Evolutionary Theory of Depression

The key assumption of the evolutionary approach is that behaviours and skills studied by modern psychologists evolved in a very different environment, the environment of evolutionary adaptation, (EEA). This means that behaviours which appear to be detrimental to survival in society today may have been highly adaptive thousands of years ago, increasing probability of survival, social and reproductive success. This results from the genome lag, or the fact that our genetic inheritance lags behind our rapidly developing environment.

  • Think about the prevalence of depression across all human cultures, what does this suggest about the function of depressive symptoms?
  • Look back at the clinical characteristics of depression; in what situations would these behaviours improve fitness?
  • Could any of these symptoms be helpful to our hunter-gatherer ancestors on the African savannah?

The Social Competition Hypothesis – Price et al (1994)

Depressive symptoms have evolved as a response to loss of position or status following a conflict.  For example, humans who showed submissive behaviours in a conflict situation were able to exit the situation before sustaining further injury, successfully signaling to the stronger opponent that they were defeated. The function of depressive symptoms may therefore be described as ‘damage limitation’.

Depressive symptoms allowed the defeated opponent to accept the loss and adjust to their subordinate role in the dominance hierarchy, or ‘pecking order’ within the social group. This also preserves stability within the social group, which is necessary for the group to function successfully, thus increasing each individual’s fitness.

Some innate behaviours (fixed action patterns) cut in automatically when triggered by certain environmental stimuli, (innate releasing mechanisms).  The symptoms of depression could be explained in this way, that in the presence of certain stimuli which are indicative of ‘loss’, a set of involuntary (reflexive) submissive behaviours come into operation, which reduces

  • the individual’s level of aspiration
  • the probability of the individual continuing to engage in a futile battle

This means that in our modern day environment, certain loss situations, (e.g. redundancy, marital breakup) might trigger behaviours which may be maladaptive.

Evaluation of social competition hypothesis

There is evidence from twin, adoption and familial studies to suggest that  depression may be, at least in part, genetic and this suggests that depression may have served some function in our EEA.

  • Give an example of a study which supports this…
  • This type of research should be viewed with caution however, as …

Brown et al (1995) describes clinical evidence of cases of depression brought about through social competition which have lifted through reconciliation and restored social harmony.

This is an important finding as it not only supports that social competition may have caused the depression but in practical terms it suggests that in order to alleviate depressive symptoms, individual’s should…

Evolutionary arguments are infamously difficult to test scientifically, however, Gilbert and Allen (1998) have presented correlational data which suggests that in groups of normal and depressed patients, feelings of entrapment and depression were positively associated.

  • However, one has to be cautious of correlational studies which …
  • In this study entrapment may be the cause of the depression, however, depression may also cause feelings of being trapped because…


Although depression could be adaptive, this detracts from the devastating negative aspects of the depression in the modern world. Depression is also plausibly explained through cognitive and behavioural theories, bio-chemical imbalances etc each of which has been successfully applied through a variety of treatments which have helped sufferers to regain quality of life; evolutionary theory does not offer any comprehensive strategies for treatment. However, we should also be aware that just because a treatment programme alleviates symptoms, this does not necessarily mean that the principles on which the programme is based have caused the problem in the first place.

This is known as The T…………………………/A…………………………….F………………………..

Social Navigation Hypothesis – Watson and Andrews, (2002)

Depression has two complementary social problem solving functions:

  1. The Social Rumination Function

Cognitive demands increase at times such as divorce or bereavement when individuals require time and effort to think matters through. Limited cognitive resources are focused on planning ways out of complex social problems. Decreased involvement in usual social, leisure and work activities allows the individual to focus on ‘priorities’.

Social rumination theory can be seen as a valid and plausible account due to its ability to explain key clinical characteristics and research findings. For example,

The key clinical characteristic of ‘anhedonia’ (loss of pleasure derived from previously enjoyed activities) is well explained by this theory.

Hartlage et al (1993) demonstrated that depressives exhibit diminished performance on cognitively demanding tasks of non-social nature (e.g. IQ tests, memory tasks). Social rumination theory would explain this finding by suggesting that the depressives were…

Research by Gannon et al (1994) has demonstrated that depressives demonstrate enhanced analysis of social information and pay more attention to the processing social information and this supports the social rumination function of depression.

The evolution of the depressive attributional style: Depression may be so prevalent because depressive people are actually more accurate in their social and self perception and this enhanced ability to ‘read’ social situations may bestow social and reproductive success.

This is idea is explained by the fact that non-depressed people tend to exhibit what is termed the ‘self serving bias’ – they attribute success to their personal ability and failure to chance or lack of effort. Depressives, on the other hand, use the depressive attributional style, attributing success to chance or environmental circumstances and failure to personal factors.

This could be said to be a distortion of reality, however, Ackermann and DeRubeis, (1991) have shown that depressives may in fact be more accurate in their self perception. In our EEA this might have been adaptive as recognising personal weakness would encourage withdrawal from certain activities which could be dangerous, whereas today, the withdrawal from social activities may confer no survival disadvantage and in fact cuts off important sources of social support.

  1. The ‘social motivation’ function 

Depressive behaviours are adaptive because they provide an honest ‘signal of need’ to others and some partners/significant others will be willing to help, e.g. to increase inclusive fitness.

Depression is costly to not just the individual but to the other individuals and social group as a whole (threatens natural and sexual selection) and therefore showing depressed behaviour should elicit help from others in order that the whole social group is not affected; social extortion hypothesis – help me or you will lose out’.


Suicide attempts stop as social relationships improve (Hawton and Fagg, 1992); the greater the risk of death the greater the social motivation incurred. Link to extortion hypothesis.

Like all the evolutionary accounts of depression, the hypothesis sidelines the negative experience of depression for the sufferer; the focus on the possible positive advantages for people living 35000-3 million years ago is unlikely to provide much comfort for the sufferer. In fact, Watson and Andrews would argue that any therapeutic approaches designed to reduce suffering may be irresponsible since they mask the functions of a potentially adaptive behaviour.

One positive aspect of the theory may be that it encourages us to think about the functions served by the depressive behaviour, and from a Behaviourist approach, this leads us to possible treatment goals which can treat the cause and not just the symptoms; the suggestion is that we need to help sufferers to learn alternative behaviours which will help them to gain social support at times of need, such as improving social communication skills.

What would Watson and Andrew’s think about anti-depressants?

They would be anti-medication because anti-depressants would hinder the social motivation function of depressive behaviour.

They would see anti-depressants as more beneficial to the depressive’s family and friends as it would decrease ‘extortion’ of their time and effort, thus improving their quality of life (typical selfish argument of evolutionary psychologists)

They might see anti-depressants as a form of social control which makes individuals fit back in again with social harmony and stop causing a nuisance to others. Of course this detracts from the cause of the depressive behaviour which is to signal a real need for support and/or ‘problems in living’, Thomas Szasz who reject the medical model of mental disorder.

depressionadapt: Further Reading
evolution-of-depression Copy of the text above as a handout.
Maybe useful to help build your essay (old AQA plans so not tailored to IB mark scheme but content and structure are very similar)


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© Amanda J Wood, 2016-2017