University of Tübingen, Tübingen, Germany.
J Cogn Neurosci. 2013 Oct;25(10):1692-701. doi: 10.1162/jocn_a_00428. Epub 2013 May 22.
Whether nonhuman primates can decouple their innate vocalizations from accompanied levels of arousal or specific events in the environment to achieve cognitive control over their vocal utterances has been a matter of debate for decades. We show that rhesus monkeys can be trained to elicit different call types on command in response to arbitrary visual cues. Furthermore, we report that a monkey learned to switch between two distinct call types from trial to trial in response to different visual cues. A controlled behavioral protocol and data analysis based on signal detection theory showed that noncognitive factors as a cause for the monkeys' vocalizations could be excluded. Our findings also suggest that monkeys also have rudimentary control over acoustic call parameters. These findings indicate that monkeys are able to volitionally initiate their vocal production and, therefore, are able to instrumentalize their vocal behavior to perform a behavioral task successfully.
几十年来，非人类灵长类动物是否能够将其先天的发声与伴随的唤醒水平或环境中的特定事件分离开来，从而实现对其发声的认知控制，一直存在争议。我们表明，可以训练恒河猴根据任意视觉提示进行命令，从而发出不同的叫声类型。此外，我们报告说，一只猴子学会了根据不同的视觉提示，在每次试验中在两种不同的叫声类型之间进行切换。基于信号检测理论的受控行为协议和数据分析表明，可以排除非认知因素是猴子发声的原因。我们的研究结果还表明，猴子也可以对声音参数进行基本控制。这些发现表明，猴子能够主动发起其发声，因此，能够利用其发声行为成功地执行行为任务。
