We studied two otherwise normal, synaesthetic subjects who `saw' a speci¢c colour every time they saw a speci¢c number or letter. We conducted four experiments in order to show that this was a genuine perceptual experience rather than merely a memory association. (i)The synaesthetically induced colours could lead to perceptual grouping, even though the inducing numerals or letters did not. (ii)Synaesthetically induced colours were not experienced if the graphemes were presented peripherally. (iii)Roman numerals were ine¡ective: the actual number grapheme was (...) required. (iv)If two graphemes were alternated the induced colours were also seen in alternation. However, colours were no longer experienced if the graphemes were alternated at more than 4 Hz. We propose that grapheme colour synaesthesia arises from `cross-wiring' between the `colour centre' (area V4 or V8)and the `number area', both of which lie in the fusiform gyrus. We also suggest a similar explanation for the representation of metaphors in the brain: hence, the higher incidence of synaesthesia among artists and poets. (shrink)

The work reported in this monograph was begun in the winter of 1967 in a graduate seminar at Berkeley. Many of the basic data were gathered by members of the seminar and the theoretical framework presented here was initially developed in the context of the seminar discussions. Much has been discovered since1969, the date of original publication, regarding the psychophysical and neurophysical determinants of universal, cross-linguistic constraints on the shape of basic color lexicons, and something, albeit less, can now also (...) be said with some confidence regarding the constraining effects of these language-independent processes of color perception and conceptualization on the direction of evolution of basic color term lexicons. (shrink)

Synesthesia is the involuntary physical experience of a cross-modal association. That is, the stimulation of one sensory modality reliably causes a perception in one or more different senses. Its phenomenology clearly distinguishes it from metaphor, literary tropes, sound symbolism, and deliberate artistic contrivances that sometimes employ the term "synesthesia" to describe their multisensory joinings. An unexpected demographic and cognitive constellation co-occurs with synesthesia: females and non-right-handers predominate, the trait is familial, and memory is superior while math and spatial navigation suffer. (...) Synesthesia appears to be a left-hemisphere function that is not cortical in the conventional sense. The hippocampus is critical for its experience. Five clinical features comprise its diagnosis. Synesthesia is "abnormal" only in being statistically rare. It is, in fact, a normal brain process that is prematurely displayed to consciousness in a minority of individuals. (shrink)

Functionalism offers an account of the relations that hold between behavioural functions, information and neural processing, and conscious experience from which one can draw two inferences: for any discriminable difference between qualia there must be an equivalent discriminable difference in function; and for any discriminable functional difference within a behavioural domain associated with qualia, there must be a discriminable difference between qualia. The phenomenon of coloured hearing synaesthesia appears to contradict the second of these inferences. We report data showing that (...) this form of synaesthesia is genuine and probably results from an aberrant projection from cortical language areas to a region specialized for the perception of colour. Since functionalism purports to be a general account of consciousness, one such negative instance, if it can be further sustained empirically, is sufficient to invalidate it. (shrink)

We examine a condition in which units of time, such as months of the year, are associated with specific locations in space. For individuals with this time-space synaesthesia, contiguous time units such as months are spatially linked forming idiosyncratically shaped patterns such as ovals, oblongs or circles. For some individuals, each time unit appears in a highly specific colour. For instance, one of the synaesthetes we studied experienced December as a red area located at arms length to the left of (...) their body. For the same individual May was a blue area located roughly at arms length to the right of their body. We studied four synaesthetes who report spatial associations for the months of the year. We found that the time-space associations experienced by these individuals were consistent across test–retest. In addition, month names directed visual attention to particular locations in space. For some synaesthetes, this directing of spatial attention was quite rapid-in accord with their reports that month names involuntarily bring to mind spatial locations. (shrink)