Chai-youn Kim - Academia.edu (original) (raw)
Papers by Chai-youn Kim
Psychonomic Bulletin & Review, Apr 1, 2007
Frontiers in Psychology
Familiarity and novelty are fundamental yet competing factors influencing aesthetic preference. H... more Familiarity and novelty are fundamental yet competing factors influencing aesthetic preference. However, whether people prefer familiar paintings or novel paintings has not been clear. Using both behavioral and eye-tracking measures, the present study aimed to investigate whether the effect of familiarity-novelty on aesthetic preference is independent or dependent on artwork properties (painting content, visual complexity) and viewer characteristics (experience in art). Participants were presented with two images of paintings, one of which was repeatedly presented but was always paired with a new painting in a randomized lateral arrangement. They were asked to indicate which of the two images they preferred with the degree of their preference. Behavioral results demonstrated an interactive influence of painting content and complexity on familiarity-novelty preference, especially alongside the distinction between representational and abstract paintings. Also, the familiarity-novelty ...
Multisensory Research, 2020
Cross-modal correspondence is the tendency to systematically map stimulus features across sensory... more Cross-modal correspondence is the tendency to systematically map stimulus features across sensory modalities. The current study explored cross-modal correspondence between speech sound and shape (Experiment 1), and whether such association can influence shape representation (Experiment 2). For the purpose of closely examining the role of the two factors — articulation and pitch — combined in speech acoustics, we generated two sets of 25 vowel stimuli — pitch-varying and pitch-constant sets. Both sets were generated by manipulating articulation — frontness and height of the tongue body’s positions — but differed in terms of whether pitch varied among the sounds within the same set. In Experiment 1, participants made a forced choice between a round and a spiky shape to indicate the shape better associated with each sound. Results showed that shape choice was modulated according to both articulation and pitch, and we therefore concluded that both factors play significant roles in sound...
Scientific Reports, 2019
Sensory information registered in one modality can influence perception associated with sensory i... more Sensory information registered in one modality can influence perception associated with sensory information registered in another modality. The current work focuses on one particularly salient form of such multisensory interaction: audio-visual motion perception. Previous studies have shown that watching visual motion and listening to auditory motion influence each other, but results from those studies are mixed with regard to the nature of the interactions promoting that influence and where within the sequence of information processing those interactions transpire. To address these issues, we investigated whether (i) concurrent audio-visual motion stimulation during an adaptation phase impacts the strength of the visual motion aftereffect (MAE) during a subsequent test phase, and (ii) whether the magnitude of that impact was dependent on the congruence between auditory and visual motion experienced during adaptation. Results show that congruent direction of audio-visual motion duri...
PloS one, 2017
Individuals possessing absolute pitch (AP) are able to identify a given musical tone or to reprod... more Individuals possessing absolute pitch (AP) are able to identify a given musical tone or to reproduce it without reference to another tone. The present study sought to learn whether this exceptional auditory ability impacts visual perception under stimulus conditions that provoke visual competition in the form of binocular rivalry. Nineteen adult participants with 3-19 years of musical training were divided into two groups according to their performance on a task involving identification of the specific note associated with hearing a given musical pitch. During test trials lasting just over half a minute, participants dichoptically viewed a scrolling musical score presented to one eye and a drifting sinusoidal grating presented to the other eye; throughout the trial they pressed buttons to track the alternations in visual awareness produced by these dissimilar monocular stimuli. On "pitch-congruent" trials, participants heard an auditory melody that was congruent in pitch w...
Frontiers in Psychology, 2017
Individuals with grapheme-color synesthesia experience idiosyncratic colors when viewing achromat... more Individuals with grapheme-color synesthesia experience idiosyncratic colors when viewing achromatic letters or digits. Despite large individual differences in grapheme-color association, synesthetes tend to associate graphemes sharing a perceptual feature with similar synesthetic colors. Sound has been suggested as one such feature. In the present study, we investigated whether graphemes of which representative phonemes have similar phonetic features tend to be associated with analogous synesthetic colors. We tested five Korean multilingual synesthetes on a color-matching task using graphemes from Korean, English, and Japanese orthography. We then compared the similarity of synesthetic colors induced by those characters sharing a phonetic feature. Results showed that graphemes associated with the same phonetic feature tend to induce synesthetic color in both within-and cross-script analyses. Moreover, this tendency was consistent for graphemes that are not transliterable into each other as well as graphemes that are. These results suggest that it is the perceptual-i.e., phonetic-properties associated with graphemes, not just conceptual associations such as transliteration, that determine synesthetic color.
