William Costello
@williamcostello.bsky.social
PhD student of Evolutionary Psychology at the University of Texas at Austin.
Pinned
Out now and open access for four weeks as the editor's choice Topic in Focus in American Psychologist.
Contrary to popular belief, evolutionary psychology hypotheses are testable and falsifiable.
psycnet.apa.org/fulltext/202...
Contrary to popular belief, evolutionary psychology hypotheses are testable and falsifiable.
psycnet.apa.org/fulltext/202...
In our new American Psychologist paper, we debunk the decades old zombie idea that evolutionary psychology is unfalsifiable.
🧵
🧵
Reposted by William Costello
⚡️"an often-overlooked aspect of evolutionary psychology: It holds itself to a higher standard than many other human behavioral sciences regarding evidentiary burden"
psycnet.apa.org/fulltext/202...
psycnet.apa.org/fulltext/202...
January 30, 2026 at 7:48 PM
⚡️"an often-overlooked aspect of evolutionary psychology: It holds itself to a higher standard than many other human behavioral sciences regarding evidentiary burden"
psycnet.apa.org/fulltext/202...
psycnet.apa.org/fulltext/202...
Reposted by William Costello
The evolutionary psychological hypothesis that ‘humans faced adaptive problem X, and so have adaptive solution Y’, can be falsified by showing that ‘they did not face problem X’, and/or ‘they do not have solution Y’ 🤷♂️
In our new American Psychologist paper, we debunk the decades old zombie idea that evolutionary psychology is unfalsifiable.
🧵
🧵
Out now and open access for four weeks as the editor's choice Topic in Focus in American Psychologist.
Contrary to popular belief, evolutionary psychology hypotheses are testable and falsifiable.
psycnet.apa.org/fulltext/202...
Contrary to popular belief, evolutionary psychology hypotheses are testable and falsifiable.
psycnet.apa.org/fulltext/202...
January 30, 2026 at 1:47 PM
The evolutionary psychological hypothesis that ‘humans faced adaptive problem X, and so have adaptive solution Y’, can be falsified by showing that ‘they did not face problem X’, and/or ‘they do not have solution Y’ 🤷♂️
Reposted by William Costello
"study supports a putative universality of attractiveness halo effects and also contributes to a deeper understanding of subtle variations in the halo effects of men’s and women’s attractiveness in more individualistic versus more collectivistic cultures"
A Cross-Cultural Comparison of the Attractiveness Halo Effect in Men and Women: https://osf.io/v9a67
January 29, 2026 at 9:41 PM
"study supports a putative universality of attractiveness halo effects and also contributes to a deeper understanding of subtle variations in the halo effects of men’s and women’s attractiveness in more individualistic versus more collectivistic cultures"
In our new American Psychologist paper, we debunk the decades old zombie idea that evolutionary psychology is unfalsifiable.
🧵
🧵
Out now and open access for four weeks as the editor's choice Topic in Focus in American Psychologist.
Contrary to popular belief, evolutionary psychology hypotheses are testable and falsifiable.
psycnet.apa.org/fulltext/202...
Contrary to popular belief, evolutionary psychology hypotheses are testable and falsifiable.
psycnet.apa.org/fulltext/202...
January 30, 2026 at 10:23 AM
In our new American Psychologist paper, we debunk the decades old zombie idea that evolutionary psychology is unfalsifiable.
🧵
🧵
Reposted by William Costello
🎯"Their discussion is relevant to all of psychology given the well-documented issues with empirical replications and ideological bias within academia more broadly" psycnet.apa.org/fulltext/202...
January 30, 2026 at 1:35 AM
🎯"Their discussion is relevant to all of psychology given the well-documented issues with empirical replications and ideological bias within academia more broadly" psycnet.apa.org/fulltext/202...
Reposted by William Costello
"False facts are highly injurious to the progress of science, for they often endure long...several evolutionary psychological hypotheses have generated specific, falsifiable predictions; undergone multiple empirical tests; and been refuted" psycnet.apa.org/fulltext/202...
