Tend-and-befriend is a purported behavior exhibited by some animals, including humans, in response to threat. It refers to protection of offspring (tending) and seeking out their social group for mutual defense (befriending). In evolutionary psychology, tend-and-befriend is theorized as having evolved as the typical female response to stress.

The tend-and-befriend theoretical model was originally developed by Shelley E. Taylor and her research team at the University of California, Los Angeles and first described in a Psychological Review article published in the year 2000.

The theory has been criticized as contradicting social science research, especially how men and women behave in non-Western cultures.

Biological bases Oxytocin has been tied to a broad array of social relationships and activities, including peer bonding, sexual activity, and affiliative preferences.Carter, C.S., Lederhendler, I.I., & Kirkpatrick, B., eds. (1999). The integrative neurobiology of affiliation. Cambridge, Mass.: MIT Press. Oxytocin is released in humans in response to a broad array of stressors, especially those that may trigger affiliative needs. Oxytocin promotes affiliative behavior, including maternal tending and social contact with peers. Thus, affiliation under stress serves tending needs, including protective responses towards offspring. Affiliation may also take the form of befriending, namely seeking social contact for one's own protection, the protection of offspring, and the protection of the social group. These social responses to threat reduce biological stress responses, including lowering heart rate, blood pressure, and hypothalamic pituitary adrenal axis (HPA) stress activity, such as cortisol responses.

According to some research, women are more likely to respond to stress through tending and befriending than men. Paralleling this behavioral sex difference, estrogen enhances the effects of oxytocin, whereas androgens inhibit oxytocin release.

A recent study suggests that men and women exhibit distinct stress responses. While men tend to display a "fight-or-flight" response, women more commonly demonstrate this "tend-and-befriend" pattern. This distinction is supported by both neuroendocrine and behavioral evidence. In both sexes, the physiological stress response generally involves activation of the sympathetic nervous system and the hypothalamic-pituitary-adrenal (HPA) axis. However, in females, the stress response is thought to draw more specifically upon attachment and caregiving processes.

Tending under stress Female stress responses that increased offspring survival would have led to higher fitness and thus were more likely to be passed on through natural selection. In the presence of threats, protecting and calming offspring while blending into the environment may have increased chances of survival for mother and child. When faced with stress, females often respond by tending to offspring, which in turn reduces stress levels. Studies conducted by Repetti (1989) show that mothers respond to highly stressful workdays by providing more nurturing behaviors towards their children. In contrast, fathers who experienced stressful workdays were more likely to withdraw from their families or were more interpersonally conflictual that evening at home. Furthermore, physical contact between mothers and their offspring following a threatening event decreased HPA activity and sympathetic nervous system arousal. Oxytocin, released in response to stressors, may be the mechanism underlying the female caregiving response. Studies of ewes show that administration of oxytocin promoted maternal behavior. Breastfeeding in humans, which is associated with maternal oxytocin release, is physiologically calming to both mothers and infants.

Cooperative breeding Tend-and-befriend is a critical, adaptive strategy that is hypothesized to have enhanced reproductive success among female cooperative breeders. Cooperative breeders are group-living animals where infant and juvenile care from non-mother helpers are essential to offspring survival. Cooperative breeders include wolves, elephants, many nonhuman primates, and humans. Among all primates and most mammals, endocrinological and neural processes lead females to nurture infants, including unrelated infants, after being exposed long enough to infant signals. Non-mother female wolves and wild dogs sometimes begin lactating to nurse the alpha female's pups.

