A Letter From the Incoming President, Dave Schmitt

HBES is a scholarly community, for many of us it is our academic home away from home. And just like most communities around the world, ours has faced considerable challenges over the past two years. In this message, I want to express my gratitude to those who helped effectively maneuver HBES through unprecedented times, especially Leda Cosmides for her work as HBES president these last two years and Doug Kenrick for his service as past-president of HBES. Thank you also to Bernhard Fink for enhancing the HBES website and improving our capacity for online engagement. Thank you to Nicole Barbaro for her incredible efforts as HBES communications officer, Catherine Salmon for her longstanding contributions as HBES treasurer, and all members of the HBES Executive Committee. HBES has remained strong and resilient because of their efforts in growing our ability to be inclusive, welcoming, and digitally connected.

I also want to express my deep appreciation to the hosts of planned HBES conferences in Detroit and Palm Springs for their flexibility and hard work over the past two years—both conferences are now on schedule for 2022 and 2023, respectively. This was no easy task. Thank you to everyone who helped make our upcoming HBES Virtually Everywhere (#HBES2021) online conference a reality, especially the host committee (Coren Apicella, Chris von Rueden, Nicole Barbaro) and programme committee (Aaron Lukaszewski, Jaimie Krems, Anne Pisor, Cari Goetz). Coren pretty much dropped everything to make HBES Virtually Everywhere happen this summer, we all owe her significant thanks. And kudos to everyone who dedicated themselves to making our HBES Roundtable Seminar Series such a tremendous success this past year (videos of these events may be viewed on YouTube here.

Finally, I want to thank those HBES members who have committed their time and energy for crucially important work on the HBES Grievance Committee and in evaluating HBES grant proposals and award nominations. Jaimie Krems, chair of the HBES Grievance Committee, deserves special thanks for helping to make our community safer and more inclusive these past two years, and thank you to Nicole Barbaro for vigilantly monitoring, analyzing, and reporting on results from our HBES conference climate survey. A key focus of HBES has been on welcoming, developing, and highlighting early-career scholars from across the evolutionary behavioral sciences. HBES has supported graduate student and prospective graduate student luncheons, methods and statistics workshops, and meetings such as Women of HBES. This year at HBES Virtually Everywhere we have an LGBTQ+ mixer event hosted by Michael Barlev (thank you, Michael!).

HBES has honored and rewarded several categories of early-career scholarship at our annual conference, including awards for best conference posters, best post-doc papers/presentations, and new investigator awards. Since 2010, we have honored the best paper published in the HBES-affiliated journal Evolution and Human Behavior with the Margo Wilson Award. We have given HBES awards for Early Career Award for Distinguished Scientific Contribution (2020 Winner, Katherine McAuliffe) and the Lifetime Career Award for Distinguished Scientific Contribution (2020 Winner, David Perrett). Through several of our HBES grant funding mechanisms, we have reached out to support a diverse array of evolution-related undergraduate student meetings, regional academic conferences, and professional organizations around the world.

HBES is truly a worldwide scholarly collaboration, but our community is only as robust and vibrant as the individual HBES members who dedicate themselves to making it so. Thank you to all HBES members whose service to our community has made a difference these past two years and for setting the stage for future generations to make it better still.

Looking forward to the future of HBES, I’m drawn back to the inspiring comments by past-president Dick Alexander during his 2008 keynote address to HBES in Kyoto, Japan. He remarked that, “The most important and frightening of all human adaptations is likely our stubborn and perhaps unique manner of alternating our most intense emotional expressions between the two extremes of amity and enmity within our own species…We need every tool available to understand such things about ourselves. These are reasons why the Human Behavior and Evolution Society has the potential to become the most important scientific organization in the world.”

Every tool available. In my view, that phrase captures the greatest potential of our HBES community. Each year we bring together a wide variety of scholars and their tools from disciplines such as Darwinian literary studies and communications, Darwinian medicine and economics, Darwinian politics and philosophy, evolutionary anthropology and biology, evolutionary neuroscience and genetics, evolutionary psychology and human ethology, evolutionary sociology and family studies, human behavioral ecology and demography, and primatology and comparative psychology (among many, many others). HBES was founded in hopes that we continuously learn from each other, that every HBES conference provides an opportunity for new sparks of connection to be made across disciplines, and that these connections help us to more fully understand the best and the worst of human behavior.

