Exploring intuitive decisions and sense of coherence in synaesthesia

Intuition refers to a holistic, unconscious, and automatic processing of information, leading to perceived knowledge without a logical explanation, accompanied by feelings of coherence. Synaesthesia is a perceptual experience where at least two senses are involuntarily and automatically coupled over time. This study aimed to investigate whether synaesthetes' intuitive performance differs and affects their intuitive sense of coherence. Grapheme-colour synaesthetes (N = 28) were compared with control subjects (N = 28) on two established tasks, assessing intuitions of semantic and visual coherence. The results indicated no global differences in intuitive performance between the groups. Significantly, synaesthetes showed a less biased intuitive judgement behaviour in both tasks, suggesting an increased experience of coherence in synaesthesia, which impairs the accuracy of intuitive judgements. Associations were also found between the vividness of mental imagery and response bias in synaesthesia. Implicit information processing is discussed concerning the cognitive properties of synaesthesia.