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Digit synaesthesia: A case study using a Stroop-type test

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Two experiments tested the effect that synaesthesia has on the processing of digits for a single participant, a 22-year-old female college student, who experiences colour mental images (photisms) for digits, music, sounds, etc. The experiments used Stroop-type materials that were digits in the colours of her photisms for two tasks: colour naming and digit naming. For colour naming, the hypothesis was that when the colour of the actual print of the digit mismatched the colour of the participant's digit photism, colour naming times would be slower than when the print and digit photism matched, or when the digit was in black print. For digit naming, it was predicted that naming the digit corresponding to a coloured circle (that corresponded to one of her photisms for digits) would take longer than naming digits printed in any colour. ANOVAs and Tukey tests supported these hypotheses (P Document Type: Research Article DOI: http://dx.doi.org/10.1080/026432999380951 Publication date: March 1, 1999 (document).ready(function() { var shortdescription = (".originaldescription").text().replace(/\\&/g, '&').replace(/\\, '<').replace(/\\>/g, '>').replace(/\\t/g, ' ').replace(/\\n/g, ''); if (shortdescription.length > 350){ shortdescription = "" + shortdescription.substring(0,250) + "... more"; } (".descriptionitem").prepend(shortdescription);(".descriptionitem").prepend(shortdescription); (".shortdescription a").click(function() { (".shortdescription").hide();(".shortdescription").hide(); (".originaldescription").slideDown(); return false; }); }); Related content In this: publication By this: publisher In this Subject: Anatomy & Physiology By this author: Mills, Carol Bergfeld ; Boteler, Edith Howell ; Oliver, Glenda K. GA_googleFillSlot("Horizontal_banner_bottom");

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... From this stems comparisons to the hypothesised mechanisms of absolute pitch and the ability to assign a label to individual notes (Gregersen et al., 2013;Profita, Bidder, Optiz & Reynolds, 1988;Takeuchi & Hulse, 1993). However, music-colour synaesthesia is not simply about the ability to label an isolated pitch or a chord and is not always accompanied by the possession of absolute pitch (Mills, Boteler & Oliver, 1999). As previously discussed, music-colour synaesthesia is often dependent on timbre, context, and key, and accompanied by shapes, spatial layouts and textures (Eagleman & Goodale, 2009). ...
... Cohen Kadosh and Terhune (2012) agree and remark that failure of a consistency test should not result in the exclusion of those that none the less report synaesthetic experiences equally well demonstrated through behavioural tests such as Stroop interference (Stroop, 1935). For example, a synaesthete who sees a '7' as green and a '6' as red may find it more difficult to identify a '7' in red ink or a '6' in green ink, should this be incongruous with their synaesthetic colour (Mills et al., 1999;Dixon, Smilek, Cudahy, & Merikle, 2000;Mattingley, Rich, Yelland, & Bradshaw, 2001). Yet, it should be noted, as demonstrated by Elias, Saucier, Hardie and Sarty (2003), that Stroop interference alone is not sufficient to confirm the existence of synaesthesia, as it may demonstrate the presence of learned associations. ...
... However, Brogaard rejects this position by arguing that some forms of projector synaesthesia are a 'kind of perceptual experience' (p. 313) based on results relating to grapheme colour synaesthesia such as the Stroop effect (Mills et al., 1999;Mattingley et al., 2001) visual search paradigms (Ramachandran & Hubbard, 2001a) and brain imaging (Simner, 2012). Brogaard's view is that from this standpoint a representationalist may not simply respond by arguing that projector synaesthesia is not a perceptual experience. ...
Article
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.
... From this stems comparisons to the hypothesised mechanisms of absolute pitch and the ability to assign a label to individual notes (Gregersen et al., 2013;Profita, Bidder, Optiz & Reynolds, 1988;Takeuchi & Hulse, 1993). However, music-colour synaesthesia is not simply about the ability to label an isolated pitch or a chord and is not always accompanied by the possession of absolute pitch (Mills, Boteler & Oliver, 1999). As previously discussed, music-colour synaesthesia is often dependent on timbre, context, and key, and accompanied by shapes, spatial layouts and textures (Eagleman & Goodale, 2009). ...
... Cohen Kadosh and Terhune (2012) agree and remark that failure of a consistency test should not result in the exclusion of those that none the less report synaesthetic experiences equally well demonstrated through behavioural tests such as Stroop interference (Stroop, 1935). For example, a synaesthete who sees a '7' as green and a '6' as red may find it more difficult to identify a '7' in red ink or a '6' in green ink, should this be incongruous with their synaesthetic colour (Mills et al., 1999;Dixon, Smilek, Cudahy, & Merikle, 2000;Mattingley, Rich, Yelland, & Bradshaw, 2001). Yet, it should be noted, as demonstrated by Elias, Saucier, Hardie and Sarty (2003), that Stroop interference alone is not sufficient to confirm the existence of synaesthesia, as it may demonstrate the presence of learned associations. ...
... However, Brogaard rejects this position by arguing that some forms of projector synaesthesia are a 'kind of perceptual experience' (p. 313) based on results relating to grapheme colour synaesthesia such as the Stroop effect (Mills et al., 1999;Mattingley et al., 2001) visual search paradigms (Ramachandran & Hubbard, 2001a) and brain imaging (Simner, 2012). Brogaard's view is that from this standpoint a representationalist may not simply respond by arguing that projector synaesthesia is not a perceptual experience. ...
Article
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. Key words: synaesthesia/synesthesia; ideaesthesia; concept; music-colour/color; chromesthesia; qualia
... We first determined whether the inducers of distinct synesthetic colors could also vary in modality (orthographic vs. phonological), if not within a synesthete, at least across individuals. To this end, we examined the effects of words presented auditorily and visually in two tasks-Auditory Priming and Visual Color Stroop-that have been extensively investigated in synesthesia research as they involve automatic and implicit word processing (Dixon et al. 2000;Gebius et al. 2009;Gray et al. 2006;Mattingley et al. 2001;Mills et al. 1999;Ward et al. 2006;Woolen and Ruggiero 1983). In the Auditory Priming Task, auditory words preceded the presentation of colored squares, whose colors the participants named. ...
... Stroop-like effects have been demonstrated with synesthetic colors (Dixon et al. 2000(Dixon et al. , 2006Laeng et al. 2011;Mattingley et al. 2001;Mills et al. 1999;Myles et al. 2003) and have taken the form of fast color naming responses when colors matched the synesthetic colors induced by visually presented words. Whether similar Stroop-like effects could be observed with segment colors and word colors was examined by asking CB and VS to name the colors with which weekdays, months and onset-related words were shown, and varying whether or not these words were colored in their segment colors or their word colors. ...
... It is the most likely that children acquire phonemes before the words inducing word colors (e.g., Saturday, May, nine), and similar delays would occur in 3 In this respect, it was indicative that pale colors were chosen for items at the beginning of sequences (1, Monday, January) when VS selected word colors. This pattern, also observed with other synesthetes (Mills et al., 1999), might appear especially with word colors that, as we found with VS, were associated with sequences. Furthermore, it is perhaps not coincidental that associations with color names (B ? ...
Article
It has long been observed that certain words induce multiple synesthetic colors, a phenomenon that has remained largely unexplored. We report here on the distinct synesthetic colors two synesthetes experienced with closed sets of concepts (digits, weekdays, months). For example, Saturday was associated with green, like other word starting with s; however, Saturday also had its specific color (red). Auditory priming and Visual Color Stroop tasks were used to understand the cognitive mechanisms supporting the distinct synesthetic colors. Results revealed that processing of word segments and whole words was specifically involved in each type of synesthetic colors. However, these mechanisms differed between participants, as they could relate either to orthography (and written words) or phonology (and spoken words). Further differences concerned the word representations, which varied as to whether or not they encoded serial positions. In addition to clarifying the cognitive mechanisms underlying the distinct synesthetic colors, our results offer some clues for understanding the neurocognitive underpinnings of a rather common form of synesthesia.
... Consistent with this hypothesis, AN's colour-naming reaction times (RTs) were significantly longer for cards containing incongruently coloured letters, than cards containing congruently coloured letters or coloured disks. Similar results were reported by Mills, Boteler and Oliver, (1999), who tested a digit-colour synaesthete (GS) using an almost identical methodology. Like AN, their synaesthete took significantly longer to name the colours of incongruently coloured digits than cards containing either congruently coloured digits or cards containing coloured disks. ...
... The available evidence from two other cases of synaesthesia also suggests that photism and colour naming speeds do not differ (Mills et al., 1999;Wollen & Ruggiero, 1983). Wollen and Ruggiero (1983) compared the letter-colour synaesthete AN's RTs for photism naming (cards containing black letters) to the RTs for colour naming (cards containing coloured disks). ...
... They found no significant difference between the RTs for photism and colour naming. Similar results were found by Mills et al. (1999), who studied the digit-colour synaesthete GS. They also found no significant difference between the RTs associated with photism and colour naming. ...
Article
Full-text available
In synaesthesia, ordinary stimuli elicit extraordinary conscious experiences. For example, standard black digits may elicit highly specific colour experiences and specific tastes may elicit unusual tactile sensations. The growing interest in synaesthesia has led to numerous experimental studies of this phenomenon. The purpose of this paper is to review these recent studies and to discuss the relationship between the results of these experimental investigations of synaesthesia and the subjective descriptions reported by synaesthetes. It is argued that when the experimental investigations of synaesthesia are interpreted in the context of synaesthetes' subjective reports, the experimental investigations synergistically advance our understanding of synaesthesia. Ultimately we suggest that a more complete understanding of this fascinating phenomenon will require a clearly articulated combination of well-designed experimental studies and the subjective reports of synaesthetes.
... There are also similarities in terms of the effects on behavior: Both crossmodal correspondences and synesthesia can give rise to interference effects in speeded discrimination tasks (such as in the Stroop color-naming task) when simultaneously presented with pairs of features that happen to be incongruent with the individual's underlying synesthetic pairings or crossmodal associations (e.g., Dixon et al., 2000;Mills, Boteler, & Oliver, 1999;Walker & Smith, 1985see Marks, 2004, for a review). There is even evidence to suggest that both types of mapping can modulate a participant's performance on visual search tasks (e.g., Klapatek, Ngo, & Spence, 2012;Laeng, Svartdal, & Oelmann, 2004;Nijboer, Satris, & Van der Stigchel, 2010;Palmieri, Blake, Marois, Flanery, & Whetsell, 2002;Ramachandran & Hubbard, 2001;. ...