Current biology : CB, Jan 28, 2017
Early visual experience sculpts neural mechanisms that regulate the balance of influence exerted ... more Early visual experience sculpts neural mechanisms that regulate the balance of influence exerted by the two eyes on cortical mechanisms underlying binocular vision [1, 2], and experience's impact on this neural balancing act continues into adulthood [3-5]. One recently described, compelling example of adult neural plasticity is the effect of patching one eye for a relatively short period of time: contrary to intuition, monocular visual deprivation actually improves the deprived eye's competitive advantage during a subsequent period of binocular rivalry [6-8], the robust form of visual competition prompted by dissimilar stimulation of the two eyes [9, 10]. Neural concomitants of this improvement in monocular dominance are reflected in measurements of brain responsiveness following eye patching [11, 12]. Here we report that patching an eye is unnecessary for producing this paradoxical deprivation effect: interocular suppression of an ordinarily visible stimulus being viewed by...
Journal of Vision, 2016
Previous studies on synesthesia have suggested non-random association between sounds of linguisti... more Previous studies on synesthesia have suggested non-random association between sounds of linguistic units and colors [1, 2]. The cross-modal association between speech sound and color has also been generalized to non-synesthetes based on results from color matching to auditorily presented vowels [3, 4]. In the current work, we examined the audiovisual relationship between consonants and colors in non-synesthetic population.
Journal of Abnormal Psychology, 2016
Severe emotional disturbances such as anxiety and depression have been closely related to aberran... more Severe emotional disturbances such as anxiety and depression have been closely related to aberrant attentional processing of emotional stimuli. However, this has been little studied in schizophrenia, which is also characterized by marked emotional impairments such as heightened negative affect and anhedonia. In the current study, we investigated temporal dynamics of motivated attention to emotional stimuli in schizophrenia. For this purpose, we tracked eye movements of 22 individuals with schizophrenia or schizoaffective disorder (ISZs) and 19 healthy controls (HCs) to emotional (i.e., happy, sad, angry) and neutral face pairs presented either for 500 ms or 1,500 ms. Initial fixation direction and viewing time at 3 successive intervals (0-500, 500-1,000, 1,000-1,500 ms) were calculated. The results showed that both ISZs and HCs were more likely to orient initial fixations and exhibited longer viewing times to emotional than neutral faces. However, compared with HCs, ISZs allocated less attention to overall faces during the late stage (1,000-1,500 ms) when one of the paired faces displayed negative emotions. Furthermore, positive symptoms were highly associated with initial fixation avoidance to angry faces while depressive symptoms were related to later avoidance of angry faces. Both social amotivation and poor interpersonal functioning were closely related to diminished sustained attention to happy faces. This suggests that early attentional capture of emotional salience may be relatively preserved in schizophrenia, but the people with this disorder display an atypical late attentional process characterized by generalized attentional avoidance of negative stimuli. Of note, aberrant attentional processes of social threat and reward were closely associated with major symptoms and functioning in this disorder. General Scientific Summary People with schizophrenia showed relatively intact early attentional capture by emotional salience but exhibited an atypical late attentional process characterized by generalized attentional avoidance of negative stimuli. Aberrant attentional processes of social threat and reward were closely associated with major symptoms and functioning in this disorder.
Journal of vision, 2015
It has been suggested that graphemes of similar sound tend to be associated with analogous synest... more It has been suggested that graphemes of similar sound tend to be associated with analogous synesthetic colors in grapheme-color synesthesia (Asano & Yokosawa, 2011; 2012; Shin & Kim, 2014). A work in our group also showed that graphemes sharing phonetic rules - i.e., the place and the manner of articulation - tend to induce similar synesthetic colors (Kang et al., ASSC 2014). In the present study, we investigated whether phonetic properties are associated with colors in a specific manner even when other visual and linguistic features of graphemes are removed. We employed Haskins Laboratories articulatory synthesizer to generate vowel sounds as our stimuli by systematically manipulating gender (male and female voice) and tongue body position ('frontness' and 'height') (Iskarous et al. 2010, Nam et al. 2004). Four Korean grapheme-color synesthetes and nine non-synesthetes underwent a modified version of the standardized color-matching procedure (Eagleman et al., 2007) ...
