The following explanatory scheme may be proposed for the need to achieve such an amplitude. There is little doubt that the human nervous system has evolved under conditions where the danger was constant and even the nearest future uncertain. In particular, this concerns the elements of the environment that constitute resources—food, territory, reproductive or any other objects of consummatory behaviors. These danger and uncertainty, interspersed by the acts of consumption, determined a very wide range of affective states within the human adaptive norm, enabled by the effective mechanisms of coping with stressful conditions, by necessity – and according to their frequency – converting them into the baseline, the homeostatic level. It is historically only recently that relative stability and security have become possible for a large proportion of the population—largely in the developed countries.
