The nature of infant color categorization: evidence from eye movements on a target detection task

Infants respond categorically to color. However, the nature of infants' categorical responding to color is unclear. The current study investigated two issues. First, is infants' categorical responding more absolute than adults' categorical responding? That is, can infants discriminate two stimuli from the same color category? Second, is color categorization in infants truly perceptual? Color categorization was tested by recording adults' and infants' eye movements on a target detection task. In Experiment 1, adults were faster at fixating a colored target when it was presented on a colored background from a different color category (between-category) than when it was presented on a colored background from the same color category (within-category), even when within- and between-category chromatic differences were equated in CIE (Committee International d'Eclairage) color space. This category effect was found for two chromatic separation sizes. In Experiment 2, 4-month-olds also responded categorically on the task. Infants were able to fixate the target when the background color was from the same category. However, as with adults, infants were faster at fixating the target when the target background chromatic difference was between-category than when it was within-category. This implies that infant color categorization, like adult color categorization, is truly perceptual.     

关于幼儿嗅、味、动、触摸感觉道记忆的研究

记忆在幼儿心理的发展过程中,具有极为重要的作用。幼儿知识的掌握,语言的学习,技巧的培养,以至个性的形成,都与记忆活动密切联系。国内外关于幼儿记忆的研究,主要限于有意与无意识记,机械与意义识记,形象与语词记忆等方面,很少从不同感觉道输入信息来进行比较。有的实验虽然涉及到不同感觉道的记忆,但被试者都是7岁以上的儿童,如斯梅德利(Smedley)和三岛、横尾等人的研究。为了全面了解幼儿的记忆发展水平,我们设计了关于幼儿不同感觉道记忆的实验研究,试图通过对幼儿各个感觉道输入信息来全面测查幼儿的视觉、听觉、味觉、嗅觉、动觉和触摸党的记忆水平,了解其发展规律及特点,以便为幼儿记忆的理论研究提供实验数据,为幼儿教育提供心理学依据。     

沃尔夫假说的新证据:范畴内和范畴间颜色辨别难度相同时语言范畴也会影响注意前颜色知觉

该研究探讨了当范畴内和范畴间颜色的辨别难度相同时,语言范畴是否会影响注意前颜色知觉。实验中,采用渐变且相邻者差别阈限数相当的A、B、C、D四种颜色（前两者为绿色,后两者为蓝色）为刺激材料,并让被试接受视觉Oddball脑电测试。脑电测试分视野给被试呈现标准刺激,以及与标准刺激属同一语言范畴（即颜色词绿色或蓝色）或不同语言范畴的偏差刺激。结果发现：在左视野呈现时,范畴内偏差刺激比范畴间偏差刺激诱发了边缘显著更大的视觉失匹配负波（vMMN）,在右视野呈现时,两类偏差刺激诱发的vMMN无显著差异;范畴内偏差刺激在不同视野呈现时诱发的vMMN无显著差异,范畴间偏差刺激则在右视野呈现时诱发了显著更大的vMMN。这一结果表明,当范畴内和范畴间颜色的辨别难度相同时,语言范畴也会影响早期的、注意前颜色知觉,支持了沃尔夫假说。     

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.     

短期习得的语言范畴使成人大脑右半球颜色范畴知觉转为左半球颜色范畴知觉

本研究探讨了色词与颜色重组训练能否让被试习得与真实情境相似的色词与颜色范畴联结, 并引起相应的偏侧化颜色范畴知觉, 从而进一步揭示语言编码对颜色范畴知觉的影响。采用六种蓝色作为材料。B1与B2为先前研究的两种蓝色。B11和B12, B21和B22分别为使B1, B2变浅和变深所得, 四者是连续的蓝色。训练被试分别用“duān”和“kěn”命名B1和B2。由于被试可能习得色词与颜色范畴的联结, 因此B12与B21为可能变范畴间颜色, B11和B12, B21和B22为可能变范畴内颜色。训练前后分别让被试完成一个视觉搜索测验。结果发现：前测中可能变范畴间颜色的辨别优于可能变范畴内颜色, 且在左视野呈现时更显著; 后测中可能变范畴间颜色的辨别同样优于可能变范畴内颜色, 但在右视野呈现时更显著。这提示：(1)人们在知觉同一语言范畴的不同颜色时可能会区分深浅范畴, 并因此引发右半球颜色范畴知觉; (2)短期习得的语言范畴能引起偏左半球颜色范畴知觉, 且使右半球颜色范畴知觉转为左半球颜色范畴知觉; (3)被试在训练中习得了色词与颜色范畴的联结; (4)范畴学习可以在仅学习一个样例的条件下自动发生。     

