Encyclopedia entry on color synesthesia with cognitive/neurscientific focus.

Researchers have long suspected that grapheme-color synaesthesia is useful, but research on its utility has so far focused primarily on episodic memory and perceptual discrimination. Here we ask whether it can be harnessed during rule-based Category learning. Participants learned through trial and error to classify grapheme pairs that were organized into categories on the basis of their associated synaesthetic colors. The performance of synaesthetes was similar to non-synaesthetes viewing graphemes that were physically colored in the same way. Specifically, synaesthetes (...) learned to categorize stimuli effectively, they were able to transfer this learning to novel stimuli, and they falsely recognized grapheme-pair foils, all like non-synaesthetes viewing colored graphemes. These findings demonstrate that synaesthesia can be exploited when learning the kind of material taught in many classroom settings. (shrink)

Encyclopedia entry on color synesthesia with cognitive/neurscientific focus.

This review provides a commentary on coloured-hearing arising on hearing music: music-colour synaesthesia. Although traditionally explained by the hyperconnectivity theory (Ramachandran & Hubbard, 2001a) and the disinhibited feedback theory (Grossenbacher & Lovelace, 2001) as a purely perceptual phenomenon, the review of eight coloured-hearing neuroimaging studies shows that it may not be assumed that these explanations are directly translatable to music-colour synaesthesia. The concept of 'ideaesthesia' (Nikolić, 2009) and the role of conceptual and semantic inducers challenge the likelihood of a single (...) mechanism underlying the cause of synaesthesia and argue for a move away from a purely sensory to sensory explanation. Finally, music-colour synaesthesia forms a challenge for established philosophical theories and the position of synaesthesia is considered within the larger context of musical qualia. (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)

��Grapheme-color synaesthesia is a neurological phenomenon in which particular graphemes, such as the numeral 9, automatically induce the simultaneous perception of a particular color, such as the color red. To test whether the concurrent color sensations in graphemecolor synaesthesia are treated as meaningful stimuli, we recorded event-related brain potentials as 8 synaesthetes and 8 matched control subjects read sentences such as ‘‘Looking very clear, the lake was the most beautiful hue of 7.’’ In synaesthetes, but not (...) control subjects, congruous graphemes, compared with incongruous graphemes, elicited a more negative N1 component, a less positive P2 component, and a less negative N400 component. Thus, contextual congruity of synaesthetically induced colors altered the brain response to achromatic graphemes beginning 100 ms postonset, affecting pattern-recognition, perceptual, and meaning-integration processes. The results suggest that grapheme-color synaesthesia is automatic and perceptual in nature and also suggest that the connections between colors and numbers are bidirectional. (shrink)

Recent research has suggested that not all grapheme-colour synaesthetes are alike. One suggestion is that they can be divided, phenomenologically, in terms of whether the colours are experienced in external or internal space. Another suggestion is that they can be divided according to whether it is the perceptual or conceptual attributes of a stimulus that is critical. This study compares the behavioural performance of 7 projector and 7 associator synaesthetes. We demonstrate that this distinction does not map on to behavioural (...) traits expected from the higher–lower distinction. We replicate previous research showing that projectors are faster at naming their synaesthetic colours than veridical colours, and that associators show the reverse profile. Synaesthetes who project colours into external space but not on to the surface of the grapheme behave like associators on this task. In a second task, graphemes presented briefly in the periphery are more likely to elicit reports of colour in projectors than associators, but the colours only tend to be accurate when the grapheme itself is also accurately identified. We propose an alternative model of individual differences in grapheme-colour synaesthesia that emphasises the role of different spatial reference frames in synaesthetic perception. In doing so, we attempt to bring the synaesthesia literature closer to current models of non-synaesthetic perception, attention and binding. (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)

Determining the nature of binding in grapheme-color synaesthesia has consequences for understanding the neural basis of synaesthesia and visual awareness in general. We evaluated type- and token-based letter-color binding using a synaesthetic version of the object-reviewing paradigm. Although mean response times failed to reveal any significant differences between synaesthetes and control participants, RT analyses with ex-Gaussian distributions revealed that the response facilitation in the synaesthesia group reflected type representations exclusively, while response facilitation in the control group, who learned (...) letter-color associations, was dominated by token representations. Thus, letter-color associations in associator synaesthetes are type-based, and do not involve binding to object tokens, consistent with their subjective reports. Contrary to recent studies that failed to find differences between synaesthetes and non-synaesthetes with behavioral measures, response time distribution analyses indicate that color sensations in synaesthetes are not simply the extreme form of normal letter-color associations, and cannot be attributed to demand characteristics. (shrink)

