The author presents a biological hypothesis of incest avoidance.
Pertinent literature from evolutionary biology, ethology, anthropology, and
clinical research is reviewed. Secure early bonding to immediate kin
predicts later adaptive kin-directed behaviors, including preferential
altruism (kin selection) and incest avoidance. Impaired bonding predicts
aberrant kin-directed behavior, including diminished altruism, neglect, and
an increased incidence of incest. Failed bonding predicts the highest
frequency of incest. Secure bonding to kin may function to establish
adaptive kin-directed behaviors, including incest avoidance. Bonding is
conceived of as the developmental foundation of a form of social
attraction, here called "familial attraction," which is evolutionarily
distinct from sexual attraction.