Advances in neuroscience seem likely to cause major changes in our society in the next few decades, for better and for worse. And when society changes, the law must change – whether to guide those social changes or merely to respond to them. In roughly 100 years the automobile has changed much about life in the developed world and much about its laws – of traffic, insurance, accidents, pollution, franchising, land use, and many other issues. Social changes from neuroscience are likely to have even greater implications for the law, as they will change both the objects of the law and, in a very direct way, how the legal system functions. Those legal changes should make up one important part of the study of what has come to be called neuroethics.

The term “neuroethics,” popularized by William Safire, has been given several kinds of meanings. One use of neuroethics describes ethical problems arising directly from research in neuroscience – for example, what should researchers doing brain imaging tell research subjects about unusual findings of no known clinical significance. The term is also used to describe neuroscience (usually imaging) research into how humans resolve ethical or moral issues – for example, what parts of the brain are “activated” when subjects are wrestling with moral dilemmas. This chapter discusses a third area of neuroethics: the implications of new discoveries in, and capabilities of, neuroscience for our society and their consequences for the legal system. It looks specifically at three different ways in which neuroscience seems likely to change our society and our law – better prediction of future behavior or mental abilities, improved detection of current mental state (including, for example, lie detection), and increased ability to “enhance” directly the workings of the human brain.