Assessing systematic differences in intermodal attention in synaesthetes

Although synaesthetes experience additional percepts during their inducer-concurrent associations that are often unrelated or irrelevant to their daily activities, they appear to be relatively unaffected by this potentially distracting information. Supporting this observation, a recent study investigating intermodal attention in visual synaesthetes (i.e. those experiencing at least one synaesthesia type triggering visual concurrents; e.g. letters-colours or calendar-forms) found that they seemed to be more efficient than non-synaesthetes at ignoring the visual irrelevant stimuli of a visuo-tactile conflict task. This might suggest that systematic differences in attentional abilities between synaesthetes and non-synaesthetes could be directly correlated with their synaesthetic concurrent experiences and thus could be explained by learning or transfer effects. To investigate this hypothesis, the performance of a group of –visual synaesthetes was compared to that of a matched non-synaesthete group in two versions of different conflict tasks: in one version they had to attend to either tactile or auditory targets while ignoring visual distractors (concurrent-related version) and in the other one the target-distractor sensory modalities were reversed – i.e. attend to visual targets while ignoring tactile or auditory distractors (concurrent-unrelated version). We found that synaesthetes, compared to controls, experienced more problems when they had to ignore visual stimuli (concurrent-related version). Moreover, this was only true for the visuo-tactile stimuli. I will discuss these results and their significance in relation to previous findings.