International Journal of Comparative Psychology

Hare et al. (2000) reported that when placed into competitive feeding situations chimpanzees exhibit evidence of reasoning about what each other can see. Subjects were reported to select food items that were hidden behind barriers and therefore were not visible to a rival chimpanzee. We report eight experiments that attempted to replicate these findings and test alternative interpretations of them. Although we robustly replicated the finding that subjects obtained more hidden than visible food items, we consistently did not replicate the more relevant result of subjects' food choice. Further studies revealed that even those subjects who showed a tendency to approach the hidden food first did not differentiate between barriers which did and did not obscure the rival’s view. Overall, the results support the idea that although chimpanzees may use a variety of competitive strategies in such tests, no predictive power is added by postulating that they are reasoning about what each other can or cannot see.