Category Boundaries Research Articles

Normalisation of the P300 response following treatment in tic disorders and body-focused repetitive behaviors

Gilles de la Tourette's syndrome (GTS) is a disorder in which obsessive-compulsive (OC), Attention Deficit Hyperactivity Disorder (ADHD) and autism symptoms occur in up to 60% of patients, suggesting shared etiology. We explored the phenotypic structure of tic, OC, ADHD, and autism symptoms as measured by the YGTSS,Y-BOCS,CAARS and AQ, in 225 GTS patients and 371 family members. First, Confirmatory Factor Analyses (CFA) were performed on the symptom structure of each separate symptom scale. Second, the symptom dimensions derived from each scale were combined in one model, and correlations between them were calculated. Using the correlation matrix, Exploratory Factor Analyses (EFA) were performed on the symptom dimensions across the scales. EFA revealed a five factor structure: tic/aggression/symmetry; OC symptoms/compulsive tics/ numbers and patterns; ADHD symptoms; autism symptoms; and hoarding/inattention symptoms. The results are partly in line with the traditional categorical boundaries of the symptom scales used, and partly reveal a symptom structure that cuts through the diagnostic categories. This phenotypic structure might more closely reflect underlying etiologies than a structure that classically describes GTS patients according to absence or presence of comorbid OCD, ADHD and autism, and might inform both future genetic and treatment studies.

Cohabitation’s boundaries and the confines of tradition

In contrast with prescriptions for law reform for unmarried cohabitants, this article studies legislative inertia on the subject. It compares France and the Canadian province of Quebec, drawing on theoretical treatment of boundaries from critical geography, queer theory, and sociolegal work on law reform. Abstinence from legislating for cohabitants has not secured legal stasis. Informally and indirectly, ad hoc responses to cohabitation have amended the boundaries of marriage and fundamental legal categories. A conservative approach to marriage and cohabitation has failed to conserve marriage. We identify a gap, not between law and social life but between law and its prevailing justification, that cohabitants are free to choose to marry or to conclude contracts. Legislative and judicial developments show that this justification fails to persuade. Finally, we read France and Quebec’s approach to cohabitation as symptomatic of an impoverished misreading of the civil law tradition.

Perception of height and categorization of Brazilian Portuguese front vowels

ABSTRACT Cross-linguistic typological observations and theoretical models in phonology suggest that certain speech sound distinctions are more complex then others. One such example is the opposition between mid-high and mid-low vowels, usually thought to be more complex than the opposition between high and mid vowels. The present study provides experimental evidence on speech sound perception which supports this notion. Native Brazilian Portuguese speakers performed vowel classification tasks involving either the distinction between the front high mid /e/ and the front high /i/, or the distinction between the front high mid /e/ and the front low mid /ε/ vowel. Measures of response time and discriminability (d') at the vowel category boundaries were obtained. Participants showed significantly slower responses and lower d' values in the "e-ε" as compared to the "i-e" classification task. Results indicate that perceptually distinguishing /e/ from /ı/ requires more processing time and resources, and involves more complex information than distinguishing /e/ from /i/.

Living liminal: Reflexive epistemological positioning at the intersection of marginalized identities

In this article, I trace the origins of my epistemological stance as a biracial woman with multiple marginalized identities that caused me to span categorical boundaries in life. My perspective has become one in which I am positioned in an ambivalent, hybrid, liminal space. I respond to the epistemological positions taken by other doctoral students and consider our common struggles with situating ourselves among established theories that do not easily accommodate the complexity and ambiguity of our lived experiences. I describe my attempts to locate myself within existing epistemological approaches that are compatible with my own perspective and my research questions about racial disparities in young adult mental health. I conclude by adopting a healthy skepticism of existing theories of knowledge and by looking forward to asking and answering questions with my own research that will help social workers to work more effectively with diverse populations.

