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William Costello

@williamcostello.bsky.social
294 followers 112 following 98 posts

PhD student of Evolutionary Psychology at the University of Texas at Austin.

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Reposted by William Costello
David P. Schmitt, Ph.D. @psychoschmitt.bsky.social · 27/08/2026
"By an overwhelming margin (85%), judges...correct about direction of gender differences...possessed notable awareness of magnitude....accurate gender stereotypes can be seen as window, albeit a somewhat clouded window, into gender disparities that still exist" www.sciencedirect.com/science/arti...
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Rob Sica @robsica.bsky.social · 10/08/2026
🔪"Falsely putting words in authors’ mouths is poor scholarship if not misrepresentation, especially words from common misconceptions & straw men posed by unscrupulous critics."
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Rob Sica @robsica.bsky.social · 10/08/2026
🔪 Peter DeScioli calling bullshit on that recent study smearing evo psych: "In matters of truth, weighing the costs and benefits is called lying. In science, it is called falsifying conclusions, concealment of evidence, obstruction of scientific investigation, fraud, and corruption."
link.springer.com
Evolutionary psychology did not make people blame the victim: comment on Persson and Hostler (2026) - Theory and Society
A recent article concluded that watching a seven-minute clip from a professor’s lecture on the evolutionary psychology of human mating made participants blame a crime victim. This conclusion is not su...
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Rob Sica @robsica.bsky.social · 18/08/2026
"a more integrative perspective in which sexual harassment may reflect the interplay between dominance-related motives and sexual desire"
journals.sagepub.com
From Dominance to Harassment: The Hidden Role of Sexual Intent Perceptions in the Workplace - Sanne Feenstra, Mark van Vugt, 2026
Sexual intent perceptions refer to instances in which individuals infer sexual interest from other people’s behavior. While past research has explored this in d...
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Reposted by William Costello
Rob Sica @robsica.bsky.social · 19/08/2026
"The strong Blank Slate—the idea that human psychology is largely written by culture—has been declared dead many times. Yet it refuses to stay dead. That is why we think of it as a zombie."
realityslaststand.com
Throwing Like a Girl: Is Biology Allowed to Explain Anything?
Fausto-Sterling’s treatment of sex differences in throwing reveals how modern Blank Slate thinking survives by acknowledging biology in principle while dismissing it in practice.
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William Costello @williamcostello.bsky.social · 13/08/2026
Mr and Mrs Costello 😎
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Reposted by William Costello
Rob Sica @robsica.bsky.social · 22/06/2026
"Modern social science models are increasingly acknowledging the benefits of an evolutionary-integrated approach where evolutionary explanations don’t replace cultural ones, but contribute to a fuller understanding of how behaviours develop."
unromanticprof.substack.com
Is singlehood different for men?
How evolutionary theory can help explain sex differences in singlehood experiences
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Reposted by William Costello
Geoff MacDonald 🇨🇦 @gmacdonalduoft.bsky.social · 22/06/2026
What can evolutionary theory tell us about what singlehood is like for men? In a guest post at The Unromantic, Immy Harrison explores this question: unromanticprof.substack.com/p/is-singleh...
unromanticprof.substack.com
Is singlehood different for men?
How evolutionary theory can help explain sex differences in singlehood experiences
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Reposted by William Costello
Rob Sica @robsica.bsky.social · 13/06/2026
"If we deny the existence of sex differences that everyone can see with their own eyes, most people won't believe us anyway. They'll just stop trusting scientists on politically charged topics. And they'll be right to do so; the scientists won't be trustworthy."
swiftpress.com
A Billion Years of Sex Differences | Swift Press
In A Billion Years of Sex Differences, evolutionary psychologist Steve Stewart-Williams tackles some of science’s most controversial questions: How do men and women differ? Where do the differences co...
