Skyler S. Place

Low target prevalence is a stubborn source of errors in visual search tasks

In visual search tasks, observers look for targets in displays containing distractors. Likelihood that targets will be missed varies with target prevalence, the frequency with which targets are presented across trials. Miss error rates are much higher at low target prevalence (1%-2%) than at high prevalence (50%). Unfortunately, low prevalence is characteristic of important search tasks such as airport security and medical screening where miss errors are dangerous. A series of experiments show this prevalence effect is very robust. In signal detection terms, the prevalence effect can be explained as a criterion shift and not a change in sensitivity. Several efforts to induce observers to adopt a better criterion fail. However, a regime of brief retraining periods with high prevalence and full feedback allows observers to hold a good criterion during periods of low prevalence with no feedback.

Multiple object juggling: Changing what is tracked during extended multiple object tracking

The multiple object tracking (MOT) task has been a useful tool for studying the deployment of limited-capacity visual resources over time. Since it involves sustained attention to multiple objects, this task is a promising model for real-world visual cognition. However, real-world tasks differ in two critical ways from standard laboratory MOT designs. First, in real-world tracking, it is unusual for the set of tracked items to be identified all at once and to remain unchanged over time. Second, real-world tracking tasks may need to be sustained over a period of minutes, and not mere seconds. How well is MOT performance maintained over extended periods of time? In four experiments, we demonstrate that observers can dynamically “juggle” objects in and out of the tracked set with little apparent cost, and can sustain this performance for up to 10 min at a time. This performance requires implicit or explicit feedback. In the absence of feedback, performance tracking drops steadily over the course of several minutes.

The Ability to Judge the Romantic Interest of Others

The ability to judge another individuals romantic interest level—both toward oneself and toward others—is an adaptively important skill when choosing a suitable mate to pursue. We tested this ability using videos of individuals on speed dates as stimuli. Male and female observers were equally good at predicting interest levels, but they were more accurate when predicting male interest: Predictions of female interest were just above chance. Observers predicted interest successfully using stimuli as short as 10 s, and they performed best when watching clips of the middle or end of the speed date. There was considerable variability between daters, with some being very easy to read and others apparently masking their true intentions. Variability between observers was also found. The results suggest that the ability to read nonverbal behavior quickly in mate choice is present not only for individuals in the interaction, but also for third-party observers.

Which way did it go? Measuring trajectory information in multiple object tracking

2 3 4 1 # of Targets (70% accuracy threshold = 30°) Observers have good resolution for target direction Purpose / Overview Purpose/Overview Multiple object tracking (MOT) experiments have demonstrated that observers can track multiple independently moving objects (Cavanagh & Alvarez, 2005; Pylyshyn, 2001). We introduce a new method to demonstrate that observers are tracking target trajectories, not merely locations. Do you have better directional information for targets than non-targets?

Rapid recovery of targets in multiple object tracking

template references Alvarez, G. A., Horowitz, T. S., Arsenio, H. C., DiMase, J. S., & Wolfe, J. M. (in press). Do multielement visual tracking and visual search draw continuously on the same visual attention resources? Journal of Experimental Psychology: Human Perception & Performance. Fencsik, D. E., Horowitz, T. S., Klieger, S. B., & Wolfe, J. M. (2004). Target reacquisition strategies in multiple object tracking, Vision Sciences Society (Vol. 4, pp. 77). Horowitz, T. S., Birnkrant, R. S., Wolfe, J. M., Tran, L., & Fencsik, D. E. (2004). Tracking invisible objects, Vision Sciences Society (Vol. 4, pp. 76). Keane, B. P., & Pylyshyn, Z. W. (2004). Tracking behind occluders is not based on predicting likely reappearance locations. Journal of Vision, 4(8), 362a.

Faster is not necessarily better in visual search

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