Abstract
Traditional models of synaesthesia seek to explain the experience of additional percepts or associations in response to inducing stimuli by proposing either excess connections between cortical areas or disinhibition of existing circuits. These models ignore an essential property of synaesthesia, however, namely that it is developmental. To get a full understanding of the nature of synaesthesia it is important to consider not only static endpoints, but also the developmental processes that have led to them. Here, I examine synaesthesia from a neurodevelopmental perspective, present evidence that it involves widespread differences in connectivity and consider this in light of the dynamic processes that shape cortical specialisation and connectivity over development.