Personally, I’ve found the best part of HBES often comes from attending sessions outside of my area of expertise. The first occasion I encountered the wonderful tool D-Place was at HBES whilst attending a presentation outside my discipline. The stimulating talks I heard and the questions and debates that transpired throughout that session greatly affected my thinking and scholarship for years to come. HBES can do that, should do that, for each of us every year. I’ve found interdisciplinarity and exploring an issue with “every tool available” is where the scholarly magic happens. Further cultivating that interdisciplinary ethos is something I very much look forward to as president of HBES in the next few years.

In these challenging times, our coming together in HBES has never been more important, to science and to our collaborative community. I look forward to seeing you and learning from you all at HBES Virtually Everywhere (#HBES2021). Stay safe.

–Dave Schmitt, President, HBES


Dave will take over duties as HBES President following the HBES 2021 conference, along with the rest of the new members of the Executive Council

There is Nobody Quite Like Grandma

by Ilona Nenko


From an early age, many of us learn that our grandmothers are invaluable in our lives. Their experiences, help, and knowledge can shape us into who we are today, and their influence stretches far beyond simple stereotypes. Grandmothers have long held a special place in almost every culture, and the human story without grandmothers is not much of a story at all. If we look back in time we find that they were even more valuable than they are in the present, with strong empirical evidence that they have helped grandchildren to survive and aided the fertility of their own offspring. These benefits to relatives are thought to have played a role in the evolution of the extended post-reproductive lifespan that separates us from other great apes. In case it isn’t clear by this point, we think grandmothers are very important. But, is every grandmother equally important?

Well, as it turns out, no. Context-dependence is crucial in the expression and outcomes of helping behaviours in other cooperative species, and humans are no different. We have a lot of evidence that maternal grandmothers play a special role in the lives of grandchildren, moreso than paternal grandmothers. It begs the question then, are all grandmother-related grandchild outcomes the same? This is an interesting question because not all grandchildren are born equal. The circumstances of birth can be hugely influential in early life: firstborn children have different outcomes to later births, twins differ in outcomes than singletons, siblings born in a short time frame can suffer negatively compared to those with a longer interval between births, and children born out of wedlock often have worse outcomes than those born within unions. These statuses may seem to be very different at a surface level, but all have a lot in common: higher risk of low birth weight, higher risk of getting lower Apgar scores, higher risk of being born prematurely and – consequently – lower chance of survival. Bad starts are just that – bad – but don’t necessarily spell doom. History is littered with examples of poor starts being overcome. Sometimes all it takes to turn around a tough beginning is a bit of luck. Sometimes it takes a little helping hand.

Here is where grandma returns. Given there are so many bad starts children could face, and given grandmothers are known to provide benefits (at least some of the time), we decided to investigate whether grandmothers increased the chances of survival of children who experienced hard starts to life. We studied Finnish genealogical data from 1730-1895, a time when medical care was very basic and contraception was not available; childhood survival was low, adult life expectancy was much lower than today, and birth rates were high. Grandmothers were very much needed. Finland is an exceptional country for doing this kind of study – Lutheran priests kept extensive records on the population, giving us a rare opportunity to look at ordinary lives in the past, and we know much of how the society operated. We also know from other work with this Finnish population that grandmother presence was not always helpful, particularly if the grandmother was frail. But did grandma help when the going got rough?

The lack of beneficial survival outcomes of grandmother presence for these poor starts reinforces the importance of investigating different contexts of possible help, and perhaps adds another piece to the slowly unraveling mystery of the evolution of extended post-reproductive life.

Alas, in most of the investigated bad starts, grandmother presence was not beneficial. Firstborns, twins, babies born two years after their older siblings, nor illegitimate children –had an increased chance of reaching the age of five if their grandmothers were alive or not. The lack of beneficial survival outcomes of grandmother presence for these poor starts reinforces the importance of investigating different contexts of possible help, and perhaps adds another piece to the slowly unraveling mystery of the evolution of extended post-reproductive life.

It wasn’t all bad news for these historic Finns though: grandmothers were extremely important to children who welcomed a younger sibling before their second birthday, with a massive 41% increase in the probability of surviving to age 5 compared to grandchildren with no grandmother. It isn’t too difficult to see why: the mother had to focus on the fully-dependent, far needier younger child, and it would therefore benefit her and the child if others in the family – chiefly the grandmother – could help. Grandma benefited from this too – by increasing the chances of survival of her daughter’s children, she increases not only the reproductive success of her daughter, but also her own biological fitness. In a way, by caring for her daughter and her grandchildren, she also cares for herself.



