In a simple reaction time task in which auditory and visual stimuli are presented in random
sequence alone (A or V) or together (AV), there is a so-called reaction time (RT) cost on
trials in which sensory modality switches (A→ V) compared to when it repeats (A→ A). This
is always true for unisensory trials, whereas RTs to AV stimuli preceded by unisensory
stimuli are statistically comparable with the Repeat condition (AV→ AV). Neural facilitation
for Repeat trials or neural inhibition for Switch trials could both account for these effects …