Effects of acute administration of diazepam and d-amphetamine on aggressive and escape responding of normal male subjects.

Normal males participated in sessions providing two operant response options and were administered either diazepam (study I and II) or d-amphetamine (study II). The acute effects of diazepam on human aggressive responding, which ostensibly subtracted points from another person, were determined in study I. Study II was conducted to determine the extent to which social context and response consequence influenced diazepam (study I) and d-amphetamine (previous research) effects on aggressive responding. In study II, the other response option was escape responding which protected the subject's counter from point losses. Aggressive and escape responding were engendered by subtracting points from the subject's counter, and maintained by initiation of intervals free of point loss. Point subtractions were attributed to the other person (study I) or to a machine (study II). Responding to accumulate points exchangeable for money was available in both studies. Acute diazepam administration decreased aggressive responding in most subjects (study I), slightly increased escape responding (study II), and decreased responding to accumulate points. In study II, d-amphetamine increased both escape responding and responding to accumulate points. The effects of d-amphetamine and diazepam were altered by the instructed source of point loss.