目标与非目标身份特征的范畴间差异对多身份追踪的促进作用

以数字和字母为实验材料, 考察了多身份追踪任务中目标与非目标的身份特征范畴性差异对目标追踪与身份识别的影响, 并探讨了其可能的认知加工机制。实验1A让被试追踪5个目标, 并操作目标与非目标的身份特征从无差异(目标与非目标为相同的数字)、范畴内差异(目标与非目标为各不相同的数字)到范畴间差异(目标为各不相同的数字, 非目标为各不相同的字母)变化, 发现随着目标与非目标差异水平的提高, 追踪正确率也显著提高。实验1B通过变化追踪目标数量为4和5操作追踪负荷, 发现中等负荷条件下(目标数量为5)实验结果与实验1A相同, 即目标与非目标身份特征的范畴内差异和范畴间差异均可促进追踪表现。实验2考察了目标与非目标身份特征的范畴间差异水平对追踪表现与身份识别的影响。结果发现随着范畴间差异水平的提高, 被试的追踪表现与身份识别表现都得到了显著提高, 但身份识别表现低于追踪表现。对可能解释以上现象的工作记忆理论、分组理论以及多身份追踪模型进行了分析讨论。     

The world in black and white: Ostracism enhances the categorical perception of social information

In two experiments, ostracized individuals showed more pronounced categorical perception of inclusion- and exclusion-related stimuli. Specifically, ostracism enhanced the ability to distinguish between-category differences (e.g., between happy and angry faces) relative to within-category differences (e.g., between two happy expressions). Participants were socially included or excluded via Cyberball (a virtual ball-tossing task). In Experiment 1, ostracized participants showed greater perceptual acuity in distinguishing between subtly happy and angry expressions combined with a reduced ability to discriminate expressions within each expression category. Experiment 2 found analogous categorical perception effects for targets varying on the dimension of race. Importantly, this effect was specific to social information; categorical perception of non-social objects was not qualified by social exclusion. These results suggest that ostracism exacerbates categorical perception, attuning perceivers to the differences between various inclusion- and exclusion-related categories relative to within category acuity, making the world appear more ‘black-and-white’ than it might otherwise.     

The cost of categorization in visual search: Incomplete processing of targets and field items

A partial processing hypothesis is proposed to account for performance under a visual search condition where target and field items belong to the different conceptual categories, letter and digit (between-category search), as compared to a condition in which they belong to the same category (within-category search). This hypothesized mechanism implies that less information is registered and/or retained in between- than in within-category search. This prediction was tested and confirmed in three experiments. The results indicate that both targets and field items are processed less deeply in between- than in within-category search.     

Is color “categorical perception” really perceptual?

Roberson and Davidoff (2000) found that color categorical perception (CP; better cross-category than within-category discrimination) was eliminated by verbal, but not by visual, interference presented during the interstimulus interval (ISI) of a discrimination task. On the basis of this finding, Roberson and Davidoff concluded that CP was mediated by verbal labels, and not by perceptual mechanisms, as is generally assumed. Experiment 1 replicated their results. However, it was found that if the interference type was uncertain on each trial (Experiment 2), CP then survived verbal interference. Moreover, it was found that the target color name could be retained across the ISI even with verbal interference (Experiment 3). We therefore conclude that color CP may indeed involve verbal labeling but that verbal interference does not necessarily prevent it.     

Neural correlates of acquired color category effects

Category training can induce category effects, whereby color discrimination of stimuli spanning a newly learned category boundary is enhanced relative to equivalently spaced stimuli from within the newly learned category (e.g., categorical perception). However, the underlying mechanisms of these acquired category effects are not fully understood. In the current study, Event-Related Potentials (ERPs) were recorded during a visual oddball task where standard and deviant colored stimuli from the same or different novel categories were presented. ERPs were recorded for a test group who were trained on these novel categories, and for an untrained control group. Category effects were only found for the test group on the trained region of color space, and only occurred during post-perceptual stages of processing. These findings provide new evidence for the involvement of cognitive mechanisms in acquired category effects and suggest that category effects of this kind can exist independent of early perceptual processes.     