Read the paper: Will granny save me? Birth status, survival, and the role of grandmothers in historical Finland

Making Simple Decisions in a Complex Social World

by Pieter van den Berg


We all know humans are social animals. So it makes sense that much of our psychology is geared towards analyzing social situations and choosing appropriate actions for them. This social psychology has to work in a complex and messy world. Every social interaction is different, involving different parties with their own desires and interests, and different possible actions to choose from. To make matters worse, we have to operate under considerable uncertainty: it is often impossible to accurately predict how our actions will turn out.

How has evolution equipped us with an effective psychology to navigate social decision making in this complex and uncertain world? This is not an easy question. Social evolution is intricate, because the fitness consequences of social behaviors depend on what others in the population are doing. A cooperative individual may be successful in a population full of trustworthy interaction partners, but that same individual may fare much worse when surrounded by cheaters. To gain insight in how evolution shapes social behaviors despite these intricacies, scholars have often relied on highly simplified models of social evolution, often reducing the messy social world to just a single type of interaction such as (most famously) the Prisoner’s Dilemma Game. The idea is that if we understand how evolution hypothetically shapes behavior in that very specific situation, we will gain an understanding of how evolution shaped parts of our social psychology.

But does evolution really tailor behavior separately for each specific social circumstance that may arise? This seems unlikely – especially given the fact that individuals often don’t even know all the specifics of the situations they find themselves in. By now, a realization has settled in that the human mind is not a smooth optimization machine, but often works in ways that seem unsophisticated or crude. This is exemplified in what are referred to as ‘cognitive biases’ – proof that people are not consistent or systematically deviate from acting in their own rational interest. Such biases can be the result of a psychological machinery that is not perfectly attuned to the situation at hand, but rather operates by using ‘heuristics’: simple behavioral strategies that work well across a range of situations, but that can ‘misfire’ in some specific circumstances.

Do people apply such rough rules of thumb in social situations, leading to behavior that is suboptimal or inconsistent? A few recent evolutionary modelling studies suggest that we might expect them to. Bear & Rand have shown that evolution can produce a psychology where individuals ‘intuitively’ invest in cooperative relationships, even if that relationship will not extend far enough into the future to make that investment worthwhile. In 2018, I developed a model to investigate how individuals are selected to behave in a ‘messy’ world with many different types of social interactions and some uncertainty about which situation they are in. This model showed that evolution predictably leads to the emergence of simple heuristic strategies that often cooperate, even in situations where it is guaranteed to lead to bad outcomes. These ‘social heuristics’ even evolved when individuals had only intermediate uncertainty about the social interactions they engaged in, and could implement more sophisticated strategies (tailoring behavior to specific circumstances) without any extra cost.

For a new study that was just published in Evolution and Human Behavior, we conducted a decision making experiment in which we confronted participants with a similar situation as the individuals in our evolutionary simulation model. Through software specially designed for this study, our test subjects were repeatedly coupled with other participants to engage in a social interaction. At the core, the social interactions were simple: both participants in a pair had to simultaneously choose whether or not to ‘help’ the other. Helping provided a benefit to the interaction partner (in points that were later converted to real money), but it also had a consequence for the helper herself. This consequences of helping varied between situations: sometimes it was directly beneficial to the helper, but in other situations it carried a crippling cost. Between different experimental treatments, we varied how much uncertainty the participants had about the consequences of helping. This ranged from no uncertainty at all, via partial uncertainty (participants were told that the consequence of helping lied in some range), to complete uncertainty.

The social heuristic our participants were using was effective in turning a situation of uncertainty into a situation of virtual certainty. But, as a side-effect, it also led them to cooperate more.

Our results show that in the treatments with more uncertainty, participants helped their interaction partners more often than if they had little uncertainty. The reason behind this can be found in social heuristics. Most participants were interpreting the uncertainty range they were given in a very simple way: they just acted as if the real consequence of helping was given by the center of the uncertainty range. For example, a participant who was told that the consequence of helping would be anywhere between a cost of 5 and 15 points acted the same way as a participant who was certain that it was 10 points. This is a simple solution to dealing with uncertainty: if you do not know which of many possible scenarios is going to unfold, just choose one that seems typical or likely and act as if you are certain that this is what is going to happen.

