Effect of short lateralized signals on arousal versus activation on tasks requiring visuospatial or elementary semantic stimulus processing, a replication with a modified experimental design.

In this experiment, which is basically a replication of an earlier experiment done in 1988, we tested the hypothesis that the brain self-regulates its own arousal and activation. When subjects perform a putative right-hemisphere task (visuospatial), the effect of a supplementary information-processing load is supposed to lead to a delayed reaction. The opposite is supposed to be true in a putative left-hemisphere task (semantic). The former effect is supposed to be the result of increased arousal, the latter is that of increased activation. In the present experiment the reactions subject to experimental treatment are compared with control reactions of the same subject. This was not the case in the earlier experiment. Still other improvements of the experimental design were made. The results clearly confirm the earlier findings. Additional evidence is offered to strengthen the plausibility of the basic hypothesis.