Humans are born helpless and altricial, mature slowly, and depend on parental investment well into their young adult lives, and often even later. Humans have spent most of human evolution as hunter-gatherer foragers. Among foraging societies without modern birth control methods, women tend to give birth about every four years during their reproductive lifespan. When mothers give birth, they often have multiple dependent children in their care, who rely on adults for food and shelter for years. Such a reproductive strategy would not have been able to evolve if women did not have help from others. Allomothers (helpers who are not a child's mother) often protect, provision, carry, and care for children. Allomothers are usually a child's aunts, uncles, fathers, grandmothers, siblings, and other persons in the community. Even in modern Western societies, parents often rely on family members, friends, and babysitters to help care for children. Burkart, Hrdy, and Van Schaik (2009) argue that cooperative breeding in humans may have led to the evolution of psychological adaptations for greater prosociality, enhanced social cognition, and cognitive abilities for cooperative purposes, including willingness to share mental states and shared intentionality. These cognitive, prosocial processes brought on by cooperative breeding may have led to the emergence of culture and language.

Befriending under stress Group living provides numerous benefits, including protection from predators and cooperation to achieve shared goals and access to resources. In modernized societies at least, it is found that women create, maintain, and use social networks—especially friendships with other women—to manage stressful conditions. During threatening situations, group members can be a source of support and protection for women and their children. Research shows that women operating in a modern and westernized paradigm are more likely to seek the company of others in times of stress, compared to men. In some cultures, women and adolescent girls report more sources of social support and are more likely to turn to same-sex peers for support than men or boys are. One study of six cultures (five of whom were non-western) found that women and girls tend to provide more frequent and effective support than men do, and they are more likely to seek help and support from other female friends and family members, although there was a degree of cultural variation based on the metric used. Women tend to affiliate with other women under stressful situations. However, when women were given a choice to either wait alone or to affiliate with an unfamiliar man before a stressful laboratory challenge, they chose to wait alone. Female-female social networks can provide assistance for childcare, exchange of resources, and protection from predators, other threats, and other group members. Smuts (1992) and Taylor et al. (2000) argue that female social groups also provide protection from male aggression. In spite of the large cultural diversity within this six-culture sample, none of the societies included demonstrated matrilineal tendencies, which have been found to negate and cancel out many supposedly "universal" sex differences (see "criticism" section below). Additionally, the metrics used by the Whitings for evaluating sex differences in social support are somewhat questionable in their ability to predict friendship and relational quality and solidarity. Many other surveys and tests, for instance, find that males actually demonstrate a greater degree of social support than women do in many non-western cultures, particularly from same-gender friendship networks.Benenson, J. F., & Markovits, H. (2014). Warriors and Worriers: The Survival of the Sexes. http://ci.nii.ac.jp/ncid/BB1672671XMoffatt, M., Schlegel, A., & Barry, H. (1992). Adolescence: an Anthropological Inquiry. Contemporary Sociology, 21(3), 367. https://doi.org/10.2307/2076290

Neuroendocrine underpinnings Human and animal studies (reviewed in Taylor et al., 2000) suggest that oxytocin is the neuroendocrine mechanism underlying the female "befriend" stress response. Oxytocin administration to rats and prairie voles increased social contact and social grooming behaviors, reduced stress, and lowered aggression. In humans, oxytocin promotes mother-infant attachments, romantic pair bonds, and friendships. Social contact or support during stressful times leads to lowered sympathetic and neuroendocrine stress responses. Although social support downregulates these physiological stress responses in both men and women, women are more likely to seek some forms of social contact during stress. Furthermore, support from another female provides enhanced stress-reducing benefits to women. However, a review of female aggression noted that "The fact that OT [oxytocin] enhances, rather than diminishes, attention to potential threat in the environment casts doubt on the popular 'tend-and-befriend' hypothesis which is based on the presumed anxiolytic effect of OT".

Benefits of affiliation under stress According to Taylor (2000), affiliative behaviors and tending activities reduce biological stress responses in both parents and offspring, thereby reducing stress-related health threats.Taylor, S.E. (2002). The tending instinct: How nurturing is essential to who we are and how we live. New York: Holt. "Befriending" may lead to substantial mental and physical health benefits in times of stress. Social isolation is associated with significantly enhanced risk of mortality, whereas social support is tied to positive health outcomes, including reduced risk of illness and death.