The social heuristic our participants were using was effective in turning a situation of uncertainty into a situation of virtual certainty. But, as a side-effect, it also led them to cooperate more. To see why, consider a simplified version in which there are just three possibilities, each equally likely: the cost of helping is either 5, 10 or 15 points. Let’s say you would be willing to help at a cost of 5 of 10 points, but not 15. If you’re like our participants, you will reduce your uncertainty by assuming you are in the most typical situation: you will just act as if you are sure that the cost is 10 points, and so you will help. This means you are helping more than if you would not have had uncertainty, because then you would only have helped in two thirds of the cases. Our experimental results can be explained in a similar way: because participants who had to deal with uncertainty used a heuristic, they ended up helping more than their counterparts that suffered no uncertainty.

So what do these results teach us about the evolution of human social behavior? They confirm that human minds are not calculators aimed at optimizing behavior in every possible scenario that might arise, but that their cognitive solutions have been shaped by a world of considerable complexity and uncertainty. The way our minds deal with this uncertainty is not to painstakingly account for it, but to reduce it to something more manageable with limited losses to inconsistency and suboptimality. Such heuristics can probably play out in many ways, but our experiment shows that they can lead to a higher willingness to cooperate with others.


Read the paper: Uncertainty causes humans to use social heuristics and to cooperate more: An experiment among Belgian university students

Mismatched Sugar High

by Richard Johnson, William Wilson, Sondra Bland & Miguel Lanaspa


How does sugar effect our behavior in modern environments? Here we present the hypothesis that fructose, which is present in added sugars such as table sugar (sucrose) and high fructose corn syrup (HFCS), may have a role in behavioral disorders associated with impulsivity and anxiety. This hypothesis is based on recent research that has found fructose to be distinct from other nutrients in activating a survival pathway that includes foraging for food as one of the behavioral responses. Specifically, fructose is distinct from other foods in that it during its metabolism it can lead to a reduction in intracellular ATP levels. This leads to the degradation of AMP that eventually generates uric acid. The accumulation of uric acid and fall in ATP are associated with a variety of metabolic responses that include the stimulation of hunger and thirst, foraging, the development of insulin resistance, and the production and storage of fat. While this is used by animals in the wild as a survival mechanism to help them store fat in preparation for times when food is unavailable, we posit that the overconsumption of added sugars today is leading to chronic stimulation of these pathways. Foraging, in particular, is associated with risk taking (entering unknown areas), impulsivity and rapid decision making, and even aggression. Here we review the evidence that chronic stimulation of foraging behaviors from consuming fructose might carry increased risk for disorders associated with impulsivity and anxiety, including ADHD and bipolar disorder. We recommend further research to investigate the possibility that fructose ingestion might be a contributory risk factor for these and related disorders.


Watch the video summary of our work, below (shared with permission)


Read the paper: Fructose and uric acid as drivers of a hyperactive foraging response: A clue to behavioral disorders associated with impulsivity or mania?

HBES Evolution of #Punishment Roundtable Seminar Series Event on May 6th

HBES is thrilled to announce the next event in our new Roundtable Seminar Series. On May 6th 2021 at  10:30am -11:45am EST Drs. Nichola Raihani, Max Krasnow, Katherine McAuliffe, & Jillian Jordan,  will engage in discussion, moderated by Dr. Pat Barclay on the topic, “The Evolution of Punishment”. We’re looking forward to engaging with our members on important discussions happening in this area.


As prior events, the live-stream of the event will be hosted on crowdcast and the password to register for the event will be emailed out to HBES members the week of the event (check your spam folder!). The recording of this event, and all prior events, will be made available on our YouTube channel shortly following the event.


If you have any questions about registering for this event, please contact the event coordinators at hbesroundtableseries@gmail.com.


We’re looking forward to seeing you soon!

When is Marriage Harmful to Women?

by David W Lawson

Feature image : A household interview, Mwanza, Tanzania; Credit: David W. Lawson


Over the last decade, my colleagues and I have grappled with the categorization of multiple forms of marriage as definitively costly to women by international development and global health organizations. Chief among these practices are polygynous marriage (sharing a husband with a cowife), ‘child marriage’ (marriage under 18 years), and most recently in our new paper in evolution and human behavior, marriages in which the husband is substantially older than the wife. Each of these phenomena are especially relevant across sub-Saharan Africa where, for example, 40% of girls marry before their 18th birthday.


