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simoncolumbus.bsky.social
Simon Columbus
@simoncolumbus.bsky.social
930 followers 410 following 460 posts
Lecturer, University of St Andrews | I work on cooperation, norms, institutions, & personality | http://simoncolumbus.com
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simoncolumbus.bsky.social
Cooperation Colloquium this week:

Terence Dores Cruz (University of Amsterdam)

The costs and benefits of gossip in reputation-based cooperation

Date: Friday, November 7
Time: 15:00 UTC+1 (Vienna) / 9am NYC

Sign up: list.ku.dk/postorius/li...
Abstract: Gossip is an ever-present feature of our social interactions. We gossip to update one another about the others in our social environment. Our persistent gossip shapes perceptions and behaviors that are key to forming, keeping, and severing social relationships. These uses of gossip have given rise to the perspective that gossip has cooperative functions. This entails that people gossip to provide information about how to (not) behave and who can(not) be trusted to cooperate. This informs people about others’ reputations, which can serve to make better decisions about whom to cooperate with and whom to avoid. First, I will present research that supports this perspective based on experience sampling, scenario studies, and behavioral experiments. I find that people use reputational information provided by gossip to shape how they think about the targets of gossip. These gossip-based impressions guide receivers’ cooperative behavior toward targets: they cooperate with people they learn are likely to be cooperative and avoid people who they learn are likely to violate norms. Second, I focus on the puzzle of gossip as key for a cooperative social life while also being commonly perceived very negatively. Gossip is needed but could lead to costs for gossipers that motivate refraining from gossip. Based on ongoing research using behavioral experiments, I will present the first steps towards understanding the puzzle of the costs and benefits of gossip. Receivers of gossip support gossip systems by punishing harm to the reputation-system from not contributing gossip or spreading false information and by rewarding accurate gossip.
November 3, 2025 at 12:39 PM
simoncolumbus.bsky.social
This week's Cooperation Colloquium:

Christian Ruff @ccruff.bsky.social

Neurocomputational mechanisms of mentalizing in social interaction

When: October 24, 15:00 UTC+2 (Vienna) / 9am NYC

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Abstract: Successful cooperation depends on mentalization—the ability to infer and adapt to others’ beliefs, intentions, and strategies. Yet, most existing studies and models treat mentalizing as a static trait rather than an adaptive, dynamic process unfolding within interactive contexts. In this talk, I will present a modelling framework and experimental paradigm that capture adaptive mentalization: the capacity to continuously update one’s internal model of another person’s behavioral sophistication and to adjust one’s own strategy accordingly. Using a social strategic game combined with computational modeling and fMRI, we develop and validate a Bayesian model indexing how effectively individuals can adapt their mental models in response to changing partner behavior, and we identify a multivariate neural signature that can predict this adaptiveness of mentalization. This neural pattern generalizes across individuals and closely tracks the flexibility of mental-state inference during interaction. Applying this paradigm to individuals with varying levels of autistic traits, we find that reduced adaptive mentalization —both behaviorally and neurally—correlates with higher trait expression. These results reveal how subtle alterations in the adaptiveness of mentalization can influence the dynamics of social interactions. By grounding social interaction in formal models of belief-updating and strategy adjustment, our work advances a more mechanistic understanding of how humans coordinate minds in social contexts—and how individual differences in these computations shape social behavior.
October 21, 2025 at 1:10 PM
simoncolumbus.bsky.social
A scene from Raphael's The Triumph of Galatea: A cupid, labelled 'Psychologist', shooting an arrow labelled 'Causality'. The cupid's privates are censored because Bsky is run by prudish robots.
October 16, 2025 at 11:54 AM
simoncolumbus.bsky.social
A scene from Raphael's The Triumph of Galatea: A cupid, labelled 'Psychologist', shooting an arrow labelled 'Causality'.
October 16, 2025 at 11:50 AM
simoncolumbus.bsky.social
This week's Cooperation Colloquium:

Setayesh Radkani @setayeshradkani.bsky.social:

