Lab cognition going wild: Implementing a new portable touchscreen system in vervet monkeys

Abstract

Touchscreen technology has provided researchers with opportunities to conduct well-controlled cognitive tests with captive animals, allowing researchers to isolate individuals, select participants based on specific traits, and control aspects of the environment. In this study, we aimed to investigate the potential utility of touchscreen technology for the study of cognition in wild vervet monkeys. We assessed the viability of touchscreen testing by comparing rates of participation between wild and sanctuary-housed vervets. Additionally, we compared performance on a simple associative learning task in order to verify that wild participants are able to engage meaningfully with a touchscreen task presented in their natural environment. We presented eight groups of vervet monkeys (four wild and four sanctuary groups, totalling 240 individuals) with a portable touchscreen device. The touchscreen displayed tasks in which food rewards could be gained by touching a stimulus displayed on the screen. We assessed individuals' likelihood of interacting with the touchscreen, their frequency of participation, and their performance on a simple associative learning task. We found that sanctuary-housed monkeys were more likely to interact with the touchscreen. Participation in wild vervet monkeys was influenced by sex and age. However, monkeys in the two contexts (sanctuary vs. wild) did not differ in their performance on a simple associative learning task. This study demonstrates that touchscreen technology can be successfully deployed in a population of wild primates. This gives us a starting point to test animal cognition under natural conditions that include varying group composition, environmental challenges and ongoing activities such as foraging, which are challenging to recreate in captivity. While rates of participation were lower than those found in captivity, reasonable sample sizes can be achieved, and wild primates can successfully learn touchscreen tasks in a manner comparable to their captive counterparts.

Keywords: captivity effect; cognitive task; free time hypothesis; participation; touchscreen field experiment; vervet monkey.