Utility of Pupillometric Methods for Studying Visual Search

Visual search is one of the most well-studied subjects in cognitive science. Not surprisingly, the methods and procedures employed by researchers have changed throughout the years, from relying almost exclusively on response time measures to the eventual adoption of eye tracking. As technology has advanced, scientists have revisited their theoretical frameworks to accommodate novel findings from emerging methodologies (e.g., insights from tracking eye movements). In this chapter, we discuss the utility and promise of pupillometric methods in visual search research. We first review foundational studies that have incorporated pupillometry into traditional visual search tasks. We then discuss how pupillometry has more recently allowed researchers to directly test assumptions that have gone unchallenged in the visual search literature. For instance, we discuss cases of the low-prevalence effect and domain-specific expertise (among others) as clear examples, wherein the use of pupillometry provided novel insights to earlier questions established in the literature. We also discuss how specific suggestions from broader theoretical frameworks can now be examined, and perhaps supported, by including pupillometry methods in research. Finally, we conclude by highlighting the key features (and limitations) that make this emerging method valuable for understanding the processes involved in visual search.