Your mood swings may give you an evolutionary advantage

Hmmm really? Let us do some critical thinking here. You are studying evolutionary psychology and the claims that many human behaviours have evolved over time to ensure the survival of the best adapted to our environment. While this theory, based on Darwin’s theory of physical adaptations offering an evolutionary advantage, has a strong band of proponents, the most fundamental flaw is that it often relies on speculations about what might have happened in the distant past.

This recent media post regarding a new study suggesting that moodiness may actually be “an evolutionary relic that may have been advantageous for early humans” is an example of just such speculation.

A study, conducted by a team at UCL and published in Trends in Cognitive Science, found that mood influences our perception of reward outcomes “such that outcomes are perceived as better when one is in a good mood relative to when one is in a bad mood.” This is logical – we feel better about what happens to us when we are in a good mood, and this then reinforces our good mood. However, the researchers conclude that “The ubiquity* of moods and the extent of their impact on our lives tells us that, throughout the course of evolution, our moodiness must have conferred a significant competitive advantage… the ability to adapt quickly when facing momentous environmental changes.” (*ubiquity = in this use, is the fact that all humans have moods).

So – they are arguing that because we have moods, and because those moods influence our perception of our environment at any one moment, therefore moods are adaptive and give an evolutionary advantage. Does this make sense? Do we know that our ancestors had moods? Breathing is ubiquitous amongst humans and definitely confers an evolutionary advantage; do we really have the evidence that moods do the same?

There has been research into the effect of a sad mood on cognition, and you will look at the effect of the hormone cortisol on mood and cognition when studying Abnormal Psychology. The link between mood and cognition has been supported by controlled studies. But the leap to then saying this is adaptive behaviour is a leap of faith rather than one founded on empirical evidence.

When looking at the research on disgust this week, consider this: studies suggest that pregnant women feel a higher level of disgust at certain foods during their first trimester. Evolutionary psychologists say that this is to protect the baby. Yet elderly people, whose immune system is weaker than that of younger people, feel less disgust than most. Wouldn’t we expect the elderly to feel more disgust, to protect their frailer bodies from the devastating effects of food poisoning, for example?

This is also a useful example for TOK of a logical fallacy. Think about it!

This post was inspired by Dr Laura Swash.