The Tending Instinct: How Nurturing Is Essential to Who We Are and How We Live

Taylor describes the realization that all the classic theories of stress were based almost entirely on male subjects as a scientific epiphany. In her own words from the book's introduction, the sudden recognition was 'as stunning as being hit over the head with a club,' prompting the thought: 'I didn't know there were any big mistakes left in science.' This insight—that the fight-or-flight model had been generalized from male animals and men to the entire species without justification—drove her to investigate whether female stress responses might be qualitatively different. The tend-and-befriend model, first formalized in a 2000 Psychological Review article, was the result: a theory grounded in evolutionary biology and neuroendocrinology rather than the assumption of a universal male-derived stress response.

The model drew immediate critique from evolutionary psychologists David C. Geary and Mark V. Flinn, who argued that extending the tend-and-befriend framework too broadly to males was premature and potentially flawed. Their commentary in Psychological Review contended that human paternal investment means men's tending is predicted and observed in some stressful contexts, that coalitional male-male competition makes men's befriending a component of fight-or-flight rather than a separate response, and that female-female competition over paternal investment should also be expected. Taylor and colleagues responded in a 2002 reply, maintaining that while men's behavior under stress may also be social, extending tend-and-befriend to men is premature from the vantage points of underlying biology and the behavioral stress responses the model was designed to explain. This exchange sharpened the model's boundaries: it was explicitly about female stress responses, not a universal human social instinct.

Oxytocin is the neuroendocrine linchpin of the tend-and-befriend response. Taylor argues that oxytocin, released during stress in females, promotes affiliative behavior including maternal tending and social contact with peers. This affiliation serves tending needs—protecting offspring—and befriending needs, seeking social contact for mutual defense. The oxytocin system is also sensitive to early caregiving quality: secure attachment relations enhance oxytocin release and sensitivity, while early adverse experiences reduce them, providing a physiological mechanism by which caregiving quality becomes biologically embedded and transmitted across generations. This connects to Taylor's broader argument that nurturing is not a cultural overlay but a biological system that literally crafts the biology of offspring through genes whose expression depends on caregiving. The tending instinct, on this account, shapes gene expression itself, making social relationships a constitutive force in development.

Empirical tests have produced mixed results, with a notable pattern of findings that complicate the original model. A 2022 meta-analysis found no overall effect of biological sex on prosociality under stress, challenging the prediction that females uniquely increase prosocial behavior under stress. Some studies find women under acute stress show slightly higher transfers in economic games, though often insignificantly, while men under stress show decreased transfers consistent with fight-or-flight. However, research on chronic stress suggests the opposite: higher chronic stress in women correlates with less willingness to share, directly contradicting tend-and-befriend predictions and aligning with rational self-interested behavior. A 2025 study explicitly testing sex differences in affiliation under stress noted that prior research has not yet investigated this systematically, and that tend-and-befriend theory makes no clear-cut prediction for sex differences in prosocial stress responses because affiliation and prosociality are conceptually distinct. The model's core claim about acute stress and affiliation remains empirically unsettled.

Taylor argues that the social environment, particularly early caregiving, molds and shapes the expression of genetic heritage to the point that genetic contribution can become barely evident. She uses the metaphor of the genome as an architect's first plan, a rough projection revised during construction—rooms rotated, extensions added—as genes meet the environment in which they find expression. Her most dramatic evidence comes from Romanian orphanages after the Ceausescu regime's collapse in 1990, where relief workers found hundreds of thousands of children housed in desperate conditions, rocking, head-banging, and emotionally stunted. These children had not been tortured or raped, Taylor notes, but they had not been loved, held, or taught to recognize emotions in others. The first few years of life are critical for building emotional responses, and if a child fails to receive warm, responsive contact during those years, the disadvantages may never be fully overcome. A mother's tending, Taylor claims, can completely eliminate the potential effects of a gene—a risk for disease can fail to materialize with nurturing.

The Tending Instinct applies and popularizes the theoretical framework Taylor developed in her academic work on stress and health, particularly the biopsychosocial model that organizes her Health Psychology textbook. The tend-and-befriend response is a direct extension of her research on how social relationships moderate the stress experience and affect health outcomes. In the textbook, social support appears as a moderator of stress; in The Tending Instinct, Taylor goes further, arguing that nurturing is not merely a protective factor but an evolved biological system that shapes development, gene expression, and health across the lifespan. The book also reflects her research on cognitive adaptation to threatening events, translating academic findings into accessible prose for a general audience. The Publishers Weekly review noted Taylor's readable voice and nearly 80 pages of endnotes, making the book both accessible and rigorously documented—a characteristic of her approach across academic and popular writing.