In a real world search, it can be important to keep ‘an eye out’ for items of interest that are not the primary subject of the search. For instance, you might look for the exit sign on the freeway, but you should also respond to the armadillo crossing the road. In medicine, these items are known as “incidental findings,” findings of possible clinical significance that were not the main object of search. These errors (e.g., missing a broken rib while looking for pneumonia) have medical consequences for the patient and potential legal consequences for the physician. Here we report three experiments intended to develop a ‘model system’ for incidental findings – a paradigm that could be used in the lab to develop strategies to reduce incidental finding errors in the clinic. All the experiments involve ‘hybrid’ visual search for any of several targets held in memory. In this ‘mixed hybrid search task,’ observers search for any of three specific targets (e.g., this rabbit, this truck, and this spoon) and three categorical targets (e.g., masks, furniture, and plants). The hypothesis is that the specific items are like the specific goals of a real world search and the categorical targets are like the less well-defined incidental findings that might be present and that should be reported. In all these experiments, varying target prevalence, number of targets, etc., the categorical targets are missed at a much higher rate than the specific targets. This paradigm shows promise as a model of the incidental finding problem.

Both visual attention and visual working memory tend to be studied either with very simple stimuli and low-level paradigms, which are designed to allow us to understand the representations and processes in detail; or with fully realistic stimuli that make such precise understanding difficult but are more representative of the real world. In this chapter we argue for an intermediate approach in which visual attention and visual working memory are studied by scaling up from the simplest settings to more complex settings that capture some aspects of the complexity of the real-world, while still remaining in the realm of well-controlled stimuli and wellunderstood tasks. We believe this approach, which we have been taking in our labs, will allow a generalizable set of knowledge about visual attention and visual working memory while maintaining the rigor and control that is typical of vision science and psychophysics studies.

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Searching for a "Q" among "O"s is easier than the opposite search (Treisman & Gormican in Psychological Review, 95, 15-48, 1988). In many cases, such "search asymmetries" occur because it is easier to search when a target is defined by the presence of a feature (i.e., the line terminator defining the tail of the "Q"), rather than by its absence. Treisman proposed that features that produce a search asymmetry are "basic" features in visual search (Treisman & Gormican in

Both visual attention and visual working memory tend to be studied with very simple stimuli and low-level paradigms, designed to allow us to understand the representations and processes in detail, or with fully realistic stimuli that make such precise understanding difficult but are more representative of the real world. In this chapter we argue for an intermediate approach in which visual attention and visual working memory are studied by scaling up from the simplest settings to more complex settings that capture some aspects of the complexity of the real-world, while still remaining in the realm of well-controlled stimuli and well-understood tasks. We believe this approach, which we have been taking in our labs, will allow a more generalizable set of knowledge about visual attention and visual working memory while maintaining the rigor and control that is typical of vision science and psychophysics studies.