Factors influencing the use of internal summary evaluations versus external information in choice

Abstract Decision makers cope with more demanding tasks by shifting their cognitive strategies, balancing effort expenditure against the desire to produce an accurate response. In choice tasks, one method for reducing effort while simultaneously maintaining accuracy is to shift from a reliance on information obtained from the external environment to that retrieved from memory, particularly summary evaluations (i.e. relatively stable evaluative reactions to the overall attractiveness of individual alternatives) acquired from previous decision‐making experience. We examined four factors that should all encourage decision makers to rely to some extent on internal summary evaluations rather than external information search: (1) increased external search costs, (2) greater time pressure, (3) increased incentives to make an accurate choice, and (4) increased levels of prior experience with the choice context. Sixty experimental subjects chose their preferred alternative from a set of women's magazines. Decision processes were inferred from verbal protocols, computer‐generated search records, and decision times. Only increased external search costs led to a greater reliance on summary evaluations. Although increased time pressure, increased incentives, and increased experience with the context did lead to changes in search and evaluation processes, contrary to initial expectations decision makers did not shift to a greater reliance on summary evaluations. These results suggest that while decision makers do sometimes use summary evaluations as a substitute for external search, this is only one of several mechanisms available for effort reduction. Understanding when and where decision makers rely upon summary evaluations probably requires a broader conceptualization of knowledge structures, particularly a consideration of the knowledge that decision makers possess about different choice strategies and their effectiveness.