Cognitions and 'placebos' in behavioral research on ambient noise

摘要: Summary.-A first experiment, using visual and card-sorting tasks, found no effects of 100-db ambient noise per se, although cognitive variables in the testing situation affected both performance ratings disturbance. In two subsequent experiments some Ss were told chat a was extraneous ro their task reproducing tachistoscopic patterns, others that che being studied. Control received noise. Although group membership did not affect over-all perceprual accuracy, ic interact with other variables, indicating influence on Ss' disuibution attention. The "relevant" rated generally less disturbing, as predicted, but greater variance ratings; correlations interview data suggest had "cooperated" E by judging to be disturbing. Thus, absence any adequate "placebo" control for factors, deceptive instructions may always necessary srudies