Synaesthesia offers a unique point of view on the problem of conscious perception. However, much of synaesthesia research focused on colour only. I argue that frameworks for understanding synaesthesia can be extended into other domains (e.g., social cognition) and yield new insights into understanding the human mind and brain function, particularly, pre-linguistic intersubjectivity.
To illustrate this, I will first show that synaesthetic experiences and their inducing stimuli are not always strictly sensory (Sagiv, 2005). Some synaesthetes, for example, anthropomorphize certain concepts (e.g., letters of the alphabet) in additional to visualising them in colour. First described by Calkins (1895), the phenomenon has been largely ignored by scientists since. We collected detailed descriptions made by 30 individuals reporting such peculiar experiences (as well as behavioural data consistent with the subjective report). Many of them also reported some form of animism, i.e., they attributed feelings to inanimate objects. While normative in some cultures and among young children (Piaget, 1929), animism is rarely reported by adults in modern society. Nevertheless, it appeals to many of us and heavily utilised, e.g., in poetry or advertising (indeed, certain patterns of cross-modal correspondences seen in synaesthetes, are also found in non-synaesthetes; e.g., Sagiv and Ward, in press). How is this possible and what does it tell us about the origins of second person perspectives?
One widely accepted model of synaesthesia involves the cross activation of mechanisms involved in the perception of synaesthetic experiences and their inducers (Ramachandran and Hubbard, 2001). The principle can be extended to mechanisms implicated in processing affective properties and social meaning. Indeed, neuroimaging and electrophysiological data in humans and primates suggests that such cross-domain interactions could underlie both empathy and communication skills (Gallese, 2001). Still, it may be surprising that empathic responses or personality attributes would ever be directed towards inanimate objects or abstract concepts. I will attempt to make sense of these findings and combine phenomenological, behavioural and neurophysiological approaches. I hope to demonstrate that synaesthesia provides a window not only into the problem of visual perception but rather consciousness in a wider sense.