January 29, 2026 at 7:02 PM
"False facts are highly injurious to the progress of science, for they often endure long...several evolutionary psychological hypotheses have generated specific, falsifiable predictions; undergone multiple empirical tests; and been refuted" psycnet.apa.org/fulltext/202...
Out now and open access for four weeks as the editor's choice Topic in Focus in American Psychologist.
Contrary to popular belief, evolutionary psychology hypotheses are testable and falsifiable.
psycnet.apa.org/fulltext/202...
Contrary to popular belief, evolutionary psychology hypotheses are testable and falsifiable.
psycnet.apa.org/fulltext/202...
January 29, 2026 at 5:08 PM
Out now and open access for four weeks as the editor's choice Topic in Focus in American Psychologist.
Contrary to popular belief, evolutionary psychology hypotheses are testable and falsifiable.
psycnet.apa.org/fulltext/202...
Contrary to popular belief, evolutionary psychology hypotheses are testable and falsifiable.
psycnet.apa.org/fulltext/202...
New in Evolution and Human Behavior from Buss lab members past and present.
Project started in my 1st year of grad school & led by Rebecka Hahnel-Peeters.
Men underestimate how upset women feel after sexual assault.
Women overestimate how upset men feel.
www.sciencedirect.com/science/arti...
Project started in my 1st year of grad school & led by Rebecka Hahnel-Peeters.
Men underestimate how upset women feel after sexual assault.
Women overestimate how upset men feel.
www.sciencedirect.com/science/arti...
January 29, 2026 at 2:28 PM
New in Evolution and Human Behavior from Buss lab members past and present.
Project started in my 1st year of grad school & led by Rebecka Hahnel-Peeters.
Men underestimate how upset women feel after sexual assault.
Women overestimate how upset men feel.
www.sciencedirect.com/science/arti...
Project started in my 1st year of grad school & led by Rebecka Hahnel-Peeters.
Men underestimate how upset women feel after sexual assault.
Women overestimate how upset men feel.
www.sciencedirect.com/science/arti...
Reposted by William Costello
Important: evolutionary mismatch is not a vague just-so story. It generates testable predictions about when traits should become impairing: rapid environmental change, decoupling of cues from outcomes, and loss of developmental calibration.
January 19, 2026 at 1:18 AM
Important: evolutionary mismatch is not a vague just-so story. It generates testable predictions about when traits should become impairing: rapid environmental change, decoupling of cues from outcomes, and loss of developmental calibration.
Reposted by William Costello
"[M]ale’s sexual overperception bias strengthens throughout mid-to-late adolescence and may first emerge around age 17. In contrast, female’s sexual underperception bias appears to be activated and relatively stable already by age 16."
I thought we were just friends! Emergence of Sexual Misperception Biases in Adolescence - HBES
– by Marius Stavang Imagine you’re on a movie date with someone. Everything seems to be going great. The conversation flows easily, you laugh together, you exchange smiles—there’s chemistry. After the...
www.hbes.com
January 15, 2026 at 8:48 PM
"[M]ale’s sexual overperception bias strengthens throughout mid-to-late adolescence and may first emerge around age 17. In contrast, female’s sexual underperception bias appears to be activated and relatively stable already by age 16."
Thrilled that our forthcoming article in American Psychologist: “Evolutionary Psychology Hypotheses Are Testable and Falsifiable” has been chosen as the journal’s Topic in Focus & Editor’s Choice.
Coming soon with two commentaries + our reply.
Open access for the first 4 weeks.
Coming soon with two commentaries + our reply.
Open access for the first 4 weeks.
January 16, 2026 at 8:04 PM
Thrilled that our forthcoming article in American Psychologist: “Evolutionary Psychology Hypotheses Are Testable and Falsifiable” has been chosen as the journal’s Topic in Focus & Editor’s Choice.
Coming soon with two commentaries + our reply.
Open access for the first 4 weeks.
Coming soon with two commentaries + our reply.
Open access for the first 4 weeks.
Terrific essay from Mitch Brown, one of the best ambassadors our field could hope for.
inquisitivemag.org/articles/fie...
inquisitivemag.org/articles/fie...
