Is it time to jettison the alpha male stereotype of leadership?

– by Adi Wiezel & Doug Kenrick

Women make up slightly over 50 percent of the U.S. population. Why then are only a quarter of U.S. Senators and a tenth of Fortune 500 CEOs women? Why have none of 45 American Presidents been a woman? According to some experts on leadership, the explanation involves two steps: first, people’s stereotype of a leader involves masculinity and dominance (the human incarnation of an “Alpha Male” chimpanzee); second, this stereotype translates into a preference. When voters go the polls, or when boards of directors choose executives, the Alpha Male stereotype drives their choices.

But a recently published series of studies suggests that this story is only half true: Most people’s mental image of a leader is a man. But does that mean most people prefer men as leaders? No, in fact, there is a slight preference for women as leaders. This is true whether people are evaluating candidates for a position in a business organization, or for a political office.

More importantly than the slight preference for women, there is a strong bias against leaders who manifest the Alpha Male brand of dominance.

To understand the antipathy towards dominance, it’s important to recognize a distinction between dominance and prestige. In many animal species, positions of status are acquired by aggression and threats, as in the case of Alpha Male chimpanzees. No doubt some of human status is achieved by bullying and threats, with power-hungry individuals fighting to win control over others. But human beings also have another route to status – via prestige. Because human groups involve a great deal of cooperation and mutual problem-solving, people often freely confer status, and leadership positions, on individuals who are especially socially skilled and who can mediate and reduce conflict within and between groups. Unlike dominance, prestige is bestowed by other group members, rather than taken by force. And unlike dominance, prestige is not particularly sex-typed.

In five studies, our research team explored the relationship between leader stereotypes and preferences. In the first study, we found that most people asked to imagine a leader spontaneously thought of a man. This was true whether they were asked to think of a dominant leader (“… has a lot of power and has authority and control over people. People don’t get in this person’s way”) or a prestigious leader (“… has a lot of prestige and has people’s respect and admiration. People seek this person out.”). A follow-up study found this true whether people were prompted to think of a leader in the military, politics, business, sports, science, or the arts.

After imagining a leader, however, people were asked “How much would you like to work for this person?” Did preferences follow stereotypes? No. In fact, there was a slight preference favoring female leaders. More importantly, there was a strong preference to be led by a prestigious rather than a dominant leader. This preference for female over male leaders was corroborated in an analysis of a nationally representative sample from the Pew American Trends Panel.

In another experimental study, people evaluated two candidates for a leadership position in an organization. One leader was described as dominant (forceful, commanding), the other as prestigious (well-respected, looked up to). Sometimes the dominant candidate was a woman and the prestigious candidate was a man, and sometimes the woman was the prestigious candidate. In both cases, people strongly preferred the prestigious over the dominant leader—regardless of whether that person was a woman or a man.

In another study, participants judged actual politicians from facial photographs (European parliamentarians, not known to American participants). People viewed women as more likely to use prestige- over dominance-based leadership strategies, and when asked whether they would vote for this person as governor of their state, showed a slight preference for the women over the men.

But do voters still choose men over women in real elections? No. Analyses of actual U.S. elections confirm that women are (very slightly) favored when they do run for elected office, even at the highest levels. There has only been one instance in which a woman ran against a man for the U.S. presidency, and she earned the majority of the popular vote.

But if people have no prejudice against women leaders, why doesn’t American leadership reflect the fact that half the population is female? The answer is that fewer women tend to run for high office and may be less likely to be chosen by party leaders. Hence, social scientists who persist in promoting the belief that there is a prejudice against females in leadership positions may be unintentionally contributing to the problem. The data suggest it is time to update our models.

This set of studies also raised further questions. Some of these were addressed by seven thoughtful commentaries from prominent scholars in the field, including Alice Eagly and Steven J. Karau, Joey Cheng, Mark van Vugt, Charleen Case and Laurel Detert, Nina Rodriguez and Jaimie Krems, Chris von Rueden, and Patrick Durkee and Aaron Lukaszewski. For example, Case and Detert asked why women were stereotyped as more prestigious than men—is it that men and women vary in their capacity to wield dominance, or that men and women are differentially rewarded for using these two strategies (such that women are more often punished for using dominance)? Moreover, since dominance was less preferred as measured in the present studies, it is worth considering whether this would still be the case for more expanded definitions of dominance. For instance, as Durkee and Lukaszewski suggest, it may be that people dislike dominance when it is used to inflict net costs on the group, but not when it used to provide net benefits to the group. Collectively, commentaries like these suggest the importance of considering further nuance in our models of human leadership. One promising future direction involves considering what ancestral functions leaders may have served, what traits and capacities may have been useful for those roles, and what mismatches we see today.

Read the original article: Wiezel, A., Barlev, M., Martos, C.R., & Kenrick, D.T. (2024). Stereotypes vs. preferences: revisiting the role of alpha males in leadership. Evolution & Human Behavior45(3), 292-308.

Read the commentary articles and authors’ response:

  • Patrick Durkee & Aaron Lukaszewski: Deconstructing “dominance” to refine leadership search (see here)
  • Alice Eagly & Steven Karau: Implications of dominance versus agency in the interpretation of preferences for female and male leaders (see here)
  • Charleen Case & Laurel Detert: Are men (believe to be) less prestige-oriented than women? (see here)
  • Christopher Von Rueden: “Think leader, think alpha male” and the evolution of leader stereotypes (see here)
  • Joey Cheng: Prestige-based leadership offers women leaders an advantage and reduces gender inequality in leadership (see here)
  • Nina Rodriguez & Jaimie Krems: Two notes on Wiezel et al.: explaining why people disfavor dominant leaders and exploring overlooked sources of women’s dominance and leadership (see here)
  • Authors’ response (Adi Wiezel, Michael Barlev & Doug Kenrick): Beyond stereotypes versus preferences: sex, dominance, and the functions of leadership (see here)

Image source (Creative Commons)


Update on Childcare at HBES2024

– Letter from the HBES President

Dear HBES community,

I’m writing with an update regarding child care arrangements for the HBES 2024 conference in Aarhus. Thank you for your patience as we have looked into available options, and to those of you who replied to our recent survey.

