Distributions of decision times produced by the coupled-circuit model.

<p>(A) Normalized cumulative distributions for correct trials under accuracy conditions. Darker curves correspond to more difficult tasks, determined by mean target-distractor similarity (see legend). (B) Same as in <i>A</i>, but under speed conditions. Note the different scales of the x-axis in A and B. (C) Decision times at the crossing of quantiles 0.1 and 0.9 of the distributions for correct trials under accuracy (grey) and speed (black) conditions, plotted as a function of task difficulty. Curves show the best least squares linear fit, where solid and dashed lines correspond to quantiles 0.1 and 0.9 respectively. Under each condition, the slope of the dashed line (38.6 grey, 5.8 black) is greater than that of the solid line (8.5 grey, 2.1 black), indicating that the tail of the distribution is growing more than the leading edge as difficulty increases. (D) Mean decision times on correct (solid) and error (dotted) trials under accuracy (grey) and speed (black) conditions. Error bars show standard error.