... Emphasizing the similarities: the continuum hypothesis Labeling crossmodal correspondences as synesthetic (even in the sense of weak synaesthesia; Martino & Marks, 2001), if it is not just a question of fashion or ease, means that the similarities (i.e., surprising consistent crossmodal mappings, behavioral similarities) prevail, while the differences (i.e., conscious concurrent vs. no conscious concurrent, idiosyncrasy vs. regularity, rare vs. frequent in the population) are treated as merely secondary. This, as we have argued elsewhere (see Deroy & Spence, submitted), goes with the progressive tendency toward thinking of synesthesia only through the lens of the test of consistency (also known as ToG, or test of genuineness) and the results of behavioral tests of Stroop interference (e.g., Beeli et al., 2005;Mills et al., 1999). 3 The inclusion of crossmodal correspondences within the category of synesthesia therefore accompanies the progressive relaxation of constitutive criteria for this, once upon a time, more specific condition. ...
... Until recently, one of the defining features of the synesthetic relation between the inducer and concurrent has been its apparent unidirectionality (e.g., Mills et al., 1999). While the presentation of a given inducer would reliably give rise to a certain specific concurrent, the presentation of the concurrent does not, typically, give rise to the inducer. ...
Article
Full-text available
High pitch sounds are almost universally considered as brighter and ‘higher’ in space than low pitch ones. This tendency to map sensory dimensions in a seemingly arbitrary way across audition, vision and other modalities has lead many to consider that we are all ‘weakly synaesthetic’ (e.g., Eagleman, 2009; Cohen, in press). Here we defend ‘the separatist view’ and argue that these cases are likely to form distinct kinds of phenomena despite their superficial similarities with synaesthesia. Ultimately, we provide a general definition of crossmodal correspondences as acquired, malleable, relative, and transitive pairings between sensory dimensions and integrate them as a kind of functional multisensory interaction.
... si une tonalité musicale évoque une couleur, à l'inverse, la vue de cette couleur n'évoquera pas la perception de la tonalité musicale). Rich, Yelland et Bradshaw, 2001;Mills, Boteler et Oliver, 1999;Spruyt, Koch, Vandromme, Hermans et Eelen, 2009;Ward et Sagiv, 2007 (Rouw et Scholte, 2007). Des différences structurelles dans la matière grise de ces régions corticales associées aux expériences synesthésiques ont également été trouvées, soit un volume neuronal plus élevé (Banissy et al., 2012; (Blakemore, Bristow, Bird, Frith et Ward, 2005;Hubbard, Arman, Ramachandran et Boynton, 2005a;Nunn et al., 2002;Rich et al., 2006;Rouw et Scholte, 2007). ...
... ex. Mills, Boteler et Oliver, 1999;Mills et al., 2006;Odgaard, Flowers et Bradman, 1999;Smilek et al., 2002a (Taylor, 1988 (Csikszentmihalyi, 2006). La créativité est l'habileté à apporter quelque chose de nouveau à une « culture » (Csikszentmihalyi, 1999). ...
Thesis
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La synesthésie est une condition neurologique dans laquelle une stimulation sensorielle ou cognitive dans une modalité spécifique engendre de façon automatique et involontaire une autre expérience perceptuelle inhabituelle. La synesthésie influencerait le développement de certaines habiletés cognitives, notamment sur le plan mnésique. Par ailleurs, une hypothèse intuitive populaire au sein de la communauté scientifique stipule que ces expériences sensorielles atypiques facilitent la créativité. En effet, comme elles dotent d’un répertoire perceptuel original, il est concevable qu’elles puissent mener à une aptitude à faire des associations non conventionnelles entre diverses catégories d’éléments. Par conséquent, cette recherche qualitative vise à mieux comprendre les influences des expériences synesthésiques sur la créativité, du point de vue de ceux qui vivent ces expériences. Dans le but de mieux comprendre la phénoménologie de la synesthésie en créativité, les questions de notre recherche se résument ainsi : Quel sens peut avoir l’expérience de la synesthésie en créativité et quelles répercussions a-t-elle sur la créativité? Nous sommes intéressés à comprendre comment la synesthésie peut être perçue, avoir de l’influence et être utilisée lors d’un processus créatif. À notre connaissance, il s’agit de la première étude à explorer la phénoménologie de la synesthésie tant auprès de plusieurs individus qu’au sein de plusieurs formes de synesthésie, à l’égard d’une caractéristique soi-disant centrale à cette condition, soit la créativité. Dans le cadre de cette recherche, 17 personnes avec diverses synesthésies, âgées de 21 ans à 72 ans, ont été rencontrées afin de partager leurs expériences lors d’entretiens individuels semi-dirigés. Ces entrevues ont été retranscrites et analysées d’après la méthode phénoménologique de recherche en psychologie. Au final, la structure fondamentale du phénomène étudié qui émerge de nos analyses comprend les 10 thèmes suivant en ce qui a trait au sens donné à l’expérience de la synesthésie sur le plan de la créativité : 1) L’expérience de la synesthésie oriente, module le processus créatif en fonction des associations synesthésiques afin d’être dans un état particulier et d’accroître le bien-être; 2) L’expérience de la synesthésie constitue un apport sensoriel, perceptuel et émotionnel à la créativité; 3) L’expérience de la synesthésie optimise les fonctions cognitives; 4) L’expérience de la synesthésie alimente la stimulation intellectuelle et la motivation dans un processus créatif; xvi 5) L’expérience de la synesthésie donne un sens à des éléments et à un vécu; 6) L’expérience de la synesthésie est perçue comme un système instinctif qui influence la créativité, une intuition à l’origine d’un processus de décision ou un réflexe consistant à transposer des associations qui sont indépendantes de la cognition; 7) L’expérience de la synesthésie permet de mieux se connaître, de s’identifier, d’exprimer et d’assumer ce qui constitue son individualité; 8) L’expérience de la synesthésie constitue une courroie de communication avec autrui, d’échange avec d’autres réalités; 9) L’expérience de la synesthésie peut ne pas avoir d’influence sur la créativité; les associations synesthésiques peuvent être perçues comme des états de faits qui sont d’utilité pratique et qui n’ont pas de répercussion sur les choix face à des besoins; 10) L’expérience de la synesthésie peut être un frein à la créativité. La présente étude a permis de développer une meilleure compréhension des composantes de la créativité, de faire avancer l’état des connaissances sur les expériences synesthésiques et d’identifier le coeur de leurs influences sur la créativité. Pour la première fois, l’étendue des avantages et des inconvénients des expériences synesthésiques sur la créativité a été exposée. Mener cette étude auprès de synesthètes qui présentent une variété de synesthésies a aussi permis d’identifier des processus sous-jacents à la créativité qui sont communs dans le vaste spectre de la synesthésie et d’amener des pistes d’explications quant aux différences individuelles pouvant émerger. Du coup, divers processus qui peuvent influencer et alimenter la créativité chez tous les individus ont été mis en lumière. Enfin, cette recherche peut apporter un éclairage sur les mécanismes universels d’interactions entre les sens et sur leur usage à certaines fins. De futures études avec de larges échantillons de participants devraient tenter de départager différents attributs de la synesthésie et d’explorer leur contribution respective dans divers aspects de la cognition et des émotions. Les répercussions de l’exploitation d’associations automatiques, synesthésiques ou non, pourraient aussi faire l’objet d’études dans les cadres d’interventions thérapeutiques et pédagogiques. Enfin, la mise sur pied de regroupements de chercheurs en synesthésie et de synesthètes pourrait stimuler le développement et la diffusion des connaissances sur la synesthésie et sur le potentiel humain, démarginaliser cette condition et déconstruire des conceptions erronées, et faire accroître l’épanouissement des individus de la grande communauté synesthète.
... Among the different types of synesthesia, grapheme-colour synesthesia is relatively common and it consists of colour perceptions evoked by grey scale alphanumeric images (letters and/ or digits) 1 . Synesthetic associations are consistent over time [2][3][4] and are automatic or difficult to discard when elicited 3,[5][6][7][8][9] . ...
... Grapheme-colour synesthesia has been most frequently investigated through the explicit presentation of synesthetic graphemes or digits, as shown with stroop-like tasks and visual search paradigms [5][6][7][8][9][10] . However, synesthesia remains much less studied when observers are unaware of a stimulus. ...
Article
Full-text available
Grapheme-colour synesthesia occurs when letters or numbers elicit an abnormal colour sensation (e.g., printed black letters are perceived as coloured). This phenomenon is typically reported following explicit presentation of graphemes. Very few studies have investigated colour sensations in synesthesia in the absence of visual awareness. We took advantage of the dichoptic flash suppression paradigm to temporarily render a stimulus presented to one eye invisible. Synesthetic alphanumeric and non-synesthetic stimuli were presented to 21 participants (11 synesthetes) in achromatic and chromatic experimental conditions. The test stimulus was first displayed to one eye and then masked by a sudden presentation of visual noise in the other eye (flash suppression). The time for an image to be re-perceived following the onset of the suppressive noise was calculated. Trials where there was no flash suppression performed but instead mimicked the perceptual suppression of the flash were also tested. Results showed that target detection by synesthetes was significantly better than by controls in the absence of flash suppression. No difference was found between the groups in the flash suppression condition. Our findings suggest that synesthesia is associated with enhanced perception for overt recognition, but does not provide an advantage in recovering from a perceptual suppression. Further studies are needed to investigate synesthesia in relation to visual awareness.
... This raises a question concerning a difference among synesthetic experiences, and a difference between synesthetic and ordinary experiences, in terms of their intensity. We cannot assume that the intensity remains constant throughout the duration of a particular synesthetic experience, across different experiences a synesthete undergoes during her lifetime, or across synesthetes who have experiences of the same type (Luria, 1968;Mills, Boteler, and Oliver, 1999;Motluk, 1997;Myles, Dixon, Smilek, and Merikle, 2003). ...
