別の部屋に隠された餌を見つけるためにチンパンジーは動画を参照的に利用するか？

抄録

Human receive information not only through direct experience but also through referential media such as videos. Human experience is largely expanded by the ability to utilize information which refer to particular events and objects that are out-ofsight. Such referential information can be conveyed through videos in human older than 4-year-old (DeLoache 1987). It is also known that the same age of children start to understand referential function of language and thus language acquisition may facilitate the understanding of referential function of media (Flavell et al 1990; Perner 1991). However, it is unclear whether and to what extent such referential competence is shared in nonlinguistic animals. To address this, we tested whether chimpanzees (Pan troglodytes) can garner video information about relevant events, which is not directly observed (here, food being hidden in the next room) and, if so, what factors may facilitate their usage of referential information process. Five chimpanzees first observed food-hiding in one room. A half banana was baited into one of the two cups (green/red) by an experimenter. Chimpanzee then moved to the next room received a choice test. Foodhiding was demonstrated either directly in front of them (Real condition) or through video (Video condition). Two individuals performed better than chance in both conditions suggests that chimpanzees may share the ability to acquire information based on referential media–referent association with humans. Conversely, the remaining three individuals failed in both conditions suggests that spatial dissociation and/or temporal delay between observation and choice test may be causes of failure. Future studies need to test if their understanding of referential function of video can be facilitated by improving task continuity in space and time.