As an applied anthropologist, I’m immediately wary of ethnocentrism when any practice common in the Global South is categorized as inherently harmful. A widespread tendency to frame these issues through a moralizing lens also raises concern. Plan International’s award winning ‘#stopthewedding’ campaign, for example, presents child marriage as both ‘grotesque’ and demanding of urgent external intervention. Narratives that (over)emphasize the dangers of ‘traditional culture’ can be problematic if they reinforce damaging stereotypes and sideline recognition of broader structural drivers of gender inequality. Anthropologists (and historians) have responded by illustrating the ways in which practices like early marriage may be viewed, not as the product of a morally bankrupt society, but rather rational responses to specific socioeconomic and sociopolitical circumstances.


In this sense, I am also optimistic about the potential contributions of an evolutionary perspective. The polygyny threshold model, for example, suggests that sharing a husband may be beneficial if a man is wealthy enough to provide for multiple wives. A model that receives support in some settings, but not others. And while early marriage has clear potential to be costly (e.g. via elevated risk of early pregnancy), life history theory reminds us that such costs may be tolerated given the benefits of starting a family early when life expectancy is relatively short. Parent-offspring conflict theory may also be useful in understanding why early marriages may be incentivized for parents if not daughters, especially in the context of marriage payments i.e. higher bridewealth or lower dowry for younger brides. Yet, in many cases, early marriage appears driven by female choice (including via elopements against parental will), without clear costs to wellbeing, questioning the notion that women’s agency is restricted. Context is king.


Frankly, without lived experience of societies where such practices are common, let alone the gendered power dynamics of heterosexual marriage and childrearing, I also remain cautious to weigh in on debates about what is good and bad for women. I’ve tried to strike a balance in presenting our research findings as objectively as possible, while being open to rethinking my own assumptions and those of my paradigmatic training. Key here has been a pivot into qualitative methods (spearheaded by Susan Schaffnit), prioritizing the voices of community members deemed at risk, along with collaboration with Tanzanian scholars at the National Institute for Medical Research, especially Mark Urassa, and Joyce Wamoyi.


So, are large spousal age gaps bad for women? Evolutionary psychologists have tended to focus on the mutual benefits of husband-older marriage: with women effectively exchanging youthful fecundity for the wealth and status of senior men. However, even early work in this tradition hints at the limits of this perspective. Kenrick and Keefe for example, report that, while American women find slightly older men attractive at all ages, as men get older they prefer relatively younger and younger women. Such divergent preferences are not mutually compatible.


Surveying Sukuma women living in a rural, but urbanizing community in northern Tanzania, our recent paper provides some potential answers, and raises new questions. Consistent with conflicting preferences, women routinely marry men older than their stated ideals. However, among the large majority married to older men, the age gap did not meaningfully predict self-reported depressive symptomology, autonomy in decision-making (a frequent measure of women’s empowerment), the likelihood of divorce, or reproductive success. While our ability to infer causal relationships is limited with cross-sectional data, these results suggest the magnitude of spousal age differences is of little consequence to women’s wellbeing or fitness – supporting neither a mutual benefits or a sexual conflict model.


Unexpectedly, we also found that marriage to a younger man, a rare arrangement in this community, was associated with relatively poor wellbeing for women. Qualitative findings indicate that such husband-younger marriages are socially shameful; suggesting costs of norm violation along with selection of relatively disadvantaged individuals into atypical marriages. This could come about, for example, if men with otherwise limited marriage prospects partner with older women who themselves are relatively disadvantaged prior to marriage.


These results correspond to our wider findings on polygyny and child marriage, both of which show little evidence of being directly costly to women’s wellbeing, more obviously predicted by factors like access to education and health services. In fact, in past studies we have shown that marrying polygynously is associated with relatively superior child health and food security compared to monogamous marriage; and brides under the age of 18 years report greater decision-making autonomy and community respect than their unmarried peers. As illustrated above, our results also confirm the role of social norms and norm violation in defining feasible options for girls and women. Related research shows that gender norms favoring male authority are represented and reinforced via Sukuma songs about marriage.


