Figure 2. Heterogeneous search conditions considered by Navalpakkam and Itti.
(A) Distribution of the target and distractor features. The first panel depicts a task in which the target is always vertical, but each distractor is tilted 5° to the right or 5° to the left, with equal probability. According to previous studies, this task is more difficult for than for any of the other three. (B) Predictions of a optimal model for d′ in each of these four search conditions, for single-target detection and for a fixed level of measurement noise (σ=3). No effects of distributed attention were taken into account. (C) Same as (B), but for proportion correct in single-target localization.