The Meme Machine

THREE PROBLEMS WITH MEMES 57
First, we may assume that, at least at some phase in their replication, memes
have to be physically stored in brains. As far as storage is concerned
neuroscience is making great strides in working out the biological basis of
memory. Artificial neural networks have demonstrated that many of the features
of human memory can be simulated in computers. Work on synaptic
transmission, long-term potentiation and neurotransmitters is finding out
whether real brains do anything similar. If they do, we may guess that human
memory probably works something like this (for example, see Churchland and
Sejnowski 1992).
Neural networks in the brain consist of large agglomerations of individual
cells with a layer of cells taking input (e.g. from the eyes, or from another
network), another layer providing output (e.g. to the muscles, the voice, or
another network), and many layers in between. Each neuron has connections to
many others and the strength of these connections varies according to their
history. At any given state of the network a certain kind of input will produce a
certain kind of output but this relationship is not fixed. The network can be
trained, for example by consistently pairing certain sorts of input, and this
experience changes its responses to new inputs. In other words, it can
remember.
This kind of memory is nothing like the memory of a digital computer, with
its fixed locations, nor like a tape recorder with its more or less faithful
duplication of everything fed into it. In a brain, every input builds on what went
before. In a lifetime of complex experiences we do not store each one away in a
black box to be retrieved later when we need it – rather, every experience comes
into a complex brain and has a greater or lesser effect on what it finds there.
Some things have virtually no effect and are completely unmemorable (we could
not function otherwise). Some have enough of an effect to stay briefly in shortterm
memory but are then lost, while some lead to dramatic changes so that
precise events can easily be reconstructed, whole poems recited or that special
face never forgotten.
Effective memes will be those that cause high fidelity, long-lasting memory.
Memes may be successful at spreading largely because they are memorable
rather than because they are important or useful. Wrong theories in science may
spread simply because they are comprehensible and fit easily with existing
theories, and bad books may sell more copies because you can remember the
title when you get to the bookshop – though, of course, we do have strategies for
overcoming these biases. An important task of memetics will be to integrate the
psychology of memory with an understanding of memetic selection.
Some people argue that memes are not digital (Maynard Smith 1996) and