Precision of synesthetic color matching resembles that for recollected colors rather than physical colors.

Abstract

Grapheme-color synesthesia is an atypical condition in which individuals experience sensations of color when reading printed graphemes such as letters and digits. For some grapheme-color synesthetes, seeing a printed grapheme triggers a sensation of color, but hearing the name of a grapheme does not. This dissociation allowed us to compare the precision with which synesthetes are able to match their color experiences triggered by visible graphemes, with the precision of their matches for recalled colors based on the same graphemes spoken aloud. In six synesthetes, color matching for printed graphemes was equally variable relative to recalled experiences. In a control experiment, synesthetes and age-matched controls either matched the color of a circular patch while it was visible on a screen, or they judged its color from memory after it had disappeared. Both synesthetes and controls were more variable when matching from memory, and the variance of synesthetes' recalled color judgments matched that associated with their synesthetic judgments for visible graphemes in the first experiment. Results suggest that synesthetic experiences of color triggered by achromatic graphemes are analogous to recollections of color.

Graphemes Sharing Phonetic Features Tend to Induce Similar Synesthetic Colors

“…Hence, the current results imply the involvement of phoneme processing even during grapheme processing, suggesting the coexistence of acoustic-phonetic and visual-graphemic influences in synesthesia (Simner et al, 2005; Simner, 2007). The current results are also in line with the recent finding that color experienced by grapheme-color synesthetes when viewing inducing graphemes is perceptually comparable to the color recalled from memory when hearing spoken graphemes (Arnold et al, 2012). These results might bear implications in more general context of language processing suggesting visual graphemes automatically activates phonological representations and auditory phonemes automatically activates visual graphemic information (Berent and Perfetti, 1995; Stone et al, 1997).…”

Enhanced dimension-specific visual working memory in grapheme–color synesthesia

“…Indeed, it is plausible that enhanced color working memory subserves superior color recognition memory in this population. Recently, Arnold et al (2012) showed that grapheme–color synesthetes were more precise than controls at recalling the color and luminance of a colored circle using a modifiable color patch. Insofar as participants completed the recollection task only 500 ms after stimulus presentation, this result is indicative of superior color working memory among synesthetes and thereby bolsters the present results.…”

“…For instance, both may be maintained in a phonological loop, and thus dual-coding benefits would not be expected. Alternatively, it may be that color photisms, which do not affect memory in the same way as sensory experiences (e.g., Arnold et al, 2012), do not confer an auxiliary coding advantage in working memory or short-term memory for graphemes in the same way as concurrent sensory experiences do (see also Mastroberardino et al, 2008; Rothen & Meier, 2010). Further research is needed to discriminate between these possibilities.…”

“…This enhanced processing hypothesis is supported by results showing that grapheme–color synesthetes exhibit superior low-level visual processing (Barnett et al, 2008), color discrimination (Banissy, Walsh, & Ward, 2009; Yaro & Ward, 2007), precision of color and luminance matching (Arnold, Wegener, Brown, & Mattingley, 2012), and color recognition memory (Yaro & Ward, 2007). Superior low-level visual processing may strengthen representations held in working memory by amplifying incoming sensory information or excluding external noise (Lu & Dosher, 2009) and thereby enhance maintenance of the information 1.…”

Two plus blue equals green: Grapheme-color synesthesia allows cognitive access to numerical information via color

“…In a common form of synesthesia, grapheme-color synesthesia, graphemes (i.e., letters, punctuation marks or numbers) evoke percepts of color (Cohen Kadosh et al, 2005; Day, 2005; Simner et al, 2006). The percepts can be quite vivid and are cognitively accessible in the sense that they are verbally reportable and can be used by the synesthete to perform certain perceptual and cognitive tasks ranging from color matching (Arnold, Wegener, Brown, & Mattingley, 2012; Blake, Palmeri, Marois, & Kim, 2005) to visual search (Palmeri, Blake, Marois, Flanery, & Whetsell, 2002; Ramachandran & Hubbard, 2001; Ramachandran & Hubbard, 2001) and facilitate learning and memory (Gibson, Radvansky, Johnson, & McNerney, 2012; Gross, Neargarder, Caldwell-Harris, & Cronin-Golomb, 2011; Rothen, Meier, & Ward, 2012; Watson, Blair, Kozik, Akins, & Enns, 2012). However, past accounts of grapheme-color synesthetes generally suggest that the inverse is not the case.…”