Andrew G Thomas

Swansea University | SWAN · Department of Psychology

Incels (involuntary celibates) are an online subculture of men who form their identity around their perceived inability to form sexual or romantic relationships. Incels have a nihilistic perspective of the self, strong misogynistic beliefs about women, and importantly share the view that society hates them. This novel study explores the gaps betwee...

The increasing occurrence of singlehood raises the question of whether people enjoy greater emotional wellbeing alone or in an intimate relationship. Guided by an evolutionary theoretical framework of human emotions, the current research aimed to address whether individuals are emotionally better off single than in an intimate relationship, taking...

Incels (involuntary celibates) are a misogynistic online subculture of men who form their identity around their perceived inability to establish sexual relationships. This commentary addresses the critique presented by Carian et al. (2023) in "Intervening in Problematic Research Approaches to Incel Violence," published in Men and Masculinities. Car...

While previous studies guided by evolutionary life history theory have revealed several important socioecological moderators of the influence of population density (PD) on reproduction, absent is an understanding of how individual-level factors such as personal resources and sex differences might interact and play a role. Using data from a large sa...

Objectives: A bibliometric analysis by Zagaria (2024) claimed that research in Evolutionary Psychology (EP) lags behind research grounded in the Standard Social Science Model (SSSM) in prevalence and growth rate, questioning EP’s status as a scientific revolution. This commentary aims to re-evaluate Zagaria’s findings and conclusions. We raise two...

Incels (Involuntary Celibates) are a subculture community of men who form their identity around a perceived inability to form sexual or romantic relationships. The community operates almost exclusively online, providing an outlet for misogynistic hostility. There are growing concerns about violence from incels, who have been highlighted as an (inte...

This is the largest survey of incels to-date (n=561), taken across the UK and the US. It explores their demographics, beliefs, mental health, neurodiversity, networks and propensity to violence.

Past research suggests that reactions to research on sex differences are often less positive when the findings put men in a better light than women, especially when the lead researcher is a man. The factors underlying this effect, however, are not yet fully understood. The present study aimed to provide the first experimental test of the hypothesis...

Polygamy is a form of “one-sided” consensually non-monogamous relationship where one person has multiple committed partners, each of whom is only involved with that one person. It was likely a reoccurring feature of ancestral mating that posed adaptive problems for our ancestors. Yet polygamy, and multi-partnering more generally, is understudied in...

The current research aimed to study the strategies that people employ in order to become more desirable as mates in different cultural settings. More specifically, using a closed‐ended questionnaire on a sample of 7181 participants from 14 different countries, we identified 10 different strategies that people employ to become more appealing as mate...

Mating represents a suite of fundamental adaptive problems for humans. Yet a community of men, called incels (involuntary celibates), forge their identity around their perceived inability to solve these problems. Many incels engage in misogynistic online hostility, and there are concerns about violence stemming from the community. Despite significa...

his is the second paper carved out of the lead author's MSc dissertation. In 2021, William Costello graduated with an MSc in Psychology, Culture, and Evolution from Brunel University London. Under the supervision of Prof. David P. Schmitt (co-author on this paper), his dissertation investigated the underlying psychology of incels (involuntary celib...

Sexual double standards are social norms that impose greater social opprobrium on women versus men or that permit one sex greater sexual freedom than the other. This study examined sexual double standards when choosing a mate based on their sexual history. Using a novel approach, participants (N = 923, 64% women) were randomly assigned to make eval...

Poster presentation for Society for Personality and Social Psychology (SPSP) Conference 2023. Features research from Costello et al. (2022) on Levels of Wellbeing Among Men who are Incels (Involuntary Celibates), https://link.springer.com/article/10.1007/s40806-022-00336-x#citeas Also features research from Costello et al. (in preparation) on Th...

In response to the COVID-19 pandemic, the Psychological Science Accelerator coordinated three large-scale psychological studies to examine the effects of loss-gain framing, cognitive reappraisals, and autonomy framing manipulations on behavioral intentions and affective measures. The data collected (April to October 2020) included specific measures...

Adult individuals frequently face difficulties in attracting and keeping mates, which is an important driver of singlehood. In the current research, we investigated the mating performance (i.e., how well people do in attracting and retaining intimate partners) and singlehood status in 14 different countries, namely Austria, Brazil, China, Greece, H...

