in primitive times mentioned earlier, though it no longer does. Young (2003) theorizes the cause for this phenomenon is “genome lag.” Essentially, because human civilization and technologies evolved so quickly, our biology hasn’t gone through enough generations to properly rid us of what we now think to be an extraneous biological trait. Furthermore, Andrews and Thomson (2009) found that in a study of “laboratory tasks of cognition… Relative to non-depressed controls, depressed people tend to recall fewer autobiographic memories in response to cue words and report more overgeneral memories,” however, when the depressed individuals were given an extra task beforehand, the disadvantage relented. Similarly, when giving a reading comprehension task preceded by another distracting task, the disadvantages of depressed participants once again subsided. When they were asked to concentrate on their ruminations before the task however, the disadvantage was actually intensified (Andrews & Thomson, 2009). Though depression does allow for considerably more deep thought, these ruminations can get in the way of doing much easier, more routine tasks as one can see evidenced in these studies. It’s very difficult to call depression a cognitive advantage when the most simple things one needs to do to keep themselves alive and healthy are the most difficult.
Just like any other biological trait, depression is a tool. Humans use it to slow down and reflect on issues that could be potentially detrimental to their well-being but as human social groups have expanded to include enormously larger amounts of people, depression itself has become more detrimental to some peoples' survival than the original issues at hand. Symptoms include “depressed mood lasting most of the day, nearly every day; diminished interest or pleasure in almost all activities; insomnia or hypersomnia; significant weight loss or gain; fatigue or loss of energy; feelings of worthlessness and inappropriate guilt; diminished ability to think or concentrate; indecisiveness; and recurrent thoughts of death and suicidal ideation,” (Young, 2003). While a much more moderate form of these symptoms may help baboons get past losing their spot in the congress, with the industrialized world today and the potentially life threatening severity of some depressive symptoms, it has become a serious disadvantage for modern humans.
Andrews, P. W., & J.A. Thomson.
2009 The bright side of being blue: Depression as an adaptation for analyzing complex problems. Psychological Review, 116(3): 620-654.
Watson, Paul & Paul Andrews.
2002 Toward a revised evolutionary adaptationist analysis of depression: The social navigation hypothesis. Journal of affective disorders, 72: 1-14.
2003 Evolutionary narratives about mental disorders.
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