Altering arousal in humans by varying ambient sensory conditions

Reaction times of 6 male and 6 female college students were used as a measure of arousal under different levels of ambient sensory stimulation. Subjects were tested under conditions of light-quiet, light-noise, dark-quiet and dark-noise with a non-signalled reaction-time task using a tactile stimulus. All sensory conditions were presented to each subject in a counterbalanced order and replicated in a second session 3 to 8 wk. later. Significant main effects were noise and replication. Improvement in performance across replication was related to the sex of the subject. White noise and level of illumination interacted to produce the typical U-shaped function. Results are discussed in terms of their relevance for research using behavioral and physiological measures of arousal.