EFFECT OF ILLUMINATION CONDITION ON RISK ASSESSMENT BEHAVIORS OF MICE

Levels of risk assessment evoked by either a synthetic predator odor o r noncontact exposure to live rats were examined under white or red li ght conditions. Defensive responses to the predator odor were infreque nt in white light and showed a modest, but reliable, increase under re d light. Noncontact exposure to rats, in contrast, produced considerab ly higher levels of risk assessment than did odors in white light, and these levels were nearly doubled under red light. Judicious selection of eliciting and background stimuli may provide considerable control over the intensity of risk assessment. Such procedures may prove usefu l for the study of anxiety-like states.