Social Intelligence Hypothesis Flashcards
Introduction:
define the two hypothesis
There are two hypothesis proposed to explain the adaptive pressures that led to the rapid expansion of the human brain. Technical Intelligence Hypothesis (T.I.H.) states that early hominids needed to be intelligent to make tools and weapons in order to survive on the open savannah. On the other hand, Social (Machiavellian) intelligence hypothesis suggests that the evolution of human intelligence came about by the selective pressure to out compete the members of one’s own social group.
Machiavellian intelligence
Byrne & Whiten (1988), proposed that evolutionarily inherited social intelligence is Machiavellian or selfish. Thus, if the ability to engage in clever social tactics is based on an inherited trait of social intelligence, as long as those tactics promote the tactician’s reproductive success then the trait will be maintained in the population. Even if a tactic, such as cooperation, seems “nice” or unselfish on the surface, to be selected it must in the long term promote the reproductive success of the cooperators - if the behaviour is an evolved predisposition, it must be gene-selfish.
suggestion of social intelligence hypothesis
The suggestion of social intelligence hypothesis is that the main adaptive pressure for brain expansion and cephalisation, which is assumed to correlate with intelligence in primates, is social competition. Any given individual in a group that is more able to engage in cooperative behaviour with cooperative alliances, or outsmart their social rivals is going to enjoy a benefit and this may translate into reproductive successes. If that’s the case, then larger brains that might be needed for these types of social abilities are going to be more representative in future generations so there is a kind of adaptive selective pressure.
neocortex to brain size ratio: evidence
neocortex to brain size ratio
If we assume that neocortex to overall brain size ratio is related to higher reasoning, there is more correlational evidence in support of social than technical intelligence. Dunbar (1992) found no correlation between neocortex/brain size ratios in primates and: a) degree of extractive foraging b) home range size and day journey length (adjusted for body size since large animals need large territories to find sufficient food) nor c) amount of fruit in the diet. However, Dunbar (1992, 1995) did find a positive correlation between neocortex/brain size and group size in primates (monkeys and apes). A similar correlation has been found in carnivores. Hence, if one lives in a large social group in which one needs to cope with many social relationships, then one might assume that one will need higher “computing power”. Deception is a typical Machiavellian tactic. Hence, Byrne (1995) provided strong support for the S.I.H. when he found a positive correlation (0.77) between levels of deceptive behaviour and neocortex/brain ratios in primates.
neocortex to brain size ratio: criticism
However, Dunbar is assuming that increasing group size will promote social intelligence. Many fish and bird species live in big groups, but we don’t tend to think of them as particularly intelligent and most of them are not very big brained. Why haven’t they evolved advanced social intelligence?
Evidence of Social intelligence in humans
Social intelligence can be detected in the social behaviour of young children as well as adults. Dodge et al (1986) studied peer group entry. It was found that children experienced 95% success when they used many staged tactics, which demonstrated sensitivity to the group’s frame of reference. Children only experienced 20% success by making a claim on objects or just barging in. Suggesting signs of social intelligence in young children.
However, comparing social and non-social cognition can be problematic because it is difficult to equate the input for such things as familiarity and salience (most noticible) and subject motivation to solve the task.
Evidence of Social intelligence in humans: better procedure
However, recent studies on how people solve The Wason Selection Task are largely free of this problem. It is a logic puzzle in which there are four cards, a simple rule, and the participant has to work out which cards need to be turned over to see if the rule has been broken. The original results found that less than 25% of participants correctly solved the task for the abstract problem and around 75% did so for the social problem. The Wason Selection Task has been used to show that adult humans perform better when a logical problem is set in a social context versus non-social. Hence, there is some evidence to support the idea that people have advanced social intelligence compared to other types of reasoning.
Alternative views
If intelligence is not a unitary thing (as Byrne 1995 and many others argue) then more than one factor may have lead to its evolution. Certain factors (such as social or technical) may have been more important than others, perhaps at different times in our evolution. Byrne (1995) suggests that when primates first evolved, social challenges might have promoted greater neocortex size (primates as an order have higher EQs compared to other groups). However, apes seem to differ from monkeys in EQ and cognitive complexity, but they live in comparably sized and similarly complex groups. Hence, Byrne (1995) proposes that technical more than social challenges might have promoted intelligence in apes over monkeys. But what about the spurt in human brain size, it more than tripled in size compared to the other apes? Byrne argues that language must have been an important factor, but of course language can be used to serve both technical and social roles. Whiten and Byrne (1997) conclude that, “it may be that interactions between various selective pressures, were crucial in selecting for intelligence, rather than one in isolation. It is even possible that different pressures, social and non-social, have resulted in a legacy of separate ‘intelligences’ within one brain at the same time”.