Proceedings of the National Academy of Sciences of the United States of America, Jan 15, 2015
Predictive influences of auditory information on resolution of visual competition were investigat... more Predictive influences of auditory information on resolution of visual competition were investigated using music, whose visual symbolic notation is familiar only to those with musical training. Results from two experiments using different experimental paradigms revealed that melodic congruence between what is seen and what is heard impacts perceptual dynamics during binocular rivalry. This bisensory interaction was observed only when the musical score was perceptually dominant, not when it was suppressed from awareness, and it was observed only in people who could read music. Results from two ancillary experiments showed that this effect of congruence cannot be explained by differential patterns of eye movements or by differential response sluggishness associated with congruent score/melody combinations. Taken together, these results demonstrate robust audiovisual interaction based on high-level, symbolic representations and its predictive influence on perceptual dynamics during bino...
Trends in Cognitive Sciences, 2005
What are the neural correlates of conscious visual awareness? Tackling this question requires con... more What are the neural correlates of conscious visual awareness? Tackling this question requires contrasting neural correlates of stimulus processing culminating in visual awareness with neural correlates of stimulus processing unaccompanied by awareness. To produce these two neural states, one must be able to erase an otherwise visible stimulus from awareness. This article describes and assesses visual phenomena involving dissociation of physical stimulation and conscious awareness: degraded stimulation, visual masking, visual crowding, bistable figures, binocular rivalry, motioninduced blindness, inattentional blindness, change blindness and attentional blink. No single approach stands above the others, but those producing changing visual awareness despite invariant physical stimulation are clearly preferable. Such phenomena can help lead us ultimately to a comprehensive account of the neural correlates of conscious awareness.
Psychonomic Bulletin & Review, 2007
Journal of Cognitive Neuroscience, 2004
Individuals improve with practice on a variety of perceptual tasks, presumably reflecting plastic... more Individuals improve with practice on a variety of perceptual tasks, presumably reflecting plasticity in underlying neural mechanisms. We trained observers to discriminate biological motion from scrambled (nonbiological) motion and examined whether the resulting improvement in perceptual performance was accompanied by changes in activation within the posterior superior temporal sulcus and the fusiform “face area,” brain areas involved in perception of biological events. With daily practice, initially naive observers became more proficient at discriminating biological from scrambled animations embedded in an array of dynamic “noise” dots, with the extent of improvement varying among observers. Learning generalized to animations never seen before, indicating that observers had not simply memorized specific exemplars. In the same observers, neural activity prior to and following training was measured using functional magnetic resonance imaging. Neural activity within the posterior super...
Cortex, 2006
People with color-graphemic synesthesia experience vivid, reliable color upon viewing achromatic ... more People with color-graphemic synesthesia experience vivid, reliable color upon viewing achromatic alphanumeric characters. Recent evidence indicates that synesthetic color experiences are as perceptually real as actual colors are for non-synesthetic observers. To investigate possible interactions between real and synesthetic colors, we tested two adult color-graphemic synesthetes on a pair of perceptual grouping tasks. In Experiment 1, we employed a well-known phenomenon of motion perception, bistable apparent motion, to explore whether synesthetic colors interact with real colors in grouping over time. Two-frame apparent motion sequences were presented with both path lengths and colors systematically manipulated. Results showed that synesthetic colors of motion tokens interacted with matching real colors of the corresponding motion tokens, which could subsequently bias perceived direction of motion. In Experiment 2, we exploited binocular rivalry, a condition under which two dissimilar monocular images compete with each other and result in perceptual switches, to explore whether synesthetic colors interact with real colors in grouping over space. Pairs of rival images with two different characters were presented dichoptically with colors of characters manipulated. Results showed that synesthetic and real colors of characters tended to group together, which, in turn, promoted the perceived global dominance during binocular rivalry. Therefore, the present results identify substantial interaction between synesthetic colors and real colors in perceptual grouping.
