We can discern two opposing viewpoints regarding synesthesia. According to the first, it is an oddity, an outlier, or a disordered condition. According to the second, synesthesia is pervasive, driving creativity, metaphor, or language itself. Which is it? Ultimately, I favor the first perspective, according to which cross-sensory synesthesia is an outlying condition. But the second perspective is not wholly misguided. My discussion has three lessons. First, synesthesia is just one of a variety of effects in which one sense modality (...) causally impacts and reshapes experience associated with another. These effects are utterly common. However, due to their unfamiliarity, and to their conflict with a widespread conception of the role of the senses in perception and perceptual experience, until recently they have been surprising. Second, synesthesia nevertheless must be distinguished from other inter-modal effects that lead to misperception, such as crossmodal illusions. Third, synesthesia also may be distinguished from the potentially much broader class of synesthetic effects, which could be common across the population and within individuals. (shrink)

Linguistic synesthesia (or synesthetic/intrafield/crossmodal metaphor) refers to crossmodal instances in which expressions in different sensory modalities are combined as in the case of sweet (taste) melody (hearing). Ullmann was among the first to show that synesthetic transfers seem to follow a potentially universal hierarchy that goes from the so-called “lower” (i.e., touch, taste and smell) to “higher” senses (i.e., hearing and sight). Several studies across languages, cultures, domains and text types seem to support the hierarchy in linguistic synesthesia despite some (...) crosslinguistic differences and varying explanations . To extend results to an underrepresented language and thus, to test the universality of the crossmodal hierarchy, 5,693 token cases of linguistic synesthesia in written and spoken Turkish were investigated using a general-purpose, large corpus. Token, type, and hapax legomena frequencies showed that although three backward and thus, hierarchy-inconsistent transfers (i.e., from taste to touch, from sight to smell and from sight to hearing) were more frequent than their hierarchy-consistent counterparts, forward transfers in the canonical direction were more frequent overall than the backward transfers in Turkish. We conclude that Turkish linguistic synesthesia complies with the hierarchy as a descriptive generalization. Results are discussed in comparison to the crossmodal use of sensory words in other languages. (shrink)

Synesthesia is the “union of the senses” whereby two or more of the five senses that are normally experienced separately are involuntarily and automatically joined together in experience. For example, some synesthetes experience a color when they hear a sound or see a letter. In this paper, I examine two cases of synesthesia in light of the notions of “experiential parts” and “conscious unity.” I first provide some background on the unity of consciousness and the question of experiential parts. I (...) then describe two very different cases of synesthesia. Finally, I critically examine the cases in light of two central notions of “unity.” I argue that there is good reason to think that the neural “vehicles” of conscious states are distributed widely and can include multiple modalities. I also argue that some synesthetic experiences do not really enjoy the same “object unity” associated with normal vision. (shrink)

Synesthesia is a phenomenon in which an additional nonstandard perceptual experience occurs consistently in response to ordinary stimulation applied to the same or another modality. Recent studies suggest an important role of semantic representations in the induction of synesthesia. In the present proposal we try to link the empirically grounded theory of sensory-motor contingency and mirror system based embodied simulation to newly discovered cases of swimming-style color synesthesia. In the latter color experiences are evoked only by showing the synesthetes a (...) picture of a swimming person or asking them to think about a given swimming style. Neural mechanisms of mirror systems seem to be involved here. It has been shown that for mirror-sensory synesthesia, such as mirror-touch or mirror-pain synesthesia, concurrent experiences are caused by the overactivity in the mirror neuron system responding to the specific observation. The comparison of different forms of synesthesia has the potential of challenging conventional thinking on this phenomenon and providing a more general, sensory-motor account of synesthesia encompassing cases driven by semantic or emulational rather than pure sensory or motor representations. (shrink)