Understanding the robot: Comments on Goudey and Bonnin (2016)

Goudey and Bonnin provide an important demonstration of our willingness to accept robots regardless of the degree to which they look like us. This comment seeks to expand their insights in two ways. First, by broadening our conception of what constitutes a robot, I argue that we have already accepted many non-humanoid robots, and that even robotic entities without a visual presence can be compelling and engaging. Second, I suggest expanding the original paper’s psychological treatment of category ambiguity through the anthropological treatment of Mary Douglas. Douglas suggests that category ambiguity is abhorrent because things perceived to transgress categorical boundaries challenge our cultural beliefs and social order. In the case of robots, the beliefs that are challenged are our basic understandings of what makes humans unique and privileged in the world. As machines grow more and more capable, by some accounts they threaten to eclipse and even supplant the human race. I identify several behavioral and ethical research issues that are imperative if we are to deal with and prepare for such possibilities.

The Development of White-Asian Categorization: Contributions from Skin Color and Other Physiognomic Cues.

We examined the development of racial categorizations of faces spanning the European–East Asian (“White–Asian”) categorical continuum in children between the ages of four and nine as well as adults. We employed a stimulus set that independently varied skin color and other aspects of facial physiognomy, allowing the contribution of each to be assessed independently and in interaction with each other. Results demonstrated substantial development across this age range in children’s ability to draw on both sorts of cue, with over twice as much variance explained by stimulus variation in adults than children. Nonetheless, children were clearly sensitive to both skin color and other aspects of facial physiognomy, suggesting that understanding of the White-Asian category boundary develops in a somewhat different way than understanding of the White-Black category boundary, in which attention to features other than skin color appear only somewhat later. Discussion focuses on the implications of these findings for theories of social categorization.

Speaker and Accent Variation Are Handled Differently: Evidence in Native and Non-Native Listeners.

Listeners are able to cope with between-speaker variability in speech that stems from anatomical sources (i.e. individual and sex differences in vocal tract size) and sociolinguistic sources (i.e. accents). We hypothesized that listeners adapt to these two types of variation differently because prior work indicates that adapting to speaker/sex variability may occur pre-lexically while adapting to accent variability may require learning from attention to explicit cues (i.e. feedback). In Experiment 1, we tested our hypothesis by training native Dutch listeners and Australian-English (AusE) listeners without any experience with Dutch or Flemish to discriminate between the Dutch vowels /I/ and /ε/ from a single speaker. We then tested their ability to classify /I/ and /ε/ vowels of a novel Dutch speaker (i.e. speaker or sex change only), or vowels of a novel Flemish speaker (i.e. speaker or sex change plus accent change). We found that both Dutch and AusE listeners could successfully categorize vowels if the change involved a speaker/sex change, but not if the change involved an accent change. When AusE listeners were given feedback on their categorization responses to the novel speaker in Experiment 2, they were able to successfully categorize vowels involving an accent change. These results suggest that adapting to accents may be a two-step process, whereby the first step involves adapting to speaker differences at a pre-lexical level, and the second step involves adapting to accent differences at a contextual level, where listeners have access to word meaning or are given feedback that allows them to appropriately adjust their perceptual category boundaries.

Nanoparticle-Based Medicines: A Review of FDA-Approved Materials and Clinical Trials to Date.

In this review we provide an up to date snapshot of nanomedicines either currently approved by the US FDA, or in the FDA clinical trials process. We define nanomedicines as therapeutic or imaging agents which comprise a nanoparticle in order to control the biodistribution, enhance the efficacy, or otherwise reduce toxicity of a drug or biologic. We identified 51 FDA-approved nanomedicines that met this definition and 77 products in clinical trials, with ~40% of trials listed in clinicaltrials.gov started in 2014 or 2015. While FDA approved materials are heavily weighted to polymeric, liposomal, and nanocrystal formulations, there is a trend towards the development of more complex materials comprising micelles, protein-based NPs, and also the emergence of a variety of inorganic and metallic particles in clinical trials. We then provide an overview of the different material categories represented in our search, highlighting nanomedicines that have either been recently approved, or are already in clinical trials. We conclude withsome comments on future perspectives for nanomedicines, which we expect to include more actively-targeted materials, multi-functional materials ("theranostics") and more complicated materials that blur the boundaries of traditional material categories. A key challenge for researchers, industry, and regulators is how to classify new materials and what additional testing (e.g. safety and toxicity) is required before products become available.

