Effects of Group Size, Task Complexity and Time Pressure on Decision Making Efficiency

Group decision making in organizational and social settings is very important to understand choice behavior and it has received considerable empirical and theoretical attention (Hinsz, 1999; Hirokawa & Poole, 1996; Kameda, Tindale, & Davis, 2002; Levi, 2001; Rosen, Salas, Pavlas, & Lum, 2009; Salas, Cooke, & Rosen, 2008; Stangor, 2004; Tindale & Davis, 2003; Witte, 2007; Witte & Davis, 1996). Group decision makingis a multidimensional process requiring several skills that include the ability to structure a decision problem, understand relevant information, integrate information and reason about it, and to meet an accord. Understanding effectiveness of group decisions is important in real world contexts, because in many daily occurrences group performance is more relevant and salient than individual. The aim of the present study is to analyse factors (group size, time pressure and task complexity) that affect group decision-making efficiency. It was hypothesized that by increasing group size and task complexity, with time pressure, the number of minutes, comments and bifurcations would increase. 123 subjects (M= 22.58; SD = 1.6) participated in a group decision making with a visual paradigm of thinking-externalization (Beers, Boshuizen, & Kirschner, 2002). In this research, a visual tool was used, employing a pen-and-paper version of the formalism for supporting negotiation. This device made more explicit the connections among concepts and proposals, and to generate hypotheses. The emergence of members’ statements modifying the course of the debate was considered a relevant bifurcation in the decision process. Main results were in line with the hypotheses, confirming that when group size and task complexity increased, number of minutes, comments, and bifurcations increased; further, when the group was under time pressure, all the parameters decreased. An additional interaction effect between group size and time pressure on bifurcations was found. In this chapter, the results are discussed assuming the bifurcation parameter as an operative measure of group efficiency and relying them to the multidimensional theory. This study provides evidence to the notion that time pressure, group size and task complexity can affect group decision making efficiency.