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)

(1) The induced colours led to perceptual grouping and pop-out, (2) a grapheme rendered invisible through ‘crowding’ or lateral masking induced synaesthetic colours — a form of blindsight — and (3) peripherally presented graphemes did not induce colours even when they were clearly visible. Taken collectively, these and other experiments prove conclusively that synaesthesia is a genuine percep- tual phenomenon, not an effect based on memory associations from childhood or on vague metaphorical speech. We identify different subtypes of number–colour synaesthesia (...) and propose that they are caused by hyperconnectivity between col- our and number areas at different stages in processing; lower synaesthetes may have cross-wiring (or cross-activation) within the fusiform gyrus, whereas higher synaesthetes may have cross-activation in the angular gyrus. This hyperconnec- tivity might be caused by a genetic mutation that causes defective pruning of con- nections between brain maps. The mutation may further be expressed selectively (due to transcription factors) in the fusiform or angular gyri, and this may explain the existence of different forms of synaesthesia. If expressed very diffusely, there may be extensive cross-wiring between brain regions that represent abstract concepts, which would explain the link between creativity, metaphor and synaesthesia (and the higher incidence of synaesthesia among artists and poets). Also, hyperconnectivity between the sensory cortex and amygdala would explain the heightened aversion synaesthetes experience when seeing numbers printed in the ‘wrong’ colour. Lastly, kindling (induced hyperconnectivity in the temporal lobes of temporal lobe epilepsy [TLE] patients) may explain the purported higher incidence of synaesthesia in these patients. We conclude with a synaesthesia-based theory. (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)