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Reposted by William Costello
Rob Sica @robsica.bsky.social · 03/06/2026
"even subtle sex differences, when aggregated, may contribute to the persistence of gendered patterns in behavior and life trajectories"
nature.com
The power of many small sex differences in cognition, personality, and interests - Scientific Reports
Scientific Reports - The power of many small sex differences in cognition, personality, and interests
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Geoff MacDonald 🇨🇦 @gmacdonalduoft.bsky.social · 03/06/2026
I wrote about the philosophy behind the new Oxford Handbook of Singlehood, especially how building an interdisciplinary area of research requires the right culture. unromanticprof.substack.com/p/introducin...
unromanticprof.substack.com
Introducing the Oxford Handbook of Singlehood
A passion project comes to life
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Reposted by William Costello
Rob Sica @robsica.bsky.social · 04/06/2026
"Why evolutionary psychology is comparatively resistant to junkification... Hypotheses must be linked to plausible selection pressures, fitness-relevant outcomes, and mechanistic pathways shaped by natural or sexual selection"
share.google
Frontiers | Research “junkification” is caused by researchers, not journals
Concerns about declining research quality have increasingly been framed as "junkification", whereby academic output expands in volume while declini...
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William Costello @williamcostello.bsky.social · 04/06/2026
“…evo psych positions this as a natural and immutable fact of life, which women need to consider when protecting themselves from rape. If they fail to do so, they are blamed”. Is that really a fair characterisation of EP?
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David P. Schmitt, Ph.D. @psychoschmitt.bsky.social · 15/05/2026
"Contemporary problems ranging from allergies, myopia, and obesity to chronic anxiety, loneliness, and ultralow fertility can be understood as consequences of evolutionary mismatch intensified by the polycrisis" www.mdpi.com/2076-328X/16...
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William Costello @williamcostello.bsky.social · 09/05/2026
What a prince! 💪
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William Costello @williamcostello.bsky.social · 29/04/2026
New from my stellar coauthors and me in Evolution and Human Behavior. Courtship in cross-sex friendship: novel tests of male financial provisioning as a signal and cue of mating interest. Part of the journal’s special issue on “friendship”. www.sciencedirect.com/science/arti...
sciencedirect.com
Courtship in cross-sex friendship: novel tests of male financial provisioning as a signal and cue of mating interest
Cross-sex friendships are often characterized by psychological and behavioral patterns consistent with underlying mating motivations, and many romanti…
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William Costello @williamcostello.bsky.social · 16/04/2026
Fantastic news to wake up to. Our paper on courtship in cross-sex friendship has been accepted at Evolution and Human Behavior. Coming soon in the journal’s special issue on friendship.
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Reposted by William Costello
Rob Sica @robsica.bsky.social · 15/04/2026
"As Symons would sum up, there is a female human nature and a male human nature, and those natures are painfully different."
psychologytoday.com
Sex on the Brain: In Memory of Don Symons
Don Symons's book "On the Evolution of Human Sexuality" has had a lasting impact on evolutionary psychology.
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Reposted by William Costello
Justin Lehmiller @justinlehmiller.bsky.social · 10/03/2026
Use of an AI dating simulator may help single men who struggle to connect. They experienced a reduction in anxiety, loneliness, & distress related to their sex lives. www.psypost.org/therapists-test-an-…
psypost.org
Therapists test an AI dating simulator to help chronically single men practice romantic skills
A recent study published in the Archives of Sexual Behavior suggests that artificial intelligence could help men facing chronic singlehood. Researchers found that practicing romantic skills with a guided conversational program reduced feelings of loneliness and psychological distress.
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David P. Schmitt, Ph.D. @psychoschmitt.bsky.social · 05/03/2026
Cross-sex and intrasexual theory of mind..."Men overestimated women's desire for sexual variety...Unexpectedly, women showed similar biases when estimating the desires of men...both men and women overestimated the sexual desired of their same sex peers." www.sciencedirect.com/science/arti...
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David P. Schmitt, Ph.D. @psychoschmitt.bsky.social · 03/03/2026
The interdisciplinary journal "Culture and Evolution" brings all the scientific tools for studying culture and evolution to the same table…publication fees waived for papers submitted by Dec 31, 2026; registered reports and replication studies welcomed! submit.akademiai.com/cultev/index...
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Justin Lehmiller @justinlehmiller.bsky.social · 27/02/2026
Incels capture extraordinary public attention not because they are especially numerous or violent, but because their stories tap into deep-rooted psychological biases that make them unusually memorable and shareable. www.psypost.org/the-psychology-behi…
psypost.org
The psychology behind society’s fixation on incels
Despite their small numbers, incels loom incredibly large in public consciousness. A new study explains why: their stories hit our deepest evolutionary panic buttons regarding sex, status, and societal threat.
