Post by Tamrin on Aug 20, 2012 15:57:55 GMT 10
Unravelling Hardwiring
For decades, brain development has been thought of as an orderly adding in of new wiring that enables you to perform every-more-sophisticated cognitive functions. According to this maturational viewpoint, gene activity at the appropriate time (and with the necessary experience and environment) brings about the maturation of new bits of neural circuitry. These are added in, enabling the child to reach new developmental milestones. Everyone, of course, acknowledges the essential role of experience on development. But when we think of brain development as a gene-directed process of adding new circuitry, it’s not difficult to see how the concept of hardwiring took off. It’s been helped along by the popularity of evolutionary psychology, versions of which have promoted the idea that we are the luckless owners of seriously outdated neural circuitry that has been shaped by natural selection to match the environment of our hunter-gatherer ancestors.
But our brains, as we are now coming to understand, are changed by our behaviour, our thinking, our social world. The new neuroconstructivist perspective of brain development emphasizes the sheer exhilarating tangle of a continuous interaction among genes, brains and environment. Yes, gene expression gives rise to neural structures, and genetic material is itself impervious to outside influence. When it comes to genes, you get what you get. But gene activity is another story: genes switch on and off depending on what else is going on. Our environment, our behaviour, even out thinking, can all change what genes are expressed. And thinking, learning, sensing can all change neural structure directly. As Bruce Wexler has argued, one important implication of this neuroplasticity is that we’re not locked into the obsolete hardware of our ancestors:
But our brains, as we are now coming to understand, are changed by our behaviour, our thinking, our social world. The new neuroconstructivist perspective of brain development emphasizes the sheer exhilarating tangle of a continuous interaction among genes, brains and environment. Yes, gene expression gives rise to neural structures, and genetic material is itself impervious to outside influence. When it comes to genes, you get what you get. But gene activity is another story: genes switch on and off depending on what else is going on. Our environment, our behaviour, even out thinking, can all change what genes are expressed. And thinking, learning, sensing can all change neural structure directly. As Bruce Wexler has argued, one important implication of this neuroplasticity is that we’re not locked into the obsolete hardware of our ancestors:
In addition to having the longest period during which brain growth is shaped by the environment, human beings alter the environment that shapes their brains to a degree without precedent among animals... It is this ability to shape the environment that in turn shapes our brains that has allowed human adaptability and capability to develop at a much faster rate than is possible through alteration of the genetic code itself. This transgenerational shaping of brain function through culture also means that processes that govern the evolution of societies and cultures have a great influence on how our individual brains and minds work.
It is important to point out that this is not a starry-eyed... we-can-all-be-anything-we-want-to-be viewpoint. Genes don’t determine our brains..., but they do constrain them. The developmental possibilities for an individual are neither infinitely malleable nor solely in the hands of the environment. But the insight that thinking, behaviour, and experiences change the brain, directly, or through changes in genetic activity, seem to strip the word “hardwiring” of much useful meaning. As neurophysiologist Ruth Bleier put it over two decades ago, we should “view biology as potential, as capacity and not as static entity. Biology itself is socially influenced and defined; it changes and develops in interaction with and response to our minds and environment, as our behaviours do. Biology can be said to define possibilities but not determine them; it is never irrelevant but it is also not determinant.”
Cordelia Fine, Delusions of Gender - How our minds, society and neurosexism create difference. PP 176/8