Behavior. A, Cued attention task. Proportion of rightward choices is plotted as a function of signed motion strength of the cued patch (positive coherence signifies rightward). Filled and open symbols represent trials where the direction of the uncued motion patch was the same or opposite to the direction of the cued patch, respectively, combining trials for all viewing durations. Solid and dashed curves are fits of a bounded drift-diffusion model that incorporates misrouting owing to incomplete suppression of the uncued patch or attending to it erroneously on a fraction of trials. Curves indicate the expectation of the choice-proportions for the mean stimulus duration (top, Monkey Dm; bottom, Monkey Np). B, Choice-accuracy improved as function of stimulus viewing duration in the cued attention task. Same data as in A, grouped by motion strength (colors) and quantiles of stimulus duration. Curves are fits of the same model as in A. C, Comparison of fits to models of Equations 2, 4, and 5. Model comparison favors inclusion of and λ for both monkeys. D, Variable location task with random stimulus durations. There is only one patch of motion. The proportion of choices in the positive direction (favoring the target in the neural response field) is plotted as as a function of signed coherence. The smooth curve is a fit to a simpler bounded drift-diffusion model. As in A, the proportions reflect all stimulus durations, and the fit shows predictions for the mean duration (top, Monkey Dm; bottom, Monkey Ap). E, Choice-response time version of the variable location task. The choices (top) and response times (bottom) are fit by a bounded drift-diffusion model. Fit parameters for all monkeys and conditions are in Table 1.