The importance of social behavior in nonhuman primate studies of aging: A mini-review

The fortunes and misfortunes of social life across the life course: A new era of research from field, laboratory and comparative studies

Social gradients in health and aging have been reported in studies across many human populations, and - as the papers included in this special collection highlight - also occur across species. This paper serves as a general introduction to the special collection of Neuroscience and Biobehavioral Reviews entitled "Social dimensions of health and aging: population studies, preclinical research, and comparative research using animal models". Authors of the fourteen reviews are primarily members of a National Institute of Aging-supported High Priority Research Network on "Animal Models for the Social Dimensions of Health and Aging". The collection is introduced by a foreword, commentaries, and opinion pieces by leading experts in related fields. The fourteen reviews are divided into four sections: Section 1: Biodemography and life course studies; Section 2: Social behavior and healthy aging in nonhuman primates; Section 3: Social factors, stress, and hallmarks of aging; Section 4: Neuroscience and social behavior.

Making sense of the costs of adversity throughout the lifespan on aging in humans and other animals

Social adversity, particularly early in life, can cause lifelong damage to health; by now, numerous studies examine this relationship in non-human species, producing some important themes: A) Captive animals readily lack ethological validity, giving a special place to studies of natural populations; one must appreciate though, that animal studies typically benefit humans who themselves lack ecological validity, namely Westernized subjects. B) Animal studies of the links between social adversity and psychiatric maladies potentially produce anthropomorphism; however, long-term study of our closest relatives demonstrates how convincingly another primate can, for example, experience grief, rather than display "grief-like" behavior. C) Are long-term consequences of social adversity best viewed as maladaptive and pathological, or as adaptive preparation for similar adversity later in life?; the growing literature casts light on when adversity's consequences are the purview of medicine or natural history. D) Studies examining sustained adversity and aging can increasingly distinguish between aging versus diseases of aging or cohort effects, and between aging effects arising from direct physiological mechanisms or indirect behavioral ones.

A central role for stressor appraisal in the social dimensions of health and aging in nonhuman primates

Being social is by no means the default in the animal kingdom; even most mammals meet only briefly to mate and otherwise lead happy solitary lives. Because conspecifics occupy the same ecological niche, seek the same ecological conditions and resources, they can be each other's strongest competitors when resources are scarce. Yet, sociality, i.e. associating, communicating, coordinating, cooperating, and competing in structured ways, has evolved independently many times across the tree of life. The consequences of competition and conflict are often not shared equally among members of a society, resulting in status-associated health prospects. In response, affiliative strategies have evolved to navigate such structured societies and to partially compensate for certain costs of sociality. The importance of such affiliative strategies may change with age and neurodegenerative disease. Their shared longevity, physiological and anatomical similarity, including in brain areas affected by aging, and particularly the homologies in how social status, affiliation, and cooperation structure their societies, make nonhuman primates the preferred models for the social dimensions of health and aging in humans.