The call is now closed. We appreciate a lot of applications!

We're extending the submission deadline by 5 days!🏃Now on 22 July 2025, 23:59 CET Please check the website for more info:

#ICSD2026 is coming

【研究者募集📢】RIKEN iTHEMSに新しく立ち上がった「数理社会科学チーム」で初期メンバーを募集しています！協力、社会規範、ネットワーク、社会ダイナミクスなどに興味のある方、ぜひご覧ください。 🔗 https://t.co/9sIsCFITJC ご質問あればDMでもお気軽にどうぞ！

📢 We’re hiring! RIKEN iTHEMS has launched a new Mathematical Social Science Team, and we’re looking for researchers to join us. If you're into cooperation, norms, or networks, check out the call! 🔗 https://t.co/JG2S0GYT0P Feel free to DM me if you have questions!

We are happy to announce the 3rd Workshop on Evolutionary Dynamics in social, cooperative and hybrid AI #EDAI2025 🤩 📍 Bologna, Italy at #ECAI2025 📆 October 25 or 26, 2025 🗞️ Submission deadline: 17 July 2025 23:59 CET 🔔 Workshop website:

New paper published! -> Twitter communities are associated with changing user’s opinion towards COVID-19 vaccine in Japan, Sci Rep 15, 11716 (2025).

Aura level... 💯 #F1 || #JapaneseGP 🇯🇵

Simulating social norms in societies on a #supercomputer. #fugaku #hpc @yohm13 #riken https://t.co/vOkzH27UBS

I updated the rb_call library, which allows you to call Ruby methods from Python code. It now works with the latest version of Python. https://t.co/KmbW41NqTn

博士課程の学生を対象とした生活費・研究費の支援プログラムをまとめるページ Doctoral Students Funding Calendar を更新しました！ 公開から3年、新たな支援制度も増えてきています。全容をざっくり把握したり、知らなかった選択肢を見つけたりしていただければ幸いです。 https://t.co/eYOsUeMlL9

The development and widespread deployment of advanced AI agents will give rise to multi-agent systems of unprecedented complexity. A new report from staff at CAIF and a host of leading researchers explores the novel and under-appreciated risks these systems pose. Details below.

研究を #クローズアップ科学道 にて取り上げていただきました。取材していただきありがとうございます🙏

論文がでました。人が判断を保留する状況でAIと人間が異なる判断を下した際どちらの判断が受容されるかを間接互恵の場面を用いて検証しました。正当化非協力をAIがgoodと判断し人がbadと判断した時に、人々はAIの判断を受け入れます。それ以外の組合せでは中立のままでした https://t.co/os5qVPS2ih

This suggests punishment plays a bigger role in indirect reciprocity than previously thought, especially in noisy environments where deception is common. Please check out our paper for more details. https://t.co/c1n6rfUNcg

Free riders naturally try to hide defection, making detection harder. Our analysis shows that in such cases, punishment is the most efficient evolutionarily stable strategy (ESS) to maintain cooperation.

Our study challenges this by showing that costly punishment can be highly effective when detecting free riders is difficult. If defectors can disguise their actions, punishment becomes the best strategy to sustain cooperation.

When reputation assessment is prone to errors, punishment can suppress free riders. But the earlier studies argued that frequent punishment lowers overall payoffs, making it less effective than ALLD. Its usefulness was thought to be very limited.

For instance, Ohtsuki et al. (Nature, 2009) found punishment ineffective in indirect reciprocity. When reputations are accurately assessed, simply refusing to cooperate deters free riders—costly punishment isn't needed.

Does costly punishment—paying a cost to reduce an opponent's payoff—help sustain cooperation in indirect reciprocity? Punishment is often seen as a powerful tool, but its effectiveness here is debated. Our new study explores this: https://t.co/c1n6rfUNcg 🧵