颜色类别知觉效应的机制：语言的作用

颜色类别知觉效应(Category Perception, CP效应)表明, 在颜色之间物理差异距离相等的前提下, 个体区分不同类别的颜色比区分同一类别的颜色更快、更准确。这一效应产生的机制成为普遍进化理论和Sapir-Whorf假设之间争论的重要证据。支持CP效应由语言驱动的学者提出了CP效应单侧化、受语言即时任务影响、跨语言研究和神经生理机制等证据, 以表明语言在CP效应中起决定性的作用; 支持CP效应具有普遍性的学者以CP效应双侧化、婴儿的CP效应、跨语言的反证等证据提出了质疑。近年来, 出现了第三种观点, 认为在颜色CP效应中语言驱动机制和普遍机制并存, 这种理论是普遍进化理论和Whorf假设的折衷观点。从支持CP效应由语言驱动的证据、支持CP效应独立于语言的证据以及支持两种机制并存的观点等三个方面入手, 可分析颜色CP效应的产生机制及语言在其中所起的作用, 未来研究可从概念系统渗入知觉系统的角度进行拓展。     

A conflict-based model of color categorical perception: evidence from a priming study

Categorical perception (CP) of color manifests as faster or more accurate discrimination of two shades of color that straddle a category boundary (e.g., one blue and one green) than of two shades from within the same category (e.g., two different shades of green), even when the differences between the pairs of colors are equated according to some objective metric. The results of two experiments provide new evidence for a conflict-based account of this effect, in which CP is caused by competition between visual and verbal/categorical codes on within-category trials. According to this view, conflict arises because the verbal code indicates that the two colors are the same, whereas the visual code indicates that they are different. In Experiment 1, two shades from the same color category were discriminated significantly faster when the previous trial also comprised a pair of within-category colors than when the previous trial comprised a pair from two different color categories. Under the former circumstances, the CP effect disappeared. According to the conflict-based model, response conflict between visual and categorical codes during discrimination of within-category pairs produced an adjustment of cognitive control that reduced the weight given to the categorical code relative to the visual code on the subsequent trial. Consequently, responses on within-category trials were facilitated, and CP effects were reduced. The effectiveness of this conflict-based account was evaluated in comparison with an alternative view that CP reflects temporary warping of perceptual space at the boundaries between color categories.     

The effect of Stroop interference on the categorical perception of color

In two experiments, we examined the effects of Stroop interference on the categorical perception (CP; better cross-category than within-category discrimination) of color. Using a successive two-alternative forced choice recognition paradigm (deciding which of two stimuli was identical to a previously presented target), which combined to-be-remembered colors with congruent and incongruent Stroop words, we found that congruent color words facilitated CP, whereas incongruent color words reduced CP. However, this was the case only when Stroop interference was presented together with the target color, but not when Stroop stimuli were introduced at the test stage. This suggests that target name, but not test name generation, affects CP. Target name generation may be important for CP because it acts as a category prime, which, in turn, facilitates cross-category discrimination.     

Thresholds for color discrimination in English and Korean speakers

Categorical perception (CP) is said to occur when a continuum of equally spaced physical changes is perceived as unequally spaced as a function of category membership (Harnad, S. (Ed.) (1987). Psychophysical and cognitive aspects of categorical perception: A critical overview. Cambridge: Cambridge University Press). A common suggestion is that CP for color arises because perception is qualitatively distorted when we learn to categorize a dimension. Contrary to this view, we here report that English speakers show no evidence of lowered discrimination thresholds at the boundaries between blue and green categories even though CP is found at these boundaries in a supra-threshold task. Furthermore, there is no evidence of different discrimination thresholds between individuals from two language groups (English and Korean) who use different color terminology in the blue-green region and have different supra-threshold boundaries. Our participants’ just noticeable difference (JND) thresholds suggest that they retain a smooth continuum of perceptual space that is not warped by stretching at category boundaries or by within-category compression. At least for the domain of color, categorical perception appears to be a categorical, but not a perceptual phenomenon.     

语言范畴可否引起偏侧化颜色范畴知觉？

本研究考查了语言范畴是否会引起偏侧化颜色范畴知觉,并探讨了偏侧化颜色范畴知觉是语言范畴即时分类颜色还是长期与颜色联结的结果。实验中,以测量差别阈限的方法选定的渐变、相邻颜色知觉距离相当的A、B、C、D四种颜色（A、B为绿色,C、D为蓝色）为材料,以色词与颜色重组模式训练被试用4个人造词汇分别命名4种颜色,并让被试在训练前、第一次训练和第八次训练后均完成视觉搜索任务测试。经训练,原范畴内颜色（AB,CD）变成了范畴间颜色,原范畴间颜色（BC）仍为范畴间颜色。结果显示：被试在一次训练后能以新名字区分4种颜色,八次训练后掌握了4种颜色的新名字;在训练前测试中,出现了与蓝绿色相应的偏侧化颜色范畴知觉;在第八次训练后测试中,出现了与习得的语言范畴相应的偏侧化颜色范畴知觉,但在第一次训练后测试中并未出现这一效应。这些结果表明,语言范畴能引起偏侧化颜色范畴知觉,偏侧化颜色范畴知觉是语言范畴长期与颜色联结,而非即时分类颜色的结果。     