... A close inspection of synesthetic reports reveals that synesthetes present different accounts of the location of their synesthetic colors. According to these studies (Anderson and Ward, 2015;Blake et al., 2005;Cytowic, 2002;Grossenbacher and Lovelace, 2001;Harrison and Baron-Cohen, 1995;Mills, Boteler, and Oliver, 1999;Rich and Mattingley, 2002;Sagiv and Robertson, 2005;Smilek and Dixon, 2002;Ward, 2003;Ward and Simner, 2003;Ward, Li, Salih, and Sagiv, 2007) synesthetic colors can be placed in the following locations: they can surround the inducing grapheme or a person like a halo; they can cover the surface of the inducing grapheme without spilling over the grapheme's boundaries and without blocking its original color from view; they can surround the shape of the inducing grapheme like an outline; they can hover above the inducing stimulus; they can be projected on a screen which is located at some variable distance from and above the subject's line of vision or waist; 4 they can be located in some specific area inside the subject's head, e.g., the mouth, brain, or in the mind's eye; they can float; they can have a dual locus, etc. In some cases, there is no fact of the matter about their location, since synesthetic colors cannot be determinedly located either inside or outside the subject's body, e.g., when a synesthete claims that she "knows" that a grapheme has another color even if she does not see it. ...
... While these neuroimaging studies have begun to identify the functional neuroanatomy of the synaesthetic experience, cleverly designed behavioral experiments have uncovered some laws of the synaesthetic process. For instance, psychophysical experiments on perceptual grouping (e.g., Palmeri et al., 2002;Ramachandran & Hubbard, 2001a), visual search (e.g., Palmeri et al., 2002;Smilek et al., 2001), and visual-verbal interference (e.g., Mattingley et al., 2001;Mills et al., 1999;Odgaard et al., 1999) produced unequivocal evidence for the high automaticity of synaesthetic perceptions. Based on these and similar studies, one must conclude that synaesthesia involves a genuine perceptual experience and is not the product of mere mnemonic, or language-mediated associative processes. ...
... To illustrate this, a color-digit synaesthete may report "seeing" a pink color on watching (or merely imagining) the digit 7 in colorless print (Note that this type of synaesthesia does not span across two major sensory modalities, but is nevertheless bimodal in that an achromatic stimulus triggers a color percept. Color-digit synaesthesia is among the most frequent types of synaesthesia, and has consequently been the subject of a large number of laboratory investigations (e.g., Dixon et al., 2000;Mattingley et al., 2001;Mills et al., 1999;Odgaard, et. al., 1999;Palmeri et al., 2002;Smilek et al., 2001)). ...
... In addition, argued that a complete understanding of synaesthesia requires a combination of experimental investigations of synaesthesia and synaesthetes' subjective reports. Among psychological methods, synaesthesia research has traditionally used variants of the Stroop paradigm as an objective correlate of subjective synaesthetic reports (e.g., Mills, Boteler, and Oliver, 1999;Dixon, Smilek, Cudahy, and Merikle, 2000;Mattingley, Rich, Yelland, andBradshaw, 2001, Berteletti, Hubbard, andZorzi, 2010). The other 'gold standard' used in synaesthesia research is the test of consistency of synaesthetic associations (e.g., Baron-Cohen, Harrison, Goldstein, and Wyke, 1993;Baron-Cohen et al., 1996;Asher et al., 2006). ...
... Linguistic-colour synaesthetes often report that the colours that they experience in association with graphemes are not under their voluntary control. Automatic occurrence of synaesthetic associations was confirmed by studies demonstrating that synaesthetic colours can interfere with the identification and naming of display colours in modified Stroop interference paradigms (e.g., Mills et al., 1999;Dixon et al., 2000;Lupiáñez and 86 Cognitive determinants of linguistic-colour associations Callejas, 2006). However, some research on grapheme-colour synaesthesia refers to the extent to which synaesthetic colours arise automatically, without the need for conscious effort or strategic control (e.g., Rich and Mattingley, 2002;Robertson, 2003;Jarick, Dixon, and Smilek, 2011). ...
Book
Synaesthesia is a fascinating cognitive phenomenon where one type of stimulation evokes the sensation of another. For example, synaesthetes might perceive colours when listening to music, or tastes in the mouth when reading words. This book provides an insight into the idiosyncratic nature of synaesthesia by exploring its relationships with other dimensions of individual differences. Many characteristics of linguistic-colour synaesthetes are covered including personality, temperament, intelligence, creativity, emotionality, attention, memory, imagination, colour perception, body lateralization and gender. Aleksandra Rogowska proposes that linguistic-colour synaesthesia can be considered as an abstract form of a continuous variable in the broader context of cross- and intra-modal associations. There has been a resurgence of interest in synaesthesia and this book will appeal to students and scientists of psychology, cognitive science and social science, and to those who are fascinated by unusual states of mind.
... Conversion software may be downloaded here: http://www.sussex.ac.uk/synesthesia/links Automatic Synesthetic Stroop test Using a within-subjects design, a significant difference in performance for incongruent compared to congruent stimuli should be found (Wollen and Ruggiero, 1983;Mills, 1999;Odgaard et al., 1999;Dixon et al., 2000;Smilek et al., 2001). For interpretation of synesthesia-related behavior, it is important to include a within-subject baseline measure, such as digit or letter naming in addition to (synesthetic) color naming (Mills, 1999), and especially when the case cannot be compared to a group of matched controls Automaticity refers to the involuntary nature of the experience of the synesthetic concurrent, which elicits interference with task demands. ...
... Automatic Synesthetic Stroop test Using a within-subjects design, a significant difference in performance for incongruent compared to congruent stimuli should be found (Wollen and Ruggiero, 1983;Mills, 1999;Odgaard et al., 1999;Dixon et al., 2000;Smilek et al., 2001). For interpretation of synesthesia-related behavior, it is important to include a within-subject baseline measure, such as digit or letter naming in addition to (synesthetic) color naming (Mills, 1999), and especially when the case cannot be compared to a group of matched controls Automaticity refers to the involuntary nature of the experience of the synesthetic concurrent, which elicits interference with task demands. It is important to note that the presence of a Stroop effect does not necessarily imply that the association is at a perceptual level ...
... will (Mills, 1999;Mattingley et al., 2001;Lupiáñez and Callejas, 2006). Usually, it is an unidirectional perception (Grossenbacher and Lovelace, 2001), but in principle it can also occur indirectly subconsciously in both directions (Brugger et al., 2004;Cohen Kadosh et al., 2007;Meier and Rothen, 2007). ...
Article
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Grapheme-color synesthesia is a normal and healthy variation of human perception. It is characterized by the association of letters or numbers with color perceptions. The etiology of synesthesia is not yet fully understood. Theories include hyperconnectivity in the brain, cross-activation of adjacent or functionally proximate sensory areas of the brain, or various models of lack of inhibitory function in the brain. The growth factor brain-derived neurotrophic (BDNF) plays an important role in the development of neurons, neuronal pathways, and synapses, as well as in the protection of existing neurons in both the central and peripheral nervous systems. ELISA methods were used to compare BDNF serum concentrations between healthy test subjects with and without grapheme-color synesthesia to establish a connection between concentration and the occurrence of synesthesia. The results showed that grapheme-color synesthetes had an increased BDNF serum level compared to the matched control group. Increased levels of BDNF can enhance the brain's ability to adapt to changing environmental conditions, injuries, or experiences, resulting in positive effects. It is discussed whether the integration of sensory information is associated with or results from increased neuroplasticity. The parallels between neurodegeneration and brain regeneration lead to the conclusion that synesthesia, in the sense of an advanced state of consciousness, is in some cases a more differentiated development of the brain rather than a relic of early childhood.
... The process of SS (both natural and artificial) is subjected to learning, and it has been found to improve with experience [3,5]. Since SS has been proposed as a form of artificial synaesthesia due to the induction of some form of conscious concurrent experience or the presence of patterns of crossmodal interference, both characterizing synaesthesia, the condition in which individuals experience a percept in one sensory or cognitive pathway when another one is stimulated (e.g., perceiving colors while hearing a music) [13,33,34], it is important to pointing out the differences between two phenomena: synaesthesia is a totally involuntary process, and it is not subjected to any type of learning, while SS is sensitive to training [13]. ...
Article
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Sensory Substitution (SS) allows the elaboration of information via non preferential sensory modalities. This phenomenon occurs in robotic-assisted surgery (RAS), in which haptic feedback is lacking. It has been suggested that SS could sustain surgeons’ proficiency by means of visual clues for inferring tactile information, that also promotes the feeling of haptic phantom sensations. A critical role in reaching a good performance in procedural tasks is also sustained by the Sense of Embodiment (SE), that is, the capacity to integrate objects into subjective bodily self-representation. As SE is enhanced by haptic sensations, we hypothesize a role of SS in promoting SE in RAS. Accordingly, the goal of this systematic review is to summarize the evidence pertaining the study of SS in RAS in order to highlight the impact on the performance, and to identify a mediating role of the SE in increasing dexterity in RAS. Eight studies selected from the MEDLINE and Scopus® databases met inclusion criteria for a qualitative synthesis. Results indicated that haptic to other modalities SS enhanced force consistency and accuracy, and decreased surgeon fatigue. Expert surgeons, as compared to novices, showed a better natural SS processing, testified by a proficient performance with and without SS aids. No studies investigated the mediating role of SE. These findings indicate that SS is subjected to learning and memory processes that help surgeons to rapidly derive haptic-correlates from visual clues, which are highly required for a good performance. Also, the higher ability of doing SS and the associated perception of haptic sensations might increase multisensory integration, which might sustain performance.
