Fig. 4 |. Experiment 2.

a–d, Presaccadic condition. a, Group-averaged psychometric functions (d′ versus contrast). d_max and C₅₀ of the group-averaged psychometric functions are plotted to the right and bottom of the figure. The error bars represent the 95% bootstrapped confidence interval. b, The bootstrapped distribution of the difference of d_max (top) and the difference of C₅₀ (bottom) between the towards and away conditions. Asterisks denote that the distribution is significantly different from zero. c, Grey dots, best-fitted d_max of individual observers; grey ellipse, the ellipse with the 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; 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. d, C₅₀ illustrated in the same format as in c. e–h, Covert endogenous attention condition; corresponding to a–d. i–l, Covert exogenous attention condition; corresponding to a–d and e–h.