Cross-modal perception is “the capacity to abstract and exchange information between different sensory modalities” (Davenport et al. 1973). One aspect of the cross-modality of perception is the occurrence among people of certain natural and universal mappings of certain stimulus features in one modality into stimulus features in another modality (e.g. high-pitched sounds are associated with bright light, as well as with jagged shapes; words containing the vowel a are connected with bigger objects, those containing i with smaller ones). Synaesthesia is a special case of cross-modal perception. It is a condition in which stimulation in one sensory modality gives rise to a sensation in a different modality, or in the same modality but involving different qualities of the stimulus (Sagiv 2005). Two major theories have been proposed to explain synaesthesia: 1) failure of neural pruning resulting in cross-activation between some brain regions which in a non-synaesthetic brain are not strongly connected, and 2) weakened inhibition of feedback from certain brain regions, which interferes with the processing of information of a particular kind.