Several lines of research have documented early-latency non-linear response interactions between audition and somatosensation in humans and non-human primates. The fact that these effects have been obtained under anesthesia, passive stimulation, as well as speeded reaction time tasks would suggest that early multisensory effects are not directly influencing behavioral outcome. To address this issue more specifically and empirically, we separately averaged trials leading to fast and slow reaction times (using a median split of individual subject data for each experimental condition) from a previously published study that required stimulus detection (Murray et al., 2005 Cereb Cortex 15:963-974). We show that non-linear neural response interactions between multisensory and constituent unisensory stimuli are present for both trials leading to fast and slow reaction times. However, these effects were also modulated within the initial ~100ms as a function of subjects’ reaction times, with larger and earlier effects for trials leading to fast reaction times. These results suggest that early multisensory phenomena are indeed behaviorally relevant, even if also observable under varied subjective states and task demands.