Multidimensional stimulus identification: instructing subjects in the order of reporting stimulus dimensions.

Two experiments were conducted to investigate the effects of order of report on identification of multidimensional stimuli under various experimental conditions. Statistical analysis showed that order of report affected speed of identification. Subjects responded faster if a natural and more appropriate way of reporting stimulus dimensions was used. Further, subjects reacted more slowly if they were free to report stimulus dimensions in any order than when they were forced to report in a particular order. Their performance was even worse when order of report was a with-in-subject factor. Response competition and response inhibition were proposed as possible explanations of the results. The implications of the results for multidimensional identification tasks are to designate an appropriate order of reporting stimulus dimensions and to instruct subjects to respond in that order.