Although the local hosts put Herculean efforts into arranging childcare, they were unable to do so at the conference venue due to complicated local legal and liability reasons, including that the hosts and host institution were not legally allowed to be involved. They did find one option that worked within those constraints, but it required a startup fee of over $7000 plus a high hourly fee per child. Given that we only heard from three attendees who would use this service in our most recent survey, the executive council decided against this plan.

The host committee has arranged for an alternative: a dedicated on site room that is equipped with a large screen TV and some toys. It will be open for children, parents, and other caregivers to use for the duration of the conference. There will not be staff assigned to the room, but families and other caregivers will be free to use this space throughout the conference.

Families may wish to pursue their own childcare options while in Aarhus. If parents wish to independently contract caregivers in Aarhus, these caregivers will have access to the family room space. We have found a few websites that enable parents to search for independently contracted child care in Aarhus. A few of these sites are listed below.

Note that we have not vetted these sites, nor are they affiliated with the conference. Contracts and arrangements for child care must be made by conference attendees, and neither HBES nor Aarhus University can be officially involved. However, host committee co-chair Marc Malmdorf Andersen ( has generously offered to help if assistance is needed with translation or other issues. Marc will also create a WhatsApp group for parents who wish to coordinate with each other – please e-mail him with your phone number to join.

Again, thank you for your patience during this process. We are looking forward to seeing you all, and your families, in Aarhus. Please let us know if you have any questions.

Clark Barrett, HBES President on behalf of the HBES Council

Mating Fast and Slow?

– By Tran Dinh and Steve Gangestad

Why do humans vary in their willingness to have multiple sexual relationships or tendency to form long-term bonds with a single partner? Evolutionary-minded researchers often look at patterns observed in nonhuman animals to gain insight into human nature. Indeed, much research has been done to explain the array of mating strategies across and within species: why individuals engage in intense mating contests, display exaggerated physical characteristics, cheat on their partners—and also why they form monogamous bonds or mate with many partners.

Over the past few decades, some scholars have argued that variations in human sociosexuality—their willingness to have sex without commitment or interest in having multiple sex partners—are part of fast vs. slow life history strategies. Across species, those that are fast life history strategists reproduce at an early age, have many offspring, and die young. Slow strategists invest in their health, have offspring late, have few of them, and live long lives. Within humans, fast and slow life history strategies may exist too. According to dominant views, humans achieve fast or slow reproductive outcomes by having uncommitted sex with multiple partners (unrestricted sociosexuality, a “fast” strategy) or settling down with one committed partner and having few lifetime sex partners (restricted sociosexuality, a “slow” strategy).

At first blush, it may seem a compelling argument. More sex leads to more offspring, right? Less commitment leads to more sex partners which leads to more offspring. The logic sparked much research into life history trajectories explaining not just variations in sociosexuality, but also personality traits and aggression. Here, we focus just on the question of whether restricted vs. unrestricted sociosexuality solves the adaptive problem of reproducing at a slow vs. fast rate. Before we get into addressing that question (spoiler: the answer is no), it is important to first discuss life history theory.

Life History Theory and the Fast-Slow Continuum

            The life histories and life cycles of animals vary tremendously. The giant sunda rat lives less than a year, the bowhead whale over 200 years. Yet both grow, develop, and successfully reproduce within their lifespans. How has natural selection shaped such a vast diversity of life cycles? How can it pay members of one species to spend more time gestating a single offspring than members of another species spend living? Life history theory seeks to answer these questions.

The theory argues that species’ life courses vary along a fast-to-slow dimension. Fast species tend to reproduce early in life. They put a lot of effort into reproduction, which means that they have less to invest in fighting infections, suppressing cancer, avoiding or defending against predators, and other tactics for extending their life. Slow species start reproducing later in life. They instead prioritize growth and development. Their strategy is to put more effort into living longer, which comes at the expense of reproducing more slowly.

The “winning” strategy partly depends on the cost that members of a species must pay to avoid death. When the chances of dying young are low or can be reliably avoided, reproducing slowly across a longer lifespan—and “helping” each offspring survive and reproduce—becomes more profitable. But waiting to reproduce when the world is sufficiently dangerous risks not reproducing at all. Reproducing early and plentifully—but not investing heavily in any one offspring—becomes a better strategy.

These differences between species sparked the idea that life history strategies may differ within a species too. Humans may also differ in the speed that they grow, reach puberty, have kids, and age. These differences may arise from growing up in an environment with high chances of relatively uncontrollable death, or in a relatively safe controllable environment.

Sociosexuality as Part of a Fast vs. Slow Strategy

            So far, these ideas are conceptually plausible. But there is an additional element to dominant viewpoints—that sociosexual orientations underlie fast vs. slow reproductive strategies. Fast female strategists are purportedly more open to mating with multiple males (serially or concurrently) in relatively uncommitted or transient relationships. Their unrestricted sociosexuality or “short-term” mating strategy serves the purpose of reproducing sooner, having more offspring, and caring less for each child. In contrast, slow female strategists desire strong, stable romantic relationships and are less open to having uncommitted sex. Their restricted sociosexuality or “long-term” mating strategy allows them to reproduce later and within a lasting relationship in which both partners intensively care for fewer offspring.

