Table 2.

p Values for Planned Comparisons of Parameters

Comparison of Sessions	a	Ter	η	sz	v1	v2	v3	v4	po	st	vc	z
Session 1
Experimental vs. control	.961	.997	.766	.868	.812	.411	.336	.730	.248	.970	.373	.862
Session 2
Experimental vs. control	.008*	.279	.076	.000*	.013*	.011*	.006*	.255	.028*	.023*	.467	.021*
Session 3
Experimental vs. control	.122	.701	.016*	.161	.527	.490	.948	.503	.065	.765	.728	.118
Experimental Group Only
Sleep-deprived vs. baseline	.055	.232	.118	.000*	.003*	.020*	.012*	.465	.017*	.065	.429	.164
Sleep-deprived vs. recovery	.042*	.392	.755	.003*	.000*	.002*	.003*	.064	.015*	.004*	.570	.179

Note—a, upper boundary of accumulation of information over time; T_er, mean of the distribution of times taken up by the nondecision component, in seconds. η, s_z, and s_t represent across-trial variability in drift rate, in starting point, and in the nondecision component, respectively. v₁, v₂, v₃, and v₄ represent the four distinct drift-rate parameters for the eight numerosity categories (see the text for details). p_o, proportion of contaminants; v_c, drift criterion; z, starting point of accumulation of information over time. Session 1, baseline; Session 2, sleep-deprived (or control); Session 3, recovery. Group × session interactions are as follows: For a, F(2,46) = 7.40; for T_er, F(2,46) = 4.20; for η, F(2,46) = 2.34; for s_z, F(2,46) = 7.04; for v₁, F(2,46) = 8.77; for v₂, F(2,46) = 10.39; for v₃, F(2,46) = 6.07; for p_o, F(2,46) = 8.08; for s_t, F(2,46) = 4.2. The critical value was F_.95(2,46) = 3.2.

^*p < .05.