Recently, swimming-style colour synaesthesia was introduced as a new form of synaesthesia. A synaesthetic Stroop test was used to establish its genuineness. Since Stroop interference can occur for any type of overlearned association, in the present study we used a modified Stroop test and psychophysiological synaesthetic conditioning to further establish the genuineness of this form of synaesthesia. We compared the performance of a swimming-style colour synaesthete and a control who was trained on swimming-style colour associations. Our results showed that behavioural (...) aspects of swimming-style colour synaesthesia can be mimicked in a trained control. Importantly, however, our results showed a psychophysiological conditioning effect for the synaesthete only. We discuss the theoretical relevance of swimming-style colour synaesthesia according to different models of synaesthesia. We conclude that swimming-style colour synaesthesia is a genuine form of synaesthesia, can be mimicked behaviourally in non-synaesthetes, and is best explained by a re-entrant feedback model. (shrink)

People with grapheme-color synesthesia perceive specific colors when viewing different letters or numbers. Previous studies have suggested that synesthetic color experience can be bistable when induced by an ambiguous character. However, the exact relationship between processes underlying the identity of an alphanumeric character and the experience of the induced synesthetic color has not been examined. In the present study, we explored this by focusing on the temporal relation of inducer identification and color emergence using inducers (...) whose identity could be rendered ambiguous upon rotation of the characters. Specifically, achromatic alphabetic letters and digits were presented at varying angles to 9 grapheme-color synesthetes. Results showed that grapheme identification and synesthetically perceived grapheme color covary with the orientation of the test stimulus and that synesthetes were slower naming the experienced color than identifying the character, particularly at intermediate angles where ambiguity was greatest. (shrink)

Synaesthesia is a heterogeneous phenomenon, even when considering one particular sub-type. The purpose of this study was to design a reliable and valid questionnaire for grapheme-colour synaesthesia that captures this heterogeneity. By the means of a large sample of 628 synaesthetes and a factor analysis, we created the Coloured Letters and Numbers questionnaire with 16 items loading on 4 different factors . These factors were externally validated with tests which are widely used in the field of synaesthesia research. The questionnaire (...) showed good test–retest reliability and construct validity . Our findings are discussed in the light of current theories and new ideas in synaesthesia research. More generally, the questionnaire is a useful tool which can be widely used in synaesthesia research to reveal the influence of individual differences on various performance measures and will be useful in generating new hypotheses. (shrink)

The phenomenon of synesthesia has undergone an invigoration of research interest and empirical progress over the past decade. Studies investigating the cognitive mechanisms underlying synesthesia have yielded insight into neural processes behind such cognitive operations as attention, memory, spatial phenomenology and inter-modal processes. However, the structural and functional mechanisms underlying synesthesia still remain contentious and hypothetical. The first section of the present paper reviews recent research on grapheme-color synesthesia, one of the most common forms of (...) synesthesia, and addresses the ongoing debate concerning the role of selective attention in eliciting synesthetic experience. Drawing on conclusions of the first half, the paper’s second half examines the various models proposed to explain the cognitive mechanisms behind grapheme-color synesthesia, and discusses the explanatory virtues of a new model suggesting that grapheme-color synesthesia is grounded in memory. The last section offers an examination of some of the broader philosophical implications of synesthesia. (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)

Synesthetic experiences of color have been traditionally conceptualized as a perceptual phenomenon. However, recent evidence suggests a role of higher order cognition in the formation of synesthetic experiences. Here, we discuss how synesthetic experiences of color differ from and influence veridical color processing, and how non-perceptual processes such as imagery and color memory might play a role in eliciting synesthetic color experience.

Synesthetic experiences of color have been traditionally conceptualized as a perceptual phenomenon. However, recent evidence suggests a role of higher order cognition in the formation of synesthetic experiences. Here, we discuss how synesthetic experiences of color differ from and influence veridical color processing, and how non-perceptual processes such as imagery and color memory might play a role in eliciting synesthetic color experience.