For multiple reasons, we question how well these proposed links are theoretically grounded.

First, pair-bonding does not systematically associate with fast-slow life history variation across species. Bats have amongst the slowest life histories of any mammal. Yet female bats mate with multiple males and rear young without male assistance. Among bird species, some slow strategists, such as albatrosses, pair-bond for life. But so do some relatively fast strategists, including many geese and swans. Similarly, primate species that pair-bond do not systematically have slower life histories than those that do not pair-bond.

Second, a reason for these patterns is that pair-bonding and biparental care do not promote offspring quality at the expense of offspring quantity. Females of bird species that pair-bond and engage in biparental care have more offspring than female birds that do not have male assistance. Female marmosets and tamarins—primates that raise offspring in pairs or small family groups—have relatively high rates of reproduction among primates.

Third, reflection of how humans have evolved (e.g., as cooperative breeders) offers little basis for thinking that female “fast mating” and having many unstable sexual relationships promote the speed that offspring are produced. Human offspring require investment across nine months of pregnancy. In foraging societies, mothers breastfeed children for a year or more. Having additional sex partners during this time does not increase how fast a woman has children. Having sex with one man or several men may result in one child. Indeed, fidelity to a single partner, who helps provide nutrition or care for children, may best promote the rate that women can have children. Across foraging societies, how much men provide food negatively covaries with the spacing between births and the number of children women have.

The Take-Home

It is plausible that variation in rates of growth and development, such as when girls have their first menstrual period, partly reflects differences in life history strategies. Mating propensities likely systematically vary as well, as reflected in differences in tendencies to form stable pair-bonds or willingness to have multiple sexual relationships. However, there is little compelling reason to think that variations in sociosexuality explain differences in reproductive rate or offspring quality vs. quantity in humans—or, for that matter, across nonhuman animal species. What may appear to be a logical link is not supported by evolutionary thinking or pertinent data. Our understanding of both life history variations among humans and variations in mating propensities will benefit from seeing them as largely unrelated phenomena.

Read the full article here: Dinh, T., & Gangestad, S.W. (2024). Mating fast and slow? Sociosexual orientations are not reflective of life history trajectories. Evolution and Human Behavior, 45(1), 27-40.

Grant opportunity for Religion & Cooperation

The following is a grant opportunity for researchers studying religion & cooperation, posted on behalf of Michael McCullough:

With the support of a grant from the Templeton Religion Trust, in advancement of their ambitious, multi-decade Social Consequences of Religion (SCORE) Initiative, the SCORE Project for Advancing Research on Religion and Cooperation (SPARRC) welcomes proposals from investigators from all scientific disciplines to research the social consequences of religion for cooperation and prosocial behavior.

 SPARRC is the first Strand of the SCORE Initiative. It is currently entering a two-stage research phase. In the Seed Project Stage, we expect to fund approximately ten Seed Grants with budgets up to $150,000 each. In the Landmark Project Stage, we will award up to $4 million for Landmark Projects with budgets up to $3 million. We will consider projects from investigators in all scientific disciplines, including but not limited to anthropology, biology, cognitive science, communications, computer science, demography, digital humanities, economics, epidemiology, human development, linguistics, neuroscience, political science, psychology, sociology, and quantitative history.

You can find the request for proposals here.

Between Clans and Cattle: Third-party Peacemakers Among the Hamar Agro-pastoralists

Photo credit: Zachary Garfield. Hamar women gather for a community meeting

– by Zachary Garfield

How do we resolve conflicts? Who helps resolve conflicts and why? To answer these questions, my colleague Luke Glowacki and I analyzed data from ongoing long-term fieldwork among Hamar pastoralists in Ethiopia’s Omo Valley, now published in Evolution and Human Behavior.

The Hamar are an interesting ethnographic case study for conflicts and their mediation. They live in the culturally diverse Omo Valley, home to over a dozen distinct ethnic groups, most of which practice pastoralism to some degree. There’s also much history of inter-group conflict, warfare, and large-scale cattle raids between these groups. So, ethnic identity is powerful. Most men over 50 have fired rifles at neighboring groups when herding cattle, and several have killed other men in the context of inter-group raids. Inter-group threats are assumed to help sustain within-group cooperation and, by extension, theoretically, limit within-group conflicts. Alternatively, it could be argued that cultural values favoring warriors and ferocity could lead to elevated potential for aspiring or well-known warriors to increase or maintain their status through competitive displays, creating additional opportunities for within-group conflicts.

Hamar society, like most East African pastoralists, is clan-based, and birthright membership in a patrilineal clan is a salient feature of one’s social identity. This is part of what makes what is called a kinship-intensive society. Clan-based societies have long been thought to be more likely to experience large-scale conflicts (and this has been recently demonstrated empirically), given that disputes between individuals from different clans or social groups can move up the social levels, recruiting substantially more significant numbers of engaged individuals with every ratchet up. “Me against my brother, me and my brother against my cousin, me and my cousin against the world,” the old proverb goes. This might be somewhat equivalent to, say, if, during a friendly football match between RasenBallsport Leipzig and Toulouse Football Club, an overly enthusiastic Toulousian and Leipziger got into a drunken brawl, which, if left unresolved, was likely to lead to a more significant conflict between the Saxony and Occitanie regions, and then an all-out war between Germany and France. Thankfully, as we all know, this is extremely unlikely to happen (especially in post-industrialized and Western cultural contexts). In kinship-intensive societies, however – which were probably the norm throughout our evolutionary history and remain common in many parts of the world today –  an open question is, how do clan-based social structures promote or inhibit conflicts between individuals?

