Ignorance, ideology and… voodoo?

Earlier this year I was sat in a qualitative research methods lecture when the lecturer asked what area of psychology I am interested in. When I mentioned evolutionary psychology (EP), he smiled and said how ridiculous it is to think one can validly research human behaviour from an evolutionary perspective. On another occasion, during a conversation with a fellow student, human evolution was described as 'voodoo' and impossible to prove. I wholeheartedly disagree with these viewpoints. In fact, I find it strange that anyone could dismiss the idea that humans' evolutionary past has vastly influenced our contemporary individual and collective behaviour. Why is it, then, that EP gets such a hard time?   

From Darwin to denial

The theory of evolution is a well-established yet contentious topic. The English naturalist and biologist Charles Darwin (1809-1882) is often credited as the father of evolutionary theory, which was first outlined in his revolutionary 1859 book On the Origin of Species. Darwin's theory, evolution by natural selection, assumes that complex life has gradually evolved from more simplistic ancestors over long periods of time. As genetic mutations randomly occur within a population, the beneficial mutations perpetuate because they are more likely to be passed on to subsequent generations, and the accumulation of these mutations en masse results in the generation of new, independent species.  

All good so far – now for the controversial bit. Evolution is also assumed to be responsible for differences within species. Whilst this is not controversial for other organisms – no-one seems to deny, say, the evolved sexual size difference in elephant seals and chimpanzees – it tends to incite a stronger reaction when applied to humans. To take the same example, human males have evolved to be physically bigger and stronger (on average!) than females. This is commonly linked to the different roles adopted by males and females in our evolutionary past, often discussed in relation to sexual selection (Pawlowski et al., 2000).  Similarly, in a more psychological example, sex drive in males is typically higher in unmarried compared to married men, and in men who have not yet had children compared to men who have. This is hypothesised to show a shift in cognitive resources away from mating and parenting goals once they are satisfied, and is dictated by testosterone levels (Burnham et al., 2003; Gettler et al., 2011).

An abundance of research along these lines has explored evolutionary differences in humans, both physical and psychological, and it is within this domain that much of the controversy relating to evolutionary theory is seen. My own experience as a student has revealed just how averse some branches of psychology and the social sciences are to their evolutionary counterpart. Whilst lecturers and fellow students do not seem to disagree with the concept of evolution, its application to human behaviour is often met with scepticism and, in some cases, denial.  

Traditionalist views?

One common argument is that EP has been used as a vehicle to justify traditionalist views of gender, race and sexuality, thus hindering the progress of female, non-white and homosexual individuals in society. This is based on the idea that the study of human behaviour from an evolutionary perspective is founded in the prejudiced agenda of evolutionary theorists, who wish to position others as inferior to themselves. 

An oft cited example of this is the work of Herbert Spencer (1820-1903), who coined the phrase 'survival of the fittest' yet has also been accused of promoting sexist notions such as women being stunted versions of men. Indeed, this is a ridiculous idea, and it is not hard to see why some may jump to conclusions based on notions such as this. Nevertheless, Spencer wrote this in 1860, when On the Origin of Species was less than a year old, William James was still a student, and the right to vote for women in the UK was half a century away. Even the more recent contentions remain a healthy lifetime away.  

It was not just academia that was sexist, racist et al. – society was. Those days should not be used to criticise EP in the 21^st century. Contemporary EP, when done right, provides a powerful tool for exploring human behaviour through the generation and testing of novel hypotheses – any insinuations of injustice are entirely independent of the scientific value of EP. Recent research exploring gender differences from an evolutionary perspective has demonstrated this (see Stewart-Williams, 2014). 

In any case, all these critics really say is that EP fails to align with their own ideological stance. Unfortunately, this practise of criticising theory and research based on its potential socio-political implications is becoming ever more common, and EP seems to be taking one of the biggest hits. Some branches of the social sciences are arguably evolving to the point where they no longer identify as science, and where knowledge is discounted in favour of social justice. This was recently demonstrated by the controversial 'grievance studies hoax', which exposed the culture of unscholarly practice in disciplines such as 'gender studies' and 'fat studies' through the publication of hoax papers (Lindsay et al., 2018). It is no wonder that EP falls foul in the eyes of many when its critics are driven by ideology, not data.  

No proof?

Another common criticism of EP is that there is no proof of evolution impacting human behaviour, largely because we have not actually observed the human evolutionary process. My aforementioned course-mate, who described EP as 'voodoo', seemed to take this stance, alongside a surprisingly large section of psychology students. 

This is a more valid criticism and the arguments are somewhat better developed, although I do not necessarily agree with them. Such an argument presupposes that we must observe something to 'prove' it, yet this is patently at odds with many areas of science – would the same critics deny the existence of gravity, or the big bang? As far as I am concerned the evidence for EP is overwhelming. Taxonomy has shown us that the genetic makeup of every species, plant and animal, collates to form a near-perfect evolutionary family tree, one that humans seamlessly fit into. Furthermore, recent research in EP has provided strong evidence for evolutionary concepts including adaptive memory; the relative mnemonic advantage for stimuli processed in relation to evolutionary fitness (Nairne & Pandeirada, 2008); and evolved navigation theory, the tendency for humans to estimate the size of a vertical drop as greater from the top, due to the evolutionary consequences of falling (Jackson & Cormack, 2007).  