American Journal on Intellectual and Developmental Disabilities, 2010
Williams syndrome is a genetic neurodevelopmental disorder with a distinctive phenotype, includin... more Williams syndrome is a genetic neurodevelopmental disorder with a distinctive phenotype, including cognitive–linguistic features, nonsocial anxiety, and a strong attraction to music. We performed functional MRI studies examining brain responses to musical and other types of auditory stimuli in young adults with Williams syndrome and typically developing controls. In Study 1, the Williams syndrome group exhibited unforeseen activations of the visual cortex to musical stimuli, and it was this novel finding that became the focus of two subsequent studies. Using retinotopy, color localizers, and additional sound conditions, we identified specific visual areas in subjects with Williams syndrome that were activated by both musical and nonmusical auditory stimuli. The results, similar to synesthetic-like experiences, have implications for cross-modal sensory processing in typical and atypical neurodevelopment.
Frontiers in Psychology
It has been shown that there is a non-random association between shape and color. However, the re... more It has been shown that there is a non-random association between shape and color. However, the results of previous studies on the shape-color correspondence did not converge. To address the issue, we focused on shape complexity among a number of shape properties, particularly in terms of 3D shape, and parametrically manipulated the shape complexity and all three components of color. With two experiments, the current study aimed to closely examine the correspondence between shape complexity of 3D shape and color in terms of hue (Experiment 1), luminance, and saturation (Experiment 2). Participants were presented with the 3D shapes in either visual or visuo-haptic modes of exploration. Subsequently, they had to pick from a color palette the color best matching each shape of the object. In Experiment 1, we found that as shapes became more complex, the best associated hue changed from those with long wavelengths to ones with short wavelengths. Results of Experiment 2 demonstrated that a...
American Journal on Intellectual and Developmental Disabilities, 2010
Williams syndrome (WS) is a genetic neurodevelopmental disorder with a distinctive phenotype incl... more Williams syndrome (WS) is a genetic neurodevelopmental disorder with a distinctive phenotype including cognitive-linguistic features, non-social anxiety, and a strong attraction to music. We performed functional MRI studies examining brain responses to musical and other types of auditory stimuli in young adults with WS and typically-developing controls. In Study 1, the WS group exhibited unforeseen activations of the visual cortex to musical stimuli, and it was this novel finding that became the focus of two subsequent studies. Using retinotopy, color localizers and additional sound conditions, we identified specific visual areas in WS subjects that were activated by both musical and non-musical auditory stimuli. The results, similar to synesthetic-like experiences, have implications for cross-modal sensory processing in typical and atypical neurodevelopment. §Corresponding author.
Psychonomic Bulletin & Review, Apr 1, 2007
Frontiers in Psychology
Familiarity and novelty are fundamental yet competing factors influencing aesthetic preference. H... more Familiarity and novelty are fundamental yet competing factors influencing aesthetic preference. However, whether people prefer familiar paintings or novel paintings has not been clear. Using both behavioral and eye-tracking measures, the present study aimed to investigate whether the effect of familiarity-novelty on aesthetic preference is independent or dependent on artwork properties (painting content, visual complexity) and viewer characteristics (experience in art). Participants were presented with two images of paintings, one of which was repeatedly presented but was always paired with a new painting in a randomized lateral arrangement. They were asked to indicate which of the two images they preferred with the degree of their preference. Behavioral results demonstrated an interactive influence of painting content and complexity on familiarity-novelty preference, especially alongside the distinction between representational and abstract paintings. Also, the familiarity-novelty ...
Multisensory Research, 2020
Cross-modal correspondence is the tendency to systematically map stimulus features across sensory... more Cross-modal correspondence is the tendency to systematically map stimulus features across sensory modalities. The current study explored cross-modal correspondence between speech sound and shape (Experiment 1), and whether such association can influence shape representation (Experiment 2). For the purpose of closely examining the role of the two factors — articulation and pitch — combined in speech acoustics, we generated two sets of 25 vowel stimuli — pitch-varying and pitch-constant sets. Both sets were generated by manipulating articulation — frontness and height of the tongue body’s positions — but differed in terms of whether pitch varied among the sounds within the same set. In Experiment 1, participants made a forced choice between a round and a spiky shape to indicate the shape better associated with each sound. Results showed that shape choice was modulated according to both articulation and pitch, and we therefore concluded that both factors play significant roles in sound...
