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Chromesthesia or sound-to-color synesthesia is a type of synesthesia in which heard sounds automatically and involuntarily evoke an experience of color.〔Cytowic, Richard E; Eagleman, David M (2009). Wednesday is Indigo Blue: Discovering the Brain of Synesthesia (with an afterword by Dmitri Nabokov). Cambridge: MIT Press. pp. 309. ISBN 0-262-01279-0〕 For the purpose of disambiguation, this article will refer to this chromesthesia in inducer-concurrent terms used to describe other forms of synesthesia. With sounds inducing color concurrents, chromesthesia is more accurately termed sound-color synesthesia. Individuals with sound-color synesthesia are consciously aware of their synesthetic color associations/perceptions in daily life.〔Simner, J. (2012a). Defining synaesthesia. British Journal of Psychology, 103, 1-15. doi: 10.1348/000712610x528305〕 Synesthetes that perceive color while listening to music experience the colors in addition to the normal auditory sensations that would be triggered in the average person. That is, the synesthetic color experience supplements, but does not obscure real, modality-specific perceptions.〔 As with other variations of synesthesia, individuals with sound-color synesthesia perceive the synesthetic experience spontaneously, and without effort, and in a way that the individual learns to accept as normal within their realm of experience.〔 ==Individual variance== The color associations, that is, which color is associated to which sound, tone, pitch, or timbre is highly idiosyncratic, but in most cases, consistent over time.〔〔Head, P. D. (2006). Synaesthesia: Pitch-color isomorphism in RGB-space? Cortex, 42(2), 164-174.〕 Individuals with synesthesia have unique color pairings. However, all studies to date have reported that synesthetes and non-synesthetes alike match high pitched sounds to lighter or brighter colors and low pitched sounds to darker tones, indicating that there may be some common mechanism that underlies the associations present in normal adult brains.〔Ward, J (2006). Sound-color Synaesthesia: to what extent does it use cross-modal mechanisms common to us all? Cortex, 42, 264-280.〕 There are forms of pseudo-chromesthesia that may be explained by associations synesthetes have made and forgotten from childhood. As with other variants of synesthesia, sound-color synesthesia can be divided into groups based on the way the colors are experienced. Those that 'see' or perceive the color as being in the external space are often called projectors, and those that perceive the color in the mind's eye are often called associators, but these terms can be very misleading in terms of understanding the true nature of the experience.〔〔 For most synesthetes, the condition is not wholly sensory/perceptual.〔 For some individuals, the synesthesia is only triggered by speech sounds, while others' synesthesia can be triggered by all known auditory stimuli.〔Goller, A., Otten, L., Ward, J. (2008). Seeing Sounds and Hearing colors: An Event-related Potential Study of Auditory-Visual Synesthesia. Journal of Cognitive Neuroscience, 21:10, 1869-1881.〕 In a study investigating variability within categories of synesthesia, 40% of subjects with synesthesia for spoken words reported that voice pitch, accent, and prosody influenced the synesthetic concurrent, whereas few subjects reported that volume or speed of talking had any influence.〔Van Leeuwen, T. (2012). Modality and Variability of Synesthetic Experience. American Journal of Psychology, 125(1), 81-94.〕 Within these subjects, many reported that the speaker's emotional inflection could influence the synesthetic color, but only two reported that their own mood had such influence.〔 Of participants categorized as having synesthesia for music in this study, 75% reported concurrents exclusively when listening to notes being played.〔 When asked whether the experience of the concurrent could be voluntarially controlled, only 33% of participants indicated an ability to smother, ignore, or willfully evoke their concurrents without great effort.〔 Attention to the inducing stimulus was reported as influential in 59% of participants.〔 Other contributing factors included concentration level, fatigue, sleep habits, fever, emotions, and substances, such as caffeine or alcohol.〔 Sound-color synesthesia is far more common than color-sound synesthesia, although there are reported cases where sounds and colors activate bidirectionally. One individual, JR, sees colors when she hears sounds and also hears sounds when she sees colors.〔 This type of synesthesia interferes greatly with daily life. It is interesting to note that this individual's associations were highly consistent over time, but the associations were not necessarily the same in either direction.〔 There may be an effect of semantic mediation in some individuals with sound-color synesthesia. One subject, MH, self-triggered notes on a synthesizer and noted the color associations. When the synthesizer was transposed without her knowledge, she reported identical color associations to the notes that she believed she was hearing, rather than the absolute pitch of the tones.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Chromesthesia」の詳細全文を読む スポンサード リンク
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