For the vast majority of the population, culturally recognized techniques for satisfying needs operate with such efficiency that chronic stress within the system varies within tolerable limits. Some severe but still tolerable stress may remain general in the population, and a fairly constant incidence of persons under, for them, intolerable stress may employ “deviant” techniques (e.g., psychotics). Gradual modification or even rapid substitution of techniques for satisfying some needs may occur without disturbing the steady state, as long as (1) the techniques for satisfying other needs are not