Categorical Perception Of Color Research Articles

Categorical perception of voicing, colors and facial expressions: A developmental study

The aim of the present paper was to compare the development of perceptual categorization of voicing, colors and facial expressions in French-speaking children (from 6 to 8 years) and adults. Differences in both categorical perception, i.e. the correspondence between identification and discrimination performances, and in boundary precision, indexed by the steepness of the identification slope, were investigated. Whereas there was no significant effect of age on categorical perception, boundary precision increased with age, both for voicing and facial expressions though not for colors. These results suggest that the development of boundary precision arises from a general cognitive maturation across different perceptual domains. However, this is not without domain specific effects since we found (1) a correlation between the development of voicing perception and some reading performances and (2) an earlier maturation of boundary precision for colors compared to voicing and facial expressions. These comparative data indicate that whereas general cognitive maturation has some influence on the development of perceptual categorization, this is not without domain-specific effects, the structural complexity of the categories being one of them.

Representation of colour concepts in bilingual cognition: The case of Japanese blues

Previous studies demonstrate that lexical coding of colour influences categorical perception of colour, such that participants are more likely to rate two colours to be more similar if they belong to the same linguistic category (Roberson et al., 2000, 2005). Recent work shows changes in Greek–English bilinguals' perception of within and cross-category stimulus pairs as a function of the availability of the relevant colour terms in semantic memory, and the amount of time spent in the L2-speaking country (Athanasopoulos, 2009). The present paper extends Athanasopoulos' (2009) investigation by looking at cognitive processing of colour in Japanese–English bilinguals. Like Greek, Japanese contrasts with English in that it has an additional monolexemic term for ‘light blue’(mizuiro). The aim of the paper is to examine to what degree linguistic and extralinguistic variables modulate Japanese–English bilinguals' sensitivity to the blue/light blue distinction. Results showed that those bilinguals who used English more frequently distinguished blue and light blue stimulus pairs less well than those who used Japanese more frequently. These results suggest that bilingual cognition may be dynamic and flexible, as the degree to which it resembles that of either monolingual norm is, in this case, fundamentally a matter of frequency of language use.

Color categories affect pre-attentive color perception

Categorical perception (CP) of color is the faster and/or more accurate discrimination of colors from different categories than equivalently spaced colors from the same category. Here, we investigate whether color CP at early stages of chromatic processing is independent of top–down modulation from attention. A visual oddball task was employed where frequent and infrequent colored stimuli were either same- or different-category, with chromatic differences equated across conditions. Stimuli were presented peripheral to a central distractor task to elicit an event-related potential (ERP) known as the visual mismatch negativity (vMMN). The vMMN is an index of automatic and pre-attentive visual change detection arising from generating loci in visual cortices. The results revealed a greater vMMN for different-category than same-category change detection when stimuli appeared in the lower visual field, and an absence of attention-related ERP components. The findings provide the first clear evidence for an automatic and pre-attentive categorical code for color.

Newly trained lexical categories produce lateralized categorical perception of color

Linguistic categories have been shown to influence perceptual discrimination, to do so preferentially in the right visual field, to fail to do so when competing demands are made on verbal memory, and to vary with the color-term boundaries of different languages. However, because there are strong commonalities across languages in the placement of color-term boundaries, the question remains open whether observed categorical perception for color can be entirely a result of learned categories or may rely to some degree on innate ones. We show here that lateralized color categorical perception can be entirely the result of learned categories. In a visual search task, reaction times to targets were faster in the right than the left visual field when the target and distractor colors, initially sharing the same linguistic term (e.g., "blue"), became between-category colors after training (i.e., when two different shades of blue had each acquired a new name). A control group, whose conditions exactly matched those of the experimental group except that no new categories were introduced, did not show this effect, establishing that the effect was not dependent on increased familiarity with either the color stimuli or the task. The present results show beyond question that lateralized categorical perception of color can reflect strictly learned color categories, even artificially learned categories that violate both universal tendencies in color naming and the categorization pattern of the language of the subject.