Scientific Reports, 2019
Sensory information registered in one modality can influence perception associated with sensory i... more Sensory information registered in one modality can influence perception associated with sensory information registered in another modality. The current work focuses on one particularly salient form of such multisensory interaction: audio-visual motion perception. Previous studies have shown that watching visual motion and listening to auditory motion influence each other, but results from those studies are mixed with regard to the nature of the interactions promoting that influence and where within the sequence of information processing those interactions transpire. To address these issues, we investigated whether (i) concurrent audio-visual motion stimulation during an adaptation phase impacts the strength of the visual motion aftereffect (MAE) during a subsequent test phase, and (ii) whether the magnitude of that impact was dependent on the congruence between auditory and visual motion experienced during adaptation. Results show that congruent direction of audio-visual motion duri...
PloS one, 2017
Individuals possessing absolute pitch (AP) are able to identify a given musical tone or to reprod... more Individuals possessing absolute pitch (AP) are able to identify a given musical tone or to reproduce it without reference to another tone. The present study sought to learn whether this exceptional auditory ability impacts visual perception under stimulus conditions that provoke visual competition in the form of binocular rivalry. Nineteen adult participants with 3-19 years of musical training were divided into two groups according to their performance on a task involving identification of the specific note associated with hearing a given musical pitch. During test trials lasting just over half a minute, participants dichoptically viewed a scrolling musical score presented to one eye and a drifting sinusoidal grating presented to the other eye; throughout the trial they pressed buttons to track the alternations in visual awareness produced by these dissimilar monocular stimuli. On "pitch-congruent" trials, participants heard an auditory melody that was congruent in pitch w...
Frontiers in Psychology, 2017
Individuals with grapheme-color synesthesia experience idiosyncratic colors when viewing achromat... more Individuals with grapheme-color synesthesia experience idiosyncratic colors when viewing achromatic letters or digits. Despite large individual differences in grapheme-color association, synesthetes tend to associate graphemes sharing a perceptual feature with similar synesthetic colors. Sound has been suggested as one such feature. In the present study, we investigated whether graphemes of which representative phonemes have similar phonetic features tend to be associated with analogous synesthetic colors. We tested five Korean multilingual synesthetes on a color-matching task using graphemes from Korean, English, and Japanese orthography. We then compared the similarity of synesthetic colors induced by those characters sharing a phonetic feature. Results showed that graphemes associated with the same phonetic feature tend to induce synesthetic color in both within-and cross-script analyses. Moreover, this tendency was consistent for graphemes that are not transliterable into each other as well as graphemes that are. These results suggest that it is the perceptual-i.e., phonetic-properties associated with graphemes, not just conceptual associations such as transliteration, that determine synesthetic color.
Current biology : CB, Jan 28, 2017
Early visual experience sculpts neural mechanisms that regulate the balance of influence exerted ... more Early visual experience sculpts neural mechanisms that regulate the balance of influence exerted by the two eyes on cortical mechanisms underlying binocular vision [1, 2], and experience's impact on this neural balancing act continues into adulthood [3-5]. One recently described, compelling example of adult neural plasticity is the effect of patching one eye for a relatively short period of time: contrary to intuition, monocular visual deprivation actually improves the deprived eye's competitive advantage during a subsequent period of binocular rivalry [6-8], the robust form of visual competition prompted by dissimilar stimulation of the two eyes [9, 10]. Neural concomitants of this improvement in monocular dominance are reflected in measurements of brain responsiveness following eye patching [11, 12]. Here we report that patching an eye is unnecessary for producing this paradoxical deprivation effect: interocular suppression of an ordinarily visible stimulus being viewed by...
Journal of Vision, 2016
Previous studies on synesthesia have suggested non-random association between sounds of linguisti... more Previous studies on synesthesia have suggested non-random association between sounds of linguistic units and colors [1, 2]. The cross-modal association between speech sound and color has also been generalized to non-synesthetes based on results from color matching to auditorily presented vowels [3, 4]. In the current work, we examined the audiovisual relationship between consonants and colors in non-synesthetic population.
