A STUDY TO DETERMINE THE EFFECTS OF PLACEBOS UPON PERFORMANCE IN A VIGILANCE TASK

Abstract : An experiment was undertaken to determine the effects of ingested placebos upon signal detection performance in a vigilance task. The observers were given to understand that the placebos (pills) had certain specific, though alleged, effects upon human alertness. One placebo, colored white, was alleged to contain chemicals which affected performance in an unknown manner. Another placebo, colored orange, was alleged to make people more alert. A third placebo, yellow, was alleged to make people less alert. Eighty observers undertook a conventional vigilance task, 20 assigned to each condition of white pill, orange pill, and yellow pill, and 20 performed the task without a pill. There were no differences in detection performance among the four conditions. It was concluded that in a conventional vigilance task the ingestion of placebos which observers believe to be drugs having definite positive, negative, or unknown effects upon signal detection performance does not affect performance. (Author)