Abstract
Previous research based on predictions of complexity theory has often varied information load and measured characteristics of group decision making. A reinterpretation of related data on success and failure effects suggests that the obtained load effects may be confounded by simultaneous variation of information load and information relevance. To begin studying the separate effects of the two variables, information load was held constant at the previously determined optimal level and information relevance was varied as a proportion of load. It was found that integrated decision making (a complex decision response) was modified by changes in information relevance; but that respondent decision making and information search (simple decision responses) did not change. The results were tentatively interpreted to suggest that complex decision making varies with relevance, while simple decision making varies with information load. It was suggested that complexity theory might be correspondingly modified.