Auditory congnition in the chimpanzee

在第一年，黑猩猩获得了使用声音产生对象对采样任务的视听多模式匹配。并将表演转移到不同对和新的对发声对象上。然而，与视觉或视听样本刺激相比，黑猩猩很难根据物体的声音来选择物体的图片。即使受试者表现出高水平的表现，反应时间也比视觉或视听样本刺激长两到三倍。第二年，研究人员检查了一个听觉样本的工作记忆。在听觉样本和视觉选择刺激之间插入延迟间隔。听觉样本的衰减是突然的，在延迟16 s时，表现下降到一个机会水平。然后，考察了“人”与“物”概念的形成。样本刺激是人的声音或物体的声音。选择刺激是人脸图片和产生这些声音刺激的物体。逐步引入22对人对物（44种刺激）。随着新配对的加入，匹配性能得到了提高。在第一次试验中，受试者对44个刺激中的34个做出了正确的反应。这些结果表明，黑猩猩获得了“人”和/或“物体”的概念。

In the first year, a chimpanzee acquired an audio-visual intermodal matching to sample task using sound producing objects. And the performance was transfered to different pairs and new pairs of sound producing objects. However, compared with a visual or audio-visual sample stimulus, it was very difficult for the chimpanzee to choose a picture of an object based on sound of the object. Even if the subject showed a high level of performance, reaction time was two to three times longer than that for a visual or an audio-visual sample stimulus. In the second year, working memory of an auditory sample was examined. The delay interval was inserted between the auditory sample and visual choice stimuli. The decay of auditory sample was abrupt and performance dropped to a chance level at the 16-s delay interval. Then, the formation of "human" and "object" concepts was examined. The sample stimulus was human voices or sounds of an object. The choice stimuli were picture of a human face and an object which produced these acoustic stimuli. Twenty-two human and object pairs (fourty-four stimuli) were gradually introduced. Matching performance was improved as new pairs were added. And for thirty-four out of the 44 stimuli the subject showed a correct response in the first trial. These results suggest that the chimpanzee acquired the concepts of "human" and/or "object" .