What people learn from punishment: A cognitive model

Date: Friday, Oct 10
Time: 15:00 UTC+2 Vienna / 9 am NYC

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Abstract: Authorities, from parents of toddlers to leaders of formal institutions, use punishment to communicate disapproval and enforce social norms. However, punishment is often interpreted in contrasting ways: at times it teaches and enforces norms, but at other times it fails or even backfires, undermining the authority’s legitimacy. We show that these seemingly contradictory effects of punishment can only be understood by considering the cognitive processes in the minds of human observers of punishment. In a series of experiments, we showed the systematic variability in how adults and children interpret punishment. We developed a formal cognitive model, derived from a standard model of how people make sense of each others’ actions (Inverse Planning), that captures and explains these inferences quantitatively and parsimoniously. This work reveals the rational logic behind how people learn from punishment, and a key constraint on the function of punishment in establishing shared social norms.
October 6, 2025 at 9:33 AM
simoncolumbus.bsky.social
Cooperation Colloquium this week:

Talbot M. Andrews @talbotmandrews.bsky.social (Cornell):

Overcoming the social dilemma of climate change

Friday, Sep 26, 15:00 UTC+2 Vienna / 9 am NYC

Sign up: list.ku.dk/postorius/li...
Abstract: Mitigating the increasing threat of climate change poses a uniquely challenging cooperative problem. Multiple strategic features of climate change impede coordinating around successful action. For example, there is uncertainty about the timing and dynamics of climate change impacts. Different actors vary in their historic contribution to the problem and vulnerability now. There are many solutions available to mitigate climate change, but they differ in their effectiveness and probability of success. And, compounding all of this, there are asymmetries in information between elite decision-makers and the publics that they govern. In this talk, I argue economic games are well-suited to understand both how these strategic features delay successful climate action and provide insights into how to overcome these problems through public policy. Focusing on the case of governing emerging mitigation technologies, I will present the empirical evidence that people are willing to pay costs to avert climate disaster. While mistrust between the public and policymakers erodes cooperation, I will also present solutions that emerge from these experiments. I conclude by discussing how insights from the lab can inform real-world messaging and policymaking to encourage successful climate change mitigation.
September 22, 2025 at 2:26 PM
simoncolumbus.bsky.social
Spent a few lovely days at the Matterhorn Symposium in Brig 🇨🇭, where I presented joint work with @mkasper.bsky.social and others on biased institutions. Next stop: Kassel for #DPPD25 and a talk on our new scale for HEXACO personality states.
A view from a Swiss alp near the Aletsch Glacier towards the Matterhorn.
September 21, 2025 at 11:38 AM
simoncolumbus.bsky.social
Buonasera Milano
A photo of a table. On it lays Banu Mushtaq's collection of short stories, Heart Lamp, next to an Aperol spritz.
September 17, 2025 at 5:30 PM
simoncolumbus.bsky.social
First Cooperation Colloquium of the semester!

Doruk İriş @dorukiris.bsky.social:
Normative expectations of reciprocal negotiators

Friday Sep 12, 14:00 UTC+2 (Vienna) / 8 am NYC

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Abstract: This paper develops a theoretical framework to examine how normative expectations--what one considers others should do based on their fairness perceptions--in shaping the behavior of players with reciprocal preferences in a public goods game. Standard reciprocity models typically assume uniform, exogenously determined, and moderate expectations. By contrast, I allow players to (i) vary in how demanding they are of others, (ii) disagree about what counts as fair, and (iii) form self-centered normative expectations endogenously. In noncooperative play, strong reciprocal concerns transform the payoff structure from a material payoff dilemma into a coordination game in utilities, with one exception. In coalition formation, three central results emerge: (i) the empty coalition is always stable, (ii) the grand coalition becomes stable once reciprocal concerns are sufficiently strong, and (iii) partial coalitions can be stable under specific conditions. Exogenous expectations create distinct effects on cooperation: lower expectations facilitate the stability of the grand coalition, whereas higher expectations increase the size of partial coalitions, potentially leading to a majority coalition. This latter finding is more consistent with empirical observation.
September 8, 2025 at 10:37 AM
simoncolumbus.bsky.social
Off to Vienna 🇦🇹 on this lovely Dundee morning
August 31, 2025 at 6:28 AM
simoncolumbus.bsky.social
A poet on measurement
The opening lines to Garth Greenwell's Small Rain: "They asked me to describe the pain but the pain defied description, on a scale of one to ten it demanded a different scale."
August 30, 2025 at 10:25 AM
simoncolumbus.bsky.social
Okay, this is officially my favourite figure:

From www.sciencedirect.com/science/arti...
August 29, 2025 at 8:18 PM
simoncolumbus.bsky.social
Trade offer? Extortion by the seagull mafia?
A photo of a fish on a balcony. *My* balcony. Another photo of a fish on a balcony. Still my balcony.
August 28, 2025 at 5:47 PM
simoncolumbus.bsky.social
⚡ Autumn 2025 Cooperation Colloquia ⚡

We are excited to announce the next run of Cooperation Colloquia. With @talbotmandrews.bsky.social, @setayeshradkani.bsky.social, @kris-smith.bsky.social, @alexmesoudi.com, & more.

