Department of Psychiatry and Psychotherapy, Charité-Universitätsmedizin Berlin, D-10117 Berlin, Germany.
Proc Natl Acad Sci U S A. 2011 Dec 20;108(51):20661-5. doi: 10.1073/pnas.1112605108. Epub 2011 Dec 5.
Humans share implicit preferences for certain cross-sensory combinations; for example, they consistently associate higher-pitched sounds with lighter colors, smaller size, and spikier shapes. In the condition of synesthesia, people may experience such cross-modal correspondences to a perceptual degree (e.g., literally seeing sounds). So far, no study has addressed the question whether nonhuman animals share cross-modal correspondences as well. To establish the evolutionary origins of cross-modal mappings, we tested whether chimpanzees (Pan troglodytes) also associate higher pitch with higher luminance. Thirty-three humans and six chimpanzees were required to classify black and white squares according to their color while hearing irrelevant background sounds that were either high-pitched or low-pitched. Both species performed better when the background sound was congruent (high-pitched for white, low-pitched for black) than when it was incongruent (low-pitched for white, high-pitched for black). An inherent tendency to pair high pitch with high luminance hence evolved before the human lineage split from that of chimpanzees. Rather than being a culturally learned or a linguistic phenomenon, this mapping constitutes a basic feature of the primate sensory system.
人类在某些跨感觉组合上存在隐含偏好；例如，他们始终将高音与更浅的颜色、更小的尺寸和更尖锐的形状联系在一起。在联觉的情况下，人们可能会在知觉程度上体验到这种跨模态对应（例如，真正地看到声音）。到目前为止，还没有研究探讨非人类动物是否也存在跨模态对应。为了确定跨模态映射的进化起源，我们测试了黑猩猩（Pan troglodytes）是否也将高音与更高的亮度联系起来。33 名人类和 6 名黑猩猩被要求根据听到的无关背景声音的音高（高音或低音）对黑白方块进行颜色分类。当背景声音与分类一致（白色为高音，黑色为低音）时，两种物种的表现都优于不一致（白色为低音，黑色为高音）时。因此，在人类与黑猩猩的谱系分离之前，就已经进化出了将高音与高亮度配对的内在倾向。这种映射不是文化习得或语言现象，而是灵长类动物感觉系统的基本特征。
