Fig. 1

Example stimuli and theoretical model illustrating the predicted results. a Example dual-target display. The easy target (dark gray rotated T) is located in the upper left quadrant and the hard target (light gray T) is located in the lower left. b Theoretical depiction of underlying difficulty distributions from which the “Hard” (light gray) and “Easy” (dark gray) targets for each trial were drawn from. More difficult-to-find targets fall farther to the right on the distribution and will take longer to find. The prediction is that expectations about the underlying trial structure differentially set the quitting threshold (low-expectation in orange, high-expectation in blue). c Hypothetical distribution of found targets for the low-expectation quitting threshold in panel B. d Hypothetical distribution of found targets for the high-expectation quitting threshold in panel B. Comparing panels C and D, illustrates the prediction that the higher quitting threshold leads to higher hit rates by allowing time for the searcher to find the more difficult targets from the far right of the distribution in panel B. In turn, the mean response time for finding a target increases with the higher quitting threshold, particularly for the hard targets