Studies of linguistic synaesthesias in English have shown a range of fine-grained language mechanisms governing the associations between colours on the one hand, and graphemes, phonemes and words on the other. However, virtually nothing is known about how synaesthetic colouring might operate in non-alphabetic systems. The current study shows how synaesthetic speakers of Mandarin Chinese come to colour the logographic units of their language. Both native and non-native Chinese speakers experienced synaesthetic colours for characters, and for words spelled in the (...) Chinese spelling systems of Pinyin and Bopomo. We assessed the influences of lexical tone and Pinyin/Bopomo spelling and showed that synaesthetic colours are assigned to Chinese words in a non-random fashion. Our data show that Chinese-speaking synaesthetes with very different native languages can exhibit both differences and similarities in the ways in which they come to colour their Chinese words. (shrink)

The aim of this article is to give both a sustained interpretation of Wittgenstein’s obscure remarks on the experience of meaning of language, synthaesthesia and secondary use and to apply his insights to recent philosophical discussions about synthaesthesia. I argue that synthaesthesia and experience of meaning are conceptually related to aspect-seeing. The concept of aspect-seeing is not reducible to either seeing or imaging but involves a modified notion of experience. Likewise, synthaesthesia involves a modified notion of experience. In particular, the (...) concept of synthaesthesia involves a secondary use of ‘experience’ and hence is intrinsically dependent on the primary use of language. Recent discussions tend to overlook this distinction between the primary and secondary use of language. (shrink)

The aim of this article is to give both a sustained interpretation of Wittgenstein’s obscure remarks on the experience of meaning of language, synthaesthesia and secondary use and to apply his insights to recent philosophical discussions about synthaesthesia. I argue that synthaesthesia and experience of meaning are conceptually related to aspect-seeing. The concept of aspect-seeing is not reducible to either seeing or imaging but involves a modified notion of experience. Likewise, synthaesthesia involves a modified notion of experience. In particular, the (...) concept of synthaesthesia involves a secondary use of ‘experience’ and hence is intrinsically dependent on the primary use of language. Recent discussions tend to overlook this distinction between the primary and secondary use of language. (shrink)

In a promising working note to the Visible and Invisible, Merleau-Ponty proposes that we understand Being according to topological space – relations of proximity, distance, and envelopment – and move away from an image of Being based on homogeneous, inert Euclidean space. With reference to treatments of cross-sensory perception, color-blindness, and the concept of quale or qualia, I seek to rehearse this shift from Euclidean to topological Being by illustrating how modern science confines color itself to a Euclidean (...) model of color space. I discuss “being as Object” in Merleau-Ponty’s later work before showing how color, and indeed all perception, is reduced to being as Object in the form of “quale”. Next, I address discussions in Merleau-Ponty’s work and contemporary research to illustrate how synesthesia and so-called color-blindness are rendered abnormal by this objectified being of color. Merleau-Ponty’s reading of synesthesia follows directly from his rejection of quale, and his use of color perception serves as a rejection of solipsism. With appeal to his proposed topological model of Being, I conclude by recognizing the problematic nature of synesthesia and color-blindness as being ontological, not psychological.Dans une note de travail, à mon sens décisive, du Visible et l’Invisible, Merleau-Ponty propose que l’on comprenne l’Être à partir de l’espace topologique – relations de proximité, distance et enveloppement – allant à l’encontre d’une l’image de l’Être fondée sur un espace euclidien homogène et inerte. En faisant référence aux traitements de la perception synesthésique, au daltonisme et au concept de quale ou qualia, j’essayerai de décrire ce passage de l’Être euclidien à l’Être topologique en montrant que la science moderne finit par confiner la couleur dans un modèle euclidien d’espace-couleur. J’examinerai « l’Être-objet » dans les derniers écrits de Merleau-Ponty avant de montrer comment la couleur, et plus en général la perception, est réduite à être comme un Objet dans la forme d’un « quale ». Ensuite, en examinant les analyses merleau-pontiennes et les recherches contemporaines, je montrerai comment la synesthésie et le daltonisme sont donc considérés comme anormaux à partir de cette objectivation de la couleur. La lecture que Merleau-Ponty donne de la synesthésie est la conséquence directe de son refus du quale, et l’utilisation qu’il fait de la perception des couleurs sert comme un refus du solipsisme. En faisant appel au modèle topologique de l’Être qu’il propose, je conclurai en constatant que la nature problématique de la synesthésie et du daltonisme est ontologique et non pas psychologique.In una nota di lavoro al Visibile e l’invisibile, Merleau-Ponty propone di comprendere l’Essere a partire da uno spazio topologico – secondo le relazioni di prossimità, distanza e avvolgimento – e abbandona l’immagine di un Essere fondato su uno spazio omogeneo, inerte, euclideo. Facendo riferimento ai trattamenti per le percezioni sinestetiche, al daltonismo e al concetto di quale o qualia, si cercherà di provare questo passaggio da un Essere euclideo a uno topologico, illustrando quanto la scienza moderna tenda a ridurre il concetto stesso di colore a un modello euclideo di spazio-colore. Si esaminerà l’“Essere-oggetto” degli ultimi lavori di Merleau-Ponty, mostrando come il colore, e in realtà la percezione tout court, vengano ridotti a oggetto nella forma di “quale”. Infine, si esaminerà l’opera merleau-pontiana e la ricerca contemporanea al fine di illustrare quanto la sinestesia e il daltonismo siano resi anormali da questa oggettivazione dell’essere del colore. L’interpretazione merleau-pontiana della sinestesia deriva proprio dal suo rifiuto del quale, e il suo uso della percezione del colore funge da rifiuto del solipsismo. Ricorrendo al modello topologico di Essere elaborato da Merleau-Ponty, si conclude riconoscendo che il problema della sinestesia e del daltonismo è, a tutti gli effetti, ontologico e non psicologico. (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)

