Mirror-touch synaesthesia: the role of shared ... - UCL Discovery

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1.5 Synaesthesia and models of typical cognition
Chapter 1
The preceding sections reviewed evidence for the authenticity of synaesthesia.
While this is now well established, there is growing interest in using the condition to
inform us about non-synaesthetic perceptual and cognitive processing. Following the
logic of cognitive neuropsychology, the positive symptoms related to synaesthesia
may be able to constrain theories on multisensory interactions and inform about the
relationship between multisensory processing and other aspects of cognition (Ward
and Mattingley, 2006; Cohen Kadosh and Henik. 2007).
So far, a number of examples have been cited whereby synaesthetic
interactions have been shown to rely upon similar neurocognitive mechanisms as
those observed in non-synaesthetes and therefore may inform us about general
principles of multisensory interactions (e.g. feature binding in grapheme-colour
synaesthesia; cross-modal interactions in touch-colour synaesthesia; heightened
visual-tactile interactions in mirror-touch synaesthesia). Non-random associations,
which are similar to those found in non-synaesthetic subjects, have also been found
between pitch and lightness in tone-colour synaesthetes (individuals who experience
colour sensations in response to tones) – both synaesthetes and non-synaesthetes show
a tendency to associate low pitches with dark colours and high pitches with light
colours, although only synaesthetes experience these colours consciously (Ward et al.,
2007; also see Parise and Spence, 2009). Evidence of non-random associations in
other variants have also been documented, including number and lightness in digit-
colour synaesthesia (Cohen Kadosh and Walsh, 2008); word form properties and
colour associations in linguistic-colour synaesthesia (Barnett, Feeney, Gormley, and
Newell, 2009); and phonology and tastes in lexical-gustatory synaesthesia (Ward and
Simner, 2003).