Visual Search for Events with Dynamic Optical Information

In classic visual search experiments, observers memorize a static symbol then look for it from similar items. Although this task has yielded much understanding about visual attention, it may not fully explain real-world search, where observers often search for events, not static symbols. Events constitute objects in motion and event-specifying information is dynamic. The current study investigates whether observers could search for a target event using mainly dynamic information. Participants first learned a target point-light walker (PLW), then reported its presence or absence in an array of PLWs presented in frontal (Experiment 1) or side (Experiment 2) views. In some trials, the target remained visible throughout search, and participants could look at, instead of memorizing it, and use it as a reference to compare to each search array item. In both experiments, accuracy was above chance; search time was longer than when searching for static items. Having a visible target throughout search improved accuracy and subjectively rated confidence, but increased search time. Eye-tracking data revealed that participants compared search array items with the reference target when available. Therefore, visual search for events is an embedded process, where observers detect dynamic information in real time to discriminate events.