Fig. 5 |. Experiment 3.

a,b, The procedure of experiment 3 is the same as the presaccadic attention task in experiment 2, except that the test stimuli were presented with location uncertainty. Stimuli appeared at one of five predefined iso-eccentric locations. Stimulus locations were randomly and independently selected in the left and right placeholder. The dashed circles (not displayed during the experiments) indicate the possible stimulus locations (five in each placeholder; the figures here are for the purpose of illustration only. See Methods for the details of the stimulus parameters). c–f, Medium-uncertainty condition. c, Group-averaged psychometric functions (d′ versus contrast). d_max and C₅₀ of the group-averaged psychometric functions are plotted at the right and bottom of the figure. The error bars represent 95% bootstrapped confidence interval. d, The bootstrapped distribution of the difference of d_max (top) and the difference of C₅₀ (bottom) between the towards and away conditions. Distributions significantly different from zero are denoted with asterisks. e, Grey dots, best-fitted d_max of individual observers; grey ellipse, the ellipse with major axes oriented towards the difference and the sum of the d_max across two conditions. The difference (or sum) of d_max is first computed for individual observers, and the major axis of the ellipse represents ±1 s.d. of the difference (or sum). The black dot shows the group-averaged d_max and the error bar represents the standard deviation of the bootstrapped distribution of the difference between the towards and away conditions. f, C₅₀ illustrated in the same format as in e. g–j, High-uncertainty condition, corresponding to c–f.