Music education can alleviate students’ psychological stress and play a positive role in the healthy growth and development of students. Synaesthesia theory is a relatively special cognitive phenomenon that can achieve connections between different sensory organs. Colour psychology can influence the change of mental state through the change of vision. In this study, synaesthesia theory and colour psychology were applied to music education, and the traditional music education method was used as the contrast method to set up the experiment. The (...) article focuses on the experimental results with regard to the Hamilton anxiety scale (HAMA) score of the use of traditional music by students. It shows that the music education mode integrating synaesthesia theory and colour psychology can better improve the classroom quality of music education, so as to better relieve the pressure of students and promote their healthy, happy and positive growth. Contribution: Difficult learning tasks add pressure to the student’s learning capabilities, which leads to psychological problems such as anxiety and stress. Music education can relax students’ nerves and psychology, so as to relieve students’ psychological pressure. The research applies synaesthesia theory and colour psychology to music education to improve the classroom quality of music, so as to better alleviate student pressures and promote healthy, happy and positive growth. This research represents data, which can be utilised by scholars in the field of religious education and public theology. (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 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)

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)

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)

Although several studies have investigated the cognitive nature of the synaesthetic experience, very little is known about the stage in information processing at which the synaesthetic response arises. Specifically, we are still unclear about how much perceptual processing of an inducing stimulus is required before synaesthesia is experienced. Is synaesthesia induced by particular featural properties of a stimulus or might it be driven by a more abstract representation determined by lexical meaning? Or perhaps synaesthesia is triggered by some combination of (...) bottom-up and top-down processing of a representation which is invariant to specific perceptual properties of the stimulus but dependent on it cognitive category. Recent studies on grapheme-colour synaesthesia provide some insight into this issue. In the following chapter, I begin with an overview on how letters and words may be represented in both the neurotypical and synaesthete brain. I then extend the discussion to evidence suggesting that synaesthetic colours may not be triggered by low-level, pattern-specific properties of these stimuli but by a more multisensory representation. Moreover, results from a large number of multi-lingual synaesthetes do not concur with the idea that synaesthesia is consistently linked to a lexical semantic representation. Instead, our studies suggest that colours are induced by the concept of the inducing stimulus, which involves an intermediate, multisensory representation that may be more heavily weighted by visual than auditory perceptual information. The extent to which this cognitive process holds true for all grapheme-colour synaesthetes, or indeed other types of synaesthesia, has yet to be determined. (shrink)

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)