Fig 3. Attention improves performance, especially when it is focused on a small range of directions.

Bars indicate mean discrimination performance of all six observers, pooled across all levels of coherence. Colors indicate cue type. For each cue type, there is a significant difference between validly and invalidly cued trials, indicating that the cue lead to deployment of feature-based attention. In addition, the two types of cues (narrow and broad focus cues) lead to a significant difference in discrimination performance for validly, but not invalidly cued trials. Error bars indicate plus/minus one standard error. P values correspond to paired t-tests.