Biology and the social sciences parted company at a time when evolution itself was poorly understood. As a result, the social sciences left with a rather impoverished view of evolution, and therefore failed to take note of the developments that emerged later. Among these have been an appreciation of Tinbergen's “Four Whys”, Hamilton's broadening of the concept of fitness into what he termed “neighbour modulated fitnesses” and multi-level selection (as distinct from group selection). I argue that a better appreciation of some of these developments might go some way towards facilitating a rapprochement between the social and evolutionary sciences.
The social brain hypothesis offers an explanation for why primates should (a) have larger brains than other species and (b) differ so strikingly in terms of their cognitive abilities. In this chapter, I outline the social brain hypothesis and some of the evidence that has been adduced to support it, and then explore the extent to which possible cognitive constraints arising from brain volume might limit human social behaviour. I explore two particular aspects of human behaviour: the dynamics of conversation groups and social network size. Two conclusions are suggested by studies that we have undertaken. One is that there is a relationship between an individual's ability to cope with the extended layers of intentional tasks and the size of their social network. The other is that the hierarchical structure of our social networks, consisting of a series of expanding circles containing progressively more individuals, is a function of both the emotional intensity of relationships and the frequency of interaction.
Evolutionary approaches to literature can take one of two directions. One is to ask what functions story-telling serves. The second is to ask what role cognitive mechanisms play in the production of story-telling. I argue that story-telling evolved as part of the group-bonding processes that are concerned primarily with limiting the freedom of movement of freeriders within society. I then examine the extent to which stories reflect the author's intuitive grasp of the evolutionary principles that underpin human behaviour. Finally, I examine the extent to which human social cognitive capacities constrain both audience and composer in the production of stories. I argue that, to be successful, story-tellers have to work at cognitive levels beyond the norm for adult humans, and this may explain why good story-tellers are rare even though the ability to appreciate stories is universal. I suggest that an author's success may be determined both by his/her intuitive understanding of the evolutionary factors that ultimately drive human behaviour and by the extent to which he/she is able to work at the cognitive limits of the target audience.
As suggested by previous research, childlessness can thoroughly affect
the likelihood of giving and receiving help to kin, even in modern societies.
In this paper we show that childless women over thirty-five have had more recent
contact with their nephews/nieces than mothers. Yet, both groups showed no
significant differences in contact with their uncles/aunts. This suggests
heightened social investment in kin with high reproductive value by childless
women compared to mothers. Results are discussed with reference to kin
Although Duchenne smiles have been shown to have a social signal value, there is limited evidence as to whether this effect generalises to most positive attributes, or whether it is restricted to a particular social domain. As opposed to non-Duchenne smiles, Duchenne smiles involve the activity of facial muscles in the eye region (orbicularis oculi). The hypothesis that Duchenne and non-Duchenne smiles produce different responses in receivers was tested in a face perception experiment. People were asked to rate neutral and smiling faces on ten attributes: attractiveness, generosity, trustworthiness, competitiveness, health, agreeableness, conscientiousness, extroversion, neuroticism, and openness to experience. Results showed that the type of smile had a stronger impact on the ratings of generosity and extroversion. The difference between neutral and smiling was larger when faces showed a Duchenne than a non-Duchenne smile, though the effect of smile type on attributions of generosity appeared to be restricted to male faces. Therefore the Duchenne marker shows some specificity to judgements of altruism and sociability.