In this paper, we reflect on three long-standing problems: The relationship between the physical world and the perceived world, accounting for individual differences in the way in which we perceive the world around us, and the problem of understanding other minds. We begin by examining the relationship between synaesthesia and hallucinations, as well as between hallucinations and normal percept...

In auditory-visual synaesthesia, all kinds of sound can induce additional visual experiences. To identify the brain regions mainly involved in this form of synaesthesia, functional magnetic resonance imaging (fMRI) has been used during non-linguistic sound perception (chords and pure tones) in synaesthetes and non-synaesthetes. Synaesthetes showed increased activation in the left inferior parie...

Synaesthesia takes place when ordinary stimuli elicit extraordinary conscious experiences. As a rhetorical figure, synaesthesia consists on giving a thing a quality that in fact it cannot have because the thing and the quality are perceived by different senses (e.g. “white noises”). But the physiological and the conceptual or linguistic realities are in fact part of a whole that can be approach...

Synaesthesia is a condition characterized by unusual perceptual or cognitive pairings – for example, words might trigger tastes (Ward & Simner, 2003), letters may trigger the sensation of texture (Eagleman & Goodale, 2009), or music may induce the sensation of shapes and colour (Ward, Huckstep, & Tsakanikos, 2006). To date, there are estimated to be up to 150 reported forms of synaesthesia (Cyt...

Synaesthesia is a condition in which one property of a stimulus triggers a secondary experience not typically associated with the first (e.g., seeing achromatic graphemes can evoke the perception of color). Recent work has explored a variety of cognitive and perceptual traits associated with synaesthesia. One example is in the domain of personality, where higher rates of positive schizotypy and...

In this paper, we reflect on three long-standing problems: The relationship between the physical worlds and the perceived world, accounting for individual differences in the way in which we perceive the world around us, and the problem of understanding other minds. We begin by examining the relationship between synaesthesia and hallucinations, as well as between hallucinations and normal percep...

This study examines the role of four regions of the parietal lobe in grapheme-colour synaesthesia. TMS applied over a right parieto-occipital region disrupts performance on a synaesthetic priming task. TMS over the left parietal or a more anterior right parietal site did not have a reliable effect on synaesthesia even though one of the sites had been implicated in synaesthesia by previous fMRI ...

Are the kinds of abnormal cross-modal interactions seen in synaesthesia or following brain damage due to hyperconnectivity between or within brain areas, or are they a result of lack of inhibition? This question is highly contested. Here we show that posthypnotic suggestion induces abnormal cross-modal experience similar to that observed in congenital grapheme-color synaesthesia. Given the shor...

In 1812, Georg Sachs published a medical dissertation concerning his own albinism and that of his sister. However, he also goes on to describe another phenomenon--namely synaesthesia involving colors for music and simple sequences (including numbers, days, and letters). Most contemporary researchers of synaesthesia fail to cite the case when offering a history of the subject and fewer still wil...