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160 EFFECTS OF EARLY MALTREATMENT AND STRESSThis finding enabled us to examine the effects of stress-induced alterations inmaternal behavior independent of the presence of the stressor during prenatal life.As with the second litter, the adult offspring of the High LG-ABN/gestationallystressed mothers were again comparable to those of Low LG-ABN dams on measuresof behavioral and HPA responses to stress.The effects of gestational stress were also apparent in the maternal behavior ofthe female offspring. The female offspring of High LG mothers exposed to gestationalstress behave toward their pups in a manner consistent with the behavior oftheir mothers; as adults, these females are Low LG-ABN mothers. Hence the effectsof environmental adversity are effectively transmitted from parent to offspring.Taken together with the data from studies of human and nonhuman primates, thesefindings suggest that environmental adversity in mammals alters maternal behaviorthrough effects on anxiety and that such effects are then apparent as individualdifferences in mother-offspring interactions, with predictable consequences fordevelopment.Adaptive Effects of Stress Reactivity in OffspringThe findings we have reviewed suggest that the offspring of Low LG mothers showincreased fearfulness and enhanced HPA responses to stress. Additionally, thereare affects on cognitive systems that suggest greater vulnerability for stress-inducedimpairments in attentional processes, as well as in learning/memory under certainconditions. It is important to appreciate the potential adaptive virtues of increasedstress reactivity. Under conditions of adversity, stress hormones promotealterations in metabolism (mobilization of glucose and lipid stores) that assist inmeeting the increased energy demands associated with stress, increased vigilanceand alertness, and enhanced defensive responses, all of which serve to enhancesurvival under conditions of chronic stress. Indeed, we suggest that such effectsmay be considered as adaptive within certain contexts (children in extremelyimpoverished and violent environments). The cost of enhanced stress reactivityis likely reflected in an increased vulnerability for stress-induced disease. However,such developmental strategies have been shaped by evolutionary pressuresthat focus on survival and reproduction: Chronic illness is relevant only to theextent that it impinges on these fundamental outcomes. At least two studies inhuman populations have identified the advantages associated with increased stressreactivity (i.e., behavioral inhibition) for children living in poverty (Farringtonet al., 1988; Haapasap & Tremblay, 1994).Within evolutionary biology, maternal or parental effects are defined as sustainedinfluences on any component of the phenotype of the offspring that is derivedfrom either the mother or the father, apart from nuclear genes. Such parentaleffects have been studied across a variety of species, and the results indicate thatenvironmentally induced modifications of the parental phenotype can be transmittedto offspring through an epigenetic mechanism. Epigenesis refers to any