Every second Friday, 15:00 CE(S)T

Sign up here: list.ku.dk/postorius/li...
Speaker list for the Autumn 2025 Cooperation Colloquia: 2025-09-12 | Doruk İriş (Sogang University) 2025-09-26 | Talbot M. Andrews (Cornell University) 2025-10-10 | Setayesh Radkani (MIT) 2025-10-24 | Christian Ruff (University of Zürich) 2025-11-07 | Bianca Beersma (Vrije Universiteit Amsterdam) 2025-11-21 | Kristopher M. Smith (Washington State University) 2025-12-05 | Alex Mesoudi (University of Exeter)
August 26, 2025 at 10:31 AM
simoncolumbus.bsky.social
Yup, and here's the third paper, also in Ecological Indicators
August 26, 2025 at 6:32 AM
simoncolumbus.bsky.social
For the last few weeks, Cecilie Strandsbjerg from @cphsodas.bsky.social visited me at St Andrews as part of a project on developing new personality scales for experience sampling studies. To round off the visit, we went for a coastal hike with @qinyuxiao.bsky.social, who's visiting from Vienna.
Two people standing between the pillars of Buddo Rock, a sandstone rock on the coast of Fife near St Andrews.
August 18, 2025 at 10:16 AM
simoncolumbus.bsky.social
Before they go on the shelves: all physical books I've acquired since I last had access to my library two years ago.
August 8, 2025 at 8:39 PM
simoncolumbus.bsky.social
Already on the 'right' side ;-) Usually Mana for coffee or Espresso Lab to write. How does tomorrow look?
July 17, 2025 at 10:21 AM
simoncolumbus.bsky.social
Join us on Friday for the last Cooperation Colloquium of the semester:

Fernando P. Santos @fernandopsantos.bsky.social

Cooperation and indirect reciprocity in human-AI systems

Date: June 6
Time: 15:00 UTC+2 (Vienna) / 9 am NYC

Sign up: list.ku.dk/postorius/li...
Abstract: Indirect reciprocity is a key mechanism to understand the evolution of cooperation among unrelated individuals. By helping someone, individuals may improve their reputation, which may be shared in a population and change the predisposition of others to reciprocate in the future. The reputation of individuals depends, in turn, on social norms that define a good or bad action. Over the years, theoretical and empirical research has unveiled many features of cooperation under IR, exploring norms with varying degrees of complexity and information requirements. Often, however, it is assumed that 1) reputations spread for free, 2) individuals can adopt arbitrarily complex norms and 3) populations are fully composed by homogeneous individuals. In this presentation, I will discuss a way to quantify the complexity of norms and strategies in indirect reciprocity and the challenges introduced by complex rules and costly reputation sharing. We will observe that cooperation can prevail with simple norms and costly reputation sharing, provided that individuals can anticipate the reporting intentions of their opponents. I will conclude by discussing the potential of indirect reciprocity to sustain cooperation in populations that include both humans and artificial agents.
June 2, 2025 at 2:42 PM
simoncolumbus.bsky.social
This weeks's Cooperation Colloquium:

Catherine Molho @cmolho.bsky.social

Guilt drives prosocial behavior across countries

Date: May 23
Time: 15:00 UTC+2 (Vienna) / 9 am ET (NYC)