The research investigating adaptive memory and evolved navigation theory are both good examples of EP research 'done right' – they use unassuming experimental designs to test hypotheses which are drawn from theory. To take another, perhaps more innovative example, researchers at the University of California found that the impression of being watched – manipulated by displaying a pair of eyes on a computer screen – increased generosity in an economic game almost twofold compared to controls. This was in line with their prediction that the impression of being watched would lead to greater prosocial behaviour due to human perceptual systems being tuned to detect cues indicating the presence of others, meaning that behaviour can be adjusted accordingly. Using an evolutionary perspective, we can ascertain that this tendency evolved because of the social repercussions of being viewed by others as selfish. (Haley & Fessler, 2005). 

Not all good EP research is lab-based, though. A recent longitudinal study of the Tsimane people of Bolivia, spanning eight years, investigated how cooperation and social status are related in human groups. It was revealed that higher-status individuals within a group tend to cooperate with more people, and that individuals gain status by cooperating with those of a higher status than themselves (von Rueden et al., 2019). Again, the researchers tested their hypothesis using a robust research design, and we have learnt more about human behaviour as a result!

More clarity needed

The question remains: what can we do to alleviate the hostility shown towards EP? Firstly, I think the issues mentioned in this piece need to be addressed.  Evolutionary psychologists are often inclined to turn their noses up at any accusation of promoting inequality, and I understand why, it's a deeply fallible claim. However, this does not help to solve the problem of unscientific political arguments being used to criticise robust EP research. I believe the best way to deal with this is to embrace more evidence-based discussion between fields.  Notably, I think evolutionary psychologists need to provide more clarity on the nature of differences they discuss. A possible remedy would be to include a short section at the start of any EP materials which explains how average differences work, and to routinely include the 'on average' caveat. I am also a strong advocate for EP to be a permanent fixture in all undergraduate psychology courses. The many misconceptions about EP, including the supposed lack of proof, could easily be addressed in lectures and seminars. We devote ample time to issues in other areas of psychology, so why not extend this to EP?  

Ultimately, evolution is one of the great scientific concepts; it tests theory against data, marries genetics and the environment, and explains previously baffling aspects of human behaviour. Although it is not perfect, psychology's ignorance towards EP has hindered our shared goal of understanding human behaviour. Whether that ignorance is born out of the illusion of social justice or a lack of understanding of the literature, as a community we have a duty to embrace EP. With civilised and informed debate, the empirical method, and ultimately plain common-sense, will triumph.

References

Burnham, T. C., Chapman, J. F., Gray, P. B., McIntyre, M. H., Lipson, S. F., & Ellison, P. T. (2003). Men in committed, romantic relationships have lower testosterone. Hormones and Behavior, 44(2), 119–122. https://doi.org/10.1016/S0018-506X(03)00125-9

Darwin, C. (1859). On the Origin of the Species by Natural Selection. Murray.

Gettler, L. T., McDade, T. W., Feranil, A. B., & Kuzawa, C. W. (2011). Longitudinal evidence that fatherhood decreases testosterone in human males. Proceedings of the National Academy of Sciences of the United States of America, 108(39), 16194–16199. https://doi.org/10.1073/pnas.1105403108

Haley, K. J., & Fessler, D. M. T. (2005). Nobody's watching?: Subtle cues affect generosity in an anonymous economic game. Evolution and Human Behavior, 26(3), 245–256. https://doi.org/10.1016/j.evolhumbehav.2005.01.002

Jackson, R. E., & Cormack, L. K. (2007). Evolved navigation theory and the descent illusion. Perception & Psychophysics, 69(3), 353–362. https://doi.org/10.3758/BF03193756

Lindsay, J. A., Boghossian, P., & Pluckrose, H. (2018, October 3). Academic Grievance Studies and the Corruption of Scholarship. Retrieved 22 April 2019, from Areo website: https://areomagazine.com/2018/10/02/academic-grievance-studies-and-the-corruption-of-scholarship/

Nairne, J. S., & Pandeirada, J. N. S. (2008). Adaptive Memory: Remembering With a Stone-Age Brain. Current Directions in Psychological Science, 17(4), 239–243. https://doi.org/10.1111/j.1467-8721.2008.00582.x

Pawlowski, B., Dunbar, R. I. M., & Lipowicz, A. (2000). Tall men have more reproductive success. Nature,403(6766), 156–156. https://doi.org/10.1038/35003107

Stewart-Williams, S. (2014). The Sticking Point: Why Men Still Outnumber Women in Science. Retrieved 1 October 2019, from Psychology Today website: http://www.psychologytoday.com/blog/the-nature-nurture-nietzsche-blog/201402/the-sticking-point-why-men-still-outnumber-women-in

von Rueden, C. R., Redhead, D., O'Gorman, R., Kaplan, H., & Gurven, M. (2019). The dynamics of men's cooperation and social status in a small-scale society. Proceedings of the Royal Society B: Biological Sciences, 286(1908), 20191367. https://doi.org/10.1098/rspb.2019.1367