About

Steven Gaulin is a Professor Emeritus in the Department of Anthropology at the University of California, Santa Barbara. His specialization is in Integrative Anthropological Sciences, with particular interests in evolutionary psychology, cognitive adaptations, the human voice, sexual selection, evolution of sex differences, lipid metabolism, and brain evolution. He holds a B.A. in Anthropology and Psychology from the University of California Berkeley and a Ph.D. in Anthropology from Harvard University. Professor Gaulin's research focuses on the influence of sexual selection on human anatomy, physiology, cognition, and behavior, as well as broader questions in evolutionary psychology. His work involves a wide range of field and laboratory techniques and has been published across disciplines including evolutionary theory, ecology, anthropology, psychology, and philosophy of science. He is the senior author of a leading textbook titled 'Evolutionary Psychology' (2nd edition) and has served as Co-editor-in-Chief of the journal 'Evolution and Human Behavior' for ten years. His projects include studying the influence of sexual selection on the human voice, the evolution of sex differences in spatial behavior and cognition, the evolution of female fat metabolism and its effects on male mating preferences, and the impact of dietary fatty acids on cognitive function and mental health.

Research topics

• Social psychology
• Psychology
• Communication

Selected publications

• Masculine voice is associated with better mucosal immune defense in adolescent and adult males

  Evolution and Human Behavior · 2024-06-24 · 3 citations

  article
  PublisherDOI

• Offspring and parent preferences for a spouse or in-law in an arranged marriage context

  Evolution and Human Behavior · 2024-08-12 · 3 citations

  articleOpen accessSenior author

  Parental influence over mate choice and marriage is a norm across many cultures and throughout human history; however, more attention has been given to preferences of the mating individuals than to the preferences of parents selecting a son- or daughter-in-law. Using data collected in Nepal, a culture with a tradition of arranged marriages, we compare the preferences of unmarried adults and parents of unmarried adults using a budget allocation task in which respondents allocated two budgets (high and low) to design their ideal spouse or in-law from a set of 14 traits. To compare overall similarities and differences in allocations across all 14 traits, we calculated the Mahalanobis Distance for each dyad type (father-son, father-daughter, mother-son, and mother-daughter) for high and low budgets separately. Parents and offspring disagreed more in high budget allocations than in low budget allocations, indicating that they may agree more on the minimally necessary traits in a spouse/in-law. Parents and offspring showed the largest divergence in allocations over same caste/ethnicity (preferred more by parents) and physical attractiveness (preferred more by offspring), in line with previous comparisons of parent and offspring preferences. Differences in the preferences of parents and offspring were at least as large as differences in preferences between men and women in this sample, indicating that parent-offspring disagreement is substantial and should be given more consideration in the literature on mate choice. Additional research is needed to investigate how parents and offspring negotiate their preferences in arranged marriage contexts.

  PublisherDOI

• Substantial but Misunderstood Human Sexual Dimorphism Results Mainly From Sexual Selection on Males and Natural Selection on Females

  Frontiers in Psychology · 2022-05-17 · 41 citations

  articleOpen accessSenior authorCorresponding

  Human sexual dimorphism has been widely misunderstood. A large literature has underestimated the effect of differences in body composition and the role of male contest competition for mates. It is often assumed that sexually dimorphic traits reflect a history of sexual selection, but natural selection frequently builds different phenotypes in males and females. The relatively small sex difference in stature (∼7%) and its decrease during human evolution have been widely presumed to indicate decreased male contest competition for mates. However, females likely increased in stature relative to males in order to successfully deliver large-brained neonates through a bipedally-adapted pelvis. Despite the relatively small differences in stature and body mass (∼16%), there are marked sex differences in body composition. Across multiple samples from groups with different nutrition, males typically have 36% more lean body mass, 65% more muscle mass, and 72% more arm muscle than women, yielding parallel sex differences in strength. These sex differences in muscle and strength are comparable to those seen in primates where sexual selection, arising from aggressive male mating competition, has produced high levels of dimorphism. Body fat percentage shows a reverse pattern, with females having ∼1.6 times more than males and depositing that fat in different body regions than males. We argue that these sex differences in adipose arise mainly from natural selection on women to accumulate neurodevelopmental resources.

