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Julien Lie-Panis

@jliep.bsky.social
284 followers 440 following 28 posts

I study the psychology of large-scale cooperation: how human minds give rise to the rules, norms, and institutions that make societies possible. jliep.github.io

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Reposted by Julien Lie-Panis
Benoît de Courson @bdecourson.bsky.social · 29/09/2026
Very cool project by Cédric Perret (Université de Lausanne): a flexible Julia package to model evolutionary dynamics github.com/CedricPerret...
github.com
GitHub - CedricPerret/JuliassicPark.jl: Julia package to easily build and simulate evolutionary models
Julia package to easily build and simulate evolutionary models - CedricPerret/JuliassicPark.jl
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Reposted by Julien Lie-Panis
Gallicagram @gallicagram.bsky.social · 24/09/2026
Gallicagram s'embourgeoise : on a obtenu dix mille euros de la MSH Paris Saclay ! On vous prépare des merveilles pour la présidentielle, vous n'êtes pas prêts 🎶
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Daniel Nettle @danielnettle.bsky.social · 17/09/2026
Pleased to announce the publication of the second edition of 'From Questions to Knowledge: Data Analysis for Psychology and Behavioural Science Using R' mybook.to/questionstok...
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Society for Philosophy and Psychology @socphilpsych.bsky.social · 09/09/2026
Why human societies adopt rigid moral rules: The efficiency–robustness trade-off 
🚨Work by Julien Lie-Panis, Léo Fitouchi, Nicolas Baumard & Jean-Baptiste André
pnas.org
PNAS
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans...
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Human Behavior & Evolution Society @humbehevosoc.bsky.social · 07/09/2026
A second Ig Nobel Prize winner! 🏆 Congratulations to Jaimie Krems, Rebecka Hahnel-Peeters, Laureon Merrie, Keelah Williams, and Daniel Sznycer on their 2026 Ig Nobel Peace Prize! 🏆👏 Read the award-winning research in Evolution and Human Behavior: www.sciencedirect.com/science/arti...
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Hanna Kokko @kokkonut.bsky.social · 04/09/2026
Are you into mathematical modelling of ecological and evolutionary systems? Look at this job ad for a senior lecturer in Lund. I've visited many times, splendid compact city, splendid department! lu.varbi.com/en/what:job/...
lu.varbi.com
Senior Lecturer in Computational Biology
Lund University welcomes applicants with different backgrounds and experiences. Gender equality, equal opportunities and diversity are fundamental principles in all parts of the University’s activit
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Julien Lie-Panis @jliep.bsky.social · 02/09/2026
Really enjoyed this commentary by Jörg Gross on our paper on rigid rules and reputational ambiguity — turns out we’ve been thinking about some of the same problems! www.pnas.org/doi/abs/10.1...
pnas.org
PNAS
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans...
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Olympia L K Campbell @olkcampbell.bsky.social · 02/09/2026
New Paper out now in PNAS: Is cousin marriage associated with greater or lower exposure to physical intimate partner violence and coercive control? www.pnas.org/doi/10.1073/...
pnas.org
Cousin marriage and reduced exposure to intimate partner violence and coercive control | PNAS
Cousin marriage, practiced by over 10% of the world’s population, restructures kinship networks by overlapping blood and affinal ties. Theory makes...
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Omar Wasow @owasow.bsky.social · 16/08/2026
Did Nazi marches persuade or polarize voters? In 1932 Hamburg, full exposure raised Nazi vote share by ~1 pp (18% of citywide gain), but only by widening divides: support rose in Nazi-leaning areas and fell in opposition areas. Spillovers made up ~half the effect. academic.oup.com/jeea/advance...
GOING VIRAL: PROTESTS AND POLARIZATION
IN 1932 HAMBURG
Bruno Caprettini
University of St. Gallen, Switzerland
Marcel Caesmann
University of Zurich, Switzerland
Hans-Joachim Voth
University of Zurich, Switzerland
David Yanagizawa-Drott
University of Zurich, Switzerland
Abstract
Political polarization is a growing concern in many countries. Are mass protests merely a sign of increasing cleavages, or do they polarize societies? In this paper, we estimate the impact of Nazi marches in 1932 Hamburg, using granular data from 622 voting precincts during six elections.
We show propaganda can persuade—but it does so by raising the share of areas with high levels of Nazi support. Importantly, marches can also backfire, repelling voters. Thus, protest marches lead to polarization.
These effects diffused through social networks, measured using contagion patterns across neighborhoods during the 1918 Spanish flu outbreak. The electoral effects of social spillovers are similar in importance to those of direct exposure and grow over time.