Synesthesia literally means a “union of the senses” whereby two or more of the five senses that are normally experienced separately are involuntarily and automatically joined together in experience. For example, some synesthetes experience a color when they hear a sound, although many instances of synesthesia also occur entirely within the visual sense. In this paper, I first mainly engage critically with Sollberger’s view that there is reason to think that at least some synesthetic experiences can be viewed as truly (...) veridical perceptions, and not as illusions or hallucinations. Among other things, I explore the possibility that many forms of synesthesia can be understood as experiencing what I will call “second-order secondary properties,” that is, experiences of properties of objects induced by the secondary qualities of those objects. In doing so, I shed some light on why synesthesia is typically one-directional and its relation to some psychopathologies such as autism. (shrink)

Synaesthesia is most often characterised as a union or mixing of the senses. i Richard Cytowic describes it thus: “It denotes the rare capacity to hear colours, taste shapes or experience other equally startling sensory blendings whose quality seems difficult for most of us to imagine” ([1995] 1997, 7). One famous example is of a man who “tasted shapes”. When he experienced flavours he also experienced shapes rubbing against his face or hands. ii Such popular characterisations are rough and (...) ready. What is certainly true about synaesthesia is that it involves the interaction between sensory phenomena: in response to certain stimuli some sensory phenomena are elicited in synaesthetes that are not elicited in non-synaesthetes. However, the exact nature of the additional sensory phenomena forms a large part of the debate on the nature of synaesthesia. Synaesthesia is a condition that has been known about for some time. In the late nineteenth century, and early twentieth, century very many articles appeared on the topic in the psychological literature. iii Much of this work on synaesthesia relied on introspective reports of subjects. In consequence, when later in the twentieth century psychologists eschewed introspective reports and radical behaviourist methodology became the order of the day, synaesthesia was rarely a topic of research. In more recent times, however, psychology has once again changed tack. With the advent of cognitive psychology and of objective techniques that try to probe the nature of conscious states of the mind that are reported in introspection, psychological interest in synaesthesia has resumed. Many new findings about the subject have recently been brought to light. In philosophy, interest in synaesthesia is only just beginning to arise. The phenomenon is potentially philosophically interesting for several reasons.. (shrink)

In this work we present the complex relationship between sound and color in musical creation throughout history that continues to be fruitful in current musical composition. Synesthesia in music establishes a correspondence between sound and color and has been a constant debate since the 17th century. The complex nature of sound appears from ancient Greece in the school of Pythagoras in which the number becomes the configurator of harmony. Since then, different aesthetic attempts have arisen to relate color and sound (...) that reach today's electronic procedures in contemporary music. (shrink)

It has been repeatedly suggested that synesthesia is intricately connected with unusual ways of exercising one’s mental imagery, although it is not always entirely clear what the exact connection is. My aim is to show that all forms of synesthesia are forms of (often very different kinds of) mental imagery and, further, if we consider synesthesia to be a form of mental imagery, we get significant explanatory benefits, especially concerning less central cases of synesthesia where the inducer is not sensory (...) stimulation. (shrink)

Synesthetes are people who report having perceptual experiences that are very unusual, such as ?seeing? sounds as colors or ?smelling? colors as odors. It is commonly assumed these days that such synesthetic experiences must be instances of misperceptions. Against this widespread assumption, I will highlight that there is reason to think that at least some synesthetic experiences can be viewed as truly veridical perceptions, and not as illusions or hallucinations. On this view, which I will back up by conceptual arguments (...) and empirical data, synesthesia does sometimes enable the individual to truly pick up on worldly features. In failing to take this possibility on board, the participants in this debate have thus unduly restricted the scope of dialectical options. Finally, the reassessment of synesthetic experiences that I defend in this paper will turn out to have important ramifications not just for synesthesia research, but also for perception theories more generally. (shrink)