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William Costello @williamcostello.bsky.social · 27/02/2026
Evolutionary psychology distinguishes between two broad mate retention strategies Benefit-provisioning Cost-inflicting (derogation, restricting autonomy) The manosphere advocates the latter Research consistently finds cost-inflicting tactics are used more often by lower mate value individuals.
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Reposted by William Costello
Philip N Cohen @philipncohen.com · 27/02/2026
As of 2024: 81% of US women have kids by their 40s, down 9 points from 1976. 79% get married (seven-of-eight of them have kids). 21% don't get married (half of them have kids). Since the 1970s, married with kids dropped about 20 points, while never-married with kids increased 10 points.
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William Costello @williamcostello.bsky.social · 27/02/2026
Coming soon…
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William Costello @williamcostello.bsky.social · 26/02/2026
as for the overly male perspectives being prioritized. There have been many many female leaders in the field of evolutionary psychology since its very inception.
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William Costello @williamcostello.bsky.social · 26/02/2026
I don’t read it as a criticism of deriving hypotheses from an evolutionary perspective per se either. I just think that the caricature depiction of how evolutionary psychologists conceptualise the EEA is really quite juvenile. As for relying on self reports… bsky.app/profile/will...
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William Costello @williamcostello.bsky.social · 26/02/2026
If anyone is interested in an alternative to this “just so story” (ironic) about how evolutionary psychology derives hypotheses and its conceptualisation the environment(s) of evolutionary adaptedness that shaped our psychological mechanisms, then I suggest you read for yourself.
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William Costello @williamcostello.bsky.social · 26/02/2026
See Buss and Schmitt (2019) Annual Review of Psychology. Mate Preferences and Their Behavioral Manifestations. labs.la.utexas.edu/buss/files/2...
labs.la.utexas.edu
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William Costello @williamcostello.bsky.social · 26/02/2026
See Buss and Schmitt (2019) Annual Review of Psychology Mate Preferences and Their Behavioral Manifestations. labs.la.utexas.edu/buss/files/2...
labs.la.utexas.edu
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William Costello @williamcostello.bsky.social · 26/02/2026
Remarkable to characterise evolutionary psychology as solely interested in self report when it’s been triangulating diverse sources of evidence for hypotheses for decades, including substantial cross cultural evidence for the behavioral manifestations of mate preferences.
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David P. Schmitt, Ph.D. @psychoschmitt.bsky.social · 24/02/2026
"14,532 participants across 42 societies...sex similarities and differences in the strength of social motives across adulthood and sociocultural contexts, employing generalized additive models that account for spatial autocorrelation" royalsocietypublishing.org/rspb/article...
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Rob Sica @robsica.bsky.social · 19/02/2026
🎯"[T]here are so many who are ideologically motivated to dismiss evolutionary psychology... There are those who think that we should not bother defensively correcting misconceptions and instead just focus on improving our field. I think we can and should do both."
psypost.org
Evolutionary psychology is unfalsifiable? New scientific paper aims to kill this "zombie idea"
Critics have long dismissed evolutionary psychology as “just-so stories.” A new conceptual review challenges this view, arguing the field generates rigorous, falsifiable predictions—some of which have...
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William Costello @williamcostello.bsky.social · 16/02/2026
Evolutionary themed valentines cards in our house. Saff couldn’t decide so got me two 😂
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Rob Sica @robsica.bsky.social · 10/02/2026
"In placing human agents—and their evolved interests—at the heart of cultural dynamics, the ecological approach to culture [...] reclaims the original power of inclusive fitness theory that grounded the evolutionary study of behavior"
hbes.com
Reconciling Our Three Traditions: Human Behavioral Ecology, Evolutionary Psychology, and Cultural Evolution - HBES
– by Nicolas Baumard & Jean-Baptiste André The evolutionary social sciences are grounded in the idea that evolutionary theory provides a unified framework to explain human behavior, including social n...
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Ed Hagen @edhagen.net · 09/02/2026
Just a reminder. (From the evolutionary psychology FAQ I wrote as a grad student back in the 90's). 🧪 grasshoppermouse.github.io/evpsychfaq/
If my 'genes made me do it', am I still responsible?

Yep. Sorry. If you tell the judge that your genes made you do it, she can tell you that her genes are making her throw you in jail.