Individual differences in men’s short-term mating interest are well studied, both at state and trait levels. Yet, the role of sexual arousal as a source of intra-individual variation has been neglected. This research represents the first attempt to integrate sexual arousal into the human mate plasticity literature. We argue that sexual arousal dire...

Incels (involuntary celibates) are a subculture community of men who build their identity around their perceived inability to form sexual or romantic relationships. To address the dearth of primary data collected from incels, this study compared a sample (n = 151) of self-identified male incels with similarly aged non-incel males (n = 378) across a...

The COVID-19 pandemic (and its aftermath) highlights a critical need to communicate health information effectively to the global public. Given that subtle differences in information framing can have meaningful effects on behavior, behavioral science research highlights a pressing question: Is it more effective to frame COVID-19 health messages in t...

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about...

Polygamous relationships are permitted in most traditional human societies and were likely a reoccurring feature of ancestral mating. Yet research on polygamous interest in cultures which prohibit non-monogamous marriage is sparse. Across two studies we examine polygamous interest in samples from the UK. In Study 1 (n = 393), modest interest was fo...

Expressions of sexual disinterest vary in assertiveness, consistency, and clarity. The high prevalence of predominantly male-on-female sexual harassment suggests sex differences in understanding and/or accepting rejection. Persistence is a defining yet understudied aspect of sexual harassment, one that can turn a sexual interaction into harassment....

Two studies (total N = 778) looked at (1) how people react to research finding a sex difference depending on whether the research puts men or women in a better light and (2) how well people can predict the average man and average woman's reactions. Participants read a fictional popular‐science article about fictional research finding either a male‐...

Preprint of the first paper from my dissertation research carried out as part of my MSc in Psychology, Culture and Evolution at Brunel University. The dissertation investigated levels of wellbeing and mating psychology among men who are incel (involuntary celibate). This first paper focuses on levels of wellbeing. Abstract Incels (involuntary celi...

The study of moral judgements often centres on moral dilemmas in which options consistent with deontological perspectives (that is, emphasizing rules, individual rights and duties) are in conflict with options consistent with utilitarian judgements (that is, following the greater good based on consequences). Greene et al. (2009) showed that psychol...

Incels (involuntary celibates) are a sub-culture community of men who build their identity around their perceived inability to form sexual or romantic relationships. To address the dearth of primary data collected from incels, this study compared a sample (n = 151) of self-identified male incels with similarly aged non-incel males (n = 378) across...

Significance Communicating in ways that motivate engagement in social distancing remains a critical global public health priority during the COVID-19 pandemic. This study tested motivational qualities of messages about social distancing (those that promoted choice and agency vs. those that were forceful and shaming) in 25,718 people in 89 countries...

How humans choose their mates is a central feature of adult life and an area of considerable disagreement among relationship researchers. However, few studies have examined mate choice (instead of mate preferences) around the world, and fewer still have considered data from online dating services. Using data from more than 1.8 million online daters...

We report a direct replication of our earlier study looking at how people react to research on sex differences depending on whether the research puts men or women in a better light. Three-hundred-and-three participants read a fictional popular-science article about fabricated research finding that women score higher on a desirable trait/lower on an...

Using an outcome expectancy framework, this research sought to understand sex differences in the underlying beliefs that influence harassment perception. One hundred and ninety-six participants (52% women) read a series of vignettes depicting common examples of digital male-on-female sexual harassment. They were asked to what extent they thought ea...

Research has demonstrated that increases in testosterone (T) concentration can affect the expression of behaviours and preferences that are typical of high mating effort. However, little research has considered whether such T increases affect mating strategy more generally and whether this is achievable using a physical intervention. In this pilot...

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about...

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about...

Sociosexuality and sexual compulsivity predict sex differences in voyeuristic interest in the population. In this study, we used a sample of 1113 participants from the UK (46% men) to consider whether sociosexuality and sexual compulsivity interacted to explain these sex differences and whether this relationship extended to the related domain of ex...

The current research aimed to examine the reasons people are single, that is, not in an intimate relationship, across eight different countries-Brazil, China, Czech Republic, Greece, Hungary, India, Japan, and the UK. We asked a large cross-cultural sample of single participants (N = 6,822) to rate 92 different possible reasons for being single. Th...