Synesthesia is a condition in which features that ordinarily are processed by distinct perceptual or cognitive streams are bound together in a single stream, yielding an aberrant perceptual, image‐like or thought‐like experience. One of the most common forms of synesthesia is grapheme‐color synesthesia. It is divided into two distinct forms: Projector synesthesia, which tends to be perception‐like, and associator synesthesia, which tends to be more like imagery or thought. There has been an ongoing debate in philosophy about whether synesthesia can (...) provide any insight into the philosophical question of the nature of perception. I argue here that at least some forms of projector synesthesia provide a challenge for reductive representationalism, the view that the phenomenal properties of perceptual experience is exhausted by an externalist, representational content. I conclude by arguing that a rejection of representationalism does not saddle us with a peculiar qualia view. (shrink)

Synaesthesia is considered a rare perceptual capacity, and one that is not capable of cultivation. However, meditators report the experience quite commonly, and in questionnaire surveys, respondents claimed to experience synaesthesia in 35% of meditation retreatants, in 63% of a group of regular meditators, and in 86% of advanced teachers. These rates were significantly higher than in nonmeditator controls, and displayed significant correlations with measures of amount of meditation experience. A review of ancient texts found reports suggestive of (...) synaesthesia in advanced meditators from India and China. These findings suggest that synaesthesia may be cultivated by meditation, and that laboratory studies of meditators could be rewarding. (shrink)

A myriad of sensations inform and direct us when we engage with the environment. To understand their influence on the development of our habitus it is important to focus on unifying processes in sensing. This approach allows us to include phenomena that elude a rather narrow view that focuses on each of the five discrete senses in isolation. One of the central questions addressed in this volume is whether there is something like a sensual habitus, and if there is, how (...) it can be defined. This is especially done by exploring the formation and habituation of the senses in and by a culturally shaped habitat. Two key concepts, Synaesthesia and Kinaesthetics, are addressed as essential components for an understanding of the interface of habitat and the rich and multisensory experience of a perceiving subject. At a Berlin-based conference Synaesthesia and Kinaesthetics, scholars from various disciplines gathered to discuss these issues. In bringing together the outcome of these discussions, this book gives new insights into the key phenomena of sensory integration and synaesthetic experiences, it enriches the perspectives on sensually embedded interaction and its habituation, and it expands this interdisciplinary inquiry to questions about the cultures of sensory habitus. (shrink)

Synaesthesia is a strange sensory blending: synaesthetes report experiences of colours or tastes associated with particular sounds or words. This volume presents new essays by scientists and philosophers exploring what such cases can tell us about the nature of perception and its boundaries with illusion and imagination.

Synaesthesia has an emotional side. Many synaesthetes have a sense of certainty about the reality and accuracy of their experiences. Consequently, when their synaesthesia is mimicked in real life these synaeshtetes report a positive emotion whereas when the opposite is true, they experience discomfort. Synaesthesia can also be induced by emotions, and emotions can also be the synaesthetic experience. Here we review the research on these types of synaesthesia and study the current evidence for the true (...) nature of these emotions associated to synesthetic perceptions as studied in grapheme-colour synaesthesia. We begin by presenting evidence of how they can be measured in a laboratory setting and proceed to report studies showing that emotions are automatically activated and can vary in degree as a function of certain factors. We lastly review a study showing that these emerging emotions can be so strong and vivid that they can influence attitudes towards otherwise neutral stimuli. We conclude by presenting a model that could account for the findings reported here. (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)

Encyclopedia entry on color synesthesia with cognitive/neurscientific focus.

Although the condition known as synaesthesia is currently undergoing a scientific resurgence, to date the literature has largely focused on the heterogeneous nature of synaesthesia across individuals. In order to provide a better understanding of synaesthesia, however, general characteristics need to be investigated. Synaesthetic experiences are often described as occurring ‘internally’ or in the ‘mind’s eye’, which is remarkably similar to how we would describe our experience of visual mental imagery. We assessed the role of visual imagery (...) in synaesthesia by sampling a large group of synaesthetes and found that they report experiencing more vivid mental images than controls. These findings have important implications for our general understanding of synaesthesia and, in particular, emphasize the need to control for visual imagery in behavioural and neuroimaging paradigms. (shrink)

This is an encyclopedia entry on Synesthesia. It provides a summary of our current knowledge about the condition and it reviews the philosophical implications that have been drawn from considerations about synesthesia. It's import for debates about consciousness, perception, modular theories of mind, creativity and aesthetics are discussed.