(JEL: D72, D74, N44)Figure 3. Nazi Party swing. The map shows a heatmap of the change in NSDAP vote share after the marches. The change is calculated between the two elections before the marches (13 March and 10 April 1932) and the three elections afterward (31 July 1932–5 March 1933).
Voting behavior is observed at the polling-station level. The average change in NSDAP vote share is computed using a spatial kernel with a fixed bandwidth of 500 meters around each polling station and divided into 10 equally sized groups. Darker colors indicate larger gains for the NSDAP. Black lines show the routes of the two Nazi marches in April 1932.
Sources: Voting data: Statistical Bulletin of Hamburg (Sköllin 1932a, 1932b, 1933); Nazi marches: SA Hamburg documents (State Archive Hamburg 1932a, 1932b).Figure 5. Distribution regression of direct exposure. The figure plots the estimated effect of direct exposure to Nazi marches using the main panel of elections from 1932 and 1933 (y-axis). The dependent variable equals 1 when the NSDAP vote share exceeds the threshold shown on the x-axis. Thresholds range from the 5th to the 95th percentile of the NSDAP vote-share distribution in increments of 2 percentage points.
The vertical line marks the 29% crossing point between backlash—a negative effect of direct exposure—and persuasion—a positive effect. The p-value for backlash tests whether all exposure coefficients below the 29% threshold are jointly zero. The p-value for persuasion applies the analogous test to all coefficients above 29%.
The regressions control for polling-station and election fixed effects, street and demographic characteristics interacted with election fixed effects, and indirect exposure to the marches. Standard errors are clustered at the polling-station level. See equation (3) and the paper for details of the joint tests.Figure 7. Indirect effect. Panel (a) plots a bin scatter of flu-based indirect exposure (x-axis) against the change in NSDAP vote share after the marches (y-axis). The change in NSDAP vote is calculated between two elections before the marches (13 March and 10 April 1932) and three elections afterward (31 July and 6 November 1932, and 5 March 1933). The t-statistic is estimated from a bivariate regression with robust standard errors. See the main text and Online Appendix for the construction of the flu-based indirect-exposure measure.
Panel (b) plots estimates of flu-based indirect exposure from equation (6), with corresponding 95% confidence intervals by election (computed from Table 4, column 5).
Sources: Nazi marches: SA Hamburg documents (State Archive Hamburg 1932a, 1932b); indirect exposure: death records (State Archive Hamburg 1917, 1918, 1919); voting data: Statistical Bulletin of Hamburg (Sköllin 1930, 1932a, 1932b, 1933).
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Zach Garfield @zhgarfield.com · 04/08/2026
I’m now @grinnellcollege.bsky.social in Anthropology where I’ll be offering a series of new courses on human #evolutionary social #science & #biologicalanthropology and launching a new lab to support student research and expand my research program. 🧪 #HBES 🌾💎 #Grinnell
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Charles Mullon @charlesmullon.bsky.social · 03/08/2026
Looking for an Associate Prof position? Interested in behavioural ecology & cultural evolution? Come join us at the Dpt of Ecology and Evolution in Lausanne🇨🇭 @dee-unil.bsky.social @unil.bsky.social! Great department & great place to live. Pls RP. Apply here: wwwfbm.unil.ch/releve/appli...
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Alejandro Pérez Velilla @apvelilla.bsky.social · 30/07/2026
Out now in PNAS. www.pnas.org/doi/10.1073/... Thank you to all peers and colleagues who provided invaluable feedback during the process!
pnas.org
A demographic theory of similarity-biased social learning | PNAS
We develop a demographic theory of similarity-biased social learning that formalizes our understanding of when and why individuals should preferent...
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Paul Smaldino @psmaldino.bsky.social · 30/07/2026
A Demographic Theory of Similarity-Biased Social Learning. Now out in PNAS, led by the incomparable @apvelilla.bsky.social . We use modeling to explore conditions for the (cultural) evolution of parochial (and anti-parochial) learning biases. www.pnas.org/doi/10.1073/...
Humans adapt by learning from others, but risk acquiring maladaptive behaviors when learning from individuals facing different conditions. We present an evolutionary model exploring how individuals use social identity markers to select learning targets in diverse populations. Learners evolve biases that track reliable information sources: preferring similar individuals when in-group knowledge is adaptive, and dissimilar individuals when in-group behaviors are disadvantageous. Our framework demonstrates that this adaptive bias makes social learning viable even when it is costlier than individual learning. Additionally, we show that a minimum threshold of reliable cultural information is required for social learning to spread, providing a mathematical explanation for how demographic diversity drives population-level patterns of cultural segregation and assimilation.