... Research has sought to demonstrate synaesthesialike experiences as a result of training (e.g., Bor et al., 2015), post-hypnotic suggestion (e.g., Cohen Kadosh et al., 2009), psychedelic drug use (e.g., Luke and Terhune, 2013), flavour perception (Stevenson and Boakes, 2004;Stevenson and Tomiczek, 2007) and the use of sensory substitution devices (e.g., Farina, 2013;Proulx and Stoerig, 2006;Ward and Meijer, 2010). These phenomena have each been (in)directly linked to synaesthetic experience because they either induce some form of conscious concurrent experience or show patterns of crossmodal interference that characterise canonical cases of synaesthesia (such as the Stroop interference effect, e.g., Mills, 1999;see Eagleman et al., 2007, for a review of the existing tests). ...
... Thus, in incongruent conditions, the automatic reading of words was conflicted by the task to name colors which lead to more mistakes and longer naming times than in congruent conditions (Stroop, 1935). This classical Stroop task has been adapted for the investigation of a grapheme-color synesthete who experienced colors upon the perception of written numbers (Mills, Boteler, & Oliver, 1999). In this experiment the synesthete was required to name the printed color of numbers that was either congruent or incongruent with the concurrent color perception. ...
... The Stroop paradigm has been used to demonstrate the automaticity of concurrent sensations in several forms of synesthesia, including grapheme-color (van der Veen, Aben, Smits, & Roder, 2014), sound-color (Ward et al., 2006), and digit-color (Mills, Howell Boteler, and Oliver, 1999). The Stroop paradigm has also successfully been used for the investigation of the neural correlates of pitchpitch name association in absolute pitch (AP) (Itoh, Suwazono, Arao, Miyazaki, & Nakada, 2005;Schulze, Mueller, & Koelsch, 2013), which is the ability to identify the pitch class of a musical pitch without being given a reference pitch (Takeuchi & Hulse, 1993). ...
Article
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Pitch classes (e.g., do, re, and mi) in music evoke color sensations in pitch class-color synesthesia, which is a recently described form of synesthesia in musicians. The synesthetic color sensations were confirmed to be consistent over an extended time interval, fulfilling a widely-accepted criterion for the authenticity of synesthesia. However, it remains unclear whether the color sensations occurred automatically (i.e., without voluntary effort), which is another defining property of synesthesia. We utilized the Stroop paradigm to investigate this issue in 10 pitch class-color synesthetes. Participants were visually presented with pitch class names in font colors that were either congruent or incongruent with the participants' own color sensations. The speed for reporting the font color was slower when it was incongruent with the synesthetic sensation than when it was congruent. The finding verifies the authenticity of pitch class-color synesthesia by demonstrating that the color sensations occur automatically, even when unnecessary.
... These induced sensations, images, or qualities are vivid and can sometimes interact with the processing of non-synesthetic perceptual information, for example, in perceptual grouping (Ramachandran & Hubbard, 2001;Kim et al., 2006) and in synesthetic analogs to Stroop interference paradigms. In a task requiring subjects to identify the colors of digits printed in red and green ink, a person with digit-color synesthesia who sees 3 as synesthetically red and 5 as synesthetically green may find it relatively difficult to identify a green 3 and a red 5 quickly and accurately, due to interference from the synesthetic colors (e.g., Mills et al., 1999;Odgaard et al., 1999;Dixon et al., 2000;Mattingley et al., 2001). ...
Article
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Puzzling in its diversity and resistant to simple theoretical accounts, synesthesia has been a subject of scrutiny and investigation for more than a century. Over 30 years ago, the present author treated synesthesia as a perceptual, cross-modal phenomenon, in which a stimulus presented in one modality produces an additional sensation in another, and sought to understand synesthesia in light of principles of multisensory processing, under a broad framework of the ‘ unity of the senses.’ Research over the ensuing three decades has highlighted the role of learning and cognition in most kinds of synesthesia, many of which are not cross-modal, while pointing to some of the neural processes associated with synesthetic experience. One approach to understanding synesthesia, monism, treats synesthesia as an end-point of a continuous trait. Another approach, dualism, aims to distinguish synesthesia from non-synesthesia and searches for the common denominators that underlie synesthesia in all of its manifestations. An alternative to both monism and dualism is pluralism, which posits several distinct categories of synesthesia, not all necessarily equal : One category (or more) may be prototypical, a good candidate being cross-modal synesthesia. The principles that characterize cross-modal perceptual synesthesia also characterize cross-modal perception in non-synesthetes, and the mechanisms that underlie prototypical cross-modal synesthesia may serve as the wellspring for the development of synesthesia’s diverse other forms.
... For example, hearing particular voice frequencies might induce the perception of red, but viewing red would not necessarily induce a reciprocal frequency (Moos, Simmons, Simner, & Smith, 2013). Similarly, grapheme-color synesthetes are individuals for whom graphemes elicit a sense of color, though colors are not thought to induce numbers (Mills, Boteler, & Oliver, 1999). However, there is a growing body of evidence suggesting that a bidirectional component to grapheme-color synesthesia may exist (e.g., Brugger, Knoch, Mohr, & Gianotti, 2004;Cohen Kadosh & Henik, 2007;Knoch, Gianotti, Mohr, & Brugger, 2005). ...
Article
Grapheme-color synesthetes experience a sense of color when viewing graphemes (e.g., digits and letters). Traditionally, these synesthetic perceptions are considered to be unidirectional, where viewing a grapheme elicits a nonveridical sensation of color, but viewing a color does not induce a reciprocal sense of a grapheme. A growing body of research has emerged that suggests the potential for bidirectional percepts, wherein color facilitates additional grapheme perception. We present here a novel paradigm in which we presented two sets of pure color patches, based on synesthete’s reported colors, side-by-side and asked participants to indicate the color patch with the greater affiliated magnitude. Results indicated that the odds of answering correctly on trials were significantly greater for synesthetes (80.2% accuracy) than nonsynesthetes (52.1% accuracy). These results are aligned with other reports that support the notion of inducing a sense of magnitude from color in synesthetes. These findings challenge the traditional model of synesthesia as a unidirectional phenomenon and have implications of the neuronal communications that underlie perception in general.
... The results of Stroop-like interference tasks are sometimes cited as evidence for the view that synaesthesia is sensory (Mills et al., 1999) and sometimes for the conflicting view that synaesthesia is conceptual (Dixon et al., 2000;Mattingley et al., 2001) but neither inference is justified. Stroop interference merely shows that the association between the grapheme and the colour is automatic. ...
Article
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We investigated grapheme--colour synaesthesia and found that: (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 perceptual 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 colour 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 hyperconnectivity might be caused by a genetic mutation that causes defective pruning of connections 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 purp...
... The link between digits and their elicited colors is thought to depend critically on attention to the inducer (Edquist, Rich, Brinkman, & Mattingley, 2006;Mattingley, Payne, & Rich, 2006;Rich & Mattingley, 2010;Sagiv, Heer, & Robertson, 2006). Once an inducer is attended, though, synaesthetic colors occur involuntarily, such that they influence color naming times (e.g., Chiou et al., 2013;Mattingley, Rich, Yelland, & Bradshaw, 2001;Mills, Boteler, & Oliver, 1999;Odgaard, Flowers, & Bradman, 1999;Wollen & Ruggiero, 1983). Although the conscious synaesthetic experience is typically unidirectional (digits evoke colors but not vice versa), there is evidence that the link between the two can result in subtle bidirectional effects (Brugger, Knoch, Mohr, & Gianotti, 2004;Cohen Kadosh et al., 2005;Knoch, Gianotti, Mohr, & Brugger, 2005). ...
Article
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For digit-color synaesthetes, digits elicit vivid experiences of color that are highly consistent for each individual. The conscious experience of synaesthesia is typically unidirectional: Digits evoke colors but not vice versa. There is an ongoing debate about whether synaesthetes have a memory advantage over non-synaesthetes. One key question in this debate is whether synaesthetes have a general superiority or whether any benefit is specific to a certain type of material. Here, we focus on immediate serial recall and ask digit-color synaesthetes and controls to memorize digit and color sequences. We developed a sensitive staircase method manipulating presentation duration to measure participants' serial recall of both overlearned and novel sequences. Our results show that synaesthetes can activate digit information to enhance serial memory for color sequences. When color sequences corresponded to ascending or descending digit sequences, synaesthetes encoded these sequences at a faster rate than their non-synaesthetes counterparts and faster than non-structured color sequences. However, encoding color sequences is approximately 200 ms slower than encoding digit sequences directly, independent of group and condition, which shows that the translation process is time consuming. These results suggest memory advantages in synaesthesia require a modified dual-coding account, in which secondary (synaesthetically linked) information is useful only if it is more memorable than the primary information to be recalled. Our study further shows that duration thresholds are a sensitive method to measure subtle differences in serial recall performance. (PsycINFO Database Record
... Most synaesthetes report to perceive synaesthesia for 'as long as they can remember' (Cytowic 2002). Its main characteristics are consistency (Baron-Cohen et al. 1987;Simner and Logie 2007) and automaticity (Mills et al. 1999). Consistency is actually used as a 'gold standard' in order to determine whether someone is a synaesthete or not (Baron-Cohen et al. 1987;Eagleman et al. 2007). ...
Article
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Neurobiological aspects of synaesthesia are discussed from the perspective of the broader philosophical topic of “syn-aisthesis” and the basic fundamentals of a neuropsychological understanding of perceptual inter-modal integration. Herein, the predominance of conceptualization processes in regard to top-down functions of the brain appears as a prerequisite for perception. Functional Magnet Resonance Imaging (fMRI) data of synaesthetes compared to controls are discussed, providing evidence for the theory that prefrontal and parietal conceptualization processes by themselves exert transmodal functions and thus contain properties of “binding”. A partial hyperactivity of such processes in synaesthesia may thus be a causal factor of this condition.
... The accepted wisdom in research for many years was that synesthesia is an asymmetric phenomenon, and that, for example, in grapheme-color synesthesia, a grapheme will trigger the experience of color, but not vice versa (Mills 1999). Yet, growing evidence that has accumulated during the past decade indicates that synesthesia may be bidirectional, and that mutual influence may exist between the inducer and the concurrent (Brugger et al. 2004;Cohen Kadosh and Henik 2013;Cohen Kadosh et al. 2005;Gebuis, Nijboer, andVan der Smagt 2009a, 2009b;Gevers et al. 2010;Johnson, Jepma, and De Jong 2007;Knoch et al. 2005;McCarthy et al. 2013;Richer, Beaufils, and Poirier 2011;Weiss, Kalckert, and Fink 2009). ...