On the one hand, knowing that certain marriage practices do not predict poor wellbeing when girls and women are contrasted within a community usefully steers us away from simplistic interventions that might punish the families involved. We have argued, for example, that criminalizing marriage under 18 years may be damaging for female adolescents by limiting options, unless such interventions are also effectively combined with policies addressing the vulnerabilities experienced by those delaying marriage, i.e. exposure to risky sexual behavior, premarital childbearing, and negative social judgements of unmarried women.


Our research cautions against portraying ‘traditional’ marriage practices as the lynchpin, that once unlodged will dismantle patriarchy. But leaves open the possibility that community-wide changes in these practices may nevertheless have positive impacts for women by disrupting wider social norms.


On the other hand, it would be erroneous to imply that our results imply marriage arrangements such as large spousal age gaps are harmless. Critical here is the realization that a girl or woman may opt for a certain marital arrangement as the best available alternative, but the fact that her option set is remarkably limited by wider cultural norms can itself be considered an indirect act of coercion. These instances, perhaps best considered forms of ‘structural violence’, are less often considered within adaptationist frameworks that certainly model sexual conflict, but more often via theorizing about opposing individual optima and emergent strategies, rather than tackling more systemic forms of oppression. The challenge ahead is to disentangle to what extent specific marriage practices are best understood as the product of patriarchal regimes, or themselves a root cause of gender inequality.


Our research cautions against portraying ‘traditional’ marriage practices as the lynchpin, that once unlodged will dismantle patriarchy. But leaves open the possibility that community-wide changes in these practices may nevertheless have positive impacts for women by disrupting wider social norms. We need more social scientists, including evolutionary-minded scholars, with their keen adherence to the importance of context and variation, to apply themselves to these tricky questions. Fundamentally, the question is not if, but when and where, polygyny, early marriage and large spousal age gaps can be harmful to women. We also need to be mindful to make sure that investigation into these sensitive topics is fully inclusive of researchers and communities in the Global South. Above all, as argued recently by Akurugu and colleagues Gender activism needs to be sensitive to contextual norms and respectful of the ‘oppressed’ subjects of ‘liberation”


Read the paper: Lawson DW, Schaffnit SB, Hassan A, & Urassa M. (2021). Shared interests or sexual conflict? Spousal age gap, women’s wellbeing and fertility in rural Tanzania. Evolution and Human Behavior. 42: 165-175

Does the Nose Know? Exploring the links between smell, disgust, and mating strategies

by Marjorie Prokosch, Zachary Airington, and Damian Murray



Our sense of smell helps us to make sense of the world. Our mornings can be improved by smelling a cup of coffee; our nose tells us which foods in the fridge may have turned; the smell of a loved one’s worn shirt transports us to the emotions of that relationship. However, despite how daily experiences are influenced by smell, relatively little research has examined how smell guides human social cognition and behavior.

Previous research points to two social processes in which our sense of smell is especially important: 1) deciding with whom we should form and maintain close relationships, and 2) helping us to avoid things and people that could make us sick. People rate smell as being an important factor in romantic partner choice, and tend to find the smells of a romantic partner to be more comforting and attractive than the scents of others. People also tend to be disgusted by and avoid the sources of foul, disease-connoting odors (like the body odors of sick people). New research is now beginning to examine how individual differences in how well we smell might also shape these processes.

In a recent study, we explored how smelling ability, disease avoidance, and one aspect of close relationships—mating strategy—are related. Here, by mating strategy we refer to people’s interest and participation in monogamous romantic relationships (long-term mating strategy) and short-term sexual relationships (short-term mating strategy). We predicted that smell ability would relate to people’s trait disease avoidance and mating strategies. For example, people who can more easily detect smell-related disease threats might tend to be more disease avoidant. Further, people with greater ability to smell relevant cues of quality or compatibility in potential partners (or, proximally, who might be more easily disgusted by unfamiliar body odors) might be less inclined to engage in short-term sexual relationships. Past research has also found that people high in disease– and sex– related disgust are less inclined to engage in short-term sexual relationships, so we expected to find a similar link in our study, too.

To measure smell ability, we tested participants with Sniffin’ Sticks—a battery commonly used in clinical smell research.  The Sniffin’ Sticks test measures three facets of smell ability: threshold, discrimination, and identification.

