Send to

Choose Destination
Conscious Cogn. 2013 Sep;22(3):955-64. doi: 10.1016/j.concog.2013.05.012. Epub 2013 Jul 17.

Is "Σ" purple or green? Bistable grapheme-color synesthesia induced by ambiguous characters.

Author information

Department of Psychology, Korea University, Seongbuk-Gu, Anam-Dong, Seoul 136-701, Republic of Korea.


People with grapheme-color synesthesia perceive specific colors when viewing different letters or numbers. Previous studies have suggested that synesthetic color experience can be bistable when induced by an ambiguous character. However, the exact relationship between processes underlying the identity of an alphanumeric character and the experience of the induced synesthetic color has not been examined. In the present study, we explored this by focusing on the temporal relation of inducer identification and color emergence using inducers whose identity could be rendered ambiguous upon rotation of the characters. Specifically, achromatic alphabetic letters (W/M) and digits (6/9) were presented at varying angles to 9 grapheme-color synesthetes. Results showed that grapheme identification and synesthetically perceived grapheme color covary with the orientation of the test stimulus and that synesthetes were slower naming the experienced color than identifying the character, particularly at intermediate angles where ambiguity was greatest.


Bistability; Color naming; Grapheme identification; Grapheme-color synesthesia; Temporal relation

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center