Journal of Abnormal Psychology, 2016
Severe emotional disturbances such as anxiety and depression have been closely related to aberran... more Severe emotional disturbances such as anxiety and depression have been closely related to aberrant attentional processing of emotional stimuli. However, this has been little studied in schizophrenia, which is also characterized by marked emotional impairments such as heightened negative affect and anhedonia. In the current study, we investigated temporal dynamics of motivated attention to emotional stimuli in schizophrenia. For this purpose, we tracked eye movements of 22 individuals with schizophrenia or schizoaffective disorder (ISZs) and 19 healthy controls (HCs) to emotional (i.e., happy, sad, angry) and neutral face pairs presented either for 500 ms or 1,500 ms. Initial fixation direction and viewing time at 3 successive intervals (0-500, 500-1,000, 1,000-1,500 ms) were calculated. The results showed that both ISZs and HCs were more likely to orient initial fixations and exhibited longer viewing times to emotional than neutral faces. However, compared with HCs, ISZs allocated less attention to overall faces during the late stage (1,000-1,500 ms) when one of the paired faces displayed negative emotions. Furthermore, positive symptoms were highly associated with initial fixation avoidance to angry faces while depressive symptoms were related to later avoidance of angry faces. Both social amotivation and poor interpersonal functioning were closely related to diminished sustained attention to happy faces. This suggests that early attentional capture of emotional salience may be relatively preserved in schizophrenia, but the people with this disorder display an atypical late attentional process characterized by generalized attentional avoidance of negative stimuli. Of note, aberrant attentional processes of social threat and reward were closely associated with major symptoms and functioning in this disorder. General Scientific Summary People with schizophrenia showed relatively intact early attentional capture by emotional salience but exhibited an atypical late attentional process characterized by generalized attentional avoidance of negative stimuli. Aberrant attentional processes of social threat and reward were closely associated with major symptoms and functioning in this disorder.
Journal of vision, 2015
It has been suggested that graphemes of similar sound tend to be associated with analogous synest... more It has been suggested that graphemes of similar sound tend to be associated with analogous synesthetic colors in grapheme-color synesthesia (Asano & Yokosawa, 2011; 2012; Shin & Kim, 2014). A work in our group also showed that graphemes sharing phonetic rules - i.e., the place and the manner of articulation - tend to induce similar synesthetic colors (Kang et al., ASSC 2014). In the present study, we investigated whether phonetic properties are associated with colors in a specific manner even when other visual and linguistic features of graphemes are removed. We employed Haskins Laboratories articulatory synthesizer to generate vowel sounds as our stimuli by systematically manipulating gender (male and female voice) and tongue body position ('frontness' and 'height') (Iskarous et al. 2010, Nam et al. 2004). Four Korean grapheme-color synesthetes and nine non-synesthetes underwent a modified version of the standardized color-matching procedure (Eagleman et al., 2007) ...
Proceedings of the National Academy of Sciences of the United States of America, Jan 15, 2015
Predictive influences of auditory information on resolution of visual competition were investigat... more Predictive influences of auditory information on resolution of visual competition were investigated using music, whose visual symbolic notation is familiar only to those with musical training. Results from two experiments using different experimental paradigms revealed that melodic congruence between what is seen and what is heard impacts perceptual dynamics during binocular rivalry. This bisensory interaction was observed only when the musical score was perceptually dominant, not when it was suppressed from awareness, and it was observed only in people who could read music. Results from two ancillary experiments showed that this effect of congruence cannot be explained by differential patterns of eye movements or by differential response sluggishness associated with congruent score/melody combinations. Taken together, these results demonstrate robust audiovisual interaction based on high-level, symbolic representations and its predictive influence on perceptual dynamics during bino...
Trends in Cognitive Sciences, 2005
What are the neural correlates of conscious visual awareness? Tackling this question requires con... more What are the neural correlates of conscious visual awareness? Tackling this question requires contrasting neural correlates of stimulus processing culminating in visual awareness with neural correlates of stimulus processing unaccompanied by awareness. To produce these two neural states, one must be able to erase an otherwise visible stimulus from awareness. This article describes and assesses visual phenomena involving dissociation of physical stimulation and conscious awareness: degraded stimulation, visual masking, visual crowding, bistable figures, binocular rivalry, motioninduced blindness, inattentional blindness, change blindness and attentional blink. No single approach stands above the others, but those producing changing visual awareness despite invariant physical stimulation are clearly preferable. Such phenomena can help lead us ultimately to a comprehensive account of the neural correlates of conscious awareness.
Psychonomic Bulletin & Review, 2007
Journal of Cognitive Neuroscience, 2004
Individuals improve with practice on a variety of perceptual tasks, presumably reflecting plastic... more Individuals improve with practice on a variety of perceptual tasks, presumably reflecting plasticity in underlying neural mechanisms. We trained observers to discriminate biological motion from scrambled (nonbiological) motion and examined whether the resulting improvement in perceptual performance was accompanied by changes in activation within the posterior superior temporal sulcus and the fusiform “face area,” brain areas involved in perception of biological events. With daily practice, initially naive observers became more proficient at discriminating biological from scrambled animations embedded in an array of dynamic “noise” dots, with the extent of improvement varying among observers. Learning generalized to animations never seen before, indicating that observers had not simply memorized specific exemplars. In the same observers, neural activity prior to and following training was measured using functional magnetic resonance imaging. Neural activity within the posterior super...