Language suppression effects on the categorical perception of colour as evidenced through ERPs

It is unclear how language influences colour perception so as to lead to the categorical perception of colour. This is particularly true when considering visual tasks that involve minimal memory requirements. In the present experiment we investigated this question by employing a “same–different” judgment task in which participants were asked to compare the colours of two presented visual features (a square and its surrounding frame), presented to the left visual field (LVF) or the right visual field (RVF), while event-related potentials (ERPs) were recorded. The “different” colour trials were of two types, including those consisting of within-category differences (e.g. two different shades of blue) and those consisting of between-category differences (i.e. blue vs. green), with matching hue differences for within-category comparisons and between-category comparisons. The ERP results show that, over the midline fronto-central scalp region, responses to the within-category stimuli presented in the RVF demonstrated a more negative N2 component (260–310ms post-stimulus) than either the responses to the between-category stimuli in the RVF, the between-category stimulus in the LVF, or the within-category stimulus in the LVF. Further, the responses for the within-category stimulus in the RVF resulted in a P3 component with a longer latency than that observed for the other three conditions. The results observed in this rapid colour discrimination task suggest that the categorical perception of colour stimuli presented in the RVF may result from an effect of language-related processes suppressing the capacity to discriminate two shades of colour within the same colour category.

Categorical color perception in natural scenes under different illuminants

Categorical color perception in natural scenes under different illuminants

Cross-species Assessment of the Linguistic Origins of Color Categories.

Cross-species Assessment of the Linguistic Origins of Color Categories by Jules Davidoff, University of London Joël Fagot, CNRS-Université de Provence Reading Options: Download/Read PDF | Add to Endnote Abstract This article considers the relation between language and categorical perception (CP) of color.

若年者・高齢者・色覚異常者の基本色名に基づいた色分類

若年者・高齢者・色覚異常者の基本色名に基づいた色分類

The Whorfian mind

Color perception has been a traditional test-case of the idea that the language we speak affects our perception of the world.1 It is now established that categorical perception of color is verbally mediated and varies with culture and language.2 However, it is unknown whether the well-demonstrated language effects on color discrimination really reach down to the level of visual perception, or whether they only reflect post-perceptual cognitive processes. Using brain potentials in a color oddball detection task with Greek and English speakers, we demonstrate that language effects may exist at a level that is literally perceptual, suggesting that speakers of different languages have differently structured minds.

Effects of language on categorical perception of color are modulated by the visual hemifield as revealed by fMRI

Effects of language on categorical perception of color are modulated by the visual hemifield as revealed by fMRI

Electrophysiological markers of categorical perception of color in 7-month old infants

The origin of color categories has been debated by psychologists, linguists and cognitive scientists for many decades. Here, we present the first electrophysiological evidence for categorical responding to color before color terms are acquired. Event-related potentials were recorded on a visual oddball task in 7-month old infants. Infants were shown frequent presentations of one color (standard) interspersed with infrequent presentations of a color that was either from the same category (within-category deviant) or from a different category (between-category deviant) to the standard. Differences in the event-related potentials elicited by the stimuli were found that were related to the categorical relationship of the standard and the deviant stimuli. The data are discussed in relation to the processes that underlie categorical responding in infancy, as well as the debate about the origin of color categories in language and cognition.

Categorical Perception of Color is Restricted to the Right Visual Field in Korean Speakers Who Maintain Central Fixation

Categorical Perception of Color is Restricted to the Right Visual Field in Korean Speakers Who Maintain Central Fixation

Language regions of brain are operative in color perception.

The effect of language on the categorical perception of color is stronger for stimuli in the right visual field (RVF) than in the left visual field, but the neural correlates of the behavioral RVF advantage are unknown. Here we present brain activation maps revealing how language is differentially engaged in the discrimination of colored stimuli presented in either visual hemifield. In a rapid, event-related functional MRI study, we measured subjects' brain activity while they performed a visual search task. Compared with colors from the same lexical category, discrimination of colors from different linguistic categories provoked stronger and faster responses in the left hemisphere language regions, particularly when the colors were presented in the RVF. In addition, activation of visual areas 2/3, responsible for color perception, was much stronger for RVF stimuli from different linguistic categories than for stimuli from the same linguistic category. Notably, the enhanced activity of visual areas 2/3 coincided with the enhanced activity of the left posterior temporoparietal language region, suggesting that this language region may serve as a top-down control source that modulates the activation of the visual cortex. These findings shed light on the brain mechanisms that underlie the hemifield- dependent effect of language on visual perception.