We are sometimes led to a different picture of things when something unexpected occurs which needs explaining. The aim of this thesis is to examine a series of related issues in the philosophy of mind in the light of the unusual condition known to psychologists as ‘synaesthesia’. Although the emphasis will be on the philosophical issues a view of synaesthesia itself will also emerge. Synaesthesia is a distinct type of cross-modal association: stimulation of one sensory modality automatically (...) triggers an additional phenomenal character of experience associated with a second sensory modality in the absence of any direct stimulation of the second modality. Chapter 1 introduces synaesthesia to a philosophical audience by outlining the early history of synaesthesia studies, by summarising contemporary research and by indicating areas of philosophical interest to be considered in the rest of the thesis. Chapter 2 uses synaesthesia to examine one important philosophical model of the mind, Fodor’s modularity hypothesis, and, in turn, investigates the nature of synaesthesia in the light of that model. Fodor claims that cognitive modules can be thought of as belonging to a psychological natural kind in virtue of their possession of most or all of nine specified properties. The most common form of synaesthesia possesses Fodor’s nine specified properties of modularity, and hence it should be understood in terms of an extra cognitive module, and thus as belonging to the abovementioned psychological natural kind. Many psychologists believe that synaesthesia involves a breakdown in modularity. A breakdown in modularity would also explain the apparent presence of the nine specified properties in synaesthesia. I discuss the two concepts of function which underlie the respective theories, defending the breakdown thesis, arguing, in any case, that properties deriving from evolutionary history should also be used to decide between the two theses and thus ultimately membership of a psychological natural kind such as Fodor suggests. The argument is then used to respond to two challenges to the notion of a psychological natural kind. Chapter 3 focuses on the phenomenal character of synaesthetic experience. Externalists about the phenomenal character of experience tend to argue that the character of perceptual experience is to be explained either by the properties objects present to percipients, or by the properties objects are represented by percipients as having. Some internalists argue that there is a need to postulate hrther properties of the individual - in other words, qualia - to account for the individuation of the character of perceptual experience. The existence of additional phenomenal characters of experience in synaesthesia, which cannot directly be explained by reference to features of objects, suggests the existence of extra qualia and thus the presence of qualia in normal perception. The aim of this chapter is to meet the challenge presented by synaesthesia and the extra quaZia argument, and contrariwise, use synaesthesia as a way of fbrther clarifjmg the merits of the respective externalist positions. In the previous chapters the locution of ‘coloured hearing’ will have been adopted. Occasionally the process underlying synaesthesia is described as one of ‘hearing colours’. Chapter 4 rejects the latter usage. In so doing it focuses on the place of synaesthesia vis-a-vis normal perceptual processes. Considerations from previous chapters are further developed in order to shed light both on the metaphysical individuation of perceptual modalities and on how we know the distinctive perceptual modalities. Given the actual content of our concepts of perceptual modalities, it is argued that the actual world is one in which even synaesthetes are unable to hear colours. Consideration is given as to whether there is a possible world in which people could hear colours. The justification of the usage of ‘coloured-hearing’ then leads to a discussion of the relative importance of the individuating conditions of modes of perception. The thesis focuses largely on coloured hearing. What merits the preceding considerations have might be supported if they can be generalised. Chapter 5 goes a small way in that direction. (shrink)

Does synesthesia undermine representationalism? Gregg Rosenberg (2004) argues that it does. On his view, synesthesia illustrates how phenomenal properties can vary independently of representational properties. So, for example, he argues that sound/color synesthetic experiences show that visual experiences do not always represent spatial properties. I will argue that the representationalist can plausibly answer Rosenberg.

