Behavioral assessment of risk-taking and psychophysical functions in the baboon.

Laboratory procedures have been developed for the experimental analysis of risk-taking and psychophysical functions in dog-faced baboons (Papio anubis). In a procedure analogous to the traffic light situation, animals are rewarded with food pellets for completing a fixed ratio of 100 responses in the presence of a green light. Superimposed upon this baseline performance are 5-second presentations of a yellow warning light terminated by a red light in the presence of which all responses are punished with electric shock. When the yellow light is introduced late in the sequence (e.g., after 93 responses have been completed), response rates increase and the 100-response ratio is completed before the 5-second yellow light times out. When the yellow light appears early in the sequence (e.g., after 73 responses) a marked decrease in response rate is observed with cessation of responding before onset of the red light. The sensitivity of components of this risk-taking performance to pharmacological toxicants is reported and psychophysical assessment of relevant sensory-motor effects described.