Drugs and Placebos: Effects of Instructions upon Performance and Mood under Amphetamine Sulphate and Chloral Hydrate with Younger Subjects

This is a brief report of the third experiment using a new design to study the effects of drugs and placebos upon human performance and mood. The earlier studies, using older male Ss, had demonstrated significant effects attributable to differences in drugs and in expectations arising from instructions given. The present study, with younger Ss, did not yield significant results. Possible explanations are discussed.