Stories of lemurs and robots - Narrative Intelligence - page 67

telligence led to the possibility to think about people in terms of objects to be
manipulated, in a similar way as physical objects can be manipulated. Although
it is still unknown why hominids needed or chose to live in social groups, this
feedback principle soon led to the development of highly sophisticated levels of
organization and control in human societies (cf. Russell (1993)).
In non-human primate societies cohesion is maintained through time by
social grooming . Social grooming patterns generally reflect social relationships:
“The vervets clearly differentiated between the animals they groomed regu-
larly and those they didn't. A grooming partner is something special, some-
one who deserves particular attention, who should be supported in moments
of need, on whose behalf the taking of risks is warranted.” (Dunbar 1996: 22)
Given the neocortical size of modern humans, we can extrapolate from the
non-human primate regression and predict a group size of 150 for human so-
cieties. This number limits the number of relationships that an individual hu-
man can monitor simultaneously, it is the upper group size limit which still
allows social contacts that can be regularly maintained, supporting effective
coordination of tasks and information-flow via direct person-to-person con-
tacts. Such relationships are personal relationships , they have sufficient depth to
be relied on, they provide the basis of mutual support and coalition formation
that are necessary in cases of attack or the need to access resources. The num-
ber 150 is supported by evidence from analyzing contemporary and historical
human societies. Dunbar suggests that 1) there is a cognitive limit to the num-
ber of individuals with whom any one person can maintain stable relationships
(depending on personal knowledge, face-to-face interactions), 2) that this limit
(which he terms cognitive group size ) is a direct function of relative neocortex
size, and 3) that this in turn limits group size. But how do humans preserve
cohesion in groups of 150 individuals, a function that (physical) social groom-
ing serves in non-human primate societies? In terms of survival needs (resting,
feeding etc.) primates can only afford to spend around 20 % of their time on
social interactions and social grooming. However, a group size of 150 predicted
for humans would require that about 42 % of the total time budget of a human
primate are devoted to social grooming. It was therefore suggested by Dunbar
(1993) that in order to preserve stability and coherence in human societies, hu-
man language has evolved as an efficient mechanism of social bonding ,replac-
ing social grooming mechanisms in non-human primate societies with direct
physical contact (allowing only much smaller groups). Following this argu-
ment, language allowed an increase in group size while still preserving stability
and cohesion within the group.