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Justin Lehmiller @justinlehmiller.bsky.social · 09/02/2026
As the perceived time available to make a sexual decision decreases, men's odds of saying yes increases—a scarcity effect. www.sexandpsychology.com/blog/2020/…
sexandpsychology.com
Men are More Likely to Agree to a Hookup When Their Phone's Battery Level is Low - Sex and Psychology
We’ve long known that scarcity plays an important role in sexual attraction. For example, in a classic study, research assistants approached people at a bar at different points during the night and asked them to rate the attractiveness of other patrons.What they found was that, for men and women alike, perceived attractiveness increased as the night went on and the bar got ready to close. This finding has been replicated a few times and has been dubbed “the closing-time effect.” Basically, it means that as our opportunities for finding a hookup decrease, our standards change.
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Rob Sica @robsica.bsky.social · 08/02/2026
vilifying victims is an effective strategy for perpetrators seeking to avoid blame"
sciencedirect.com
Bad victims: Moral transgressions against immoral victims are judged less harshly
Four preregistered studies find that perpetrators who commit moral transgressions are judged less harshly when their transgressions impact individuals…
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Reposted by William Costello
Jay Van Bavel, PhD @jayvanbavel.bsky.social · 05/02/2026
People don't like individuals who vigilantly monitor and reprimand wrongdoings at work. These "hall monitors" are seen as less moral and hyper competitive (the only people who like them are other vigilantes). www.sciencedirect.com/science/arti...
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William Costello @williamcostello.bsky.social · 05/02/2026
Congrats, Tom! Well deserved!
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William Costello @williamcostello.bsky.social · 05/02/2026
That’s interesting, which ones?
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Antoine Marie PhD @a-marie-sci.bsky.social · 05/02/2026
The belief that evolutionary psychology makes unfalsifiable hypotheses is old, but deeply misconceived: New paper by @costellowilliam @ProfDavidBuss et al. psycnet.apa.org/fulltext/202...
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William Costello @williamcostello.bsky.social · 04/02/2026
Sorry to tell you that evolutionary psychology continues to flourish. Political psychology, incidentally, is a domain of great evolutionary psychology work (see work from Michael Bang Peterson et al.) link.springer.com/article/10.1...
link.springer.com
The Scientific Revolution of Evolutionary Psychology: Current Status and Future Directions. A Commentary on Zagaria (2024) - Adaptive Human Behavior and Physiology
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 ...
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William Costello @williamcostello.bsky.social · 04/02/2026
😂. I'm quite happy that many people in America assume I'm mafia affiliated based on my surname!
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Human Behavior & Evolution Society @humbehevosoc.bsky.social · 04/02/2026
Risk of contracting sexually transmitted infections may be elevated for women during the days when the endometrium is receptive to embryo implantation (“the implantation window”).
hbes.com
Decreased Sexual Motivation during the Human Implantation Window - HBES
– by James R. Roney A lot of research has investigated shifts in women’s psychology and behavior across different phases of the menstrual cycle. One pattern that has emerged in multiple studies is an…
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Alberto Acerbi @acerbialberto.com · 04/02/2026
Now out in Evolutionary Psychological Science. OA link: rdcu.be/e2g4X
rdcu.be
Why Incels Capture Attention: A Cultural Attraction Theory Perspective
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William Costello @williamcostello.bsky.social · 04/02/2026
Thanks, I agree that there’s nothing unique to EP about obstruction. Also, do you think the flagrant hostility toward evolutionary psychologists might also drive some young scholars away and perhaps cultivate a somewhat defensive mindset among those who stay?
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William Costello @williamcostello.bsky.social · 03/02/2026
Like any field, many terrible studies and bad actors abound. Glad to hear you don’t count me among them 🫡 You may be blinded by my sheer sex appeal though 😂😜
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William Costello @williamcostello.bsky.social · 03/02/2026
ya maybe. Could also see Walter et al. (2020) failed replication of the greater importance of physical attractiveness in highly pathogenic environments. Anyway, stay tuned for more inwardly critical work and pre-registered predictions from our lab coming soon. Thanks again for the review(s) 👍
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William Costello @williamcostello.bsky.social · 03/02/2026
I guess I don't interpret him developing a full competing theory (mate switching) when a hypothesis he originally endorsed (ovulation shifts/dual mating) was falsified as an "uneasy Burgfrieden". See also his initial chastity mate preference hypothesis being unsupported by his own data.
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