Reading from Left to Right

PSYCHOLOGY Categorical perception is a robust phenomenon and can be illustrated by the more rapid discrimination of two colors separated by a fixed chromatic distance when the colors fall on opposite sides of a category boundary, such as blue/green, than when they both lie within a single category. Both adults and infants exhibit this capacity, and Franklin et al. have investigated the influence of hemispheric lateralization and of language in a pair of studies. First, by presenting the colors in the left or right visual field (LVF or RVF), they show that adults react more quickly to RVF stimuli and hence that categorical perception of color is lateralized (in a relative, though not absolute, sense) to the left hemisphere, to which the RVF projects. Consistent with a left-hemispheric predominance of language skills, a verbal interference task blocked categorical perception in adults, whereas a visual interference task did not. Prelinguistic infants, on the other hand, displayed a right-hemispheric (LVF) superiority in the categorical perception of colors. Second, they recruited a group of toddlers 2 to 5 years of age and assessed their comprehension of the words blue and green. When tested on the same paired colors, the reaction times of these toddlers did not vary as a function of semantic knowledge, but those that had mastered the words demonstrated a hemispheric lateralization that was adult-like; that is, categorical perception for RVF stimuli. Toddlers who were still learning about blue and green retained the LVF pattern of categorical perception. — GJC Proc. Natl. Acad. Sci. U.S.A. 105 , 3221; 18221 (2008).

Lateralization of categorical perception of color changes with color term acquisition

Categorical perception (CP) of color is the faster and more accurate discrimination of two colors from different categories than two colors from the same category, even when same- and different-category chromatic separations are equated. In adults, color CP is lateralized to the left hemisphere (LH), whereas in infants, it is lateralized to the right hemisphere (RH). There is evidence that the LH bias in color CP in adults is due to the influence of color terms in the LH. Here we show that the RH to LH switch in color CP occurs when the words that distinguish the relevant category boundary are learned. A colored target was shown in either the left- or right-visual field on either the same- or different-category background, with equal hue separation for both conditions. The time to initiate an eye movement toward the target from central fixation at target onset was recorded. Color naming and comprehension was assessed. Toddlers were faster at detecting targets on different- than same-category backgrounds and the extent of CP did not vary with level of color term knowledge. However, for toddlers who knew the relevant color terms, the category effect was found only for targets in the RVF (LH), whereas for toddlers learning the color terms, the category effect was found only for targets in the LVF (RH). The findings suggest that lateralization of color CP changes with color term acquisition, and provide evidence for the influence of language on the functional organization of the brain.

An Evidence for the Effect of Categorical Perception on Color Perception

It has been well documented that color perception exhibits the characteristics of categorical perception such that participants' performance is better when discriminating stimuli across color category boundaries than within the same color category.However,it is unclear whether the effect of categorical perception on color perception is in fact a perceptual phenomenon.Most of the evidence for the categorical perception of color was derived from tasks that considerably involved working memory;therefore,it is possible that the categorical effect results from the involvement of verbal labeling in working memory rather than being a pure perceptual phenomenon.Thus,it is important to provide tests that separate the perceptual process from verbal memory.The present study extended the research of Franklin(2005) and Gilbert et al.(2006) by incorporating the two experimental paradigms and aimed to identify whether categorical perception of color occurs in the perceptual stage of the task. A 2(interference tasks: no interference vs.verbal interference)×2(color stimuli: within category vs.between categories)×2(visual field: left visual field vs.right visual field) within-subject design was implemented in the present study.Eighteen participants(19~22 years old) were tested.First,each participant's blue green lexical boundary was determined.Subsequently,they were required to perform a target detection task.Each stimulus display consisted of one color square on a different background color.The color square was randomly presented on one of the 12 locations around the fixation point.The participants were required to respond to the stimulus by pressing one of the two keys after detecting whether the color square appeared on the left-hand side or the right-hand side of the stimulus display. The result indicated that the reaction times in the between categories condition were much faster than those in the within category condition;this suggested that categorical perception does affect color perception.Moreover,this effect was unaffected by the verbal-interference task.Further,for both the left and right visual fields,there were significant effects of categorical perception;however,there was no significant difference in the magnitude of the effect between left and right visual fields. These results suggest that the categorical perception of color occurs during the perceptual stage.Meanwhile,since the effect of categorical perception on color perception was found in both the left and right visual fields and the difference between the effects was not at a significant level,the results are consistent with the notion that there is no significant difference between the left and right hemispheres on color perception.

