The present study investigated the effects of two attributes of the experimenter (gender and professional status) on the report and tolerance of pain in male and female subjects. 160 non-psychology students (80 male and 80 female, aged 17-59 years) participated in a cold-pressor task. Subjects were assigned to one of 8 groups: male (M) and female (F) experimenters tested male (m) and female (f) students. In each combination (Mm, Mf, Fm, Ff), the cold-pressor task was conducted by either one of two faculty members (high professional) or one of two students (low professional). Subjects were asked to immerse their non-dominant hand as long as possible in cold water (-1 degrees C). Dependent variables were pain threshold, pain tolerance, and pain intensity. Results indicated a significant main effect for professional status of the experimenter on pain tolerance. Subjects tolerated pain longer when they were tested by a professional experimenter. Further, a significant interaction of experimenter gender and subject gender on pain tolerance indicated that subjects also tolerated pain longer when they were tested by an experimenter of the opposite sex. Additionally, a significant main effect for experimenter gender showed higher pain intensities for subjects tested by female experimenters. The observation that pain responsivity is influenced by the professional status of the experimenter might have implications for the study of pain in general and should be addressed in more detail in future experiments.

Changes of two components of the auditory event-related potential, the evoked 40-Hz response and the N350, were studied during different stages of wakefulness and sleep. The evoked 40-Hz response has been proposed to represent an attention-modulating mechanism; the N350 seems to reflect an inhibitory process associated with reduced information processing. Because recent literature suggests that both components reflect opposite mechanisms, an inverse relationship was expected. Ten participants were presented with tone pips while reading, lying awake in bed, and during light sleep, slow wave sleep, and REM sleep. A significant evoked 40-Hz response was observed during reading and lying awake in bed. N350 was evident in all conditions and, as expected, peaked during light sleep. The hypothesized inverse relationship was confirmed. These findings support former proposals that relate both components to attention. Possibly, the N350 is most pronounced during the sleep transition period because its inhibitory processes have to prevail over the attentional mechanisms (40-Hz response) to permit sleep onset.