This study seeks to clarify the nature of linguistic synesthesia using a lexical-conceptual account. Based on a lexical analysis of Mandarin synesthetic usages, we find that linguistic synesthesia maps the metaphorical meaning between two domains; and linguistic synesthetic mappings and conceptual metaphoric mappings have similar behaviors when sense modalities are treated as conceptual domains that contain a set of mappings constrained by Mapping Principles. This lexical-conceptual account is designed to capture the fact that linguistic synesthesia involves mapping between lexicalized concepts (...) of sensory properties, instead of the real-time sensory input that is processed in neurological synesthesia. The incorporation of a lexical semantic view with the framework of Conceptual Metaphor Theory not only offers a coherent and comprehensive account for the nature of linguistic synesthesia, but also handles aspects of linguistic synesthesia previously only accounted for by non-metaphorical accounts. These design features make this proposal the most comprehensive account to fit the current data. Furthermore, by showing linguistic synesthesia as a type of metaphor, our study strengthens the role of conceptual metaphors as the link between the perceived world and our conceptualization of that world. (shrink)

Wager has argued that synaesthesia provides material for a counterexample to representational theories of the phenomenal character of experience. He gives a series of three cases based on synaesthesia; he requires the second and third cases to bolster the doubtfulness of the first. Here I further endorse the problematic nature of the first case and then show why the other two cases do not save his argument. I claim that whenever synaesthesia is a credible possibility its phenomenal (...) character can be understood in terms of misrepresentation. (shrink)

Encyclopedia entry on color synesthesia with cognitive/neurscientific focus.

Synaesthesia is an excellent model for understanding perceptual binding in the human brain. Current evidence suggests that if synaesthetic colour is bound, it is through the same attention-dependent integration of feature maps that occurs in other forms of binding. synaesthetic colour arises after the point that separate wavelengths blend in normal colour vision, which creates a perceptual paradox where synaesthetic and print colour can appear bound to a single location without blending. If a letter is printed in a colour (...) that is different from the synaesthetic colour it induces, the two hues will activate different hue-selective maps allowing for dual representation of colour, but if synaesthetic and print colours are the same/similar they will co-activate the same hue-selective map and create an amplified colour signal. Studies suggest that the parietal cortex plays a key role in this binding of synaesthetic and/or print colour to shape. (shrink)

The research presented in this volume demonstrates that it is no longer reasonable to ask whether or not synesthesia is real--we must now ask how we can account ...

The aim of the present paper is to sketch a new structural version of the Representative Theory of Perception which is supported both by conceptual and empirical arguments. To this end, I will discuss, in a first step, the structural approach to representation and show how it can be applied to perceptual consciousness. This discussion will demonstrate that perceptual experiences possess representational as well as purely sensational properties. In a second step, the focus will switch to empirical cases of (...) class='Hi'>synaesthesia. In particular, I will stress that certain synaesthetic experiences are well-suited to corroborating a structural account of the perceptual mind. The overall picture that emerges in this paper prompts a new view of perceptual consciousness that is ruthlessly structural. (shrink)

J. A. Gray et al. have recently argued that synaesthesia can be used as a counterexample to functionalism. They provide empirical evidence which they hold supports two anti-functionalist claims: disparate functions share the same types of qualia and the effects of synaesthetic qualia are, contrary to what one would expect from evolutionary considerations, adverse to those functions with which those types of qualia are normally linked. I argue that the empirical evidence they cite does not rule out functionalism, rather (...) the reverse. The fact that the effects of synaesthesia are adverse shows that understanding synaesthetic experiences requires a concept of dysfunction, which in turn presupposes a functionalist account. Such an account, moreover, shows how tokens of the same types of qualia can be associated with different causal histories, thus disarming their first objection. (shrink)

