Masaki Tomonaga

This study compares chimpanzee and orangutan reactions to reward inequity, finding chimpanzees show aversion but not orangutans, suggesting convergent evolution of fairness.

The study examines the face-inversion effect in Japanese macaques using a preferential looking task, finding that familiarity reduces the inversion effect for unfamiliar faces.

The paper shows Japanese macaques spend more time looking at upright monkey faces than inverted ones, suggesting face inversion effect is face-specific.