Evolution is thrifty and tinkering. It has had available, in the brains of numerous species, decision-making mechanisms that are body-based and survival-oriented, and those mechanisms have proven successful in a variety of ecological niches. As the environmental contingencies increased and as new decision strategies evolved, it would have made economical sense if the brain structures required to support such new strategies would retain a functional link to their forerunners. Their purpose is the same, survival,
