Congruence or coherence? Emotional and physiological responses to colours in synaesthesia

Abstract

LexicalÁchromatic synaesthesia is a condition in which letters and/or words elicit percepts of synaesthetic colours, termed photisms. Anecdotal data suggest that synaesthetes are particularly sensitive to inconsistencies between their synaesthetic percepts and the real world, e.g., it can be annoying and unpleasant for them to see a letter printed in a colour different than the respective photism colour. For R, a synaesthete subject who participated in the present study, the photisms possess specific emotional values (a red photism is pleasing and attractive, green is repulsive and unpleasant, etc.). In contrast to the anecdotal data, R does not always find the colourÁphotism incongruence to be disturbing. More importantly, he states that it is the emotional coherence between the stimulus and the corresponding photism that matters. In a series of experiments, we studied this new concept of emotional coherence on three levels*subjective (self-report), behavioural, and physiological, corroborating R's introspective statements. Besides the implications of the concept of coherence itself, the results presented here suggest that even highly subjective cognitive constructs can be approached and measured experimentally, uncovering the workings of the underlying psychophysiological mechanisms.

Affect-related synesthesias: a prospective view on their existence, expression and underlying mechanisms

“…If synesthesia and crossmodal processing are based on a partially overlapping aetiology, more synesthesias should be observable linking affect and sensory (including bodily) experiences. As indicated above, such published observations are relatively rare (Cytowic, 1989; Ward, 2004; Callejas et al, 2007; Ramachandran and Brang, 2008; Hochel et al, 2009; Sinke et al, 2012) probably because understudied. For future studies, we would suggest accounting for “emotionality” (discrete emotions, valence) but to also move beyond such more traditional assessments of emotionality by considering a variety of neurophysiological and spatiotemporal body measures as well as cognitive appraisal driving affective experiences.…”

“…Recent studies report that synesthetes react with feelings of “correctness” or “pleasantness” to experiences in which the synesthetic and actual perceived features of a stimulus match (e.g., a grapheme is presented in its synesthetically matching color) and react with feelings of “incorrectness” or “unpleasantness” in the case of mismatches (e.g., a grapheme is presented in a synesthetically non-matching color) (Ramachandran and Hubbard, 2001a; Cytowic, 2002; Callejas et al, 2007). Such subjective experiences yielded psychophysiological correlates (Hochel et al, 2009). …”

“…The affective component is (1) the trigger or inducer (Cutsforth, 1925; Dudycha and Dudycha, 1935; Fitzgibbon et al, 2010), (2) the concurrent (Ramachandran and Brang, 2008; Ramachandran et al, 2012), or (3) neither the inducer nor the direct concurrent, but a moderator or mediator of the synesthetic coupling (Cytowic, 1989; Emrich et al, 2004; Ward, 2004; Simner and Holenstein, 2007; Hochel et al, 2009; Ramachandran et al, 2012). For instance, reactions to words of affective valence as well as to personally known faces triggered emotionally mediated color synesthesia (Ward, 2004).…”

“…This author replicated previous reports that darker and less saturated colors (e.g., brown, black) tend to be associated with negative emotions and lighter and more saturated colors (e.g., yellow, green, red) tend to be associated with positive emotions (p. 770). In another single case study, independent authors reported that “Pleasing pictures and faces were typically red to R, while repulsive visuals or unpleasant human faces elicited a pale green color in R's mind's eye” (Hochel et al, 2009; p. 705). In other cases, feeling particular textures triggered specific emotions (Ramachandran and Brang, 2008), and emotional situations triggered the synesthetic experience of color (Cutsforth, 1925).…”

“…Synesthetes are also known for liking or disliking certain letters based on their apparent “personality”—a synesthetic form coined “ordinal linguistic personification” in which letters have a gender, personality, and emotional connotation (Simner and Holenstein, 2007; Smilek et al, 2007). Moreover, overall affective judgment of colors was influenced by the emotional coherence between the stimulus and photism (Hochel et al, 2009). Finally, a synesthete with a diagnosis of Asperger's syndrome better understood his and other persons' emotions when he could associate them to a particular color (Ramachandran et al, 2012).…”