Our study asked 99 adults, all willing participants in one Hamar community, to report on conflicts they had experienced with other adults, disputes between different community members they were aware of, or which they had been involved in as a third-party mediator. We also asked each participant to report on the nature and cause of the conflict, who was involved and their relationships, how relatively severe the conflict was, and the outcomes of the conflict, i.e., was it resolved and do the people in conflict get along today. Based on these data, we could analytically explore the socio-ecology of disputes and their mediation in this particular Hamar society.

A first and intriguing result: we observed that 54% of conflicts reported involved the intervention of a third-party mediator. This figure intriguingly aligns with findings from other autonomous, subsistence-based societies worldwide. For instance, von Rueden’s 2022 research with the Tsimane horticulturalists in the Bolivian Amazon demonstrated that, across four villages and seven observations, men reported the involvement of a third-party mediator in 56% of conflicts. Likewise, Singh and Garfield’s 2022 study with the Mentawai horticulturalists in Indonesia revealed that, out of 217 disputes, nearly half (49.8%) involved third-party mediation. These parallel findings across varied cultures and methods—from self-reports to observations—underscore a common thread: almost half of all interpersonal conflicts within these communities see the peacemaking hand of a third-party mediator.

We also found that pastoralists’ economic systems powerfully shape inter-individual conflicts. More than half of all reported conflicts were related to livestock grazing in someone’s agricultural plots or due to some other livestock management issue. Social disputes, such as those that arise from intoxication, quarreling children, or personal insults, were relatively more common among women, which we interpret as a consequence of gendered divisions of labor, more significant social interactions among women, and demographic patterns of greater mobility among younger adult men. Overall, these results paint a picture of a society where economic, social, and personal dimensions strongly interlace in the emergence of conflicts.

One of the most striking findings was the active involvement of both men and women in conflicts and their resolution, albeit in varying capacities. Men were more likely to be involved in economic and resource-based disputes, whereas women were more likely to be involved in resolving social conflicts. Furthermore, men are typically the mediators of disputes between other men; the same goes for women. However, conflicts between a man and a woman were equally likely to be mediated by a woman or a man. This highlights not only the significance of gender dynamics in conflict resolution but also the nuanced roles women play in these processes, even in a predominantly patriarchal society.

We also found that third-party mediation is more likely for social conflicts and when conflicts emerge between clan members but less likely for disputes between blood relatives. Surprisingly, more severe conflicts were not more likely to involve third-party mediation once other factors were considered. This emphasizes the importance of maintaining social cohesion within clans and suggests blood relatives may more easily be able to resolve conflicts on their own.

This study is just one small piece of the puzzle of human conflicts and resolution. Our results suggest that social structures can be designed to help limit and effectively mediate interpersonal disputes and that we should consider the social, economic, and cultural contexts of human groups and societies to understand what drives conflicts’ emergence and facilitates their resolution.

Read the original article here: Garfield, Z.H., & Glowacki, L. (2023). Interpersonal conflicts and third-party mediation in a pastoralist society. Evolution and Human Behavior, 44(6), 613-623.

To learn more about our work, our nonprofit, and philanthropy in Southwest Ethiopia, see The Omo Valley Research Project.

Childcare at HBES 2024 Aarhus

Dear HBES members,

We are pleased to announce that HBES will be offering a childcare option for parents attending the HBES 2024 conference in Aarhus. The Society has contracted with the Nanny Agency, based in Copenhagen and Aarhus, to provide childcare services:

The hourly rate for childcare will be $20 USD during the day from 8am-7pm. There is also a possibility of childcare during the evening at a higher rate.

We will ask HBES attendees to sign up for child care by April 15 in order for the Agency to be able to guarantee the required staff and hours. By that date, we will ask parents to commit to their preferred childcare schedule (dates and times) and pay for the hours specified in that schedule.

For parents traveling with children, HBES strongly recommends that parents obtain travel insurance for themselves and their children, in order to have full coverage for possible accidents and hospitalization. The childcare agency has required liability coverage under Danish law, but it is limited to accidents caused by agency staff during hours of supervision.

As part of the registration process, HBES will provide a portal for parents to register and pay for childcare service. Stay tuned!

The Ups and Downs of Fieldwork – A Personal “Dispatch From the Field”

– by Nicole Hess

[Communication Officer’s Note: Readers of Evolution & Human Behavior are used to reading the results of fieldwork when the papers get published. However, unless they themselves are field researchers, readers of E&HB may not be as familiar with the *process* of fieldwork and what it’s like to collect such data (I count myself in this category). This blog entry is a personal account of the fieldwork process for one of the papers in the recent special issue on “Dispatches From the Field”. It highlights some of challenges and joys of fieldwork and of adapting protocols from MTurk into the field. Of course, every field site is unique, so anthropologists’ experiences will vary as much do the cultures they study – this is just one illustrative experience. The paper described herein is: Hess, NH, & Hagen, EH (2023). The impact of gossip, reputation, and context on resource transfers among Aka hunter-gatherers, Ngandu horticulturalists, and MTurkers. Evolution and Human Behavior, 44(5), 442-453.]

In the summer of 2012, when our daughters were 2 and 6, my spouse was preparing to head to the Central African Republic (CAR) to continue his fieldwork on recreational drug use by Aka hunter-gatherers. This was his 3rd or 4th trip, and I would be staying home (again) with our young children. I also have a PhD in Anthropology, so as he applied for visas and secured research materials, I wondered if I could join to work with one of the few foraging groups left in the world, the Aka, and revitalize my evolutionary psychological research on gossip as reputational competition. My teaching responsibilities would not be disrupted, because we’d be back just before our university’s fall term started.

