Robert G. Moulder

The serial‐order effect wherein originality increases over time is one of the most robust findings in modern psychology. This effect, found in either individual or group sessions, is based on associative and spreading activation mechanisms: Mental association takes place in temporal sequential order from commonly (closely) to unusually (distantly) related semantic concepts stored in long‐term memory. Thus, data from previous studies might suggest that, in collective problem‐solving, we endure long meetings and pay closer attention to ideas presented toward the end of the meeting. However, members in innovative organizations have been reported to typically generate ideas on their own before group brainstorming. We hypothesized that in the subsequent group brainstorming session members would state their most appealing ideas first due to impression management. Our results from the individual‐then‐group hybrid brainstorming paradigm show that idea quality during the group session peaks early and then decays, in terms of both the number of high‐quality ideas produced and the proportion of ideas that are high‐quality. This “reverse” serial‐order effect implies that meeting for a reasonably brief time and looking into ideas shared early during the meeting may lead to better decisions—if individuals generated ideas prior to the meeting. We also found that flexibility (the rate at which new idea categories were introduced) dropped rapidly, but at a certain point of time, it stopped decreasing. This potentially suggests that extended group interaction after individual idea generation could bring greater idea diversity rather than higher overall quality. In addition, we found that the updated, cognitively constrained organizational norm for brainstorming, which likely narrows the scope of search, led to greater idea quantity (fluency), quality, and flexibility than the traditional, unconstrained norm. Our work challenges the traditional application of spreading activation theory to interpersonal, group, or organizational settings and calls for attention to the specific communicative processes of problem‐solving and decision‐making in question.