Light Reinforcement, Noise and Arousal Level

Abstract

RATS placed in a dark box will press a bar more often if dim light onset is contingent on this behaviour. Most of the explanations suggested for the reinforcing effect of light onset have been in terms of the absolute characteristics of the stimulation—stimulus change¹ and illumination². But alternatively, the reward value of a stimulus may be a function of its arousal value, which will depend on the initial state of arousal of the organism³. The arousal hypothesis is supported by the finding⁴ that the reinforcing effect of the light can be modified by the level of auditory stimulation maintained before testing, if the auditory stimulation is assumed to change the basic arousal level of the organism. Administration of drugs affecting arousal level during the test period also influences the rate of bar pressing^{4, 5}; but in this case direct effects of the drugs on perception cannot be ruled out.