Reduced audio-visual integration in synaesthetes indicated by the double-flash illusion.
It has been suggested that synaesthesia is the result of a hyper-sensitive multimodal binding-mechanism. To address the question whether multi-modal integration is altered in synaesthetes in general, grapheme-colour and auditory-visual synaesthetes were studied using the double-flash illusion. This illusion is induced by a single light flash presented together with multiple beep sounds, which is then perceived as multiple flashes. By varying the separation of auditory and visual stimuli, the hypothesis of a widened temporal window of audio-visual integration in synaesthetes was tested. As hypothesised, the results show differences between synaesthetes and controls concerning multisensory integration, but surprisingly other than expected synaesthetes perceive a reduced number of illusions and have a smaller time-window of audio-visual integration compared to controls. This indicates that they do not have a hyper-sensitive binding mechanism. On the contrary, synaesthetes seem to integrate even less than controls between vision and audition.
Department of Psychiatry, Social Psychiatry and Psychotherapy, Hannover Medical School, Carl-Neuberg-Straße 1, 30625 Hanover, Germany.
Janina
J
Neufeld
Christopher
C
Sinke
Markus
M
Zedler
Hinderk M
HM
Emrich
Gregor R
GR
Szycik
D000161:Acoustic Stimulation; D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D005260:Female; D006801:Humans; D007088:Illusions / Q000502:physiology*; D008297:Male; D010775:Photic Stimulation; D014796:Visual Perception / Q000502:physiology*