When the eyes have it and when not: How multiple sources of activation combine to guide eye movements during multiattribute decision making

Memory plays a major but underexplored role in judgment and decision making (JDM). Studying eye movements—especially how people look at empty spatial locations when retrieving from memory information previously associated with those locations—provides useful information about how memory influences JDM. This so-called looking-at-nothing behavior is thought to reflect memory-driven allocation of attention. However, eye movements are also guided toward salient visual stimuli, such as test items presented on a screen. It is unclear how these multiple sources of activation combine to guide looking-at-nothing in JDM. We investigated this question in two experiments in which participants solved multiattribute categorization tasks using an exemplar-based decision strategy. In the first experiment, we tested how the occurrence and the strength of looking-at-nothing vary with the presentation format and the amount of training participants received. Looking-at-nothing occurred during categorizations when test-item information was presented auditorily and visually, but for the latter only after visual information was removed from the screen. It occurred both when training items were learned by heart and when they were presented 10 times on the screen. A second experiment revealed that an explicit instruction to imagine retrieval-relevant information during categorizations increased looking-at-nothing but did not change the decision-making process. The results shed light on the interaction between eye movements and attention to information in memory during JDM that can be explained in light of a shared priority map in memory. A detailed understanding of this interaction forms the basis for using eye movements to study memory processes in JDM