Of Soldiers and Diplomats

Abstract

Perhaps we cannot apply the hawk and dove model of animal behavior and its implications to endocrinology and metabolism to humans as it is. There have been a few attempts to apply these concepts to humans, but there are some problems with this approach. Sapolsky [1] thinks that socioeconomic status (SES) in humans is comparable to social dominance and subordination in animals, and therefore, lower socioeconomic strata suffer from the same health problems as low-ranking primates. There are many problems with the argument. First of all, Sapolsky himself shows that not in all animal species low social rank is associated with high corticosteroids, which is said to be one of the markers of stress-related health problems. The negative association appears to be certainly true for species in which physical strength and aggression are the most important determinants of social rank but not necessarily so in other species. In orangutans, for example, there is a clear developmental and morphometric distinction between the dominant and subordinate males. The subordinate males are “arrested” in a juvenile-like morph, although they are sexually mature. These subordinate males are aggressive and often coercively mate with females. Here, we see that unlike most other species, subordinate males do not have higher glucocorticoid levels [1–6]. This may be because glucocorticoids have a stronger negative association with aggression than with social status. Orangutans are an ideal example where there is sufficient evidence to show that “dominant” and “subordinate” are actually two distinct mating strategies of males. Here the subordinates show aggressive behavior towards females, and their corticoid levels appear to be determined by aggression rather than subordination. Therefore it appears to be not the dominance hierarchy itself but the ways of attaining it and its behavioral consequences that decide the physiological correlates. In modern human society, physical aggression is not the predominant means of attaining high socioeconomic status (SES), and therefore, SES in humans may not be equivalent to social dominance hierarchy in animals as Sapolsky claims. The other reason to doubt Sapolsky’s claim is that human data all over the world does not show the same trends across socioeconomic groups. Sapolsky refers to the picture in America where obesity and metabolic syndrome are claimed to be more prevalent in the lower socioeconomic class. But that is not necessarily the case across the globe and at all times. Even within the USA, studies addressing this question are not equivocal [7, 8]. In South Asia and Africa, T2D and CVD have been disorders of the affluent so far [9–12], although the prevalence might be rapidly increasing in lower strata recently. The third reason to doubt Sapolsky’s conclusion is that although there is no doubt that humans evolved from animals, human evolution has taken a somewhat different line with respect to cognitive, emotional, and social aspects of life. It is possible therefore that some of the concepts that we discussed in the last chapter apply to humans but others do not. Much careful reexamination of these concepts is therefore needed before we can make any inferences about behavior and physiology of humans.