The Meme Machine

THE LIMITS OF SOCIOBIOLOGY 117
begin to starve. Therefore, genes for good jumping or strong back legs spread in
the gene pool and soon all the creatures are more like frogs. Jumping improves
and the selection pressure now favours even higher leaps. Behaviour has, in a
perfectly Darwinian fashion, affected selection.
Now imagine that the flies vary in appearance and goodness to eat. Let us
suppose that striped flies are inedible while spotty flies are excellent food.
Froglings that prefer spotty flies will be at an advantage and so the mechanisms
required for preferring spotty flies, such as sensitive spot detectors in the visual
system, will spread. However, it might be the case that the pattern on the flies
changes faster than frogling evolution can track. In this case it will pay the little
frogling: to be able to learn which flies to eat. Any frogling that cannot learn
will be at a disadvantage and so genes for a general ability to learn will spread.
This is the Baldwin effect.
As Baldwin himself puts it – the highest phenomena of intelligence,
including consciousness, the lessons of pleasure and pain, maternal instruction
and imitation, culminate in the skilful performances of human volition and
invention. ‘All these instances are associated in the higher organisms, and all of
them unite to keep the creature alive . . . By this means those congenital or
phylogenetic variations are kept in existence, which lend themselves to
intelligent, imitative, adaptive, and mechanical modification during the lifetime
of the creatures which have them. Other congenital variations are not thus kept
in existence.’ (Baldwin 1896, p, 445, italics in the original.) In more modern
terms, genes for learning and imitation will be favoured by natural selection.
Baldwin thus saw that natural selection, without need of the inheritance of
acquired characteristics, could account for the evolution of the capacity to learn.
The Baldwin effect creates new kinds of creatures that are capable of adapting to
change far more quickly than their predecessors. But this is not the only step in
this direction. Dennett explains, using his metaphor of the ‘Tower of Generate
and Test’, an imaginary tower in which each floor has creatures that are able to
find better and smarter moves, and find them more quickly and efficiently
(Dennett 1995).
On the ground floor of Dennett’s tower live the ‘Darwinian creatures’. These
creatures evolve by natural selection and all their behaviour is built in by the
genes. Mistakes are very costly (unsuccessful creatures have to die) and slow
(new creatures have to be built each time).
On the next floor live the ‘Skinnerian creatures’, named after B. F. Skinner
(1953) who explicitly saw operant conditioning (learning by trial and error) as a
kind of Darwinian selection. Skinnerian creatures can learn. So their behaviour