Material specific hemispherical arousal.

It has been previously demonstrated that warning stimuli (WS) reduce reaction time (RT) by causing cortical activation. The purpose of this study was to use verbal and non-verbal WS to see if these stimuli asymmetrically activate the cerebral hemispheres.Sixteen right-handed Ss were given a manual RT task using a light as the RT stimulus and either verbal or non-verbal sounds as WS. RTs by the right hand were significantly faster with verbal WS than with non-verbal WS. There were no significant differences for the left hand between the verbal and non-verbal WS. These results give partial support to the asymmetrical activation hypothesis.