Rutter – environment

What it means is that aspects of development, including brain development, are influenced by experiences, so that the notion that all of this is independent of what’s going on in the environment is just not right. But there are three rather different ways in which experience and brain development come together. Firstly, there are certain sorts of experiences that you have to have for normal brain development to take place. So that kind of work that Hubel and Wiesel did, for which they won the Nobel Prize, showing that you needed to have patterned visual input for the development of that part of the brain dealing with vision would be an example of that kind. But then there are other experiences which are different in the sense of functioning to adapt the brain to the environment at the time, so that the brain, like the body as a whole, is an adaptive organism and so that the brain will develop in particular ways according to the environment.  

The most clear-cut example of that is the fact that up to the age of about six months all babies throughout the world make the same discriminations between sounds. But from about six months onward, all of that changes and the Japanese babies are able to make discriminations on sounds that are in the Japanese language, English babies do it in English. So that here it’s not saying that it’s needed for normal development, it’s simply saying the brain develops according to deal with a particular environment’s experiences. But then there is the more general feature that all experiences bring about brain changes. So that the example that at least English people like to remember is the one about London taxi drivers, who have this horrendous three-year training program to learn about the streets of London, and that has effects on the size of the particular part of the hippocampus, which is a small part of the brain. So experiences in adult life also change the brain. What’s different about that though, is that it’s not, as it were, influencing the development of the brain in a way that carries on. These are things that come and go.