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Reposted by Julien Lie-Panis
Michael Muthukrishna @michael.muthukrishna.com · 29/07/2026
🚨 PNAS paper: "Indirect reciprocity undermines indirect reciprocity destabilizing large-scale cooperation" w/ Eric Schnell How do we achieve global cooperation on climate or conflict reduction? The problem isn't selfishness as much as it is cooperation itself - at a smaller scale. 1/
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Open Mind @openmindjournal.bsky.social · 29/07/2026
No Evidence of Experimenter Demand Effects in Three Online Psychology Experiments
direct.mit.edu
No Evidence of Experimenter Demand Effects in Three Online Psychology Experiments
Abstract. Experimenter demand effects occur when participants alter their behavior to align with perceived study hypotheses, threatening internal validity. Concern about demand effects is pervasive…
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Max Taylor-Davies @maxtaylordavies.bsky.social · 29/07/2026
🍄 New paper out in PLOS Computational Biology! 🍄 I, and others, have previously drawn a comparison between the classic “cost-avoidance” argument for social learning and the central idea of resource rationality... (1/8)
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Evolution Students @ssegrad.bsky.social · 27/07/2026
1/4 In today's funding climate, every grant and fellowship matters. Based on feedback from our GSAC Community Check-In Survey, we're building a growing hub of graduate & postdoctoral funding opportunities and job boards to make them easier to find. 🧵
Funding and job board curated by Dieter Lukas and Pro Manna
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Evolution Students @ssegrad.bsky.social · 27/07/2026
3/4 Our graduate funding database was compiled by @prothamamanna.bsky.social. The postdoctoral funding & job board resources were originally compiled by @dieterlukas.fediscience.org.ap.brid.gy and are shared with permission.
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James Holland Jones @juemos.bsky.social · 28/07/2026
Do you study human ecology, human behavior, or human institutions? Is your work relevant to climate change, adaptation, or sustainability? Join us at Stanford! 🌲🤓🌲 My department will be running a junior search in Environmental Behavioral Sciences this year. Happy to answer any questions.
facultypositions.stanford.edu
Assistant Professor in Environmental Social Sciences, Stanford Doerr School of Sustainability (Environmental Behavioral Sciences) - Stanford University, California, United States
Stanford University invites applications for a tenure-track Assistant Professor in the field of Environmental Behavioral Sciences within the Department of Environmental Social Sciences. The scope of t...
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Jay Van Bavel, PhD @jayvanbavel.bsky.social · 18/07/2026
Why do human societies adopt rigid moral rules? People often have legitimate reasons for failing to cooperate, yet those reasons are often opaque, allowing opportunists to disguise selfishness as justified hardship. Rigidity preserves cooperation when trust is fragile www.pnas.org/doi/10.1073/...
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Tobias Gerstenberg @tobigerstenberg.bsky.social · 20/07/2026
The Causality in Cognition Lab is pumped for #CogSci2026 🇧🇷
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tadegquillien.bsky.social @tadegquillien.bsky.social · 20/07/2026
You roll a fair die, hoping to get a 6. If you are successful, did you *intentionally* roll a 6? In a new paper, I explain why people hesitate to call lucky outcomes intentional:🧵 direct.mit.edu/opmi/article...
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Paul Smaldino @psmaldino.bsky.social · 20/07/2026
Want to do a PhD to work on models of opinion dynamics and the inequalities of information flow, with an emphasis on climate change and climate policy? Apply by October 15 to work with Ago Merico and myself, based at @leibniz-zmt.de in Bremen, Germany. www.leibniz-zmt.de/en/vacancies...
leibniz-zmt.de
Doctoral candidate (gn) - WG Systems Ecology
Das Leibniz-Zentrum für Marine Tropenforschung (ZMT) erforscht tropische und subtropische Küstenökosysteme und ihre Bedeutung für Natur und Menschen erforscht.
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Erez Yoeli @erezyoeli.bsky.social · 11/07/2026
"... rigid moral rules act as a social technology: they trade efficiency for robustness, extending the reach of reputation-based cooperation."
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Léo Fitouchi @lfitouchi.bsky.social · 10/07/2026
Why do human societies adopt rigid moral rules? Our new paper, led by @jliep.bsky.social, proposes a new model in PNAS @pnas.org! www.pnas.org/doi/10.1073/...
pnas.org
Why human societies adopt rigid moral rules: The efficiency–robustness trade-off | PNAS
Humans are capable of remarkably flexible moral judgment. Yet societies rely on rigid rules—obligations and prohibitions that apply categorically, ...