Article
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Most studies of synesthesia have documented its unidirectional nature. For example, in grapheme-color synesthesia, a digit (e.g., 5) triggers a color (e.g., yellow) but not vice versa. This has led many to believe synesthesia is unidirectional. However, research has provided evidence that synesthesia might be bidirectional. Similarly, discussions of metaphors have suggested that metaphors are unidirectional and, in particular, move from the concrete to the abstract dimensions. For example, the smell of fish might induce suspicion ("Something smells fishy"). However, research has suggested that metaphors might work in the other direction also, namely, from abstract to concrete. For example, induction of suspicion leads to improved detection of the smell of fish than of other odors. Are these similarities between synesthesia and metaphors just superficial or do they tell us something about our cognitive mechanisms? The present paper reviews research on directionality in synesthesia and metaphors and attempts to propose some future research directions in order to answer this question.
... If the letter R is synaesthetically experienced as orange, synaesthetes will be slower in naming the ink's colour when the letter is printed in blue than when it is printed in orange (e.g. Mills et al, 1999). These results underscore what we have already suggested: the concurrent and the experienced inducer are two aspects of the same experience, intricately connected and difficult to disentangle when asked to attend selectively to one of them. ...
Chapter
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Synaesthetes experience additional sensory features (concurrents) when presented with certain objects such as letters (inducers). Because synaesthetic experiences are involuntary, vivid, and systematic, scientists assimilate them with perceptual experiences—an assimilation which turns out to be difficult to reconcile with the dominant philosophical theories of perception. However, this chapter stresses that the philosophical difficulties dissolve once certain questionable assumptions are corrected. First, synaesthesia is a very varied condition, perhaps not even unified, and only rare cases might count as being similar enough to perceptual experiences. Second, synaesthetic experiences should not be analysed as a conjunction of two distinct phenomena: one for the inducer, enjoyed by synaesthetes and non-synaesthetes alike, and one for the concurrent, enjoyed only by synaesthetes. This chapter proposes an alternative account, whereby synaesthetic experiences are better captured as richer, unified experiences, where an additional sensory attribute gets hosted in the perceptual experience of the inducer. This novel account leads us to reconsider the philosophical challenges raised by synaesthesia.
... Potentially subconscious processes in synesthesia have been explored using a Stroop technique (Mills, Boteler & Oliver, 1999). As with the IAT discussed earlier (Greenwald et al., 1998), discrimination analysis could give more precise information at the start, in less time for the participant and the investigator. ...
Working Paper
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[This is a re-revised version (4) in 2010 of the Working Paper originally circulated to colleagues in 2009. The date 2013 given on Research Gate was when that MS was copyrighted for mounting online.] *Abstract* This paper presents the simplest known theory of processes involved in a person’s unconscious and conscious achievements such as intending, perceiving, reacting and thinking. The basic principle is that an individual has mental states which possess quantitative causal powers and are susceptible to influences from other mental states. Mental performance discriminates the present level of a situational feature from its level in an individually acquired, multiple featured norm. The effect on output of a moderate disparity between input and norm is scaled in a universal unit of discrimination (Weber’s fraction), with the norm’s level being zero. When one process converts separate sources of input into an output, their discriminative distances from norm are summated. Distinct processes converging on an output combine their discriminations from norm orthogonally. An output may be influenced by other outputs as well as by inputs. Descriptive performance is the influence of one category of input on a verbal output. Reasoning is minimally the effect of one verbal process on another. In deeper mental processing, the influence on a response comes from a concept modulating a description: this process gives the meaning to an emotion or a motive. Descriptive modulation of stimulation corresponds to a bodily sensation or other conceptualized percept. When an output is explained solely by sources of input, that response to the stimulation may be mediated unconsciously. Development of a person within physical and communal environments embodies such mental causation within material causation and acculturates that mind to social causation.
... Potentially subconscious processes in synesthesia have been explored using a Stroop technique (Mills, Boteler & Oliver, 1999). As with the IAT discussed earlier (Greenwald et al., 1998), discrimination analysis could give more precise information at the start, in less time for the participant and the investigator. ...
Working Paper
Full-text available
Abstract (for the combined three Parts of version 5). This paper presents the simplest known theory of processes involved in a person’s unconscious and conscious achievements such as intending, perceiving, reacting and thinking. The basic principle is that an individual has mental states which possess quantitative causal powers and are susceptible to influences from other mental states. Mental performance discriminates the present level of a situational feature from its level in an individually acquired, multiple featured norm (exemplar, template, standard). The effect on output of a moderate disparity between input and norm is scaled in a universal unit of discrimination (Weber’s fraction), with the norm’s level being zero. When one process converts separate sources of input into an output, their discriminative distances from norm are summated. Distinct processes converging on an output combine their discriminations from norm orthogonally. An output may be influenced by the constructs of other outputs as well as by inputs. Descriptive performance is the influence of one category of input on a verbal output. Reasoning is minimally the effect of one verbal process on another. In deeper mental processing, the influence on a response comes from a response construct modulating a description: this process gives the meaning to an emotion or a motive. Descriptive modulation of stimulation corresponds to a bodily sensation or other conceptualized percept. When an output is explained solely by sources of input, that response to the stimulation may be mediated unconsciously. Development of a person within physical and communal environments embodies such mental causation within material causation and acculturates that mind to social causation.
... És a dir, per exemple, per a un sinestèsic pel qui la lletra A és vermella, tant se si li presenta la A vermella (condició congruent) com si se li presenta la A verda (condició incongruent), ha de donar la resposta de vermell. Varis estudis (Wollen i Ruggiero, 1983;Mills, Boteler i Oliver, 1999;Odgaard, Flowers i Bradman, 1999;Dixon, Smilek, Cudahy i Merikle, 2000;Mattingley, Rich, Yelland i Bradshaw, 2001;Dixon, Smilek i Merikle, 2004;Ward, Li, Salih i Sagiv, 2007) han demostrat que els sinestèsics són considerablement més lents en la condició incongruent que en la congruent per la interferència que suposa l'associació involuntària sinestèsica (efecte Stroop sinestèsic), i per això s'ha suggerit que aquest test podria ser usat com a eina de diagnòstic de la condició. ...
Thesis
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Synaesthesia is a sensory neurological condition characterised by the fact that the attribute of a stimulus triggers inevitably the conscious experience of an additional attribute (e. g., the letter A is seen as red). Several investigations have observed that non-synaesthetes trained in synaesthetic associations can mimic the results obtained by synaesthetes behaviourally (Synaesthetic Stroop test), but not physiologically (skin conductance response –SCR– synaesthetic conditioning test). The aim of the present study is to corroborate the validity of the SCR synaesthetic conditioning test as a physiological measure to evaluate synaesthesia. In order to do so, 10 non-synaesthetes (experimental group) performed an intensive synaesthetic association training (letters->colours) of 60-70 minutes and were evaluated with the previously mentioned tests, and 9 additional non-synaesthetes (control group) undertook only the evaluation tests. The results obtained indicate that only the experimental subjects, who performed the training, showed a synaesthetic Stroop effect. However, both the experimental and the control subjects did not show a SCR synaesthetic conditioning effect. Hence, the present data provide new evidence which suggests that the SCR synaesthetic conditioning test could be a valid physiologic measure to evaluate synaesthesia.
... In such tasks observers are presented with a grapheme, which is colored either congruently or incongruently with regard to their synesthetic experience, and they name the color of each grapheme as quickly as possible (e.g. [21][22][23][24][25]). Usually, synesthetes are quicker at naming congruently colored graphemes, demonstrating the automaticity of synesthesia, and that it influences cognition even when it is task-irrelevant and harmful to performance. ...
Article
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Grapheme-color synesthesia is a condition where the perception of graphemes consistently and automatically evokes an experience of non-physical color. Many have studied how synesthesia affects the processing of achromatic graphemes, but less is known about the synesthetic processing of physically colored graphemes. Here, we investigated how the visual processing of colored letters is affected by the congruence or incongruence of synesthetic grapheme-color associations. We briefly presented graphemes (10–150 ms) to 9 grapheme-color synesthetes and to 9 control observers. Their task was to report as many letters (targets) as possible, while ignoring digit (distractors). Graphemes were either congruently or incongruently colored with the synesthetes' reported grapheme-color association. A mathematical model, based on Bundesen's (1990) Theory of Visual Attention (TVA), was fitted to each observer's data, allowing us to estimate discrete components of visual attention. The models suggested that the synesthetes processed congruent letters faster than incongruent ones, and that they were able to retain more congruent letters in visual short-term memory, while the control group's model parameters were not significantly affected by congruence. The increase in processing speed, when synesthetes process congruent letters, suggests that synesthesia affects the processing of letters at a perceptual level. To account for the benefit in processing speed, we propose that synes-thetic associations become integrated into the categories of graphemes, and that letter colors are considered as evidence for making certain perceptual categorizations in the visual system. We also propose that enhanced visual short-term memory capacity for congruently colored graphemes can be explained by the synesthetes' expertise regarding their specific grapheme-color associations.
... The synesthetic color provides a marker identifying particular numbers or objects that are invisible to people without this special perception, who are unable to distinguish discrete numbers within the masking array. In addition, researchers such as Mills, Boteler, and Oliver (1999) are designing tests to determine that synesthete reports are accurate over time. ...
... We administered the synesthetic congruency task to ensure that all synesthetes tested had robust involuntary responses in the primary direction (digit to color) providing a basis for potential reverse, bidirectional effects (color to digit). Previous studies have demonstrated that synesthetes are slower to name the display color of a letter or digit when this color is incongruent with the synesthetic color than when the two colors match (Dixon, Smilek, & Merikle, 2004;Mattingley, Payne, & Rich, 2006;Mattingley et al., 2001;Mills et al., 1999;Rich & Karstoft, 2013;Wollen & Ruggiero, 1983). Each of six digits were presented either in the color that matched the synesthetic color of each digit (previously matched by the synesthetes; congruent condition) or in one of the other colors (a single incongruent color for each digit; incongruent condition). ...
