Parameter recovery for the time-window-of-integration (TWIN) model of multisensory integration in focused attention.

In multisensory settings such as the focused attention paradigm (FAP), subjects are instructed to respond to stimuli of the target modality only, yet reaction times tend to be shorter if an unattended stimulus is presented within a certain spatiotemporal vicinity of the target. The time window of integration (TWIN) model predicts successfully these observed cross-modal reaction time effects. It proposes that all the initially unimodal information must arrive at a point of integration within a certain time window in order to be integrated and thus to initiate response enhancements like the observed reaction time reductions. Here we conducted a parameter recovery study of the TWIN model for focused attention tasks, with five parameters (the durations of the visual and auditory unimodal and the integrated second stage, the width of the time window, and the effect size). Results show that parameter estimates were highly accurate (unbiased, constant error less than 5 ms) and precise (variable error less than 8 ms) throughout, speaking to a high reliability and criterion validity of the process. Further analyses ensured that the estimation procedure is consistent and sufficiently robust against contamination (faulty integration). It can thus be used to estimate reliably the point of integration and the width of the time window.