色觉疲劳、语义饱和对颜色范畴知觉的即时影响

颜色范畴知觉究竟是语言的还是知觉的, 或两者交互引起的认知冲突所致仍在探究与争议之中。本研究采用色觉疲劳和语义饱和操作分别独立地改变知觉或语义加工, 观察二者对颜色范畴知觉效应的即时影响, 以期探究语言和知觉对颜色范畴的作用。结果显示, 色觉疲劳操作导致范畴间颜色辨别反应时减少, 颜色范畴效应增强。语义饱和操作导致被饱和颜色词所属的范畴内颜色辨别反应时增加, 颜色范畴效应增强。说明单独改变知觉或语义加工能力均能影响CCP效应, 支持了语言标签对比模型, 即语言与知觉的交互作用引起颜色范畴知觉的观点。     

Categorical perception effects reflect differences in typicality on within-category trials

Many studies have shown better discrimination of two stimuli that cross a category boundary than of two stimuli belonging to the same category. This finding, known as categorical perception, is generally assumed to reflect consistently good performance on cross-category trials, relative to within-category trials. However, Roberson, D., Damjanovic, L., and Pilling, M. (Memory & Cognition, 35, 1814-1829, 2007) revealed that performance on within-category pairs of morphed facial expressions matched performance on cross-category trials when the target was a good exemplar of its category. Here, we investigate the generality of that finding by conducting new analyses of data from a series of studies of categorical perception in facial identity and color domains with speakers of different languages. Consistent with Roberson et al. (2007), the new analyses demonstrate that performance for central targets on within-category trials is as good as performance on cross-category trials. Participants perform badly on within-category items only when the target is closer to the category boundary than is the distractor. These results provide no support for the view that categorical perception is associated with increased perceptual sensitivity at category boundaries.     

颜色范畴知觉效应发生在大脑两半球：来自纳西族和汉族的证据

采用色环搜索单任务和双任务范式, 考察语言中区分蓝、绿的汉族和语言中蓝、绿混用的纳西族对蓝色和绿色的辨别是否存在颜色范畴知觉效应(Categorical perception, 以下简称为CP效应)。结果发现：(1)纳西族对蓝色和绿色的区分比汉族困难, 体现了语言的作用; (2)语言中蓝、绿混用的纳西族与语言中区分蓝、绿的汉族都出现显著的蓝绿CP效应; (3)两个民族被试的左视野的CP效应受到图形记忆次任务的显著干扰, 说明左视野的CP效应与右脑激活有关。整个研究表明, 颜色CP效应既存在普遍的知觉机制, 也存在语言驱动机制, 语言的作用存在直接效应。研究结果支持颜色词与颜色认知的相互作用理论。     

Category effects in visual search: A failure to replicate the “oh-zero” phenomenon

In the experiment of Jonides and Gleitman (1972), subjects searched displays of digits or letters for single, specified digit or letter targets. The slope of the function relating reaction time to display size was positive (mean=25 msec/item) if target and nontargets belonged to the same alphanumeric category (within-category search), but zero if target and nontargets belonged to different categories (between-category search). This held even for the target O, whose categorical relationship to nontargets was determined entirely by the name it was given. In the present paper, two attempted replications are reported, one as close as practically possible. For the unambiguous targets A, Z, 2, and 4, slopes were greater in within-category search than in between-category search, but positive and very variable in both cases. For the ambiguous target O, slopes were identical in within-category and between-category search, and again positive. The results suggest that with single, specified targets, differences between within-category and between-category search may be due entirely to variation in the average physical resemblance between target and nontargets. In line with previous findings, they show that one cannot characterize within-category search as generally “serial” and between-category search as generally “parallel.”     

Open-ended categorization of chick-a-dee calls by black-capped chickadees (Poecile atricapilla)

The authors trained black-capped chickadees (Poecile atricapilla) in an operant discrimination with exemplars of black-capped and Carolina chick-a-dee calls, with the goal of determining whether the birds memorized the calls of conspecifics and heterospecifics or classified the calls by species. Black-capped calls served as both rewarded (S+) and unrewarded (S-) stimuli (the within-category discrimination), whereas Carolina chick-a-dee calls served as S-s (the between-category discrimination) in the black-capped chick-a-dee call S+ group. The Carolina call S+ group had Carolina calls as S+s and S-s (within-category) and black-capped calls as S-s (between-category). Both groups discriminated between call categories faster than within a call category. In 2 subsequent experiments, both S+ groups showed transfer to novel calls and propagation back to between-category calls. The results favor the hypothesis that the acoustically similar social calls of the 2 species constitute separate open-ended categories.