December 15, 2025 at 10:53 PM
Terrific essay from Mitch Brown, one of the best ambassadors our field could hope for.
inquisitivemag.org/articles/fie...
inquisitivemag.org/articles/fie...
Reposted by William Costello
👍"As anyone in my field will tell you, humans evolved to maintain bonds through cooperation and helping each other. So I view my conversations with skeptics and critics in this light and as a perfect way to highlight this fact."
A Field Guide to Evolutionary Psychology — Inquisitive
Part of the job of an evolutionary psychologist is to educate people who are skeptical, or even critical, of what we do
inquisitivemag.org
December 15, 2025 at 10:00 PM
👍"As anyone in my field will tell you, humans evolved to maintain bonds through cooperation and helping each other. So I view my conversations with skeptics and critics in this light and as a perfect way to highlight this fact."
Reposted by William Costello
One of the clearest predictors of trust in groups is visibility—knowing who contributes, who helps, and who withdraws. Hunter-gatherer cooperation relied on transparency. Digital life reverses this: everyone sees the outcomes, almost no one sees the processes.
December 14, 2025 at 11:30 AM
One of the clearest predictors of trust in groups is visibility—knowing who contributes, who helps, and who withdraws. Hunter-gatherer cooperation relied on transparency. Digital life reverses this: everyone sees the outcomes, almost no one sees the processes.
Reposted by William Costello
The safest place on the internet is the r/bald subreddit. I have no idea why this came up on my Reddit, but I now follow religiously, as men support one another through the decision to go bald. It is SO positive and wholesome. Amazing to see men supporting each other about body-related concerns.
December 9, 2025 at 11:17 PM
The safest place on the internet is the r/bald subreddit. I have no idea why this came up on my Reddit, but I now follow religiously, as men support one another through the decision to go bald. It is SO positive and wholesome. Amazing to see men supporting each other about body-related concerns.
Reposted by William Costello
What evolutionary psychology to the rescue of the humanities looks like:
"The Cognitive Foundations of Fictional Stories"
"The Cognitive Foundations of Fictional Stories"
OSF
osf.io
December 8, 2025 at 2:23 PM
What evolutionary psychology to the rescue of the humanities looks like:
"The Cognitive Foundations of Fictional Stories"
"The Cognitive Foundations of Fictional Stories"
Reposted by William Costello
This trend was already evident in sociocultural anthropology twenty years ago and it was one of the main reasons I felt the need to move in a different direction.
unherd.com/2025/12/tear...
unherd.com/2025/12/tear...
The therapy-scholar is killing academia
unherd.com
December 8, 2025 at 5:56 PM
This trend was already evident in sociocultural anthropology twenty years ago and it was one of the main reasons I felt the need to move in a different direction.
unherd.com/2025/12/tear...
unherd.com/2025/12/tear...
Reposted by William Costello
We just launched Boys & Men Online, a new program at the American Institute for Boys and Men studying how digital technologies shape the lives of boys and men.
Led by David Sasaki, with fellows Isaac Rose-Berman and Bailey Way.
Learn more: aibm.org/boys-men-onl...
Led by David Sasaki, with fellows Isaac Rose-Berman and Bailey Way.
Learn more: aibm.org/boys-men-onl...
December 8, 2025 at 10:34 PM
We just launched Boys & Men Online, a new program at the American Institute for Boys and Men studying how digital technologies shape the lives of boys and men.
Led by David Sasaki, with fellows Isaac Rose-Berman and Bailey Way.
Learn more: aibm.org/boys-men-onl...
Led by David Sasaki, with fellows Isaac Rose-Berman and Bailey Way.
Learn more: aibm.org/boys-men-onl...
Reposted by William Costello
"If psychological scientists succumb to the same biases as others do, it is important to consider how harm concerns and identity-based biases might be shaping the production and dissemination of knowledge about human behavior."
Vol. 3 No. 5 (2024): ISSUE 5: Women and Men, Harm and Censoriousness: Sex-Differentiated Reactions to Information About Sex Differences by Bleske-Rechek et al. (2024)
| Journal of Open Inqui...
joibs.org
December 9, 2025 at 12:27 AM
"If psychological scientists succumb to the same biases as others do, it is important to consider how harm concerns and identity-based biases might be shaping the production and dissemination of knowledge about human behavior."
