Abstract

Ordinal sequences such as letters, numbers, days of the week or months of the year, are common inducers of synaesthesia. Common synaesthetic experiences induced by these sequences include colours and spatial patterns. However, some synaesthetes also personify letters and numbers, by attributing gender, personality, and other physical and mental attributes to such items, reminiscent of the way we think about other people. Although these attributes can be thought of as conceptual rather than simple sensory experiences, the phenomenon does share some features in common with more familiar types of synaesthesia and indeed has been considered by some to be a type of synaesthesia in its own right. Here, we provide a comprehensive overview of personification in synaesthesia. We describe the phenomenology of synaesthetic personification, as well as the behavioural and neuroimaging paradigms used to study the phenomenon. We list a variety of types of inducers and concurrents and discuss the common features of both personification and canonical forms of synaesthesia, e.g., its involuntary nature, idiosyncrasy, and relative consistency over time. We review theoretical frameworks for understanding personification in synaesthesia and discuss the similarities and differences between synaesthetic and non-synaesthetic personification.