My graduate class ran three classic reaction time experiments this semester. The tasks were the Hick-Hyman task (simple, 2-choice, 4-choice, and 8-choice reaction time), stimulus-response compatibility (ipsilateral and contralateral mappings) and the modified flanker task (neutral, congruent, and incongruent arrows). I made sure that there was at least 100 trials per participant and per condition so that I could look at the response/reaction time distributions.
Each task has two figures. The bar graphs show the reaction time means (the bars) and the reaction time standard deviations (the error bars). The line graphs are the reaction time probability distributions.
Hick-Hyman Task
The reaction time means showed the expected linear increase with the doubling of the stimulus-response alternatives.
For the reaction time distribution analysis, mu and sigma increased with the number of stimulus-response alternatives (mu 232, 288, 363, and 443 ms; sigma 17.5, 24.3, 37.9, and 56.0 ms). Tau mostly increased with the number of stimulus-response alternatives (53.2, 45.5, 60.6, and 85.4 ms).
Stimulus-Response Compatibility
We replicated the expect finding of longer mean reaction time with the contralateral mapping compared to the ipsilateral mapping.
Mu, sigma, and tau were all larger with the contralateral mapping (358, 41.3, and 63.4 ms) compared to the ipsilateral mapping (305, 30.4, and 48.4 ms).
Modified Flanker Task
Mean reaction time was comparable in the neutral and congruent conditions. Reaction time was longer in the incongruent condition. These results were as expected.
Mu, sigma, and tau were comparable in the neutral condition (363, 29.9, and 53.3 ms) and the congruent condition (361, 27.7, and 60.1 ms). All three parameters were larger in the incongruent condition (404, 39.9, and 68.0).
Overall, the increases in mean reaction time in these three tasks caused increases in mu, sigma, and tau.
Motor Behaviour 