Threshold is the ability to detect scents. Participants smelled groups of pens where two were unscented and one contained a concentration of n-butanol, which has an alcohol-like smell. Participants with a more sensitive smell threshold could correctly pick out weaker concentrations of n-butanol. Discrimination is the ability to tell scents apart from one another. Participants smelled groups of pens where two pens contained one scent and a third pen contained a different scent. Participants who were more discriminating correctly picked out more of the uniquely scented pens across trials. Identification measures the ability to recognize and name specific odors. Participants smelled a set of common scents (e.g., leather, fish, banana). Participants with greater identification ability could correctly name more of those scents. In total, the test takes about 45 minutes to administer.  Participants then completed surveys assessing their interest in short and long-term mating strategies, their dispositional sexual and disease-related disgust, and how chronically vulnerable to diseases they felt.

We found that smell discrimination–people’s ability to tell smells apart from one another—was related to people’s interest in short-term mating, such that people who were better at telling smells apart tended to report less comfort with engaging in short-term, sexual relationships.  People with greater smell discrimination also tended to report more disgust towards potentially unpleasant sexual scenarios (such as hearing others have sex). These relationships remained consistent after accounting for other factors that could meaningfully impact performance such as gender, English proficiency, and recent sickness (and after adjusting our false positive rate to account for performing multiple tests).


We found that smell discrimination–people’s ability to tell smells apart from one another—was related to people’s interest in short-term mating, such that people who were better at telling smells apart tended to report less comfort with engaging in short-term, sexual relationships.


Interestingly, we did not find a link between people’s smell discrimination abilities and their disease avoidance tendencies (disgust towards the germ-rich situations, feelings of vulnerability). Superficially, this is inconsistent with past theorizing about smell ability and disease avoidance. Smell threshold and identification abilities did not consistently relate to any of our survey measures. Why might this be the case? It is possible that there are really no relationships of interest between threshold, identification, and mating or disease avoidance. However, it’s also possible that aspects of our testing procedure, like the scents or survey measures we used, interfered with our ability to detect small but meaningful relationships.

Our results leave lingering questions for future work. Why is the ability to tell different scents apart relevant to discomfort with short-term mating situations and strategies? It’s possible that when evaluating potential partners, the ability to discriminate between different scent cues of “good partner fit” is more important than the ability to detect these cues, per se.  People especially sensitive to different scent cue combinations that signal “bad partner fit” might in turn, have a dampened desire to pursue mating strategies that emphasize casual sex. We also do not know which specific scent cues might be important for determining “good” or “bad” partner fit. Scents related to health, immune compatibility, or fertility may be worth investigating.

Another question is whether (or how) specific smelling abilities actually factor into established, long-term relationships. Although our data didn’t imply that smell sensitivity influenced actual relationship status, smell ability may still be important for forming and maintaining long-term, romantic partnerships. For example, some research does suggest that smell is related to sexual satisfaction. Specific smell abilities may play a role in aspects of long-term mating strategies that we didn’t measure in our study.

In sum, does the nose know? Our research suggests, maybe. At least, our ability to detect differences in odor cues seems to be related to our comfort with short-term mating.


Read the paper: Investigating the relationship between olfactory acuity, disgust, and mating strategies

Interview with 2020 HBES Lifetime Career Award Winner David Perrett by Carlota Batres


David Perrett is a professor at the University of St Andrews and the winner of the 2020 Lifetime Career Award for Distinguished Scientific Contribution, which he will receive at the next HBES conference. Carlota Batres, an assistant professor at Franklin and Marshall College and one of Dave’s former PhD students, interviewed him for HBES.



Carlota: Can you tell us how your academic journey started?

Dave: As a kid I grew up in the country in a house between two sloping fields. A small stream ran through the garden and churned up stones full of fossils (shells and trilobites) which I found captivating. My brother pitched a disused aeroplane nose cone (somehow acquired by my father) over the stream so I could sit inside and study life in the mud (e.g., bloodworms and what ate them). This gave me a head start in thinking about evolution and ecology (though those words were not in my head). In my teens, I had inspirational biology and chemistry teachers and took to being a swot.



Carlota: Out of your 300+ publications, which project has been the most fun for you and why?

Dave: Transforming faces lets you to poke fun at villains, politicians and friends, all in the name of science. A newspaper cheered us with the heading “Boffins help Thatcher’s image fade away” when we morphed the prime minister to a challenger.