Previous research has found that women at peak fertility show greater interest in extra-pair sex. However, recent replications have failed to detect this effect. In this study, we add to this ongoing debate by testing whether sociosexuality (the willingness to have sex in the absence of commitment) is higher in women who are at peak fertility. A sa...

Two studies investigated: (1) how people react to research describing a sex difference, depending on whether that difference favours males or females; and (2) how accurately people can predict how the average man and woman will react. In Study 1, Western participants (N = 492) viewed a fictional popular-science article describing either a male-favo...

Two studies investigated (1) how people react to research describing a sex difference, depending on whether that difference favours males or females, and (2) how accurately people can predict how the average man and woman will react. In Study 1, Western participants (N = 492) viewed a fictional popular‐science article describing either a male‐favou...

The COVID-19 pandemic is increasing negative emotions and decreasing positive emotions globally. Left unchecked, these emotional changes may have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we will examine the impact of reappraisal, a widely studied and highly effective form of emotion regulation. Pa...

Objective: Mate choice involves trading-off several preferences. Research on this process tends to examine mate preference prioritization in homogenous samples using a small number of traits and thus provide little insight into whether prioritization patterns reflect a universal human nature. This study examined whether prioritization patterns, an...

Traditionally, it has been thought necessary to lose 2% of body mass due to dehydration to disrupt functioning, although recently, adverse effects have been reported, with a loss of 0.5%-0.7%. It is, however, unclear whether the response to small reductions in mass reflects dehydration as homeostatic mechanisms are thought to be effective. As psych...

Traditionally it has been thought necessary to lose 2% of body mass due to dehydration, before functioning is disrupted, although recently adverse effects have been reported with a loss of 0.5-0.7%. It is, however, unclear whether the response to small decreases in mass reflects dehydration, mechanisms that help to adapt to a loss of bodily fluid,...

Much research on moral judgment is centered on moral dilemmas in which deontological perspectives (i.e., emphasizing rules, individual rights and duties) are in conflict with utilitarian judgements (i.e., following the greater good defined through consequences). A central finding of this field Greene et al. showed that psychological and situational...

The characteristics modern men and women desire in a partner differ as a function of mating context. Overall, this pattern reflects a general “relaxing” of standards in a short-term mating context compared to a long-term one. For example, compared to a long-term partner, both sexes are willing to tolerate a prospective casual mate who is lower in i...

One of the great challenges for evolutionary psychology has been to explain within-sex individual variation in mating behaviour. Several lines of evidence suggest that some of this variation stems from an adaptation for facultatively increasing or decreasing long- and short-term mating inclinations in response to circumstances. It remains unclear,...

The aim of this study was to explore how people's sexual history affects their attractiveness. Using an Internet survey, 188 participants rated their willingness to engage in a relationship with a hypothetical individual with a specified number of past sexual partners, ranging from 0 to 60+. The effect of past partner number was very large. Average...

This study examined the moderating effect of cortisol (C) on the relationship between testosterone (T) and hand-grip strength (HGS) in healthy young men. Sixty-five males were monitored for salivary T, C and HGS before and 15 min after a short bout (5 × 6-s trials) of sprint cycling exercise. Sprint exercise promoted (p < .05) positive changes in T...

Evolutionary psychological theory explains the large variance found in human mating behaviour through the use of a mating strategies perspective. Specifically, both sexes have short-term and long-term mating strategies containing sets of evolved psychological adaptations which guide mating effort. Individuals vary in their mating behaviour due to t...

This article looks at the evolution of sex differences in sexuality in human beings, and asks whether evolutionary psychology sometimes exaggerates these differences. According to a common understanding of sexual selection theory, females in most species invest more than males in their offspring and, as a result, males compete for as many mates as...

We respond to the commentaries on our target article, The Ape that Thought It Was a Peacock. We start with specific issues raised by the article. These relate to the magnitude of human sex differences; the evolution and relative importance of pair bonding, paternal care, and polygyny in our species; and the distinction between the males-compete/fem...

Prior research has shown that individuals engage in impression management online, both in a social networking context and when using avatars. However, avatar creation research often directly asks participants about their creation motivations or primes a specific social context. Such direct methodologies potentially lead to biases which may give a d...