Shan Guisinger, Ph.D.

Shan Guisinger, Ph.D

David Schuldberg, Ph.D.

The University of Montana– Missoula

Growing genetic evidence indicates that symptoms of anorexia nervosa (AN), representing illness today, were selected in the past. Eight genes have been identified in AN individuals that decrease appetite and increase activity, triggered by falling weight. The adapted-to-flee-famine hypothesis (Affh) has proposed that abilities to ignore hunger, deny starvation, and move energetically are remnants of archaic adaptations that helped some in starving hunter-gatherer bands lead others from depleted home range. Yet, only 1-2% carrying the genes develop the disorder, which also exhibits sex differences. Maynard Smith clarified when natural selection results in stable polymorphisms; density-dependent selection describes how net individual benefit depends on behavioral strategies of others. We model effects of a variety of variables — including number of potential leaders, survival of those leaving home, refeeding success, reproductive outcomes for “successful” anorectics, and syndrome lethality — evaluating effects on the prevalence and sex distribution of AN.

American Psychologist March 1995

…In addition to emphasizing that natural selection works at the level of the individual, not the society, it is also important to note that the current human genotype is a result of past evolution. Furth (1995) states that we hold that the two ontogenetic developmental lines mentioned in our article have been selected for “the evolutionary advantage this dialectic attains in modern humans” (Furth, 1995, p. 176). If a trait or structure selected over the millions of years of hominid evolution is currently adaptive, that is indeed fortunate; however, “modern” humanity accounts for only a tiny fraction of the time humans and humanlike primates have been on the earth and subject to selection pressures. Thus, these two developmental lines must have been advantageous over a long period of premodern hominid evolution…

Developmental Lines, Schemas, and Archetypes

Psychological Review 2003

Anorexia nervosa (AN) is commonly attributed to psychological conflicts, attempts to be fashionably slender, neuroendocrine dysfunction, or some combination of these factors. Considerable research reveals these theories to be incomplete. Psychological and societal factors account for the decision to diet but not for the phenomenology of the disorder; theories of biological defects fail to explain neuroendocrine findings that suggest coordinated physiological mechanisms. This article presents evidence that AN’sdistinctive symptoms of restricting food, denial of starvation, and hyperactivity are likely to be evolved adaptive mechanisms that facilitated ancestral nomadic foragers leaving depleted environments; genetically susceptible individuals who lose too much weight may trigger these archaic adaptations. This hypothesis accounts for the occurrence of AN-like syndromes in both humans and animals and is consistent with changes observed in the physiology, cognitions, and behavior of patients with AN.

Adapted to Flee Famine: Adding an Evolutionary Perspective

American Psychological Association 1994

Western psychologies have traditionally given greater importance to self-development than to interpersonal relatedness, stressing the development of autonomy, independence, and identity as central factors in the mature personality. In contrast, women, many minority groups, and non- Western societies have generally placed greater emphasis on issues of relatedness. This article traces the in- dividualistic bias and recent challenges to this view. It is proposed that evolutionary pressures of natural selection result in two basic developmental lines: interpersonal relatedness and self-definition, which interact in a dialectical fashion. An increasingly mature sense of self is contingent on interpersonal relationships; conversely, the continued development of increasingly mature interpersonal relationships is contingent on mature self-definition. Conclusions include implications for social policy and for facilitating more balanced development of both dimensions all members of society.

Individuality and Relatedness – Evolution of a Fundamental Dialectic