| Abstract: | The automatic skeletal motor responses of 20 male and 20 female student subjects (aged 20–36) receiving a painful stimulation (electric shock) were studied by examining voluntary concomitant extensions and flexions of the arm. These movements were either of long duration, allowing for an on-line control of their execution or, of short duration, requiring extensive pre-programming. Subjects were instructed either to push or to pull a lever upon receipt of an acoustic signal, which was paired or unpaired with an electric shock. Latencies for long duration movements (regardless of direction) were reduced by reception of painful stimulation. Latencies of short duration extensions and flexions were respectively reduced and increased by painful stimulation. Latencies of short duration movements were larger for females than males, regardless of movement direction. These data suggest that painful stimulation elicits automatic movements which affect programming of the termination of simultaneous voluntary movements. Implications of these findings for the study of aggressive behavior are discussed. © 1994 Wiley-Liss, Inc. |
