A third source of support for the importance of practical skills comes from theories of managerial performance. Rational theories that are based on conventional notions of how people solve problems (e.g., Kepner and Tregoe, 1965; Plunkett and Hale, 1982) do not accurately represent the problem solving of experienced and successful managers. These observations led theorists to describe managerial problem solving as non-linear, convoluted, and action-oriented (e.g. McCall and Kaplan, 1985; Mintzberg et al., 1976). Furthermore, knowledge of how to solve problems can be characterized as tacit, and it may only enter into conscious awareness through reflection (Schön, 1983). The recognition that rational models of managerial problem solving do not explain the behavior of successful practitioners suggests that alternative approaches are needed to identify the practical skills underlying performance.

Finally, the research on tacit knowledge described throughout this volume offers an approach to understanding practical cognition. Over the course of studies with academic psychologist (Wagner, 1987; Wagner and Sternberg, 1985), business managers (Wagner and Sternberg, 1990), salespersons (Wagner et al., 1994), U.S. Air Force recruits (Eddy, 1988), and military leaders (Hedlund et al., 1999), we have found that tacit knowledge offers insight into the practical skills associated with success.

Several conclusions can be drawn from this program of research. First, these studies showed that tacit knowledge exists in the stories successful practitioners share about the lessons they learned in the process of performing their respective roles. These stories provide rich insights about the practically-oriented knowledge that practitioners are often unaware that they have acquired. Second, we showed that tacit knowledge can be measured through instruments that take into account the procedural and context-specific nature of tacit knowledge. Third, using such instruments, we have found that individuals who exhibit the skill to acquire and use tacit knowledge are more effective in their respective performance domains. Furthermore, tacit knowledge helps to explain some of the additional variance in performance that is not accounted for by measures of general cognitive skill. Fifth, although the acquisition of tacit knowledge may be influenced, to some extent, by g and amount of experience, tacit-knowledge inventories are not simply new measures of these constructs. Finally, tacit knowledge generally appears to be a singular construct within domains, but the content of tacit knowledge varies across domains. In other words, tacit knowledge appears to reflect a single underlying skill, which we label practical cognition. But, this underlying skill is not sufficient for performing well on domain-specific tacit-knowledge tests. Experience in a particular domain is important in the acquisition of tacit knowledge.