Search Strategies Improve With Practice, but Not With Time Pressure or Financial Incentives

When searching for an object, do we minimize the number of eye movements we need to make? Under most circumstances, the cost of saccadic parsimony likely outweighs the benefit, given the cost is extensive computation and the benefit is a few hundred milliseconds of time saved. Previous research has measured the proportion of eye movements directed to locations where the target would have been visible in the periphery as a way of quantifying the proportion of superfluous fixations. A surprisingly large range of individual differences has emerged from these studies, suggesting some people are highly efficient and others much less so. Our question in the current study is whether these individual differences can be explained by differences in motivation. In two experiments, we demonstrate that neither time pressure nor financial incentive led to improvements of visual search strategies; the majority of participants continued to make many superfluous fixations in both experiments. The wide range of individual differences in efficiency observed previously was replicated here. We observed small but consistent improvements in strategy over the course of the experiment (regardless of reward or time pressure) suggesting practice, not motivation, makes participants more efficient. Public Significance Statement In this study, neither time pressure nor financial incentive led to improvements in visual search strategies, ruling out motivation as the explanation for the large individual differences in search efficiency seen in previous studies. Small but consistent improvements in strategy over time suggest experience, rather than differences in motivation, could help explain why some participants are more efficient than others.