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Julien Lie-Panis @jliep.bsky.social · 10/07/2026
Thanks to @dailyneuron.bsky.social for this thoughtful and accessible write-up of our recent paper: dailyneuron.com/rigid-moral-... You can also read our own thread: bsky.app/profile/jlie...
dailyneuron.com
The Rules We Treat as Sacred Are Really Built on Distrust - Daily Neuron
The strictest moral rules ignore context on purpose, and the reason comes down to how easily a good excuse can be faked.
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Julien Lie-Panis @jliep.bsky.social · 09/07/2026
Why do societies rely on rigid moral rules? Don't lie. Keep your promises. Don't steal. We all recognize there are good reasons to make exceptions. So why are moral rules so often categorical? Our new paper proposes an answer. 🧵
Screenshot of article title page, "Why human societies adopt rigid moral rules"
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Chadi Saad-Roy @chadisaadroy.bsky.social · 02/09/2025
I'm super excited to have joined @ubcmath.bsky.social and @ubcmicroimmuno.bsky.social !! Please get in touch if you might be interested in graduate studies or postdoctoral research opportunities!
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Michael Sieber @michaelsieber.bsky.social · 01/07/2026
Have ideas for your own, independent research program in Theoretical Biology? Then come and join us as a Group Leader at the @mpi-evolbio.bsky.social in Plön, Germany!
mpg.de
Group Leader in Theoretical Biology (m/f/d)
Experience in Theoretical Biology, Applied Mathematics, Theoretical Physics
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Oleg Sobchuk 🇺🇦 @sobchuk.bsky.social · 29/06/2026
📣 I'm hiring! Two positions (PhD student & Postdoc) in my ERC project Macroevolution of European Literature. Let's study the cultural evolution of literature using massive data 📚📈 📍Frankfurt | Apply by August 15 Details: www.aesthetics.mpg.de/en/career/jo... Please repost to help spread the word!
Job announcement of two positions at the Max Planck Institute for Empirical Aesthetics in Frankfurt: postdoc (Macroevolution of European Literature) and PhD student (Computational Literary Studies). Successful candidates will be affiliated with the research group Cultural Evolution of the Arts.
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Evolutionary Psychology (the podcast) @epthepod.bsky.social · 19/05/2026
This week, in celebration of the joint @culturalevolsoc.bsky.social & @hbes2026.bsky.social meetings in Rabat, Morocco, we post a mini-episode from the field. Also, the podcast turns 1-year-old today! youtu.be/4E81OTQm4Q0 podcasts.apple.com/us/podcast/e... www.podbean.com/eas/pb-7ddp2...
youtu.be
CES & HBES 2026 special episode
YouTube video by Evolutionary Psychology (The Podcast)
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Human Behavior & Evolution Society @humbehevosoc.bsky.social · 18/05/2026
Congratulations to Elizabeth Agey, winner of the #HBES2026 Postdoctoral Investigator Award! 🎉 For her work on “Parental influence on mate choice shapes reproduction and socioeconomic resources in Nepal.” 👏
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Rob Sica @robsica.bsky.social · 23/04/2026
"Modern life looks strange not because it escaped our evolutionary past, but because it multiplies the means through which ancient motivations can be expressed. The surface complexity seems culturally specific. The underlying, ultimate logic is not."
edgardubourg.substack.com
Ultimate motivations and the strange things we do every day
Why modern behavior looks evolutionarily strange. And why it isn’t. A framework for reconnecting everyday cultural practices to the ultimate motivations that make them matter.
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Paul Harper @paulharper.eurosky.social · 15/04/2026
Not quite going the way the Daily Mail hoped. Excellent. Feel free to join in... www.dailymail.co.uk/news/article...
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Catherine Molho @handle.invalid · 11/04/2026
Excited to launch the website for our EASP pre-conference on Prosocial & Antisocial Behavior: Cross-Cultural Perspectives and Methods 📅 June 30 | Strasbourg ⏰ Early bird deadline: April 14 Program: sites.google.com/view/prosocial-and-antisocial/ @easp2026.bsky.social @shuxianjin.bsky.social
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Brett Karlan @oldjerryfodor.bsky.social · 07/04/2026
One thing we have to do as a society, if we are going to get through this, is make the FIFA Peace Prize actually MEAN something again 😤😤
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Saptarshi Pal @saptarshi.bsky.social · 07/04/2026
Hey all! Been away from BSky for a while but this Friday I am giving a talk on our latest PNAS Nexus paper on repeated games! We model situations where players, instead of acting simultaneously, act in order. We study the status of well-known equilibrium strategies when simultaneity is broken.