Article
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Digit-colour synaesthetes report experiencing colours when perceiving letters and digits. The conscious experience is typically unidirectional (e.g., digits elicit colours but not vice versa) but recent evidence shows subtle bidirectional effects. We examined whether short-term memory for colours could be affected by the order of presentation reflecting more or less structure in the associated digits. We presented a stream of coloured squares and asked participants to report the colours in order. The colours matched each synaesthete’s colours for digits 1-9 and the order of the colours corresponded either to a sequence of numbers (e.g., [red, green, blue] if 1=red, 2=green, 3=blue) or no systematic sequence. The results showed that synaesthetes recalled sequential colour sequences more accurately than pseudo-randomised colours, whereas no such effect was found for the non-synaesthetic controls. Synaesthetes did not differ from non-synaesthetic controls in recall of colour sequences overall, providing no evidence of a general advantage in memory for serial recall of colours.
... When tested immediately, C showed significantly better performance than the control group on both the black and congruent matrices however, her recall for the incongruent matrix was below average. This demonstrates how stimuli incongruent with synaesthesia can disrupt memory because the synaesthetic percept cannot be ignored and interferes (Mills, Boteler, & Oliver, 1999;Odgaard, Flowers, & Bradman, 1999) and also that memory may only be enhanced for stimuli which elicits a synaesthetic response. ...
Article
The multi-modal sensory integration that is the experience of synaesthesia has often been affiliated with extraordinary abilities in memory as reflected by Luria's reports of subject "S", Russian mnemonist, Solomon V. Shereshevskii, who had all five senses integrated. This literature review aimed to assess the present evidence of a link between synaesthesia and memory. A wide range of literature was explored, including neuroanatomical evidence, case studies, group studies, and a possible theoretical explanation. In conclusion, the literature indicates a clear link between synaesthesia and greater memory performance, however this link is not as significant as suggested by case studies such as Luria's subject S and appears to be limited within the domain or domains of the specific synaesthetic experience of each synaesthete. Whether memory is improved at encoding, storage or retrieval is discussed as well as a cue-induced theory of synaesthesia and memory. Findings suggest greater memory performance may be due to differences in neuroanatomical structure and/or the synaesthetic experience providing additional cues to memory.
... This resulted in a quick transfer of the original synesthetic color experiences from their native Latin alphabet to Glagolitic graphemes never seen before the experiment (Mroczko et al., 2009). Also, Stroop-type tests (Stroop, 1935;Mills et al., 1999;Nikolić et al., 2007) indicated that these new synesthetic associations were immediate and involuntary. ...
Article
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Currently, little is known about how synesthesia develops and which aspects of synesthesia can be acquired through a learning process. We review the increasing evidence for the role of semantic representations in the induction of synesthesia, and argue for the thesis that synesthetic abilities are developed and modified by semantic mechanisms. That is, in certain people semantic mechanisms associate concepts with perception-like experiences—and this association occurs in an extraordinary way. This phenomenon can be referred to as “higher” synesthesia or ideasthesia. The present analysis suggests that synesthesia develops during childhood and is being enriched further throughout the synesthetes’ lifetime; for example, the already existing concurrents may be adopted by novel inducers or new concurrents may be formed. For a deeper understanding of the origin and nature of synesthesia we propose to focus future research on two aspects: (i) the similarities between synesthesia and ordinary phenomenal experiences based on concepts; and (ii) the tight entanglement of perception, cognition and the conceptualization of the world. Importantly, an explanation of how biological systems get to generate experiences, synesthetic or not, may have to involve an explanation of how semantic networks are formed in general and what their role is in the ability to be aware of the surrounding world.
... The synaesthetic Stroop test involves the presentation of colored graphemes that are either congruent or incongruent to the grapheme-color association of a particular synaesthete and the participant is required to name the color of the grapheme as quickly as possible. This test has often been used to demonstrate the genuineness of synaesthesia, because synaesthetes show slower responses to incongruent compared to congruent colors, while non-synaesthetes do not show this effect (e.g., Mills et al., 1999;Odgaard et al., 1999;Dixon et al., 2004;Ward et al., 2007). However, it has been demonstrated that this effect can be induced through training grapheme-color associations in non-synaesthetes (Elias et al., 2003;Meier and Rothen, 2009;Rothen et al., 2013a;Rothen and Meier, 2014). ...
Article
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In synaesthesia, stimuli such as sounds, words or letters trigger experiences of colors, shapes or tastes and the consistency of these experiences is a hallmark of this condition. In this study we investigate for the first time whether there are age-related changes in the consistency of synaesthetic experiences. We tested a sample of more than 400 grapheme-color synaesthetes who have color experiences when they see letters and/or digits with a well-established test of consistency. Our results showed a decline in the number of consistent grapheme-color associations across the adult lifespan. We also assessed age-related changes in the breadth of the color spectrum. The results showed that the appearance of primary colors (i.e., red, blue, and green) was mainly age-invariant. However, there was a decline in the occurrence of lurid colors while brown and achromatic tones occurred more often as concurrents in older age. These shifts in the color spectrum suggest that synaesthesia does not simply fade, but rather undergoes more comprehensive changes. We propose that these changes are the result of a combination of both age-related perceptual and memory processing shifts.
... In this task, inducers are presented in colors that are either congruent or incongruent with their associations and the subject must name the color as quickly as possible. Response times are slower when the color is incongruent with their association (Mills et al., 1999;Dixon et al., 2000). Several training studies find a similar effect Frontiers in Human Neuroscience www.frontiersin.org ...
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Learning and synesthesia are profoundly interconnected. On the one hand, the development of synesthesia is clearly influenced by learning. Synesthetic inducers – the stimuli that evoke these unusual experiences – often involve the perception of complex properties learned in early childhood, e.g., letters, musical notes, numbers, months of the year, and even swimming strokes. Further, recent research has shown that the associations individual synesthetes make with these learned inducers are not arbitrary, but are strongly influenced by the structure of the learned domain. For instance, the synesthetic colors of letters are partially determined by letter frequency and the relative positions of letters in the alphabet. On the other hand, there is also a small, but growing, body of literature which shows that synesthesia can influence or be helpful in learning. For instance, synesthetes appear to be able to use their unusual experiences as mnemonic devices and can even exploit them while learning novel abstract categories. Here we review these two directions of influence and argue that they are interconnected. We propose that synesthesia arises, at least in part, because of the cognitive demands of learning in childhood, and that it is used to aid perception and understanding of a variety of learned categories. Our thesis is that the structural similarities between synesthetic triggering stimuli and synesthetic experiences are the remnants, the fossilized traces, of past learning challenges for which synsethesia was helpful.
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In Nyāya philosophy, a special kind of extraordinary sensory connection is admitted named jñānalakṣaṇā pratyāsatti or jñānalakṣaṇa sannikarṣa. It is held that sometimes our sense-organ can be connected to such an object which is not amenable to the operating sense-organ. In such cases, cognition (jñāna) plays the role of sensory connection and connects the content of itself to the operating sense-organ. The paradigmatic example of jñānalakṣaṇa perception is to ‘see’ fragrant sandal through visual sense from non-smellable distance. This hypothesis of jñānalakṣaṇa has been criticized by the opponents being considered as counterintuitive, mysterious and theoretically overloaded. This paper tries to demystify the notion. It shows that although it seems to be metaphysically mysterious phenomenon at first sight, it is not so at all. The paper explores the psychological process involved in this sensory connection. The hypothesis is shown to have sufficient explanatory power, because the Naiyāyikas have used this hypothesis to explain five different epistemic situations. Hence, this paper argues that it is not a theoretical overload. The opponents counter-argue that all those five cognitive situations can be explained without admitting jñānalakṣaṇa. Moreover, if we admit jñānalakṣaṇa, then a particular kind of inference will become redundant. The paper answers all those objections and defends the hypothesis. The second part of the paper presents an empirical evidence in support of the hypothesis. The arguments leveled against the hypothesis of jñānalakṣaṇa can be contested on the ground that they try to disprove something which is supported on experimental ground. Experiments represent universally acceptable objective facts supported by experience—denying which amounts to anubhavavirodha, which philosophers would want to avoid. Hence, supporting jñānalakṣaṇa on the ground of scientific experiments can be considered as a philosophical stand. Now, there is a clinically recognized and neurophysiologically proved condition, called synaesthesia, where stimulation of a particular sensory modality automatically and involuntarily activates a different sensory modality simultaneously without a direct stimulation of the second modality. As for example, when a sound → colour synaesthete listens to a particular tone such as C-sharp, she visualizes particular colour, such as blue, in her mind’s eye; for a grapheme → colour synaesthete a particular number or alphabet is always tinged with a particular colour. This paper shows that the cognitive process involved in synaesthesia lends support to the hypothesis of jñānalakṣaṇa pratyāsatti. It has been proved through several experiments that it is a genuine perceptual phenomenon and is not a confabulation of memory. There are several alternative theories which explain the phenomenon neurophysiologically. The paper discusses the most popular one: the cross-activation hypothesis. There are two major objections against the project of comparing jñānalakṣaṇa with synaesthesia. First, synaesthesia is a neurological condition present in a few numbers of people whereas jñānalakṣaṇa is claimed to be universal phenomenon. Second, syneasthesia is a sensory experience whereas jñānalakṣaṇa involves application of concepts. The paper answers these questions. Firstly, multimodal processing in the brain is a universal phenomenon; secondly, there is a form of synaesthesia where top-down processing is involved. In those cases, concepts play important role for having synaesthetic experience.
