Synaesthesia is considered a rare perceptual capacity, and one that is not capable of cultivation. However, meditators report the experience quite commonly, and in questionnaire surveys, respondents claimed to experience synaesthesia in 35% of meditation retreatants, in 63% of a group of regular meditators, and in 86% of advanced teachers. These rates were significantly higher than in nonmeditator controls, and displayed significant correlations with measures of amount of meditation experience. A review of ancient texts found reports suggestive of synaesthesia in (...) advanced meditators from India and China. These findings suggest that synaesthesia may be cultivated by meditation, and that laboratory studies of meditators could be rewarding. (shrink)

Despite some principal similarities, there is no systematic comparison between the different types of synesthesia . This comprehensive review compares the three principal types of synesthesia and focuses on their phenomenological features and their relation to different etiological models. Implications of this comparison for the validity of the different etiological models are discussed.Comparison of the three forms of synesthesia show many more differences than similarities. This is in contrast to their representation in the literature, where they are discussed in many (...) respects as being virtually similar. Noteworthy is the much broader spectrum and intensity with the typical drug-induced synesthesias compared to genuine and acquired synesthesias. A major implication of the phenomenological comparison in regard to the etiological models is that genuine and acquired synesthesias point to morphological substrates, while drug-induced synesthesia appears to be based on functional changes of brain activity. (shrink)