Abstract
In grapheme-color synesthesia, a visual letter or digit induces a specific color sensation. This implies that grapheme-color synesthetes should experience color inconsistency each time they see graphemes (i.e., graphemes seldom appear in their own synesthetic colors). However, rather than automatically activating a specific color at these times, it is possible that synesthetes excel in suppressing certain synesthetic sensations or at least they can allocate less attention to these colors in particular contexts. This study investigates the ability of suppressing synesthetic sensation in six grapheme-color synesthetes using a visual search paradigm. The task required a search for a target digit (‘2’ or ‘5’, displayed in a digital font) among distractor digits (‘5’ or ‘2’, respectively). Both target and distractor digits were displayed in white against either a black or colored background. Results revealed that the digit search slope was statistically significantly (or marginally significantly) shallower (i.e., a more efficient search) when the background color was consistent with the synesthete's own synesthetic color for the distractor digits than when the color of the background was consistent with the synesthetic color for the target digits or when the background color was black. This suggests that items which elicit synesthetic colors consistent with irrelevant background colors were allocated less attention. Search efficiency of synesthetes in the black background condition did not differ from that of age- and gender- matched non-synesthetes, indicating that synesthetic colors for items were not activated pre-attentively and did not facilitate visual search in synesthetes. Collectively, results suggest that synesthetic colors are not pre-attentively activated. Instead, it appears that in a given task grapheme-color synesthetes can allocate less attention so that certain graphemes presented in a given color can be ignored.
Meeting abstract presented at VSS 2013