The Evolution and Development of Inferential Reasoning about Ethnic Markers

Social scientists have long argued about the relationship between ethnic phenomena, symbolic markers, and cultural traits. In this paper, we illustrate the potential of functionalist cultural and genetic evolutionary models to reconcile these debates. Specifically, we argue that we must take seriously the role of cultural similarity in delineating certain category boundaries if we are to understand the origins and development of ethnic stereotyping. We examine whether symbolic markers—namely, sartorial ones—are privileged in the development of social stereotypes by comparing how children and adults in the urban United States and rural highland Peru perform a categorization task. We find that arbitrary sartorial markers motivate generalizations about novel traits in all samples except among US children, even when they crosscut body morphology, emotional expression, and socioeconomic cues. Unlike children in the United States, children in the Peruvian sample demonstrate an even stronger reliance on sartoria...

Temporal dynamics of visual category representation in the macaque inferior temporal cortex.

Object categories are recognized at multiple levels of hierarchical abstractions. Psychophysical studies have shown a more rapid perceptual access to the mid-level category information (e.g., human faces) than the higher (superordinate; e.g., animal) or the lower (subordinate; e.g., face identity) level. Mid-level category members share many features, whereas few features are shared among members of different mid-level categories. To understand better the neural basis of expedited access to mid-level category information, we examined neural responses of the inferior temporal (IT) cortex of macaque monkeys viewing a large number of object images. We found an earlier representation of mid-level categories in the IT population and single-unit responses compared with superordinate- and subordinate-level categories. The short-latency representation of mid-level category information shows that visual cortex first divides the category shape space at its sharpest boundaries, defined by high/low within/between-group similarity. This short-latency, mid-level category boundary map may be a prerequisite for representation of other categories at more global and finer scales.

Category Membership and Semantic Coding in the Cerebral Hemispheres

Although a gradient of category membership seems to form the internal structure of semantic categories, it is unclear whether the 2 hemispheres of the brain differ in terms of this gradient. The 2 experiments reported here examined this empirical question and explored alternative theoretical interpretations. Participants viewed category names centrally and determined whether a closely related or distantly related word presented to either the left visual field/right hemisphere (LVF/RH) or the right visual field/left hemisphere (RVF/LH) was a member of the category. Distantly related words were categorized more slowly in the LVF/RH relative to the RVF/LH, with no difference for words close to the prototype. The finding resolved past mixed results showing an unambiguous typicality effect for both visual field presentations. Furthermore, we examined items near the fuzzy border that were sometimes rejected as nonmembers of the category and found both hemispheres use the same category boundary. In Experiment 2, we presented 2 target words to be categorized, with the expectation of augmenting the speed advantage for the RVF/LH if the 2 hemispheres differ structurally. Instead the results showed a weakening of the hemispheric difference, arguing against a structural in favor of a processing explanation.

"Are you looking at me?" How children's gaze judgments improve with age.

Adults' judgments of another person's gaze reflect both sensory (e.g., perceptual) and nonsensory (e.g., decisional) processes. We examined how children's performance on a gaze categorization task develops over time by varying uncertainty in the stimulus presented to 6- to 11- year-olds (n = 57). We found that younger children responded "direct" over a wider range of gaze deviations. We also found that increasing uncertainty led to an increase in direct responses, across all age groups. A simple model to account for these data revealed that although younger children had a noisier sensory representation of the stimulus, most developmental changes in gaze were because of a change in children's response criteria (category boundaries). These results suggest that although the core mechanisms for gaze processing are already in place by the age of 6, their development continues across the whole of childhood. (PsycINFO Database Record