Reposted by William Costello
New adversarial collaboration…among White Americans self-report measures of racial prejudice predict behavioral discrimination (explaining ~45% of variance)…indirect/implicit prejudice measures explain ~2.5% beyond direct, self-report measures
New paper in press at JPSP! An adversarial collaboration focusing on a large-scale test of how strongly implicit racial attitudes predict discriminatory behavior. Pre-print here: osf.io/preprints/ps...
December 2, 2025 at 5:11 PM
New adversarial collaboration…among White Americans self-report measures of racial prejudice predict behavioral discrimination (explaining ~45% of variance)…indirect/implicit prejudice measures explain ~2.5% beyond direct, self-report measures
Reposted by William Costello
This week, love and regret with Cari Goetz!
www.podbean.com/eas/pb-mazyp...
podcasts.apple.com/us/podcast/e...
youtu.be/XWTV4Wj-v4s
www.podbean.com/eas/pb-mazyp...
podcasts.apple.com/us/podcast/e...
youtu.be/XWTV4Wj-v4s
Love and Regret with Cari Goetz
YouTube video by Evolutionary Psychology (The Podcast)
youtu.be
December 2, 2025 at 4:13 PM
This week, love and regret with Cari Goetz!
www.podbean.com/eas/pb-mazyp...
podcasts.apple.com/us/podcast/e...
youtu.be/XWTV4Wj-v4s
www.podbean.com/eas/pb-mazyp...
podcasts.apple.com/us/podcast/e...
youtu.be/XWTV4Wj-v4s
Early Christmas present for the Buss lab
Coming soon along with much more in 2026
Coming soon along with much more in 2026
December 2, 2025 at 3:29 PM
Early Christmas present for the Buss lab
Coming soon along with much more in 2026
Coming soon along with much more in 2026
Reposted by William Costello
🚨 SynthNet is out 🚨
Researchers propose new constructs and measures faster than anyone can track. We (@anniria.bsky.social @ruben.the100.ci) built a search engine to check what already exists and help identify redundancies; indexing 74,000 scales from ~31,500 instruments in APA PsycTests. 🧵1/3
Researchers propose new constructs and measures faster than anyone can track. We (@anniria.bsky.social @ruben.the100.ci) built a search engine to check what already exists and help identify redundancies; indexing 74,000 scales from ~31,500 instruments in APA PsycTests. 🧵1/3
November 26, 2025 at 11:42 AM
🚨 SynthNet is out 🚨
Researchers propose new constructs and measures faster than anyone can track. We (@anniria.bsky.social @ruben.the100.ci) built a search engine to check what already exists and help identify redundancies; indexing 74,000 scales from ~31,500 instruments in APA PsycTests. 🧵1/3
Researchers propose new constructs and measures faster than anyone can track. We (@anniria.bsky.social @ruben.the100.ci) built a search engine to check what already exists and help identify redundancies; indexing 74,000 scales from ~31,500 instruments in APA PsycTests. 🧵1/3
Could you enjoy having sex with someone you hate?
X poll of 1264 respondents.
Men were much more likely than women to say that they could.
X poll of 1264 respondents.
Men were much more likely than women to say that they could.
November 23, 2025 at 3:45 AM
Could you enjoy having sex with someone you hate?
X poll of 1264 respondents.
Men were much more likely than women to say that they could.
X poll of 1264 respondents.
Men were much more likely than women to say that they could.
Reposted by William Costello
"An unexpected, but interesting finding was the role of sexism in predicting sexual harassment [H]. For women, hostile sexism [HS] strongly predicted all manifestations of H engagement/experience. In men, HS was only predictive of their H of women." journals.sagepub.com/doi/10.1177/...
November 15, 2025 at 3:00 AM
"An unexpected, but interesting finding was the role of sexism in predicting sexual harassment [H]. For women, hostile sexism [HS] strongly predicted all manifestations of H engagement/experience. In men, HS was only predictive of their H of women." journals.sagepub.com/doi/10.1177/...