“It may be hard for us to accept that human striving is ultimately driven by a welling up of ancient neurochemicals and primitive parts of the brain. This view does not easily fit our conception of ourselves as moral and spiritual Beings. Although the details of human hopes are surely beyond the imaginations of other creatures, the evidence now clearly indicates that certain intrinsic aspirations of all mammalian minds, those of mice as well as men, are driven by the same ancient neurochemistries.”