Do Synesthetic Colors Grab Attention in Visual Search?
Recent research on synesthesia has focused on how the condition may depend on selective attention, but there is a lack of consensus on whether selective attention is required to bind colors to their grapheme inducers. In the present study, we used a novel change detection paradigm to examine whether synesthetic colors guide the subject’s attention to the location of the inducer or whether selective attention is required to act as a unique feature during visual search. If synesthetic experiences are elicited by inducers (e.g., digits) without selective attention, then a target that is distinct from the distractors by virtue of its unique synesthetic color should capture attention. This should lead to efficiency in the search that is analogous to the efficiency in searches involving unique display colors (e.g., a display of red digits among black). If, however, an inducer does not elicit a synesthetic color until the subject selectively attends to it, then the search should be as inefficient as for control subjects. We found that, not only does synesthesia not provide an advantage in complicated visual search tasks, it offers a slight disadvantage, supporting the re-entrant processing hypothesis about the mechanism underlying synesthesia.