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The current article provides an overview of the state of research into synesthesia, a rare developmental condition that involves the consistent, conscious and automatic experience of a stimulus quality that is not present in the physical stimulus eliciting this experience. First, the definitional criteria and the phenomenological quality are addressed, in particular the plethora of different types which vary according to the kind of inducing stimulus (i.e., the inducer) and the kind of induced experience (i.e., the concurrent). As many forms of synesthesia involve cultural artifacts as inducers, the emergence of stable inducer-concurrent associations may not occur before school age. Most knowledge has been collected from grapheme-color synesthesia, which involves the experience of colors in response to letters or numbers. Research on the developmental trajectory of grapheme-color synesthesia indicates a steady increase in the number and consistency of the synesthetic inducer. On a neural level, synesthesia co-occurs with hyper-connectivity in the brain. The relevant theories for the formation of the condition are introduced. Moreover, the occurrence of associations with a particular cognitive and personality profile is highlighted, specifically enhanced memory function and higher propensity of engagement in art. I also review synesthesia's relationship to other clinical and neurological variations of experience such as absolute pitch, autism spectrum disorder, and schizophrenia. Finally, the article addresses the question whether synesthesia can be acquired by non-synesthetes. Overall, synesthesia can be considered as a non-pathological individual difference property, a congenital variation of experience, based on higher connectivity between brain areas.
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Grapheme-color synesthesia is a perceptual phenomenon that occurs when letters or numbers elicit an abnormal color sensation (e.g., printed black letters are perceived as colored graphemes). Grapheme-color synesthesia is typically reported following explicit presentation of graphemes. Very few studies have investigated color sensations in synesthesia in the absence of visual awareness. To address this issue, we took advantage of the dichoptic flash suppression paradigm to temporarily render a stimulus presented to one eye invisible. Synesthesic alphanumeric and non-synesthetic abstract stimuli were presented to 11 synesthete and 11 matched control participants in achromatic and chromatic experimental conditions. The test stimulus was first displayed to one eye and then masked following the sudden presentation of visual noise in the other eye. The time for an image to be perceived following the onset of the suppressive noise was calculated in each condition. Trials free of flash suppression but mimicking the perceptual suppression of the flash were also tested. Results showed that target detection by synesthetes was significantly better than by controls in the absence of flash suppression. However, no statistically significant difference was found between the groups when the test stimulus was interocularly suppressed, either for synesthetic or non-synesthetic stimuli. This study suggests that synesthesia can be associated with enhanced perception for overt recognition, but does not occur in the absence of visual awareness.
Article
This study investigates the bi-directionality of synaestesic experience by means of a flanked bisection paradigm in TT, a number-colour synaesthete. Previous studies have shown that bisection is shifted towards the larger digit flanker (e.g., Ranzini & Girelli, 2012). TT and controls performed line bisections with lines flanked by black digits (experiment 1), by TT’s photism colours (experiment 2), and by congruently (experiment 3), or incongruently coloured digits (experiment 4). While the results of the control group mainly replicated previous findings, only the colour-digit congruence elicited in TT the larger-digit bias. TT’s absence of effects in the other conditions was not due to reduced sensitivity to luminance effects (experiment 5), or to mathematical expertise (experiment 6). We suggest that grapheme-colour synaesthesia might be characterised by a rigid access to semantic representation when the inducer is task-irrelevant.
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Automaticity is a defining characteristic of synaesthesia. Here, we assess for automaticity in stimulus-parity synaesthesia; a subtype that has been documented only 3 times in the literature. Synaesthete R experiences many (nonnumerical) stimuli as being odd or even. She described a toy shape-sorter, which paired odd shapes with even colour slots (and vice versa) and relayed difficulties with the incongruency created by this simple toy. Inspired by this anecdote, we devised a computerised task in which Synaesthete R (and 10 control participants) indicated the location of a target shape, which was presented on a coloured bar. Synaesthete R (but not control participants) was faster to report the location of target shapes presented on colours of congruent synaesthetic parity, relative to target shapes presented on colours of incongruent synaesthetic parity. These results constitute the first objective demonstration as to the automatic nature of associations in stimulus-parity synaesthesia.
Article
Grapheme-colour synaesthesia is a phenomenon in which ordinary black numbers and letters (graphemes) trigger the experience of highly specific colours (photisms). The Synaesthetic Stroop task has been used to demonstrate that graphemes trigger photisms automatically. In the standard Stroop task, congruent trial probability (CTP) has been manipulated to isolate effects of automaticity from higher-order strategic effects, with larger Stroop effects at high CTP attributed to participants strategically attending to the stimulus word to facilitate responding, and smaller Stroop effects at low CTP reflecting automatic word processing. Here we apply this logic for the first time to the Synaesthetic Stroop task. At high CTP we showed larger Stroop effects due to synaesthetes using their synaesthetic colours strategically. At low CTP Stroop effects were reduced but were still significant. We directly isolate automatic processing of graphemes from strategic effects and conclusively show that, in synaesthesia, viewing black graphemes automatically triggers colour experiences.
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This study investigates the origins of specific letter-colour associations experienced by people with grapheme-colour synaesthesia. We present novel evidence that frequently observed trends in synaesthesia (e.g., A is typically red) can be tied to orthographic associations between letters and words (e.g., 'A is for apple'), which are typically formed during literacy acquisition. In our experiments, we first tested members of the general population to show that certain words are consistently associated with letters of the alphabet (e.g., A is for apple), which we named index words. Sampling from the same population, we then elicited the typical colour associations of these index words (e.g., apples are red) and used the letter → index word → colour connections to predict which colours and letters would be paired together based on these orthographic-semantic influences. We then looked at direct letter-colour associations (e.g., A→ red, B→ blue⋯) from both synaesthetes and non-synaesthetes. In both populations, we show statistically that the colour predicted by index words matches significantly with the letter-colour mappings: that is, A→ red because A is for apple and apples are prototypically red. We therefore conclude that letter-colour associations in both synaesthetes and non-synaesthetes are tied to early-learned letter-word associations.
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The phenomenon of synesthesia has undergone an invigorationof research interest and empirical progress over the past decade. Studies investigating the cognitive mechanisms underlying the condition have yielded insight into neural processes behind such cognitive operations as attention, memory, spatial phenomenologyand cross-modal processes. However, the structural and functional mechanisms underlying synesthesia still remain contentiousand hypothetical. In this chapter, BeritBrogaard, Kristian Marlow, and Kevin Rice critically review recent research on grapheme-color synesthesia, one of the most common forms of the condition, and address the ongoingdebate concerning the role of selective attention in eliciting synesthetic experience.
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In the article the concept of synaesthesia as a perceptional phenomenon is introduced. The first part describes the basic manifestations and specifics of synaesthesia (automaticity, permanency, idiosyncrasy). The second part pursues the question of emergence of synaesthesia and related theories of the human perception development (neonatal synaesthesia, crossmodal-transfer, interactive specialization approach). In the third part the so-called linguistic synesthesias, i.e. synesthesias where the linguistic units act as inducers, are examined and it is shown how the research on synaesthesia can relate to the (psycho)lin-guistic research. In the last part the upcoming Canadian-Czech research project and its main hypotheses are introduced.
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Synaesthetes' descriptions of experiences of coloured sounds are troubling for typical perceivers. Their phenomenological reports tend to be diverse and rather confusing, and they do not bring much clarity regarding the precise nature of these experiences. A way around this confusion is to analyze the experience of coloured sounds as the conjunction of two sensory contents experienced in isolation by typical perceivers, that is, as the conjunction of a typical auditory experience and of an additional colour experience. This analysis is perhaps the most attractive and frequent, in philosophy and in cognitive neuroscience, but isit the best way to capture the condition? Here I consider an alternative account which makes more sense of both the synaesthetic reports and the empirical evidence, and opens new ways to look at the perceptual status of synaesthetic experiences. In this new account, synaesthesia cover cases where individuals enjoy a single, richer experience than typical perceivers:their experience of a sound is for instance enriched by a colour dimension. The fact that this account makes such experiences hard for us to imagine should not be taken as an objection, and might even be highlighting the atypical character of synaesthetic experiences.
Article
Synaesthesia is a neurological phenomenon that often involves crossmodal or crossdimensional perceptions which are not related to environmental stimuli. Stimulation of one sense, such as hearing, triggers the normal perception of a specific sound, but also an additional perception, often in another sense, such as a specific colour. This chapter summarizes the evidence suggesting that synaesthesia is a remnant of a normal developmental process involving an initial proliferation of synaptic connections, including connections linking cortical areas that will later become specialized for unisensory processing. An argument is put forward that crossmodal and cross-dimensional associations commonly manifested in synaesthetic adults provide clues about cortical connections in early childhood that may influence perception in the typical nonsynaesthetic child. Behavioural evidence from children is provided to support this point of view. This chapter also argues that remnants of the original connections are present even in non-synaesthetic adults, in whom their influence is manifested not in conscious perception, but in implicit crossmodal associations in perception.
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Mechanisms of selective attention exert a powerful influence on visual perception. We examined whether attentional selection is necessary for generation of the vivid colours experienced by individuals with grapheme-colour synaesthesia. Twelve synaesthetes and matched controls viewed rapid serial displays of nonsense characters within which were embedded an oriented grating (T1) and a letter-prime (T2), forming a modified attentional blink (AB) task. At the end of the stream a coloured probe appeared that was either congruent or incongruent with the synaesthetic colour elicited by the letter-prime. When the prime was attended, synaesthetes showed a reliable effect of prime-probe congruency. In contrast, when the prime appeared at 350 ms following T1 (during the AB), the congru-ency effect was eliminated. Our findings suggest that focused attention is crucial for inducing letters to elicit colours in synaesthesia.
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The concept of aesthetic experience has often been regarded as an elusive one. A defence of the concept is attempted via an examination of the phenomenal features of the synaesthetic experience of colour. Some of the affinities between the two types of experience are explored.
