2.9.2 Reaction Time and Task Performance
Task performance was quantified using Hit rate. ‘Hit’ trials were defined as trials in which a participant responded to the cue between 150 and 1000 ms after cue onset (Table 2A, Figure 2F ). A secondary measure of task performance known as ‘Percent Double Press’ was computed to characterize systematic performance atypicalities in ASD by dividing the number of duplicate responses (two or more responses in an epoch) by the total number of button presses (Table 2B, Figure 2G ). For perfect task performance, each stimulus would elicit a single button press. In this case, the percentage of double presses would be 0. For a participant who systematically pressed the response button two times for each stimulus, the percentage of double presses would be 50% because half of all presses represent duplicate responses.
To examine differences in reaction time as a function of the preceding sensory cue type (A, V, AV), participant age, and clinical diagnosis (ASD, TD), a general linear mixed model (GLMM) was computed (Table 2B ). Table 2 details all model factors. Main effect terms were included for participant group and preceding sensory cue. Age was included as a covariate. Because investigation of group effects was a key focus of the current work, two-way interaction terms were included for all combinations of factors involving ‘Group’ (Group*Age, Group*Cue, Group*RT quartile). Note that ‘RT quartile’ (fastest 25% of trials, middle 25-50% of trials, middle 50-75% of trials, slowest 25% of trials) was not included as a main effect in this GLMM since these RT quartiles were constructed on the basis of the outcome measure (RT).