Monkeys Wait to Begin a Computer Task when Waiting Makes Their Responses More Effective

Abstract

Rhesus monkeys (Macaca mulatta) and capuchin monkeys (Cebus apella) performed a co mputerized inhibitory control modeled after an escalating interest task fro m a recent human study (Young, Webb, & Jacobs, 2011). In the orig inal study, which utilized a first-person shooter game, hu man part icipants learned to inhib it firing their simu lated weapon long enough for the weapons damage potential to grow in effect iveness (up to 10 seconds in duration). In the present study, monkeys earned food pellets for eliminating arrays of target objects using a digital eraser. We assessed whether monkeys could suppress trial-in itiating joystick movements long enough for the eraser to grow in size and speed, thereby making their eventual responses more effective. Monkeys of both species learned to inhibit mov ing the eraser for as long as 10 seconds, and they allo wed the eraser to gro w larger for successively larger target arrays. This study demonstrates an interesting parallel in behavioral inhibition between human and nonhuman participants and provides a method for future comparat ive testin g of human and nonhuman test groups.