Representationism is the view that the phenomenal character of an experience supervenes on its representational content. Synaesthesia is a condition in which the phenomenal character of the experience produced in a subject by stimulation of one sensory modality contains elements characteristic of a second, unstimulated sensory modality. After reviewing some of the recent psychological literature on synaesthesia and one of the leading versions of representationism, I argue that cases of synaesthesia, as instances of what I call the (...) extra qualia problem, are counterexamples to externalist versions of representationism. (shrink)

The concept of informational encapsulation has been important in promoting a view of the mind that has dominated cognitive science. Multisensory phenomena, such as synaesthesia, have been used as evidence for challenging this view. The main objective of this paper is to provide a more detailed understanding of the nature of such a challenge by examining the two types of grapheme–colour synaesthesia, projectors and associators. It is argued that the phenomena under consideration exemplify partial encapsulation failure and that (...) it is expressed in three forms: intramodal, intermodal, and top-down. Additional support for these claims is provided by considering some evidence on synaesthetic-like experiences in relation to the continuity thesis. (shrink)

A cognitive-developmental theory of synaesthesias - those subjective states fusing separate perceptual modalities - is supported by research indicating their neocortical basis and first appearance as part of the semantic learning of words, letters, numbers, and time in the early grade school years. It contrasts with models of a primitive, anomalous holdover from an earlier neural hyperconnectivity, widely assumed in recent neuroscience approaches. Classical synaesthesias, occurring most vividly in high 'fantasy proneness' children, as well as the more normative and less (...) stereotyped 'synaesthetic meanings' of mid childhood, would later be internalized as the imagistic side of Vygotsky's 'inner speech' - then introspectable as the typically diffuse felt sense of semantic significance. A synaesthetically structured felt meaning becomes the matrix for the development of metaphoric understanding in later childhood. The further exteriorized development of the full range of synaesthesias in adults high in imaginative absorption and creativity becomes central to the arts, culture, and meditative states of consciousness. This approach overlaps with that of Ramachandran on synaesthesia as a window to the evolution of language and metaphor, but separates the human capacity for cross- modal translation, as the root of all symbol formation, from the full range of synaesthesias that would be its later mid childhood differentiation and adds in the wider adult potential for higher developments of this normally implicit synaesthetic consciousness. (shrink)

Richard Cytowic has done considerable service to the scientific study of synesthesia, conducting important research and publishing two recent books on the subject. The study of synesthesia raises interesting questions about scientific method, both because of the negative reception it received initially--often being viewed as tainted by a reliance upon introspective reports--and because of the connections Cytowic has found between synesthetic perception and the limbic system, thereby possibly undermining some of the claims to objectivity in perception and scientific method. I (...) dispute some of the more extreme methodological conclusions Cytowic draws from his work and reinforce others by reference to different arguments current within the philosophy of science. (shrink)

In this article, we will describe higher order thought theories of consciousness. Then we will describe some examples from synesthesia. Finally, we will explain why the latter may be relevant to the former.

This chapter focuses on synaesthesia research in the 21st century. It begins by giving counts of publications and these are further broken down by type, focus, and measures used. Then, there is a review of major questions being addressed by current research in the area of synaesthesia. The amount of research being done in this area is growing rapidly, and is incorporating a number of different research approaches to address a wide variety of questions.

This chapter looks at synaesthesia in school aged children from approximately 5-6 years onwards. We examine how synaesthesia develops from its earliest roots both behaviourally and neurologically, and describe how this development can be affected by literacy and learning. We present evidence showing that synaesthesia emerges over time undergoing stages of 'growth' from an immature to more mature form. We also discuss the prevalence of childhood synaesthesia and the methodologies available for testing this. Next we consider (...) how the condition can have an effect on a child's schooling experience and consider both its psychological and social impact. We show where the condition has costs and benefits for synaesthetic individuals and offer suggestions for parents and educators in their approach to dealing with the synaesthetic child. (shrink)