  PublisherOA PDFDOI

• Arranged Marriage Often Subverts Offspring Mate Choice: An HRAF‐Based Study

  American Anthropologist · 2021-10-18 · 22 citations

  articleSenior author

  ABSTRACT In many species, females and males form long‐term mating bonds, but marriage—and especially arranged marriage—are uniquely human traits. While marriage practices impact many cultural phenomena, they also can have evolutionary (i.e., fitness) consequences. Strongly felt but not necessarily conscious mating preferences presumably evolved because they provide fitness benefits compared to random mating, and this prediction has been supported by experimental animal studies. Arranged marriage might similarly reduce fitness in humans, but only if parents regularly choose different mates for their offspring than offspring would choose for themselves. Here we report a broad ethnographic survey exploring whether parents and offspring disagree over partner choice in arranged marriages. Using the Human Relations Area Files, we reviewed 543 ethnographies to assess the relative frequencies of parent–offspring agreement and disagreement over partner choice, the reasons for disagreement, and the outcomes of disagreement. In all world areas, parents and offspring overwhelmingly choose different partners. Parents and offspring disagreed over fitness‐relevant traits of the potential spouse, and both parties sometimes used extreme methods to influence outcomes. These findings suggest that arranged marriages may be useful for studying the effects of mate choice in humans and for assessing the unique dynamics of human mating systems. [ parent–offspring conflict, mate choice, cross‐cultural ]

  PublisherDOI

• Does Nubility Indicate More Than High Reproductive Value? Nubile Primiparas’ Pregnancy Outcomes in Evolutionary Perspective

  Evolutionary Psychology · 2021-07-01 · 8 citations

  articleOpen accessSenior authorCorresponding

  The idea that human males are most strongly attracted to traits that peak in women in the nubile age group raises the question of how well women in that age group contend with the potential hazards of a first pregnancy. Using data for 1.7 million first births from 1990 U.S. natality and mortality records, we compared outcomes for women with first births (primiparas) aged 16-20 years (when first births typically occur in forager and subsistence groups) with those aged 21-25 years. The younger primiparas had a much lower risk of potentially life-threatening complications of labor and delivery and, when evolutionarily novel risk factors were controlled, fetuses which were significantly more likely to survive despite lower birth weights. Thus, nubile primiparas were more likely to have a successful reproductive outcome defined in an evolutionarily relevant way (an infant of normal birth weight and gestation, surviving to one year, and delivered without a medically necessary cesarean delivery). This suggests that prior to the widespread availability of surgical deliveries, men who mated with women in the nubile age group would have reaped the benefit of having a reproductive partner more likely to have a successful first pregnancy.

  PublisherDOI

• Male Mating Expectations in Brazilian and American Samples

  Frontiers in Psychology · 2021-02-10 · 2 citations

  articleOpen access

  This study aims to investigate assortative mating based on mate value from male perspective. Male participants (132 Brazilian and 106 American) evaluated hypothetical "stimulus" males described in terms of physical attractiveness, social skills, and social status (each varied in high or low levels). Participants rated each stimulus and each stimulus' preferred mating partner on nine traits. The results showed that (1) positive assortative mating was expected in romantic relationships; (2) the stimulus ratings did not vary independently, suggesting that mate value is the result of the interaction of the characteristics of individuals; and (3) that participants expected physically attractive and healthier female partners to pair with high-status male stimuli. The American and Brazilian mating expectations were similar, minor differences indicate that Brazilian participants considered men with high levels of social skills to be more ambitious and intelligent; American participants expected men of high status to be healthier; Brazilians expect men of high status to have more attractive faces, while Americans expected these men to possess more attractive bodies; and Brazilian participants assigned more attractive bodies to men of lower status. These differences reflect the influence of economic and cultural factors on the local environment. The study contributes to the understanding of the construction of market value and reveals that male expectations are in line with human mating preferences. The investigation of mating expectations can be a rich approach to investigate socio-cultural aspects that are related to mating in different cultures.

  PublisherDOI

• Was facial width-to-height ratio subject to sexual selection pressures? A life course approach

