First and foremost, this book is about our present knowledge on empathy, altruism, punishment, and fairness as human behaviors, developed along scientific findings around game theory in general and variations of the ultimatum and dictator games in particular.
If you have no idea what game theory and these games are about, this book is for you. If game theory and these games are already familiar to you but not from original research papers, this book is even more for you!
While its style is a bit too didactical and redundant to my taste (and suffers from a certain attributitis where referenced researchers are always “renowned,” “famous,” “prominent,” “eminent,” and the like), it’s very thorough. It also keeps track, meticulously and honestly, of contradicting research outcomes, conflicting interpretations, and all kinds of issues stemming from the replication crisis, convenience samples, and the focus on WEIRDs. Plus, it provides well-placed caveats of how observed behavioral typicalities might be a product of social positions, status, and similar instead of systematic differences as neurological/biological adaptations.
Initially, I feared the worst when the introduction made clear that Kobayashi would effectively use evolutionary psychology for her general argument, but it turned out to be fine. The first five out of six chapters fully rely on research from anthropologists, sociologists, economists, and honest-to-goodness psychologists and evolutionary biologists, except for one passing mention of Pinker in a footnote that doesn’t do any harm.
The references to evolutionary psychology, then, fall into the sixth and final chapter. Here, Kobayashi develops her argument that seemingly “irrational” behavior doesn’t fall into the rational vs. irrational dichotomy but rather into Gigerenzer et al.’s framework of “adaptive rationality”—a framework in close proximity to Simon’s and Allais’s concept of bounded rationality on the economic modeling side, and Kendrick’s concept of deep rationality on the evopsych side. All in all, this is much better handled than I thought it would be. Indeed, I’m very sympathetic to Kobayashi’s general argument; I just think that evopsych is a problem factory and that her argument could have been made—and indeed can be made—without it.
Kobayashi Kayoko. The Mystery of the Ultimatum Game: Why We Are Predictably Irrational. Springer Nature, 2025. Translated and updated from: 小林 佳世子。最後通牒ゲームの謎：進化心理学からみた行動ゲーム理論入門。日本評論社、2021年9月。