a long time. Paleolithic foragers used ochre, probably for purely aes-
thetic reasons. In the same way, our visual system is sensitive to sym-
metries in objects. Bilateral symmetry in particular is quite important;
when two sides of an animal or person look the same it means that they
are facing you, a relevant feature of interaction with people but also
with prey and predators. Again, you cannot find a human group where
people do not produce visual gadgets with such symmetrical arrange-
ments, from the simplest makeup or hairdressing techniques to textile
patterns and interior decoration. Finally, our visual cortex includes spe-
cialized subsystems that quickly identify objects in terms of kinds rather
than individuals, as well as other systems that are more interested in the [133]
location and motion of these objects. Artificial stimulation of either or
both of these systems—in other words, figurative art—has a long his-
tory too, as we know from the spectacular displays of Paleolithic cave
paintings like those at Chauvet or Lascaux.^37
These activities recruit our cognitive capacities in ways that make
some cultural artifacts very salient and likely to be transmitted. These
salient cognitive artifacts can be extraordinarily primitive, like glass
beads or pieces of shiny metal whose only merit is to provide an unusual
visual stimulus. But ideas too and their abstract relations can constitute
such artifacts. Jokes recruit our reasoning capacities and our expecta-
tions about situations, ending with a punch line that forces us to recon-
sider the whole situation from a new angle; paradoxes fascinate because
there seems to be no way of escaping an unacceptable conclusion.
Once we understand how brain evolution resulted in the design of
a brain with these particular inference systems, we can better under-
stand why humans are sensitive to theseparticular artifacts rather than
others. That there are pure tones in music and symmetries in visual art
is certainly no coincidence, given the way our brains were designed by
evolution.
Turning to the domain of supernatural concepts, such evolutionary
reasoning may well explain certain forms of magical beliefs. For
instance, in many places in India it would be highly polluting to share
food with a member of some low castes, say a tanner or blacksmith.
Indeed the whole household would need serious ritual cleansing. Most
people there have no idea whyit would be polluting or in what particular
waythis pollution would affect them, but they will certainly avoid such
situations. To take a less extreme example, mixing flesh and milk in a
dish will make the whole food impure, as far as traditional Jewish regu-
lations are concerned. But again there is no description of why this is so.
THE KIND OF MIND ITTAKES