A Foray into the Interval Timing Capabilities of Tufted Capuchin Monkeys (Cebus [Sapajus] apella)

Time is a critical part of life and timing on the range from milliseconds to minutes has proven to be critical for several behaviors such as foraging and movement. While the exact neurological structures of interval timing are currently undefined, several studies have been completed comparing the interval timing capabilities of humans and nonhuman primates. However, these studies have unanimously utilized members of Macaca, which limits the abilities for researchers to make apt comparisons between humans and all nonhuman primates. This study sought to investigate whether tufted capuchins (Cebus [Sapajus] apella) have the capability to measure time on the interval level (interval timing) and can demonstrate this in response to visual stimuli. The subjects of this experiment, while showing low error and high overall performance, did not display any knowledge of the interval length as indicated by the distribution and time of touches. Further experimentation utilizing stricter punishment and higher rewards alongside an extended experimentation time may provide results more in line with the hypothesis of this study.