Hancock PJB (2006) Monozygotic twins' colour-number association: a case study. Cortex, 42 (2), pp. 147-150. https://doi.org/10.1016/S0010-9452%2808%2970338-1
A case study of a pair of monozygotic twins, both of whom show a strong and enduring colour-number association, is reported. The origin of the colours, in a jigsaw puzzle, is known. Neither reports conscious photisms typical of synaesthesia, but a Stroop task of naming the colours of digits shows an interference effect with incongruent colours.
synaesthesia; number colour association; twins; Stroop test; Twins Color vision Testing; Twins Synesthesia Testing
Cortex: Volume 42, Issue 2