Masked stimuli modulate endogenous shifts of spatial attention

► Participants performed a spatial cueing task in which masked primes appeared before centrally presented symmetrical cues. ► In three experiments target letters were discriminated faster when primes and cues were congruent rather than incongruent. ► These spatial cue-priming effects exhibit similar time courses as cue-priming effects in previous non-spatial tasks. ► Cue-priming effects extend beyond a facilitation of perceptual processing of the cues. ► Results suggest unconscious stimulus features affect mechanisms of endogenously controlled orienting of spatial attention.