Law as a branch of applied psychology

Because the law for the most part consists of a system of rules for the control of human social behaviour, the law may be taken as a branch of applied psychology. However, one may well ask how good lawyers are as applied psychologists. As a partial answer to this question two well-known issues in criminal law are explored; the deterrent effect of punishment and the viability of the presumption of innocence. It is argued that lawyers, although they tend to speak in confusing ways about the deterrent effect of punishment, in practice show themselves to be pretty good applied psychologists. This is different with respect to the viability of the presumption of innocence, as they do not appear to realize that the ways in which criminal trials are commonly conducted cannot but violate this sacred principle of due process.