Posner's theory of attention: Right hemisphere processing superiority during sustained attention

Posner, proposed a theory of attention based on target detection, visual or ienting, and alertness. The latter is supposed to use brain structures main ly located in the right hemisphere. Whitehead found a right hemisphere proc essing superiority during sustained attention. An additional auditory stimu lus is thought to produce a change of alertness and should interfere with t his asymmetry, which Whitehead was able to show, too. It remains unclear ho w the left hemisphere is activated by right hemisphere pathways. Therefore we tried to replicate whitehead's findings. In our first experiment the exp ected interaction between visual field foreperiod duration, and tone was ob tained. Probably the tone used in our experiment was not intense enough to produce a sufficient change in alertness. We used a more intense tone in a second experiment. This time a three-way interaction was present but could not be interpreted in terms of Whitehead's assumptions, instead the additio nal alerting stimulus seems to influence the state of alertness in a much m ore general and long-lasting way.