In sequence-space synaesthesia, members of linguistic sequences such as numbers, days of the week and letters of the alphabet are perceived to occupy spatial positions, either in the mind's eye or as locations in space around the body. In this chapter, we begin by considering the possible sequences that can induce this type of synaesthesia, with the focus on numbers, time-units and letters. We evaluate the various methods used to test the genuineness of self-reports of this type of (...) synaesthesia, and we make suggestions for novel techniques that could address the shortcomings of the current methods. Lastly, we briefly outline the current theories on the neural basis of this type of synaesthesia, including the recent reification hypothesis. We conclude by discussing how scientific findings with sequence-space synaesthetes can be beneficial for the study of cognitive psychology more generally. (shrink)

The condition of ‘genuine perceptual synaesthesia’ has been a focus of attention in research in psychology and neuroscience over the last decades. For subjects in this condition stimulation in one modality automatically and consistently over the subject’s lifespan triggers a percept in another modality. In hearing→colour synaesthesia, for example, a specific sound experience evokes a perception of a specific colour. In this paper, I discuss questions and challenges that the phenomenon of synaesthetic experience raises for theories of perceptual (...) experience in general, and for theories thatsee the content and modality of conscious experience as being constituted and determined by the active and skilful exploration of the environment in particular. The focus of my paper will be on the latter, ‘enactive’ view of perception and its theory of what determines the modality-specific ‘feel’ of a perceptual experience. (shrink)

Synaesthesia's Renaissance comments on attitudes and developments in synaesthesia research during the 20th century, focusing in particular on the last three decades when the greatest change took place. During the last century, reaction to the phenomenon varied by group. Synesthetes were gratified to learn that their experience was bona fide and had a scientific name. Laypersons were fascinated and clamored to know more. Well-known psychologists published on it early in the century, but then academia became hostile. After 1940 (...) synesthesia was dismissed as merely subjective and unsuited to respectable scientific inquiry. For decades critics insisted that synesthesia was neither a real perception nor a brain phenomenon. Though put to rest by century's end, an attitude of disbelief can still be encountered. (shrink)

“Synaesthesia” is most often characterised as a union or mixing of the senses.i Richard Cytowic describes it thus: “It denotes the rare capacity to hear colours, taste shapes or experience other equally startling sensory blendings whose quality seems difficult for most of us to imagine” ([1995] 1997, 7). One famous example is of a man who “tasted shapes”. When he experienced flavours he also experienced shapes rubbing against his face or hands.ii Such popular characterisations are rough and ready. What (...) is certainly true about synaesthesia is that it involves the interaction between sensory phenomena: in response to certain stimuli some sensory phenomena are elicited in synaesthetes that are not elicited in non-synaesthetes. However, the exact nature of the additional sensory phenomena forms a large part of the debate on the nature of synaesthesia. Synaesthesia is a condition that has been known about for some time. In the late nineteenth century, and early twentieth, century very many articles appeared on the topic in the psychological literature.iii Much of this work on synaesthesia relied on introspective reports of subjects. In consequence, when later in the twentieth century psychologists eschewed introspective reports and radical behaviourist methodology became the order of the day, synaesthesia was rarely a topic of research. In more recent times, however, psychology has once again changed tack. With the advent of cognitive psychology and of objective techniques that try to probe the nature of conscious states of the mind that are reported in introspection, psychological interest in synaesthesia has resumed. Many new findings about the subject have recently been brought to light. In philosophy, interest in synaesthesia is only just beginning to arise. The phenomenon is potentially philosophically interesting for several reasons.. (shrink)