We could not take our young children to the field for safety reasons, mainly the high child mortality rate (5 children in the village died during our field season). Inconveniences included limited dietary options and a lack running water or electricity for cooking or personal use. We were fortunate to have reliable grandparents and great-grandparents two states away who were willing to help, and a satellite phone to call twice a week. My matriline agreed to do most of our girls’ caretaking, and my paternal grandparents (who were approaching their 90s) agreed to give them breaks by taking the girls for a day at a time over the month that we would be in Africa.

It is harder to make last-minute changes to fieldwork than lab work due to additional health, governmental, and logistical challenges. We adjusted our travel dates, applied for my visa, and added my name to research permit applications that were about to be processed by the CAR government. I took the risk of getting several vaccines at once so that all the immunities would be in effect by the time we arrived in CAR. We got all that in order, flew to Los Angeles to drop our girls off with my mother, got right back on a plane to Paris for a connecting flight to Bangui (CAR’s capital) for our permits, food, gasoline, and gifts for our hosts such as soap and medicines (aspirin, antiseptics, bandages), and finally drove to our field site; that’s over 48 hours of flights, connections, and driving.

We arrived in the Ngandu village of Bagandou, CAR in late July. The Ngandu are small-scale horticulturalists growing manioc, corn, plantains, and other crops in extensive gardens surrounding the village. They have some market integration, with families producing some cash crops, like coffee for sale outside of the village. Ngandu also trade their crops, money, and small gifts like salt and tobacco with the Aka for net-hunted small game and labor (e.g., Aka work in Ngandu gardens for manioc).

We happened to arrive in Bagandou in the middle of caterpillar season, a short period when most Aka are focused on moving far and wide in the forest to collect caterpillars to use as food. Caterpillars are consuming plant matter prior to metamorphosis into moths and butterflies; they literally rain from the trees as they feast. Caterpillar season had come unusually early this year, so we had to put our primary study, which involved reputation and access to resources, on hold because most adult Aka were not accessible. We decided to run our secondary study first, working with Ngandu participants to replicate an MTurk experiment we’d run earlier.

The MTurk resource allocation experiment involved participants being exposed to stimuli including a vignette with a fictional target individual, followed by several negative vs. positive and relevant vs. irrelevant gossip statements about the target. Participants indicated their opinions of the target, as well as their likelihood of allocating a valuable resource to the target.

The MTurk experiment used stimuli suitable to a WEIRD population. To run it with the Ngandu, we had to create new vignettes, gossip content, and dependent measures that were consistent with Ngandu culture. Initially I created vignettes involving witchcraft, as this is a common precursor to gossip in Ngandu daily life. For example, witchcraft accusations often involve jealousy over accumulations of material wealth. But our Ngandu research assistants quickly vetoed those vignettes, sternly warning us to “never talk about witchcraft” because witchcraft and witchcraft accusations led to serious consequences. They provided several accounts of witchcraft that resulted in painful losses, dangerous behavior, illness, and even death. So we brainstormed for several days with our field assistants, developing vignettes, gossip statements, and dependent measures. The Ngandu value a reputation for generosity, and resource transfers among paternal and maternal relatives are routine. With this in mind, our assistants helped us develop vignettes that reflected common local experiences: inheriting valued items and sharing them with family, and also hiring Aka laborers with whom they often shared gifts like clothing. Our assistants also helped us generate several gossip statements that were to be manipulated. To check the validity of the statements, we recruited dozens of locals to evaluate the negativity and positivity of each statement. So just adapting our stimuli to the local context took an immense amount of work – and we hadn’t even started the actual experiment!

We shared many laughs with our assistants about what kinds of behaviors were associated with “good” and “bad” reputations in our cultures. Some behaviors they viewed as important were not ones we expected; other behaviors that we thought would surely be “good” and “bad” were insignificant to the Ngandu. They told us gripping stories about encounters lions, hippos, crocodiles, and apes; we told them that, where we were from, movies and amusement parks exposed people to such animals as a form of entertainment. They laughed in disbelief at my description of the “Jungle Cruise” ride at Disneyland—and when I convinced them it really existed (with fake animals), and was an experience for which people paid a lot of money, they asked “why would you want to scare a child with this?”.

Once the study was designed, I got to work putting the materials together to present to participants, which was another challenge in the field context. We couldn’t collect data on laptops because of the limited electricity, so I cut uniform 2×6 inch strips of paper out of a flimsy, lined cahier (notebook) from the tiny local market, and neatly hand-wrote our experimental stimuli on them. Then, making good use of my packing tape, I laminated each slip, front and back. The gossip statements written on the slips were to be used hundreds of times in different random combinations for our between-subjects design, so they needed to be sturdy. I made one set in English, and one in French.

Then there was the actual running of the study. We needed translators to present our stimuli to participants who spoke the Ngandu language (diNgandu) or Sango, the main language in CAR. Not all of our research assistants spoke English, so in running our experiment, my spouse/coauthor worked with a translator who spoke diNgandu, Sango, and English, and I worked with one who spoke diNgandu, Sango, and French – some of which I thankfully still remembered from 25 years ago. With the help of our tireless translators, we were able to efficiently run our Ngandu experiment with enough participants to fill our conditions. We found that hearing more positive gossip relative to negative gossip led to a higher likelihood of giving the benefit. And, when gossip content was relevant the context of the competition (family or work), the effect was stronger.