The role of piriform associative connections in odor categorization

Distributed neural activity patterns are widely proposed to underlie object identification and categorization in the brain. In the olfactory domain, pattern-based representations of odor objects are encoded in piriform cortex. This region receives both afferent and associative inputs, though their relative contributions to odor perception are poorly understood. Here, we combined a placebo-controlled pharmacological fMRI paradigm with multivariate pattern analyses to test the role of associative connections in sustaining olfactory categorical representations. Administration of baclofen, a GABA(B) agonist known to attenuate piriform associative inputs, interfered with within-category pattern separation in piriform cortex, and the magnitude of this drug-induced change predicted perceptual alterations in fine-odor discrimination performance. Comparatively, baclofen reduced pattern separation between odor categories in orbitofrontal cortex, and impeded within-category generalization in hippocampus. Our findings suggest that odor categorization is a dynamic process concurrently engaging stimulus discrimination and generalization at different stages of olfactory information processing, and highlight the importance of associative networks in maintaining categorical boundaries.

Typicality sharpens category representations in object-selective cortex

The purpose of categorization is to identify generalizable classes of objects whose members can be treated equivalently. Within a category, however, some exemplars are more representative of that concept than others. Despite long-standing behavioral effects, little is known about how typicality influences the neural representation of real-world objects from the same category. Using fMRI, we showed participants 64 subordinate object categories (exemplars) grouped into 8 basic categories. Typicality for each exemplar was assessed behaviorally and we used several multi-voxel pattern analyses to characterize how typicality affects the pattern of responses elicited in early visual and object-selective areas: V1, V2, V3v, hV4, LOC. We found that in LOC, but not in early areas, typical exemplars elicited activity more similar to the central category tendency and created sharper category boundaries than less typical exemplars, suggesting that typicality enhances within-category similarity and between-category dissimilarity. Additionally, we uncovered a brain region (cIPL) where category boundaries favor less typical categories. Our results suggest that typicality may constitute a previously unexplored principle of organization for intra-category neural structure and, furthermore, that this representation is not directly reflected in image features describing natural input, but rather built by the visual system at an intermediate processing stage.

Is perceptual learning influenced by inherent variability of phonetic category?

A body of research has shown the effect of lexically guided perceptual learning (e.g., Norris et al., 2003), whereby listeners modify phonetic category boundaries after being exposed to critical words that contain segments that are phonetically ambiguous and serve as new exemplars of a target phonetic category. It has been shown that several factors constrain the extent of learning, and one recent study (Stevens et al., 2007) suggests that inherently variable phonetic categories might resist retuning. To test this idea, we examined modifiability of two vowel categories, [i] and [u], the latter of which has a wider range of variability than the former due to contextual variation as well as ongoing sound change. Our listeners heard exposure stimuli that were ambiguous between [i] and [u], embedded in lexical frames that yield real words only if the vowel is /i/ (/i/-words) or /u/ (/u/-words), during lexical decision tasks. Each listener’s category boundary between [i]-[u] was measured Pre- and Post-exposure. Our results show that listeners tend to shift boundaries more for [i] than [u], suggesting a way that listeners balance between flexibility and stability in speech perception.

Categorical perception for red and brown.

Recent studies suggest that the widely accepted evidence in support of categorical perception of color may be a confound of effects due to low-level sensory mechanisms that are unrelated to color categories. To reveal genuine category effects, we investigated the category boundary least prone to spurious effects of low-level mechanisms: the boundary between red and brown. We tested for low-level sensory and high-level cognitive effects of categories on color discrimination, while carefully controlling potential factors of color vision that are not related to color categories. First, we established the red-brown boundary through a naming task and measured just-noticeable differences (JNDs) for colors across the boundary. If low-level sensitivity to color differences was categorical, JNDs should decrease toward the boundary. However, this was not the case. Second, we measured performance in terms of response times and error rates in a speeded discrimination task with color pairs that were equalized in discriminability based on the empirical JNDs. There was a boost of performance (lower response times and error rates) for identifying color differences in equally discriminable color pairs, when the colors crossed the boundary. Given the particularity of the red-brown boundary, these results prove that the observed effects were due to color categories rather than low-level visual mechanisms. These findings support the idea that category effects are due to a shift of attention to the linguistic distinction between categories, rather than being a pure product of perception. These category effects do not depend on the hemispheric lateralization of language. (PsycINFO Database Record

