The Meme Machine

48 THE MEME MACHINE
learning that is influenced by observing, or interacting with, another animal or
person. Imitation is one form of social learning but there are others that are not
truly imitative. Animal researchers have recently made considerable progress in
distinguishing between these kinds of learning, and finding out which animals
are capable of true imitation (Hayes and Galef 1996). The results have been
surprising.
In 1921, in the south of England, tits (small garden birds) were seen prising
open the wax-board tops of milk bottles left on the doorstep. Subsequently, the
habit became widespread across England and some parts of Scotland and Wales,
with other species of bird joining in, and foil tops being pecked as well. That
the tits learned from each other was suggested by the way the trick spread
gradually from village to village, and across different areas, although it was
obviously independently reinvented many times (Fisher and Hinde 1949). With
the advent of supermarkets and cardboard cartons, the bottle left by the milkman
is becoming rare, but even today you will occasionally find your silver top
pierced.
The spread of milk bottle pecking was a simple cultural phenomenon but
purists would argue that it was based not on imitation, but on a simpler kind of
social learning (Sherry and Galef 1984). Imagine that one bird learned, by trial
and error, that there was cream to be had by pecking at the bottles. Then another
bird chanced by and saw the pecking and the obviously pecked top. Pecking is a
natural action for tits and now that the attention of the second bird had been
drawn to the bottle it was more likely to land on it and peck too. Reinforcement
in the form of nice tasty cream would lead this bird to repeat the action and
possibly be seen by other birds, and so on. The fact that the birds used lots of
different methods for opening the bottles also suggests they did not learn by
direct imitation.
This kind of social learning is sometimes called ‘stimulus enhancement’ – the
stimulus, in this case the bottle top, has become more readily noticed. Similarly,
‘local enhancement’ is when attention is directed towards a specific place.
Animals also learn from each other which objects or places to fear or ignore.
For example, young rhesus monkeys learn to avoid snakes after seeing their
parents react fearfully to a snake, and octopuses will attack something they have
seen others attacking. Birds and rabbits learn not to fear trains by following
others who are not afraid, and therefore become used to the frightening noise.
Oystercatchers open mussel shells by either stabbing or hammering techniques
according to their tradition, and birds learn to choose migration routes and
nesting sites from other birds (Bonner 1980, gives many interesting examples).
But none of these processes is true imitation because no new behaviours are