Neurophysiological evidence for categorical perception of color

The aim of this investigation was to examine the time course and the relative contributions of perceptual and post-perceptual processes to categorical perception (CP) of color. A visual oddball task was used with standard and deviant stimuli from same (within-category) or different (between-category) categories, with chromatic separations for within- and between-category stimuli equated in Munsell Hue. CP was found on a behavioral version of the task, with faster RTs and greater accuracy for between- compared to within-category stimuli. On a neurophysiological version of the task, event-related potentials (ERPs) showed earlier latencies for P1 and N1 components at posterior locations to between- relative to within-category deviants, providing novel evidence for early perceptual processes on color CP. Enhanced P2 and P3 waves were also found for between- compared to within-category stimuli, indicating a role for later post-perceptual processes.

Interference of verbal labels in color categorical perception

Previous studies demonstrated that color categorical perception (CP; better cross-category than within-category discrimination) was reduced by verbal interference, suggesting that CP is mediated by verbal labeling. Here, we examined chromatic generality and experience-dependency of verbal interference in CP using the Stroop effect. We employed a simultaneous two-alternative forced choice discrimination task. Congruent or incongruent words were presented prior to discrimination. In experiment 1, incongruent color names reduced CP regardless of color boundary pairs. Next, we used noncolor words that seemed to be associated with color through experience. The results showed that the tested noncolor words did not modify CP (experiment 2). However, combined presentation of color and shape produced Stroop interference (experiment 3). Our finding suggests that familiarity or mastery of categorized information through experience may be evaluated by verbal interference.

Characteristics of grouping colors for figure segregation on a multicolored background

A figure is segregated from its background when the colored elements belonging to the figure are grouped together. We investigated the range of color distribution conditions in which a figure could be segregated from its background using the color distribution differences. The stimulus was a multicolored texture composed of randomly shaped pieces. It was divided into two regions: a test region and a background region. The pieces in these two regions had different color distributions in the OSA Uniform Color Space. In our experiments, the subject segregated the figure of the test region using two different procedures. Since the Euclidean distance in the OSA Uniform Color Space corresponds to perceived color difference, if segregation thresholds are determined by only color difference, the thresholds should be independent of position and direction in the color space. In the results, however, the thresholds did depend on position and direction in the OSA Uniform Color Space. This suggests that color difference is not the only factor in figure segregation by color. Moreover, the threshold dependence on position and direction is influenced by the distances in the cone-opponent space whose axes are normalized by discrimination thresholds, suggesting that figure segregation threshold is determined by similar factors in the cone-opponent space for color discrimination. The analysis of the results by categorical color naming suggests that categorical color perception may affect figure segregation only slightly.

What can we learn from toddlers about categorical perception of color? Comments on Goldstein, Davidoff, and Roberson

We comment on Goldstein, Davidoff, and Roberson’s replication and extension ( Journal of Experimental Child Psychology, 102, 219-238 [2009]) of our study of the effect of toddlers’ color term knowledge on their categorical perception (CP) of color ( Journal of Experimental Child Psychology, 90, 114–141 [2005]). First, we discuss how best to assess color term knowledge when concerned with the effects of language on color CP. A reanalysis of our data indicates that even toddlers who do not know the terms for the relevant focal colors still show CP. Second, we comment on Goldstein and colleagues’ finding of blue–purple CP, as we did, but not of blue–green CP in Himba toddlers. We present contrasting data from Wright (unpublished PhD thesis, University of Surrey, 2006) that demonstrates blue–green CP in Himba toddlers. Finally, we discuss the limitations of the approach taken by all of these investigations and discuss theoretical accounts of the origin and nature of color CP.