Surprisingly, we still had about a week left before our flight home (only one plane left Bangui for Paris each week, and we could not miss it). We decided to attempt to run our Aka study. By this time, caterpillar season was coming to a close, and the Aka were returning to their camps which were located along trails that radiated from Bagandou into the forest. One of our research assistants who also spoke diAka helped us run this study with adult Aka participants from camps along 2 trails. This study involved non-experimental methods where participants peer-rated one another in response to a small number of questions related to reputation and access to resources (along with age, sex, and relatedness). We investigated the relationships between participants’ peer-rated contributions to their group, reputations, costs imposed on the group, and receipt of benefits from the group. Unlike typical groups of adults in the US, such as co-workers, the Aka in our study had lifelong relationships with each other, and many were biological kin. Aka results showed that contributions to family and community were associated with a good reputation, which in turn was associated with receiving benefits.

Although there were many challenges, this field experience was not just fruitful, but enjoyable. I had been expecting a physically uncomfortable site with hard-to-access participants, where language barriers would limit my ability to study gossip. But the living conditions and climate were pleasant, and language, thanks to our competent and enthusiastic assistants, was no problem at all. Members of the communities were warm, authentic, and willing to share themselves and their cultures with us, and they were curious about what we were up to; this made data collection breezy and gratifying. We wanted to return to CAR soon.

Unfortunately, a few months after these studies, CAR plunged into a civil war that is still ongoing. We get infrequent updates from our research assistants about their lives and the local political climate. Diamonds and gold were discovered in the region around the time we were there, and jobs for men in mining (a dangerous venture that can result in windfalls, but also injuries and death) dramatically increased cash flowing into Bagandou. Beyond disruptions due to civil war and dangerous mining practices, interest from international mining groups in diamonds and gold are increasingly impacting in the region. We have not been able to return in over 10 years.

Read the published paper described in this blog: Hess, NH, & Hagen, EH (2023). The impact of gossip, reputation, and context on resource transfers among Aka hunter-gatherers, Ngandu horticulturalists, and MTurkers. Evolution and Human Behavior, 44(5), 442-453.

Arranged and Self-Choice Marriage: Implications for Child Outcomes

– By Kristin Snopkowski & Annemarie Hasnain

While free choice of spouses (i.e., the love marriage) is the norm in western countries today, arranged marriage has historically been a common form of marriage.  We see this today in some cultures, like India and Pakistan where it is still common, and in the past century in many other parts of the world, including many small-scale foraging populations. Given the interest of evolutionary researchers on the topic of mate choice, which requires that individuals choose their own mates, do arranged marriages lead people to marry less preferred partners and what are the implications? Research in our recent Evolution and Human Behavior article, “Maternal investment in arranged and self-choice marriages: A test of the reproductive compensation and differential allocation hypothesis in humans,” seeks to understand the role arranged marriage plays in reproductive and child outcomes.

Research has shown that the mate one would choose for themselves may be different from the one that would be chosen as a son- or daughter-in-law. Most of this research comes from surveys that ask individuals for their preference in a mate and their preferences for a son or daughter’s spouse or those that separately ask parents and adult children for their preference in the adult child’s spouse. These studies tend to find differences, where people prefer attractiveness and an exciting personality in a potential spouse, but instead prefer similar ethnic background, religion, and social class in a potential son- or daughter-in-law.

Mating preferences likely evolved because of the fitness implications of these choices. Evidence from the non-human animal literature shows that when individuals are forced to mate with less preferred or unattractive partners, their offspring do worse (i.e., have reduced fitness).  This may be because attractiveness is an honest signal of immune function or that preferred partners have better territory that allow them to invest more in offspring or that preferred mates are more likely to produce offspring that are then preferred by individuals in the next generation, increasing their chance of finding mates. Regardless of the mechanism, these findings suggest that arranged marriage may impede an individual’s choice of an optimal partner.

There are two hypotheses that have been developed to explain investment patterns in offspring from non-preferred or unattractive partners.  The first hypothesis is the differential allocation hypothesis, which argues that individuals will invest less in the offspring of unattractive mates.  Conversely, the second hypothesis, called reproductive compensation, states that individuals will invest more in the offspring of non-preferred mates as a means to compensate for their offspring’s likely reduced prospects. These hypotheses have not previously been tested in humans, but arranged marriage may provide an opportunity to explore these hypotheses in humans. This requires that the spouse of individuals in arranged marriages are in some way less preferred, which some empirical evidence suggests given two assumptions: first, that mating preferences are evolved to optimize mate choice and, in turn, offspring outcomes and second, the preferences for a mate are different than the preferences for a son- or daughter-in-law.

Our paper tests whether there are any differences in how mothers invest in their offspring depending on their marital status (arranged marriage or self-choice marriage). The sample included about 8400 women living in Indonesia who were surveyed longitudinally from 1993 to 2015.  We examined factors like prenatal checkups, birth weight, breastfeeding duration, children’s height-for-age and weight-for-age, to determine if there are differences based on whether the parents were in an arranged marriage. We also examined fertility outcomes including the number of live births, the number of living children, marital fertility (number of births per years married), and the number of stillbirths and miscarriages.

The results show that arranged marriage is decreasing in Indonesia.  For women born prior to 1930, about 55% reported their marriage as arranged, but for those born after 1990, this has fallen to 6.7%.  When maternal investment is examined for women in arranged vs. self-choice marriages, there are no significant differences in the number of prenatal checkups, birth weight of children, breastfeeding duration, or offspring height and weight.

When the number of children is examined (live births, living children, marital fertility), results show slightly fewer children for those couples in arranged marriages. There is a significant reduction in the number of living children and a marginally significant reduction in live births and marital fertility.  Interestingly, arranged marriage couples also have a marginally higher number of stillbirths.

