Can subliminal spatial words trigger an attention shift? Evidence from event-related-potentials in visual cueing*

Abstract

Supraliminal central cue words elicit spatial attention shifts to the cued side. To investigate, if this also holds true for subliminal central words, masked cue/prime words, left or right, were shown prior to a visual colour search display. Both response times to targets and event-related brain potentials (ERPs) reflecting spatial attention (EDAN, ADAN, LDAP, N2pc) were analyzed. In Experiment 1, we found no evidence for spatial attention shifts by subliminal central words; neither significant ERPs (EDAN, ADAN, LDAP) nor significant validity effects in the behavioural data. To control for the processing of the subliminal words, we included trials with a congruent or incongruent target word (left or right) in a classic target discrimination task in Experiment 2, and additionally analyzed an ERP reflecting semantic congruence, the N400. We mainly replicated the results from Experiment 1 (no spatial attention shifts by subliminal words) and found a difference depending on the congruence between subliminal word and target word (N400) as well as a negative congruence effect in the reaction times. These findings demonstrate that the subliminal word was processed. We therefore conclude that subliminally presented central cue words–even though they are processed–cannot elicit spatial attention shifts in visual colour search.