Table 1. Mean Parameter Values and SD's Across Subjects for the Numerosity Discrimination Experiment.
Trial group | a | Ter | η | sz | p0 | st | vE | vD | χ2 | |
---|---|---|---|---|---|---|---|---|---|---|
Mean | 1-80 | 0.126 | 0.409 | 0.171 | 0.050 | 0.010 | 0.161 | 0.321 | 0.106 | 25.1 |
81-160 | 0.114 | 0.411 | 0.157 | 0.051 | 0.006 | 0.158 | 0.401 | 0.128 | 22.2 | |
161-240 | 0.118 | 0.400 | 0.138 | 0.051 | 0.009 | 0.172 | 0.383 | 0.127 | 24.5 | |
1-160 | 0.119 | 0.402 | 0.162 | 0.050 | 0.007 | 0.161 | 0.314 | 0.100 | 29.6 | |
161-320 | 0.114 | 0.398 | 0.145 | 0.051 | 0.009 | 0.171 | 0.340 | 0.115 | 33.0 | |
1-320 | 0.118 | 0.395 | 0.155 | 0.053 | 0.008 | 0.182 | 0.317 | 0.114 | 34.1 | |
321-640 | 0.114 | 0.382 | 0.145 | 0.063 | 0.008 | 0.174 | 0.324 | 0.108 | 34.6 | |
1-1200 | 0.112 | 0.374 | 0.126 | 0.064 | 0.007 | 0.180 | 0.282 | 0.107 | 50.4 | |
SD | 1-80 | 0.032 | 0.058 | 0.076 | 0.036 | 0.023 | 0.087 | 0.113 | 0.058 | 10.5 |
81-160 | 0.036 | 0.052 | 0.073 | 0.037 | 0.015 | 0.091 | 0.147 | 0.076 | 10.6 | |
161-240 | 0.032 | 0.043 | 0.070 | 0.043 | 0.018 | 0.080 | 0.150 | 0.081 | 11.4 | |
1-160 | 0.026 | 0.047 | 0.075 | 0.036 | 0.019 | 0.078 | 0.107 | 0.039 | 11.0 | |
161-320 | 0.031 | 0.042 | 0.078 | 0.034 | 0.021 | 0.076 | 0.126 | 0.052 | 15.0 | |
1-320 | 0.027 | 0.039 | 0.067 | 0.031 | 0.018 | 0.064 | 0.093 | 0.038 | 13.1 | |
321-640 | 0.029 | 0.041 | 0.061 | 0.027 | 0.015 | 0.058 | 0.104 | 0.035 | 12.0 | |
1-1200 | 0.023 | 0.035 | 0.047 | 0.021 | 0.011 | 0.049 | 0.076 | 0.033 | 20.7 | |
Mean | Simulation Parameters | 0.11 | 0.375 | 0.13 | 0.06 | 0.16 | 0.30 | 0.10 | ||
SD | 0.03 | 0.05 | 0.08 | 0.01 | 0.10 | 0.10 | 0.05 | |||
Mean | Hierarchical simulation parameters: two subject groups | 0.20 | 0.53 | 0.13 | 0.06 | 0.16 | 0.10 | 0.00 | ||
SD | 0.02 | 0.03 | 0.08 | 0.01 | 0.10 | 0.05 | 0.025 |
Note. a=boundary separation, z=starting point, Ter=nondecision component of response time, η =standard deviation in drift across trials, sz=range of the distribution of starting point (z), st = range of the distribution of nondecision times, vE and vD are the drift rates for the easy and difficult conditions respectively, and χ2 is the chi-square goodness of fit measure. For the data, the number of degrees of freedom for the fits to data was 30 and the critical value of chi-square at the .05 level was 43.8. In the simulations, the drift rates were correlated. The same random number was used to generate both drift rates with half the value added to the lower drift rate. The following were lower limits on parameter values: a, 0.07; η, 0.02; Ter, 0.25; st, 0.04, and an upper limit on sz of 0.9a. Separate sets of simulations were conducted with po 0 or 0.04.