This chapter provides a review of the hypothesis that synesthetic-like perception is present in infants and toddlers. Infants and very young children exhibit evidence of functional hyperconnectivity between the senses, much of which is reminiscent of the cross-sensory associations observed in synaesthetic adults. As most of these cross-sensory correspondances cannot be easily explained by learning, it is likely that these represent natural associations between the senses. In average adults, these 'natural associations' are felt only intuitively rather than explicitly. These observations (...) have led to the proposal of the 'neonatal synaesthesia hypothesis', which purports that all individuals are born synaesthetic, with explicit conscious perception of these natural cross-modal associations dissipating over development in typical individuals. This dissipation is likely the result of experience-dependent synaptic pruning and/or inhibition of cross-sensory neural connections. At the same time, cross-modal associations matching those common in the environment might be assumed to be learned. This hypothesis is re-evaluated in light of recent research findings, and is examined in the context of current evolutionary models of neuronal recycling and emerging evidence of longitudinal changes in children with synaesthesia. (shrink)

Visual information can be provided to blind users through sensory substitution devices that convert images into sound. Through extensive use to develop expertise, some blind users have reported visual experiences when using such a device. These blind expert users have also reported visual phenomenology to other sounds even when not using the device. The blind users acquired synthetic synaesthesia, with visual experience evoked by sounds only after gaining such expertise. Sensorimotor learning may facilitate and perhaps even be required to (...) develop expertise in the use of multimodal information. Furthermore, other areas where expertise is acquired in dividing attention amongst cross-modal information or integrating such information might also give rise to synthetic synaesthesia. (shrink)

Grapheme-colour synaesthesia is a perceptual experience where graphemes, letters or words evoke a specific colour, which are experienced either as spatially coincident with the grapheme inducer (projector sub-type) or elsewhere, perhaps without a definite spatial location (associator sub-type). Here, we address the question of whether synaesthesia can be rapidly produced using a hypnotic colour suggestion to examine the possibility of ‘hypnotic synaesthesia’, i.e. subjectively experienced colour hallucinations similar to those experienced by projector synaesthetes. We assess the efficacy (...) of this intervention using an “embedded figures” test, in which participants are required to detect a shape (e.g., a square) composed of local graphemic elements. For grapheme-colour synaesthetes, better performance on the task has been linked to a higher proportion of graphemes perceived as coloured. We found no performance benefits on this test when using a hypnotic suggestion, as compared to a no-suggestion control condition. The same result was found when participants were separated according to the degree to which they were susceptible to the suggestion (number of coloured trials perceived). However, we found a relationship between accuracy and subjective reports of colour in those participants who reported a large proportion of coloured trials: trials in which the embedded figure was accurately recognised (relative to trials in which it was not) were associated with reports of more intense colours occupying a greater spatial extent. Collectively, this implies that hypnotic colour was only perceived after shape detection rather than aiding in shape detection via colour-based perceptual grouping. The results suggest that hypnotically induced colours are not directly comparable to synaesthetic ones. (shrink)

Gray argues that my three earlier counterexamples fail to refute representational theories of phenomenal character. I maintain that, despite Gray's arguments, each example does in fact work against the particular representational theory at which it is targeted. Further, I question whether my internalism regarding phenomenal character and Gray's externalism regarding modularity are in genuine conflict with one another.

Synaesthesia is a neurological condition in which a sensory or cognitive stimulus consistently co-activates another sensory/cognitive quality in addition to its usual qualities. For example, synaesthetes might see colours when they read words. Coloured language is one of the most common and most studied types of synaesthesia. The processes that govern the associations of colours and language have been linked to the mechanisms underlying the processing of language more generally. This chapter reviews evidence from current psycholinguistic synaesthesia (...) research in Chinese, focusing in particular on how synaesthetic colouring works in Chinese characters, the basic writing units in Chinese. I consider this in relation to the psycholinguistic processes of character recognition. This chapter reviews evidence for the following facts: that synaesthetic colouring of Chinese characters is a genuine phenomenon in the Chinese population and may affect as many as 1 in 100 in the Chinese population, with a non-significant difference across the sexes that the colouring of characters is rule-based and influenced by a number of linguistic factors; and that synaesthetic colouring can transfer across Chinese and English in bilinguals. These findings are discussed in relation to native versus non-native Chinese synaesthetes, and to the Chinese versus English systems. (shrink)