academic.oup.com
Validate User
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Benoît de Courson @bdecourson.bsky.social · 07/04/2026
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Cultural Evolution Society @culturalevolsoc.bsky.social · 02/04/2026
The preliminary programme for @ces2026.bsky.social is now out. What a fabulous line up! airess.fgses-um6p.ma/CES2026?__cf...
airess.fgses-um6p.ma
Cultural Evolution Society 2026 Conference | Université Mohammed VI Polytechnique - FGSES
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Dorsa Amir @dorsaamir.bsky.social · 30/03/2026
I will never forgive AI for taking the em-dash away from me. I was — gratuitously — using it first!
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tadegquillien.bsky.social @tadegquillien.bsky.social · 30/03/2026
Our new paper (brilliantly led by Marius Mercier) finds that people make near-optimal inferences when evaluating someone's competence based on sparse data:
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Marius Mercier @mariusmercier.bsky.social · 30/03/2026
Thrilled to share that our new paper is now out in @cognitionjournal.bsky.social: "Who knows what? Bayesian Competence Inference guides Knowledge Attribution and Information Search," with @oliviermorin.bsky.social , @hugoreasoning.bsky.social & @tadegquillien.bsky.social! Link: tinyurl.com/ykyhxcc6
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Nature @nature.com · 30/03/2026
Becoming a parent is much more detrimental to women’s academic careers than it is to men’s Read the full story: go.nature.com/4v4rxmQ
IMPACT OF PARENTHOOD ON UNIVERSITY EMPLOYMENT. Line graph shows how the probability of holding a research position changes from four years before to seven years after having children.
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Rob Sica @robsica.bsky.social · 27/03/2026
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Cultural Evolution Society @culturalevolsoc.bsky.social · 04/03/2026
We're pleased to announce the call for the 2026 Richerson Award for Outstanding Doctoral Research, for a recent PhD dissertation that significantly contributes to the field of CE. Recipients receive a $300 award, a 3-yr CES membership and CES conference registration. forms.gle/p4MqcskCs2Yz...
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koenfucius @koenfucius.bsky.social · 22/03/2026
What a fascinating article by @olkcampbell.bsky.social covering the vast complexity of (the market for) marriage! This would definitely be rich pickings for an evolutionary psychology exploration—inspiration for David Pinsof and @dpietra.bss? buff.ly/VZQZjDd
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Joan Silk @jbsilk.bsky.social · 20/03/2026
I am amazed that Bob Trivers could slip from the world so quietly. You would think that the loss of such a brilliant and complicated man would rock the universe.
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Rebecca Sear @rebeccasear.bsky.social · 20/03/2026
TIL xkcd has a comic mocking dysgenic fertility 😂 xkcd.com/603/
xkcd.com
Idiocracy
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samuel mehr @mehr.nz · 19/03/2026
out now in Science: @loganjames.bsky.social collected pairs of sounds in 16 species where we *know* which sound is more attractive (to that species) he played them to ppl on themusiclab.org, asking, in each pair, which was nicer. humans agreed w other animals doi.org/10.1126/science.aea1202
cOMPaRatiVe cOGNitiONHumans share acousticpreferences with other animalsLogan S. James1,2,3,4* Sarah C. Woolley 1,2, Jon T. Sakata1,2,Courtney B. Hilton5,6, Michael J. Ryan3,4, Samuel A. Mehr5,7,8Many animals produce courtship sounds, and receivers prefersome sounds over others. Shared ancestry and convergentevolution may generate similarities in preference across speciesand underlie Darwin’s conjecture that some animals “havenearly the same taste for the beautiful as we have.” In this study,we show that humans share acoustic preferences with a rangeof animals, that the strength of human preferences correlateswith that in other animals, and that humans respond fasterwhen in agreement with animals. Furthermore, we foundgreatest agreement in preference for adorned, ancestral, andlower-frequency sounds. humans’ music listening experiencewas associated with preferences. These results are consistentwith theories arguing that biases in processing sculpt acousticpreferences, and they confirm Darwin’s century-old hunchabout the conservation of aesthetics in nature
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Benoît de Courson @bdecourson.bsky.social · 19/03/2026
Commentary call is out, deadline 3/04 for short proposals ! It's time to roast us. No hard feelings
cambridge.org
Explaining the paradoxical effects of poverty on risk taking: The Desperation Th
Explaining the paradoxical effects of poverty on risk taking: The Desperation Threshold Model
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