These results suggest that being in an arranged marriage or a self-choice marriage results in few differences in how women invest in their children. Being in an arranged marriage does not appear to significantly increase or decrease investment that influences child size, for instance through prenatal check-ups, breastfeeding, or height and weight in childhood. The only factor that had any significant effect was number of living children, which suggests some support for the differential allocation hypothesis, that individuals who choose their mates invest in having more offspring. There is no evidence supporting the reproductive compensation hypothesis, that people are increasing investment in the offspring of less preferred partners. This finding also supports research from other species that free mate choice is associated with increased reproductive success. The reasons for this effect could relate to genetic incompatibility which makes it harder to conceive or less likely to bring offspring to term for couples in arranged marriages. It is also possible that self-choice partners begin reproduction sooner because they begin their marriage well-acquainted with each other and may experience greater marital satisfaction.

Why would someone agree to an arranged marriage if it hinders their reproductive success?  While people who come from cultures where arranged marriage is rare may find the practice unappealing, it is important to point out the numerous benefits of arranged marriage. In many cultures that practice arranged marriage, it is believed that arranged marriage is an optimal family strategy, allowing more experienced parents to identify good partners for their children. Further, there is some evidence that parents provide more support to their adult children if they choose their partners, especially as parents may feel some responsibility for the success of the marriage.  There are likely tradeoffs people experience in terms of alloparental and social benefits that result from engaging in arranged marriage (especially when it is the dominant marriage pattern in a community) even though there may be slight costs to reproductive success.  A detailed examination of the costs and benefits of different marriage strategies provides a fuller understanding of the variation we see in marriage patterns across the world.

Read the original paper: Hasnain, A.M., & Snopkowski, K. (2024). Maternal investment in arranged and self-choice marriages: a test of the reproductive compensation and differential allocation hypothesis in humans. Evolution and Human Behavior, 45, 99-110.

crowd of participants in speed-dating

Funny How? Humour as an Evolved Trait

– by Henry Wainwright

Humour is an everyday part of our lives and is present in virtually all human cultures, seemingly both past and present; the oldest known surviving joke being from Bronze Age Sumer, circa 1900 B.C. And while what we find funny is likely culturally and socially influenced, the fact that we all have a sense of humour, irrespective of culture, strongly suggests that humour evolved for some purpose.

One among many evolutionary explanations is that humour may have helped our ancestors to attract a mate. Indeed, individuals today consistently report a preference for humour in a romantic partner. However, it remains unclear why, in an ultimate sense, humour is considered an attractive quality. Humour is enjoyable, of course – but there is nothing inherently enjoyable or attractive about what we describe as funny. The question becomes, why did we evolve to find certain things funny and to be attracted to funny individuals?

The ‘fitness indicator hypothesis’ argues that humour aided ancestral courtship because being funny signals underlying genetic quality. Specifically, the idea is that funniness requires mental performance (e.g. speed, intelligence, creativity), which in turn requires a high-functioning brain, which in turn requires a low load of genetic mutations. Therefore, both being funny and being attracted to funny people are evolutionarily favoured because offspring of these couplings will inherit lower mutation loads and pass on their parents’ genes more effectively.

We tested predictions from the fitness indicator hypothesis by having participants – undergraduate students from the University of Queensland – report their preferences for humour in a romantic partner (i.e. their stated preferences) before engaging in a multiple unscripted, three-minute speed dates with each other, for a total of 860 unique dates. After each date, participants rated their partner on several characteristics including their funniness, their  humour receptivity (they found me funny), and their overall attractiveness.

Audio from these interactions were also surreptitiously recorded for a subset of 563 dates, which enabled the use of an additional, objective measure of humour, in the form of laughter frequency. From there we tested the central predictions of the fitness indicator hypothesis: that funniness and humour receptivity are attractive traits. We were also interested in additional predictions of the hypothesis, namely, that in accordance with parental investment theory, there should be a sex differences in how men and women respond to humour. That is, men should be attracted to humour receptivity in a partner more than women, whereas women, more so than men, should value funniness in a partner.

Indeed, results from stated preferences were largely consistent with these predicted sex differences. However, relying on stated preferences alone is problematic because doing so assumes that participants have sufficient, bias free insight into their own preferences. In practice, stated preferences often fail to predict individuals’ evaluations of potential partners (i.e. their revealed preferences). Therefore, we continued our investigation by looking at revealed preferences using laughter as well as ratings of humour .

We began by looking at how strongly participants’ ratings of their partners’ funniness or humour receptivity correlated with their ratings of the partners’ overall attractiveness. This allowed us to first check the basic premise of the fitness indicator hypothesis: that funniness is actually attractive. Consistent with this premise, partners who were rated as funnier were also rated as having greater overall attractiveness. Notably, the same was not found for humour receptivity – partners rated as more receptive were rated no more or less attractive overall. More damaging for the fitness indicator hypothesis, though, is that the predicted sex differences were not observed at all: the associations of both funniness and humour receptivity with overall attractiveness were similar in men and women.

Using ratings as a sole assessor of revealed preferences can be troublesome, as post-interaction ratings are possibly subject to a halo effect, whereby participants might rate a partner as funnier simply because they were more physically attractive, for instance. Therefore, we examined revealed preferences using laughter as a real-time, behavioural measure of both funniness and humour receptivity. After first establishing that at-partner-laughter (i.e. participant laughter following something their partner said) was positively associated with ratings of funniness, thus partially validating laughter as a measure of humour, we found that neither funniness nor humour receptivity, as measured by laughter, predicted ratings of overall attractiveness. Furthermore, using laughter, we found no evidence that men value humour receptivity in a speed-date partner more than women do, or that women value funniness in a speed-date partner more than men do.