Carlota: Rumor has it you are retiring. Is this true? If so, what will you miss the most and what are you most looking forward to?

Dave: I am now on a 20% contract but still work most days. I already miss the privilege of planning experiments and analysing experimental data with smart researchers. Exploring data hot off the press is like opening a present, you might guess at what’s going to be inside but the reality of what you find is always more interesting. The young brains that came through the lab invariably brought humour and curiosity, making the work environment happy and stimulating. I tried to keep in mind that the process of science should be enjoyable and is more important than any result. Our lab was open plan which meant I could drift from one colleague to another and disturb all; the proximity and atmosphere kept us all on our toes.

I now look forward to leisurely breakfasts watching garden visitors (predominantly birds). They come each with their own schedule and tricks: squabbling greenfinches, blackcap bullies and feisty robins.


Carlota: You change your hair color often, and many times have several different colors at once (e.g., purple, green, blue). Is there a method to when and what colors you dye your hair?

Dave: There several drivers of colour use. At northern latitudes you need something to cheer you through the long grey months. The coloured appearance of my wife, Anne, and myself also helped mutual recognition (I am fairly face blind). Initially a change in colour would justify new additions to our wardrobe.

The academic system embraces eccentricity so I treated appearance as a kind of handicap; if people took me seriously despite how I looked then what I was doing must be OK. It is a mark of independence or stupidity, or both. I have encountered disapproval only 2 or 3 times (e.g., looking for a place to stay in Niagara Falls, a door was closed in my face). I think people are often amused, so if our eyes meet there is a positive expression to react to.


Carlota: Can you tell us about your unique exercise and eating routines?

Dave: Hmm! An earlier me loved to run most days and explore wherever I was (i.e. get vaguely or actually lost). The best times were running at Pete Henzi and Louise Barrett’s study site in the Karoo semi desert among giraffes and antelope, hoping that 4 of the big 5 would take no notice of me. Running kept me warm at -24°C, when snow lined my eyebrows and an icicle hung from my nose, and running cooled me while lapping small sweaty tropical islands.

I rationalised that the exercise needed fuel so took to eating 4-5 meals a day. Vinet Coetzee taught me about 2nd breakfast during her PhD in the lab. Since then I have disgusted/amused staff in the coffee room eating lentils or cold beans topped with chilli as the perfect mid-morning pick-me-up. Now diet is just entertainment as I eat similarly but have had to stop running through injury.


Carlota: What is something people at HBES would be unlikely to know about you?

Dave: I failed English Language O Level and have been so lucky to have had Anne using her talent and training to check every work word I’ve put my name to. We enjoy flowers and have a garden with special places for poppies (every type from the blousy Shirley to the sacred Himalayan blue). Creepy crawlies are just as important to us, so we use a UV night light to attract moths in our garden and go on fungal forays turning up oddities like a red club fungus that eats insects.

HBES 2021 Election Results

#HBES2021 Virtually Everywhere | Official Announcement

We are thrilled to announce that the annual meeting of HBES is going virtual this summer! Between June 24th and July 2nd, we will bring you an action-packed program, featuring the following (confirmed) speakers:


Keynote Address
Richard Wrangham (Harvard University)


Plenary Addresses
Michael Bang Petersen (Aarhaus University)
Magdalena Hurtado (Arizona State University)
Michael Muthukrishna (University College London)
Annie Wertz (Max Planck Institute for Human Development)
Melissa Wilson (Arizona State University)


Abstract submission will open April 1st for organized symposia, and April 16th for individual talks, blitzes, and posters. Submissions will close on April 23rd, and acceptance decisions will be sent out by May 7th.


–To avoid burnout, the conference days will be shorter than usual and spread across more days. Meeting times will shift from day to day, in order to accommodate as many international time zones as possible.
–Even if you already submitted an abstract for the in-person conference in Palm Springs, you still need to submit (again) for the virtual meeting. We are a separate host and program committee.
–HBES members will enjoy FREE registration. Not an HBES member? Join or renew today!


Stay tuned for updates about the schedule and program. We look forward to seeing you in (virtually everywhere)!


The Program Committee: Aaron Lukaszewski, Jaimie Krems, Anne Pisor, Cari Goetz
The Host Committee: Coren Apicella, Chris von Rueden, Nicole Barbaro