Sign up: list.ku.dk/postorius/li...
Abstract: Influential theories have proposed that impersonal prosociality varies across human societies. At the same time, different societies may rely on distinct mechanisms—guilt and internalized norms versus shame and external pressures—to promote prosocial behavior. We examine these mechanisms in a pre-registered experiment with 7,978 participants across 20 culturally diverse countries. Participants made monetary allocation decisions between themselves and strangers. To examine how guilt and shame affected prosociality, we introduced two variations to this standard decision-making task. First, to activate guilt, we varied information about the consequences of participants’ decisions (full versus hidden). Second, to activate shame, we varied the observability of participants’ decisions (public versus private). Additionally, we measured guilt- and shame-proneness at the individual and country levels. We find robust evidence for guilt-driven prosociality and willful ignorance across all countries. Allowing individuals to avoid information about the consequences of their actions substantially decreases prosociality. Guilt-prone, rather than shame-prone, individuals are more responsive to the presence of information about the negative consequences of their actions. In contrast, we find that making decisions observable among strangers has negligible effects on prosociality. Our study provides a first comprehensive investigation of how guilt and shame affect prosociality around the world.
May 19, 2025 at 9:30 AM
simoncolumbus.bsky.social
Learned from David Edmonds' Vienna Circle biography 'The Murder of Professor Schlick' that Otto Neurath would sign his letters with a drawn elephant. How cool is that?!
May 12, 2025 at 4:05 PM
simoncolumbus.bsky.social
Cooperation Colloquium this week:

Ro'i Zultan @rzultan.bsky.social

Perceptions of intergroup conflict

Date: May 9
Time: 15:00 UTC+2 / 9 am NYC

Sign up: list.ku.dk/postorius/li...
Abstract: In Weisel and Zultan (2016, 2021a, 2021b, 2022), we claim that whether intergroup conflict is perceived as a threat to the individual or to the group informs the behavioral responses to conflict. In this talk, I will provide an overview of this research program, and share some background and ruminations beyond the information contained in the published papers.
May 5, 2025 at 9:43 AM
simoncolumbus.bsky.social
Made it to Scotland for my new position with @standrewspsyneuro.bsky.social. Here's last night's view from the guest room -- suppose I can get used that.
A view over the River Tay from Dundee.
May 2, 2025 at 9:05 AM
simoncolumbus.bsky.social
This week's Cooperation Colloquium:

Hisashi Ohtsuki (SOKENDAI)

Evolutionary models of human cooperation; kin and reciprocation

Date: April 25
Time: 14:00 UTC+2 / 8 am NYC (one hour earlier than usual!)

Sign up: list.ku.dk/postorius/li...
Abstract: Evolutionary theories have revealed various mechanisms that promote cooperation in biological organisms, and humans are no exceptions. The modern theory classifies those mechanisms into two major categories: one is kin selection, and the other is reciprocity. Kin selection means that the benefit of cooperation is passed to a relative who shares the same gene and therefore a gene that encodes cooperation is favored by natural selection. Reciprocity means that the benefit of cooperation is later given back to the cooperator in a reciprocal manner. In this talk, I will talk about those two mechanisms and how they can explain the evolutionary origin of human cooperation. First, I discuss a game-theoretic model that hypothesizes that modern human cooperation has its origin in our ancestral time when kin selection strongly operated. Second, I will talk about indirect reciprocity, which is reputation-based cooperation, and explain my recent theoretical finding that reciprocal cooperation can be robustly maintained even if reputation information is not public.
April 22, 2025 at 10:09 AM
simoncolumbus.bsky.social
"pre-registration has now become mainstream in experimental economics"

New preprint by Taisuke Imai et al.: osf.io/preprints/me...
Abstract: The open science movement has gained significant momentum over the past decade, with pre-registration and the use of pre-analysis plans being central to ongoing debates. Combining observational evidence on trends in adoption with survey data from 519 re-searchers, this study examines the adoption of pre-registration (potentially but not necessarily including pre-analysis plans) in experimental economics. Pooling statistics from 19 leading journals published between 2017 and 2023, we observe that the number of papers containing a pre-registration grew from seven per year to 190 per year. Our findings indicate that pre-registration has now become mainstream in experimental economics, with two-thirds of respondents expressing favorable views and 86% having pre-registered at least one study. However, opinions are divided on the scope and comprehensiveness of pre-registration, highlighting the need for clearer guidelines. Researchers assign a credibility premium to pre-registered tests, although the exact channels remain to be understood. Our results suggest growing support for open science practices among experimental economists, with demand for professional associations to guide researchers and reviewers on best practices for pre-registration and other open science initiatives.
April 7, 2025 at 12:01 PM