EFFECTS OF COMPLEXITY IN SIMULTANEOUS REACTION TIME TASKS

2 experiments investigated the effects of information load (number of alternatives) and stimulus-response code in each of 2 simultaneously performed RT tasks. Ss (total N = 15) were required to make both a verbal and a manual response on each trial in the simultaneous-performance conditions. Each task was also performed alone for comparison The results were: (1) in simultaneous performance, RT in each task was greater with more alternatives or an indirect stimulus-response code in either task; (2) the complexity of the verbal task had a smaller effect on verbal RT when the complexity of the manual task was increased; and (3) details of the data argued against a response grouping interpretation. The evidence of overlap between the 2 tasks has important implications for the single-channel hypothesis. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.