  PLoS ONE · 2021-03-12 · 29 citations

  articleOpen accessSenior authorCorresponding

  Sexual selection researchers have traditionally focused on adult sex differences; however, the schedule and pattern of sex-specific ontogeny can provide insights unobtainable from an exclusive focus on adults. Recently, it has been debated whether facial width-to-height ratio (fWHR; bi-zygomatic breadth divided by midface height) is a human secondary sexual characteristic (SSC). Here, we review current evidence, then address this debate using ontogenetic evidence, which has been under-explored in fWHR research. Facial measurements were collected from 3D surface images of males and females aged 3 to 40 (Study 1; US European-descent, n = 2449), and from 2D photographs of males and females aged 7 to 21 (Study 2; Bolivian Tsimane, n = 179), which were used to calculate three fWHR variants (which we call fWHRnasion, fWHRstomion, and fWHRbrow) and two other common facial masculinity ratios (facial width-to-lower-face-height ratio, fWHRlower, and cheekbone prominence). We test whether the observed pattern of facial development exhibits patterns indicative of SSCs, i.e., differential adolescent growth in either male or female facial morphology leading to an adult sex difference. Results showed that only fWHRlower exhibited both adult sex differences as well as the classic pattern of ontogeny for SSCs-greater lower-face growth in male adolescents relative to females. fWHRbrow was significantly wider among both pre- and post-pubertal males in the Bolivian Tsimane sample; post-hoc analyses revealed that the effect was driven by large sex differences in brow height, with females having higher placed brows than males across ages. In both samples, all fWHR measures were inversely associated with age; that is, human facial growth is characterized by greater relative elongation in the mid-face and lower face relative to facial width. This trend continues even into middle adulthood. BMI was also a positive predictor of most of the ratios across ages, with greater BMI associated with wider faces. Researchers collecting data on fWHR should target fWHRlower and fWHRbrow and should control for both age and BMI. Researchers should also compare ratio approaches with multivariate techniques, such as geometric morphometrics, to examine whether the latter have greater utility for understanding the evolution of facial sexual dimorphism.

  PublisherOA PDFDOI

• Elevated recognition accuracy for low-pitched male voices in men with higher threat potential: Further evidence for the retaliation-cost model in humans

  Evolution and Human Behavior · 2020-08-20 · 8 citations

  article
  PublisherDOI

• Pitch lowering enhances men's perceived aggressive intent, not fighting ability

  Evolution and Human Behavior · 2020 · 34 citations

  • Psychology
  • Social psychology
  • Communication
  PublisherDOI

• Was facial width-to-height ratio subject to sexual selection pressures? A life course approach

  bioRxiv (Cold Spring Harbor Laboratory) · 2020-09-24 · 5 citations

  preprintOpen accessSenior author

  Abstract Sexual selection researchers have traditionally focused on adult sex differences; however, the schedule and pattern of sex-specific ontogeny can provide insights unobtainable from an exclusive focus on adults. Recently, it has been debated whether facial width-to-height ratio (fWHR; bi-zygomatic breadth divided by midface height) is a human secondary sexual characteristic (SSC). Here, we review current evidence, then address this debate using ontogenetic evidence, which has been under-explored in fWHR research. Facial measurements collected from males and females aged 3 to 40 (Study 1; US, n= 2449), and 7 to 21 (Study 2; Bolivia, n =179) were used to calculate three fWHR variants (which we call fWHR nasion , fWHR stomion , and fWHR brow ) and two other common facial masculinity ratios (facial width-to-lower-face-height ratio, fWHR lower, and cheekbone prominence). We test whether the observed pattern of facial development exhibits patterns indicative of SSCs, i.e. differential adolescent growth in either male or female facial morphology leading to an adult sex difference. Results showed that only fWHR lower exhibited both adult sex differences as well as the classic pattern of ontogeny for SSCs—greater lower-face growth in male adolescents relative to females. fWHR brow was significantly wider among both pre- and post-pubertal males in the 2D sample; post-hoc analyses revealed that the effect was driven by large sex differences in brow height, with females having higher placed brows than males across ages. In both samples, all fWHR measures were inversely associated with age; that is, human facial growth is characterized by greater relative growth in the mid-face and lower face relative to facial width. This trend continues even into middle adulthood. BMI was also a positive predictor of most of the ratios across ages, with greater BMI associated with wider faces. Researchers collecting data on fWHR should target fWHR lower and fWHR brow and should control for both age and BMI.

  PublisherOA PDFDOI

Recent grants

• Doctoral Dissertation Research: Constraint in Marriage Systems and Fitness Outcomes

  NSF · $25k · 2020–2023

• Collaborative Research: Psychological and Behavioral Preparatory Responses to Male Aggressive Vocal Signaling

  NSF · $112k · 2016–2022

Frequent coauthors

• Carolyn R. Hodges‐Simeon

  Boston University

  18 shared

• Michael Gurven

  17 shared

• William D. Lassek

  16 shared

• James S. Boster

  9 shared

• David A. Puts

  Pennsylvania State University

  6 shared

• Donald H. McBurney

  6 shared

• Jeffrey A. Kurland

  5 shared

• Timothy S. McHale

  California Polytechnic State University

  5 shared

Education

• Ph.D, Anthropology

  Harvard University

  1978

• B.A., Anthropology & Psychology

  University of California Berkeley

  1972