In summary, we found that while stated preferences largely supported the sex differences predicted by the fitness indicator hypothesis, results from revealed preferences, which are taken as more valid than stated preferences, did not support these predicted sex differences and offered only mixed support for the central premise of the hypothesis, that funniness is attractive.

Overall, our results call into question not only the fitness indicator hypothesis, but also (or alternatively) the degree to which parental investment theory can be applied to sex differences in humans’ preferences for fitness indicators. The absence of significant sex differences in revealed preferences alone does not necessarily exclude humour as a fitness indicator; instead, it may be that the degree to which parental investment theory predicts sex differences in human fitness indicators has been overestimated. Humans exhibit mutual mate choice, and as a result, fitness indictors are still expected to evolve, but not necessarily with large (or any) sex differences. So the possibility remains that humour may be a fitness indicator, but men and women differ little, if at all, in their attraction to it. The current study is partially consistent with this possibility, as there is evidence that both funniness was a desirable trait to both sexes similarly. However, further investigation, especially into the role that humour plays in romantic attraction over longer periods of acquaintance, is needed to fully investigate this possibility, as well as to comprehensively test the fitness indicator hypothesis.

Read the original article: Wainwright, H.M., Zhao, A.A.Z., Sidari, M.J., Lee, A.J., Roberts, N., Makras, T., & Zietsch, B.P. (2024). Laughter and ratings of funniness in speed-dating do not support the fitness indicator hypothesis of humour. Evolution and Human Behavior, 45(1), 75-81.

Connections beyond blood: chosen kin are integral to human social life

– by Ollie Shannon & Anne Pisor

The Vatican made it official: transgender individuals can now serve as godparents.

But what is a godparent and why are godparents important? Ultimately, answering this question requires us to think about the evolution of human social life – and the importance of chosen kin.

Humans raise children cooperatively, with alloparents – people other than the parents – usually involved. Born helpless and with long childhoods, our kids need all the help they can get.

Evolutionary social scientists have traditionally focused on biological kin as helpers, much as bio kin are the primary helpers in other cooperative breeders like crows and meerkats. But the Vatican’s declaration reminds us that in humans, the question of who helps is more complicated.

Choosing kin

Humans have a diversity of non-kin alloparents – a rich tapestry of social relationships and reciprocal obligations. Non-bio kin can be especially involved when bio kin aren’t available to help, like in communities with high residential mobility or in the Queer community, when bio kin sometimes aren’t interested in helping their Queer kids. In marginalized communities facing systematic challenges such as poverty or discrimination, individuals may face limitations in the support they can offer due to these systemic factors and may rely on a combination of bio-kin and non-kin alloparents to help everybody’s children thrive.

When humans lack needed family support, we often create the family we need. In the Black community, for example, churches and religious institutions offer a sense of community during tough times and joyful occasions. The use of kinship terms such as “brother” and “sister” in a religious context affirms and strengthens these relationships. For this reason, non-bio alloparents are often called chosen kin or, using an older term from anthropology, fictive kin.

Compadres, padrinos, and ahijados

Godparents are chosen or bio kin who commit to being a child’s alloparent, usually through a ritual – by being present at a birth, for example, supporting a child’s graduation party, or being present at a child’s baptism. In Latin America, where godparenthood (compadrazgo) is widespread in the Catholic church, the choice of godparent is often guided by a mix of considerations, including the social standing of the godparent and their ability to provide help and resources.

In rural Bolivia, the focus of our recent paper in Evolution & Human Behavior, the support and resources godparents provide is sometimes day-to-day, like after-school care, but can also be rare but big infusions of help. Godparents who live in the city, for example, can house an adult godchild when they go to university, provide help with bureaucracy, or send packages of things not available rurally, like cheap smartphones or other household items.

Given the importance of godparents in this context, we asked: how might godparents impact child outcomes? For example, if godparents often provide after-school care or house their grown godchildren, does this impact godchildren’s educational outcomes? Studying how and the degree to which godparents impact child outcomes across societies could unlock key insights – like the benefits of non-kin alloparental support to kids, parents, and the alloparent themselves – that are still not a common focus in the evolutionary literature.

In 2017, one of us (AP) led a research team that interviewed 148 adults about their children, including their adult children: we wanted to know not only whether their kids had godparents, but where those godparents lived, and what their kids’ educational outcomes were. Among the 210 adult children discussed, 163 had at least one godparent. However, these godparents didn’t have detectable impacts on their godchildren’s education in our statistical models – not on years of education, high school completion, or even pursuing a university degree. It didn’t matter if the godparent lived in the same community – where the godchild’s high school was located – or somewhere else, or even whether the godparent was actually bio kin who had been given godparent status.

Instead, we found that adult children with more older siblings were likely to have more years of primary and secondary education, complete high school, and pursue higher education. Older siblings are important alloparents in many contexts, with varying impacts on child outcomes – including educational attainment.

What next in the study of chosen kin as alloparents?

Our findings underscore that chosen kin may not have measurable effects in all domains of a child’s life – but, as captured by our ethnographic data, are still making things easier for parents and children alike, by providing care, resources, and even housing. Whether through quantitative or qualitative data collection, focusing on impacts on children or even on their parents, there is still much to be done in understanding why chosen kin are so prevalent in human societies.

In the rich tapestry of human sociality, the concept of chosen kinship serves as a testament to the flexible nature of human relationships. By embracing the complexity of chosen kinship, we honor the resilience and diversity of human social bonds, fostering a more inclusive and compassionate approach to human relationships.

Read the original article: Hubbard, E.B., Shannon, O., & Pisor, A.C. (2023). Non-kin alloparents and child outcomes: older siblings, but not godparents, predict educational attainment in a rural context. Evolution & Human Behavior, 44(6), 597-604.