Recreating Virginity in Iran: Hymenoplasty as a Form of Resistance

Hymenoplasty is a controversial surgery in Iran, where a woman's failure to present herself as virginal for marriage may result in severe social repercussions. Critical literature surrounding this clandestine surgery is sparse. During ethnographic fieldwork in Tehran, I interviewed women who have and have not undergone hymenoplasty and physicians who perform it. Using a Foucauldian framework, I argue that the medicalization of virginity is a form of female social control in Iran. The resulting narratives and discourses suggest that hymenoplasty is a covert form of resistance against socioculturally prescribed sexual inegalitarianism that restricts women to the social sphere of premarital chastity. By manipulating the medicalization of virginity, women inadvertently resist dichotomous gendered classifications that constrain them as either the deviant woman who has premarital sex or the normal woman who remains virginal until marriage. These women deviate from a fixed notion of gender embodiment, eroding socioculturally constituted categorical boundary markers regarding femininity.

NICE: A Computational Solution to Close the Gap from Colour Perception to Colour Categorization.

The segmentation of visible electromagnetic radiation into chromatic categories by the human visual system has been extensively studied from a perceptual point of view, resulting in several colour appearance models. However, there is currently a void when it comes to relate these results to the physiological mechanisms that are known to shape the pre-cortical and cortical visual pathway. This work intends to begin to fill this void by proposing a new physiologically plausible model of colour categorization based on Neural Isoresponsive Colour Ellipsoids (NICE) in the cone-contrast space defined by the main directions of the visual signals entering the visual cortex. The model was adjusted to fit psychophysical measures that concentrate on the categorical boundaries and are consistent with the ellipsoidal isoresponse surfaces of visual cortical neurons. By revealing the shape of such categorical colour regions, our measures allow for a more precise and parsimonious description, connecting well-known early visual processing mechanisms to the less understood phenomenon of colour categorization. To test the feasibility of our method we applied it to exemplary images and a popular ground-truth chart obtaining labelling results that are better than those of current state-of-the-art algorithms.

Is discrimination enhanced at a category boundary? The case of unique red.

Is chromatic discrimination enhanced at the boundary between different hues? In previous studies, we gave a positive answer for the case of the locus of unique blues and yellows, the boundary that divides color space into reddish and greenish hues. But we did not find enhancement at the locus of unique green, the boundary between yellowish and bluish hues. In the present study, we examined discrimination near the locus of unique red. In interleaved experimental runs, we obtained (1) discrimination thresholds using a four-alternative spatial forced choice and (2) phenomenological judgments of the locus of unique red. When measurements were made along lines parallel to the locus of unique blues and yellows in a MacLeod-Boynton diagram, the locus of minimal thresholds coincided approximately with the locus of unique red; however, this was not the case when measurements were made along lines orthogonal to the locus of unique blues and yellows. To account for these and earlier results, we suppose that the neural channel that determines the discrimination threshold will sometimes coincide with the channel that determines the perceptual hue equilibrium and sometimes will not. If a given point in chromaticity space is a unique hue, then it is expected to remain a unique hue independently of the direction in which measurements are made; however, discrimination thresholds almost certainly will depend on different underlying channels when measurements are made in different directions through the same point in chromaticity space.

Categories of Large Numbers in Line Estimation.

How do people stretch their understanding of magnitude from the experiential range to the very large quantities and ranges important in science, geopolitics, and mathematics? This paper empirically evaluates how and whether people make use of numerical categories when estimating relative magnitudes of numbers across many orders of magnitude. We hypothesize that people use scale words-thousand, million, billion-to carve the large number line into categories, stretching linear responses across items within each category. If so, discontinuities in position and response time are expected near the boundaries between categories. In contrast to previous work (Landy, Silbert, & Goldin, 2013) that suggested only that a minority of college undergraduates employed categorical boundaries, we find that discontinuities near category boundaries occur in most or all participants, but that accurate and inaccurate participants respond in opposite ways to category boundaries. Accurate participants highlight contrasts within a category, whereas inaccurate participants adjust their responses toward category centers.