Perceived control in continuous loud noise

The effects of two types of perceived control were assessed for performance during and following exposure to continuous loud noise at 90 dBC. Subjects performed a tracking task during exposure and the Stroop test in the period following exposure. Control could be effected either (1) by attenuating the intensity of the noise or (2) by reducing the difficulty of the tracking task. In both cases subjects were encouraged not to exercise control. Performance in treatments involving loud (90 dBC) and soft (55 dBC) noise served as baseline conditions. Perceived control of task difficulty accentuated the tendency for root-mean-square error to rise during the tracking task. There were no significant effects of noise intensi ty on tracking performance. Loud noise reduced the incidence of errors in the Stroop test but perceived control failed to influence this effect. The results are discussed in terms of the generality of perceived control phenomena.     

Auditory adaptation to gradual rise or fall in intensity of a tone

The auditory system adapts to gradual changes of intensity. After listening to a gradually loudening (or softening) tone, a steady test tone appeared to be growing gradually softer (or louder). “Tuning curves” for these aftereffects were measured by adapting to one audio frequency and testing at another. Softening tones produced larger aftereffects, which were more sharply tuned for audiofrequency, than did loudening tones.