Cortex, 2006
People with color-graphemic synesthesia experience vivid, reliable color upon viewing achromatic ... more People with color-graphemic synesthesia experience vivid, reliable color upon viewing achromatic alphanumeric characters. Recent evidence indicates that synesthetic color experiences are as perceptually real as actual colors are for non-synesthetic observers. To investigate possible interactions between real and synesthetic colors, we tested two adult color-graphemic synesthetes on a pair of perceptual grouping tasks. In Experiment 1, we employed a well-known phenomenon of motion perception, bistable apparent motion, to explore whether synesthetic colors interact with real colors in grouping over time. Two-frame apparent motion sequences were presented with both path lengths and colors systematically manipulated. Results showed that synesthetic colors of motion tokens interacted with matching real colors of the corresponding motion tokens, which could subsequently bias perceived direction of motion. In Experiment 2, we exploited binocular rivalry, a condition under which two dissimilar monocular images compete with each other and result in perceptual switches, to explore whether synesthetic colors interact with real colors in grouping over space. Pairs of rival images with two different characters were presented dichoptically with colors of characters manipulated. Results showed that synesthetic and real colors of characters tended to group together, which, in turn, promoted the perceived global dominance during binocular rivalry. Therefore, the present results identify substantial interaction between synesthetic colors and real colors in perceptual grouping.
American Journal on Intellectual and Developmental Disabilities, 2010
Williams syndrome is a genetic neurodevelopmental disorder with a distinctive phenotype, includin... more Williams syndrome is a genetic neurodevelopmental disorder with a distinctive phenotype, including cognitive–linguistic features, nonsocial anxiety, and a strong attraction to music. We performed functional MRI studies examining brain responses to musical and other types of auditory stimuli in young adults with Williams syndrome and typically developing controls. In Study 1, the Williams syndrome group exhibited unforeseen activations of the visual cortex to musical stimuli, and it was this novel finding that became the focus of two subsequent studies. Using retinotopy, color localizers, and additional sound conditions, we identified specific visual areas in subjects with Williams syndrome that were activated by both musical and nonmusical auditory stimuli. The results, similar to synesthetic-like experiences, have implications for cross-modal sensory processing in typical and atypical neurodevelopment.
Frontiers in Psychology
It has been shown that there is a non-random association between shape and color. However, the re... more It has been shown that there is a non-random association between shape and color. However, the results of previous studies on the shape-color correspondence did not converge. To address the issue, we focused on shape complexity among a number of shape properties, particularly in terms of 3D shape, and parametrically manipulated the shape complexity and all three components of color. With two experiments, the current study aimed to closely examine the correspondence between shape complexity of 3D shape and color in terms of hue (Experiment 1), luminance, and saturation (Experiment 2). Participants were presented with the 3D shapes in either visual or visuo-haptic modes of exploration. Subsequently, they had to pick from a color palette the color best matching each shape of the object. In Experiment 1, we found that as shapes became more complex, the best associated hue changed from those with long wavelengths to ones with short wavelengths. Results of Experiment 2 demonstrated that a...
American Journal on Intellectual and Developmental Disabilities, 2010
Williams syndrome (WS) is a genetic neurodevelopmental disorder with a distinctive phenotype incl... more Williams syndrome (WS) is a genetic neurodevelopmental disorder with a distinctive phenotype including cognitive-linguistic features, non-social anxiety, and a strong attraction to music. We performed functional MRI studies examining brain responses to musical and other types of auditory stimuli in young adults with WS and typically-developing controls. In Study 1, the WS group exhibited unforeseen activations of the visual cortex to musical stimuli, and it was this novel finding that became the focus of two subsequent studies. Using retinotopy, color localizers and additional sound conditions, we identified specific visual areas in WS subjects that were activated by both musical and non-musical auditory stimuli. The results, similar to synesthetic-like experiences, have implications for cross-modal sensory processing in typical and atypical neurodevelopment. §Corresponding author.