Abstract
Computational theories of stimulus-driven capture of attention calculate a colour contrast's potential to attract attention as an objective local colour difference within the image. Is that allowed? We tested whether subjective or phenomenal salience of colour contrasts could be a crucial prerequisite for stimulus-driven attentional capture by colour contrasts: Colour singletons were metacontrast masked and, thus, invisible. Under these conditions, colour singletons failed to capture attention in a stimulus-driven way. This was reflected in behavioural responses as well as in attention-related event-related potentials (ERPs). In addition, diverse control conditions corroborated the attention-grabbing power of colour singletons, ruling out that the method was insenstive to the detection of attentional capture by masked colour singletons.