Detectability of Tones in Quiet and in Noise by Rats and Monkeys

Sensory systems in humans have been investigated by means of psychophysical methods. These methods define the rules for systematic presentation of stimuli to the subject and for the analysis of the subject’s responses from which various characteristics of the particular sensory system can be abstracted. Human psychophysical experiments rely heavily on language for instruction of the subject in his task and for his cooperation throughout the study. A crucial difference between human and animal psychophysics is the absence of language in animals. Thus, a systematic investigation of sensory characteristics in animals requires application of techniques which evolved not only from psychophysics, but also from another branch of psychology, namely, conditioning. In order to instruct animals in their task in a psychophysical experiment and maintain their behavior during these experiments, conditioning techniques have been required. Both classical and instrumental conditioning techniques have supplied appropriate precedures, although instrumental conditioning has been the more prevalent source of these techniques.