Sensory and attentional components of slowing of manual reaction time to non-fixated visual targets by ipsilateral primes.

Reaction time (RT) for detecting extrafoveal targets is lengthened by a non-informative prime at the same location or in the same hemifield (RT inhibition). We assumed that sensory effects at primed locations should be the same for unilateral and bilateral primes, whereas systematic covert orienting to a primed location should occur only with unilateral primes. We found equal RT inhibition for both types of primes at 0.2 sec prime-target intervals (SOA), as contrasted with inhibition for unilateral but not bilateral primes at 0.6 sec SOAs. We conclude that RT inhibition involves a succession of sensory components and orienting-dependent components.