Effect of short lateralized signals on arousal versus activation on tasks requiring visuospatial or elementary semantic stimulus processing.

The results of the experiment offer indirect evidence for the basic hypothesis that the brain self-regulates its own arousal and activation as a function of the intensity and type of ongoing cortical activity. When subjects perform a task which can be assumed to be primarily attended to by the right hemisphere, the result of a supplementary information-processing load seems to be increased arousal. On a task primarily attended to by the left hemisphere, the consequence is increased activation. The evidence is indirect because no measurements have been made of the neurological events and processes which are assumed to intervene in this self-regulation process. Although indirect, the evidence may help to formulate more precise psychological hypotheses about the factors controlling the putative effort system which, according to Pribram and McGuinness in 1975, coordinates the arousal and activation of cerebral processes.