There is a universal and often unconscious tendency to mentally associate the number sequence with a spatial continuum (the mental number line). Here we study one individual who reports a strong and vivid sense of space when processing numbers. For him, the number sequence has a precise spatial form: a curvilinear right-to-left oriented line. We used various tasks to demonstrate that this numer...

This paper is an author response to two commentaries on 'Defining Synaesthesia' (Simner, 2012) by David M. Eagleman ('Synesthesia in its protean guises', 2012), and Roi Cohen Kadosh and Devin B. Terhune ('Redefining synaesthesia?', 2012). Together with these authors, I seek to more closely examine existing criteria on which definitions of synaesthesia have been based. In particular, I focus on ...

Simulation models of expression recognition contend that to understand another's facial expressions, individuals map the perceived expression onto the same sensorimotor representations that are active during the experience of the perceived emotion. To investigate this view, the present study examines facial expression and identity recognition abilities in a rare group of participants who show f...

Little is known about how the properties of our private mental world relate to the physical and functional properties of our brain. Studying synesthesia, where a particular experience evokes a separate additional sensory experience, offers the unique opportunity to study phenomenological experiences as a stable trait in healthy subjects. A common form of synesthesia is grapheme-color synesthesi...

BACKGROUND Synesthesia is a phenomenon where a stimulus produces consistent extraordinary subjective experiences. A relatively common type of synesthesia involves perception of color when viewing letters (e.g. the letter 'a' always appears as light blue). In this study, we examine whether traits typically regarded as markers of synesthesia can be acquired by simply reading in color. METHODOLO...

Gustatory forms of synesthesia involve the automatic and consistent experience of tastes that are triggered by non-taste related inducers. We present a case of lexical-gustatory and sound-gustatory synesthesia within one individual, SC. Most words and a subset of non-linguistic sounds induce the experience of taste, smell and physical sensations for SC. SC's lexical-gustatory associations were ...

A newly reported form of synaesthesia in which seeing visual motion induces auditory experiences challenges traditional ideas about the neural mechanisms of synaesthesia and may shed light on how the brain integrates information from sound and vision.