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( This reprinted article originally appeared in the Journal of Experimental Psychology, 1935, Vol 18, 643–662. The following abstract of the original article appeared in PA, Vol 10:1863.) In this study pairs of conflicting stimuli, both being inherent aspects of the same symbols, were presented simultaneously (a name of one color printed in the ink of another color—a word stimulus and a color stimulus). The difference in time for reading the words printed in colors and the same words printed in black is the measure of the interference of color stimuli on reading words. The difference in the time for naming the colors in which the words are printed and the same colors printed in squares is the measure of the interference of conflicting word stimuli on naming colors. The interference of conflicting color stimuli on the time for reading 100 words (each word naming a color unlike the ink-color of its print) caused an increase of 2.3 sec or 5.6% over the normal time for reading the same words printed in black. This increase is not reliable, but the interference of conflicting word stimuli on the time for naming 100 colors (each color being the print of a word which names another color) caused an increase of 47.0 sec or 74.3% of the normal time for naming colors printed in squares.… (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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A large body of research suggests that there is independent representation of the 2 languages of a bilingual at the lexical level, with common representation of a word and its translation at the semantic level. If information from lexical and semantic memory may be retrieved independently, then between-language priming of translations, as assessed with word-fragment completion, should occur only when semantic information is recruited at test. This research provides evidence that the retrieval of semantic information at test is dependent on initial study condition. Sentence processing at study leads to semantic involvement at test, and hence to between-language priming. In contrast, after the study of random-word lists, only lexical information is recruited at test, resulting in within-language priming but no between-language priming. The results are discussed in relation to bilingual representation and the retrieval processes involved in word-fragment completion. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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Reviews colored-hearing synesthesia, in which sounds induce visual images (photisms). Colored hearing manifests correlations between dimensions of auditory and visual experience. Two general findings are that (a) the brightness of photisms varies with the brightness (density) of the inducing sounds and (b) the size of photisms varies with the size (volume) of the inducing sounds. In colored hearing produced by speech sounds, the induced hues and brightnesses can be related to the formant structures of the vowels. Synesthetes align dimensions on different modalities in ways that are qualitatively similar to the ways that nonsynesthetes align them (e.g., in phonetic symbolism). Synesthesia appears to be a cross-modal manifestation of connotative meaning in a pure sensory form; its inflexibility (compared to language) makes synesthesia less significant in adulthood than in childhood. (31/2 p ref)
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The literature on interference in the Stroop Color–Word Task, covering over 50 years and some 400 studies, is organized and reviewed. In so doing, a set of 18 reliable empirical findings is isolated that must be captured by any successful theory of the Stroop effect. Existing theoretical positions are summarized and evaluated in view of this critical evidence and the 2 major candidate theories—relative speed of processing and automaticity of reading—are found to be wanting. It is concluded that recent theories placing the explanatory weight on parallel processing of the irrelevant and the relevant dimensions are likely to be more successful than are earlier theories attempting to locate a single bottleneck in attention.
Chapter
This chapter discusses sensory processes. In these many forms, the unity of the senses reflects fundamental facts of phylogenetic and ontogenetic development. It is commonly believed that all of the senses trace their evolutionary history back to a single primitive sense, a simple undifferentiated responsiveness to external stimulation. It is not difficult to imagine some early form of life, a relatively simple agglutination of cells that wriggled or withdrew when bombarded with virtually any sharp stimulus whether mechanical, radiant, or chemical. The evolution of a visual system out of an undifferentiated sensitivity took one of its most important early steps with the development of special light-sensitive pigments. It has been hypothesized that the senses of hearing and vision, both evolved from an earlier touch sense. That there is currently a close kinship between hearing and the modern touch sense is clear. Both modalities are excited by mechanical energy, that is, by changes in patterns of pressure at the receptors, and both show phenomenological as well as psychophysical similarities.
Article
Synaesthesia is a condition in which a mixing of the senses occurs; for example, sounds trigger the experience of colour. Previous reports suggest this may be familial, but no systematic studies exist. In addition, there are no reliable prevalence or sex-ratio figures for the condition, which is essential for establishing if the reported sex ratio (female bias) is reliable, and if this implicates a sex-linked genetic mechanism. Two independent population studies were conducted in the city of Cambridge, England (studies 1 and 2 here), as necessary background to the family genetic study of synaesthesia (study 3). Studies 1 and 2 arrived at an almost identical prevalence rate for synaesthesia: approximately 1 case in 2000. The sex ratio found was 6:1 (female:male). A third of cases also reported familial aggregation. In study 3 six families were examined, and first-degree relatives were tested for genuineness of the condition. All six families were indeed multiplex for synaesthesia. Alternative modes of inheritance are discussed.
Article
Discusses the history of and testing issues in synaesthesia. Distinctions are drawn between developmental synaesthesia, synasesthesia caused by neurological dysfunction, synaesthesia as the consequence of psychoactive drug use, metaphor as pseudosynaesthesia, and association as pseudosynaesthesia. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Two experiments compared the effects of verbal—nonverbal and bilingual dual coding on recall. Experiment 1 required French—English bilinguals to code a mixed list of pictures, French words, and English words by writing the English names of the pictures, translating the French words, and copying the English words. The participants were then asked unexpectedly to recall the generated English words. Experiment 2 reversed the coding task in that bilinguals were presented only English words along with coding cues that prompted them to sketch the refrents of one-third of the items, translate another third into French, and copy a third. The incidental memory test in this case required the participants to free recall the English words they had been presented. Both experiments showed that item recall increased significantly from unilingual to bilingual to verbal—nonverbal dual coding. The results favored a bilingual version of dual-coding theory over levels-of-processing and generation-effort interpretations.
Article
A case of 'chromatic-lexical' (colour-word) synaesthesia is described, and its genuineness confirmed using the criterion of stable cross-modality imagery across time. The synaesthesia could not be accounted for by a memory hypothesis, nor was it associated with any psychiatric condition. Further analysis did not identify any semantic relationship between real words and colours, but the colours of nonwords were determined by the colours of the individual letters. Numbers also had their own stable colours. The experience of synaesthesia was triggered by other auditory stimuli, but most strongly by words. Cortical electrophysiological recording failed to reveal any abnormalities. An unusual organisation of modalities in the brain is postulated to account for the phenomenon.
Article
A pure auditory tone has a range of multimodal qualities that are determined by its pitch. A reaction-time task was used to demonstrate that subjects respond immediately and automatically to these qualities. Subjects were required to press one of two keys depending on which word, from a limited set, appeared on a microcomputer screen. The words were antonyms that represented multimodal stimulus qualities, and they were assigned to alternative responses so that the two words that shared the same response were correlated in the same way with pitch. As an incidental stimulus, either a 50 Hz tone or a 5500 Hz tone accompanied the presentation of each word. Subjects were found to respond more slowly when the multimodal qualities of the tone were incongruent with the qualities represented by the test word. When the stimulus-response mapping rules were changed, however, the Stroop effect did not occur; suggesting that a polarised semantic code of the incidental tone, that embraces its multimodal features, accesses the same semantic register as the equivalent code for the test word itself.
Article
In a preliminary experiment subjects were asked to explore three wooden knobs of different sizes and to rate each one on a series of 7-point scales. The results confirmed that an object may possess a number of multimodal qualities that are contingent on its haptic size. The pattern of intercorrelations between the qualities was consistent with the pattern that is observed when subjects respond to pure auditory tones varying in pitch. For example, small (high-pitched) sounds, like small objects, are judged to be sharp, thin, light, weak, fast, tense, and bright. The main experiments used a paradigm based on the Stroop interference effect. Subjects were required to press one of two keys as quickly as possible depending on which of four possible words appeared in the centre of the screen. A 50 Hz or a 5500 Hz tone accompanied each test word, and subjects responded on two keys that differed in size. Subjects were found to respond more slowly when either the pitch of the incidental sound or the size of the key on which they responded was incongruent with the multimodal features represented by the test word. The results confirm that people are automatically and immediately sensitive to the multimodal features of a stimulus when direct sensory evidence for the features is absent.
Article
The equivalence of perceptual experience across the sensory modalities, most vividly observed in synaesthetes, is rarely discussed in contemporary cognitive psychology. It is suggested, however, that the concepts and paradigms of human information processing are ideally suited to test, for example, the fundamental assumption that the synaesthetic qualities of a stimulus are rapidly and automatically encoded. In a preliminary experiment subjects were asked to rate each of four auditory tones on a series of 7-point scales defined by pairs of antonyms. The results confirmed that a pure auditory tone has a range of qualities, determined by its pitch, that are shared by stimuli in other modalities. The main experiment used a paradigm based on the Stoop interference effect. Here the 50 Hz and 5500 Hz tones served as incidental stimuli and the subjects were required to respond as quickly as possible by pressing one of two keys depending on which one of four possible words appeared in the centre of the screen. Subjects were found to respond more slowly when the qualities of the tone were incongruent with the synaesthetic qualities represented by the test word. The results confirm that synaesthetic qualities of pitch are rapidly and automatically encoded and that the products of this encoding automatically interact with the mechanisms responsible for identifying word meaning and/or with the post-identification decision processes.
Article
Evidence was reported earlier from a single case that chromatic-lexical (CL) synaesthesia was a genuine phenomenon. A study is presented in which nine subjects were tested who also reported having coloured hearing. The following questions were addressed: (a) were these cases also genuine (ie consistent over time), (b) were they truly lexical, or rather variants of this condition, such as chromatic-graphemic (CG) or chromatic-phonemic (CP) synaesthesia, (c) did the experimental subjects show any commonalities between them, and (d) were they able to give information on a standard questionnaire about the phenomenology and ontogenesis of the condition? Subjects were asked to describe the colour sensation experienced on hearing items from a list of 130 words, phrases, and letters. The experimental group were not informed of any retest, but were retested more than one year later. A control group (n = 9), matched for IQ, memory, age, and gender, were read the same list and asked to associate a colour with each list item. They were informed at the time of testing that they would be retested on a sample of items from the list a week later. 92.3% of the responses of the experimental group when retested one year later were identical to those given in the original test, compared with only 37.6% of the control subjects' responses (retested one week later). This confirmed the genuinneess of these nine cases. All nine experimental subjects showed CG synaesthesia, none showing either CL or CP synaesthesia. Among the experimental group, some consistency was found in the colours evoked by hearing specific letters, suggesting the condition has a neurological basis.(ABSTRACT TRUNCATED AT 250 WORDS)
The mind of a mnemonist (L. Solotaroff, Trans.). Cambridge, MA: Harvard Uni-versity Press Half a century of research on the Stroop Effect: An integrative review
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Luria, A.R. (1987). The mind of a mnemonist (L. Solotaroff, Trans.). Cambridge, MA: Harvard Uni-versity Press. (Original work published 1968.) MacLeod, C.M. (1991). Half a century of research on the Stroop Effect: An integrative review. Psychological Bulletin, 109, 163–203.