A new technique for estimating the probability of attentional capture.

Latency-based metrics of attentional capture are limited: They indicate whether or not capture occurred, but they do not indicate how often capture occurred. The present study introduces a new technique for estimating the probability of capture. In a spatial cueing paradigm, participants searched for a target letter defined by color while attempting to ignore salient cues that were drawn in either a relevant or irrelevant color. The results demonstrated the typical contingent capture effect: larger cue validity effects from relevant cues than irrelevant cues. Importantly, using a novel analytical approach, we were able to estimate the probability that the salient cue captured attention. This approach revealed a surprisingly low probability of attentional capture in the spatial cuing paradigm. Relevant cues are thought to be one of the strongest attractors of attention, yet they were estimated to capture attention on only about 30% of trials. This new metric provides an index of capture strength that can be meaningfully compared across different experimental contexts, which was not possible until now.