DIURNAL PATTERN OF JOYSTICK USE BY BONNET MACAQUES FOR FOOD REWARD - EFFECTS OF TIME-LIMITED ACCESS

The diurnal pattern of joystick use by five individually caged bonnet macaque monkeys (Macaca radiata), with continuous access to a computer-controlled joystick task that required contacting a small stationary target with the cursor, was characterized by a dramatic peak occurring between 1500 and 1700 h and little activity during the morning hours. With 2 h limited daily access pseudorandomly scheduled across days, a similar pattern was found, although the number of trials completed during 2-h intervals of limited access was greater than that during the same intervals of continuous access. When an extended period of access at a fixed time each morning was compared to a similar period of fixed access time in the afternoon, the afternoon continued to be characterized by significantly higher levels of use. © 1994 Academic Press, Inc.