Intelligence and cognitive abilities in general are elements that have been deeply studied throughout the history of psychology, being something that has fascinated human beings since ancient times. Solving problems, knowing how to adapt to the environment and generate strategies and act efficiently allow both human beings and other species to survive and cope with environmental demands.

Traditionally, intelligence has been considered something inherited, largely derived from genetics and partly from our development throughout pregnancy and childhood. But it is not until relatively recently that we have begun to talk about intelligence as something that has appeared thanks to socialization. This is what is proposed by the hypothesis of social intelligence or the social brain .

This is the hypothesis of social intelligence

The hypothesis of social intelligence, developed and defended by Humphrey, proposes that intelligence and cognitive development is promoted by the fact of having to manage increasingly complex social relations . This hypothesis arose from the author’s observation of the behaviour of primates in captivity in their day-to-day lives, concluding that their social dynamics explained and promoted part of their cognitive development. We are not talking about the concept of social intelligence itself but about the emergence of intelligence as something social.

This hypothesis is based on evolutionary psychology , and insinuates that in fact the development of the cognitive capacities of the human species is due at least in part to the need to interact and communicate, by requiring coordination to hunt and defend against predators, or to prepare tools with these objectives. Also the establishment of hierarchies and relationships of power and submission, the expected behavior or role of each member or the learning of techniques and strategies became increasingly complex.

This theory leads to a reflection on how human beings have evolved and developed over the generations an intelligence much more based on communication and social interaction, developing increasingly complex and much more demanding societies (we go from small family tribes to villages, cities, kingdoms, empires or civilizations) that require an ever greater flexibility and cognitive capacity to manage them. A certain level of abstraction is required , which was gradually strengthened and developed as those who owned or learned them had greater reproductive success.

The Social Brain

The social intelligence hypothesis has found some evidence in favour within biology. The most evident example is that of Robin Dunbar , who collected, developed and deepened Humphrey’s hypothesis.

Throughout his research, this author reflected the existence of a correlation between size of social group of belonging and encephalization quotient, having a greater volume (and possibly density and connectivity) brain those animals with greater quantity and quality of relationships. This increase in volume is visible in the neocortex. However, the number of relationships that we can manage at the same time is limited : that is why, it is proposed in his theory, that as social demand increases little by little our species has been developing a higher level of neuronal connections and abstraction capacities.

This has allowed us to survive. The fact is that human beings lack the great elements that allow us to survive on our own: we are not particularly fast, nor are our senses excessively superior to those of other animals, nor do we possess horns, claws or a dentition that allows us a defense or hunting capacity. Nor do we have a strength or size comparable to that of possible predators. Evolutionarily, then, we have depended on our number and capacity to manage ourselves socially to survive , and later on our cognitive capacity (developed largely by our relational capacity).

Some evidence in the animal world

There is different evidence in favour of this hypothesis, largely coming from the observation of animal behaviour and from the performance of comparative studies and behavioural experiments with different animal species.

Recently the study and comparative analysis of the behaviour of some animals has come to light : specifically with Australian magpies. Different magpies were made to face a series of behavioural tests in which they basically have to solve certain puzzles (observing the problem-solving capacity) in order to get food. The experiments were carried out with magpies of different ages and belonging to different flocks, with each of the four jigsaw puzzles prepared in the tests dedicated to evaluating a specific skill (learning response-reward association and spatial memory between them). It was shown that the animal’s performance was better the larger the flock to which it belonged, as well as among the magpies that had been raised in these flocks since birth.

Thus, it is proposed that living in large groups is linked to and promotes greater cognitive performance, which in turn facilitates survival. In conclusion, those birds that live in large flocks tend to perform better in different tests proposed by researchers. These same conclusions have been reflected in studies carried out with crows, dolphins and different primate species.

In addition to the evidence found in animals, it is useful to think about our own development: the frontal part of the brain is one of the largest and slowest to develop, and is deeply linked to behaviour control and social behaviour management (especially the prefrontal region). We must also emphasize that Rizzolatti’s discovery of mirror neurons as an element that allows us to understand and put ourselves in the place of others is linked to this fact: by living in society, our behavior and the management of relationships makes the evolution of structures linked to capturing what our peers feel or refer to more adaptive. And this makes us, as a social species, more adaptive.

Bibliographic references

  • Ashton, B.J.; Ridley, A.R.; Edwards, E.K.; Thornton, A. (2018). Cognitive performance is linked to group size and affects fitness in Australian magpies. Nature [Online version]. Macmillan Publishers Limited. Available at:
  • Fox, K. C. R., Muthukrishna, M. & Shultz, S. (2017). The social and cultural roots of whale and dolphin brains. Nat. Ecol. Evol. 1, 1699-1705
  • Humphrey, N. (1998). Cave art, autism, and the evolution of the human mind. Cambridge Archaeological Journal, 8 (2), 165-191.
  • Humphrey, N. (2002). The mind made flesh. Oxford: Oxford University Press.
  • Morand-Ferron, J. (2017). Why learn? The adaptive value of associative learning in wild populations. Curr. Opin. Behav. Sci. 16, 73-79
  • Street, S. E., Navarrete, A. F., Reader, S. M. & Laland, K. N. (2017). Coevolución de la inteligencia cultural, la historia de la vida extendida, la socialidad y el tamaño del cerebro en los primates. Proc. Natl Acad. Sci. USA 114, 7908-7914.