Category Boundaries Research Articles

How non-epistemic values can be epistemically beneficial in scientific classification

The boundaries of social categories are frequently altered to serve normative projects, such as social reform. Griffiths and Khalidi argue that the value-driven modification of categories diminishes the epistemic value of social categories. I argue that concerns over value-modified categories are an endorsement of problematic assumptions of the value-free ideal of science. Contrary to those concerns, non-epistemic value considerations can increase the epistemic success of a scientific category. For example, the early history of the category infantile autism shows how non-epistemic value considerations can contribute to delimiting and establishing infantile autism as a distinct category in mainstream psychiatry. In the case of infantile autism, non-epistemic considerations have led to a new interpretation of existing data, the expansion of research to include biology, and the creation of diagnostic criteria that further contribute to collecting relevant data. Given this case study, we see that non-epistemic considerations may not be epistemically detrimental but can be epistemically beneficial in scientific classification.

Denominal verb formationin English and Modern Greek

AbstractCross-linguistically, there are different patterns for denominal verb formation and languages show preferences for certain patterns (cf.McIntyre, 2015). In this paper, I focus on denominal verb formation in English and Modern Greek. The analyzed data come from the TenTen corpora (Sketch Engine,Kilgariffet al., 2014). The first aim is to quantify the use of the patterns of denominal verb formations in both languages. The results of the analysis corroborate the findings of previous analyses, such as the strong preference for conversion for denominal verb formation in English and for suffixation in Modern Greek. However, the present paper aims to go a step further. The second aim is to discuss why English and Modern Greek show these preferences. I propose that the preferences can be explained if we correlate the parameters of inflectional marking, word order/configurationality, system of lexical category assignment and boundary permeability.

Producing un/professional academics: category boundary work among migrant academics in Thai higher education

ABSTRACT This article explores the process of constituting ‘professionalism’ as a discursive category amongst migrant academics working in Thailand. We animate the conceptual resource of ‘category boundary work’ to examine the inclusionary and exclusionary practices by which ‘un/professionalism’ is produced in the talk of 25 aa-jaan dtàang châat or migrant academics working in Thailand. Throughout our data, the discourse of professionalism was constructed in opposition to three key storylines which constituted the ‘unprofessional migrant academic’ as morally questionable; underqualified; and uncommitted. We argue that the constitution of unprofessionalism matters, producing tangible effects for higher education institutions and academic workers alike.

Social Identity from Categorization and Networks: A Multilevel Study of a MMOG Community

Organization ecologists argue social identity comes from category affiliation whereas structuralists argue social identity comes from networks. The same debate has been echoed in computer mediated communication as to whether it is an interpersonal or individual-group process. This paper takes a converging perspective by arguing the two forms of social identity are fundamentally interdependent at both individual and collective levels. Drawing data from a massive multiplayer online game (MMOG), this paper models the interaction of the two forms of social identity on performance by examining 207,633 individuals affiliated to 5,797 groups. The findings show that groups fragmented into clusters have higher survival rate and better performance when category boundaries are clear, and individuals with influential within-group network positions have more outstanding performance when their category identities are unfocused. Theoretical and practical implications of findings are discussed.

Silence and its mechanisms as the discursive production of the ‘normal’ in the early childhood classroom

In this paper, we aim to better understand and trouble the discursive (re)production of what is taken as the ‘normal’ in ‘inclusive’ early childhood classrooms. We do so by exploring the practices of the ‘including’ group, the so-called ‘normal, in relation to or in the presence of those who are variously labeled as ‘non-normal’. We highlight those mechanisms that are associated with silence and taboo, and through which the including group produces and maintains itself. We present data produced during a six-month ethnographic study in three early childhood classrooms in Australia. Using the notion of category boundary work in the analysis, we illuminate the practices of silence: ‘ignoring’, ‘moving away’, ‘turning away’ and ‘keeping silent’ through which children undertake the category work of the ‘normal’. The effect of this category work, we argue, is that disability or the diagnosed subject becomes ‘the elephant in the room’, strongly present but avowedly ignored. We draw out some considerations for practice in the concluding part of the paper.

How familiarity warps representation in the face space.

Recognition of familiar as compared to unfamiliar faces is robust and resistant to marked image distortion or degradation. Here we tested the flexibility of familiar face recognition with a morphing paradigm where the appearance of a personally familiar face was mixed with the appearance of a stranger (Experiment 1) and the appearance of one's own face with the appearance of a familiar face and the appearance of a stranger (Experiment 2). The aim of the two experiments was to assess how categorical boundaries for recognition of identity are affected by familiarity. We found a narrower categorical boundary for the identity of personally familiar faces when they were mixed with unfamiliar identities as compared to the control condition, in which the appearance of two unfamiliar faces was mixed. Our results suggest that familiarity warps the representational geometry of face space, amplifying perceptual distances for small changes in the appearance of familiar faces that are inconsistent with the structural features that define their identities.

A simple rule to describe interactions between visual categories.

Humans can rapidly categorise visual objects when presented in isolation. However, in everyday life we encounter multiple objects at the same time. Far less is known about how simultaneously active object representations interact. We examined such interactions by asking participants to categorise a target object at the basic (Experiment 1) or the superordinate (Experiment 2) level while the representation of another object was still active. We found that the "prime" object strongly modulated the response to the target implying that the prime's category was rapidly and automatically accessed, influencing subsequent categorical processing. Using drift diffusion modelling, we show that a prime, whose category is different from that of the target, interferes with target processing primarily during the evidence accumulation stage. This suggests that the state of category-processing neurons is altered by an active representation and this modifies the processing of other categories. Interestingly, the strength of interference increases with the similarity between the distractor and the target category. Considering these results and previous studies, we propose a general principle that category interactions are determined by the distance from a distractor's representation to the target's task-relevant categorical boundary. We argue that this principle arises from the specific architectural organisation of categories in the brain.

The relationship between phonemic category boundary changes and perceptual adjustments to natural accents.

People often experience difficulties when they first hear a novel accent. Prior research has shown that relatively fast natural accent accommodation can occur. However, there has been little investigation of the underlying perceptual mechanism that drives the learning. The current study examines whether phonemic boundary changes play a central role in natural accent accommodation. Two well-established boundary shifting phenomena were used here-recalibration and selective adaptation-to index the flexibility of phonemic category boundaries. Natural accent accommodation was measured with a task in which listeners heard accented words and nonwords before and after listening to English sentences produced by one of two native Mandarin Chinese speakers with moderate accents. In two experiments, participants completed recalibration, selective adaptation, and natural accent accommodation tasks focusing on a consonant contrast that is difficult for native Chinese speakers to produce. We found that: (a) On the accent accommodation task, participants showed an increased endorsement of accented/mispronounced words after exposure to a speaker's accented speech, indicating a potential relaxation of criteria in the word recognition process; (b) There was no strong link between recalibrating phonemic boundaries and natural accent accommodation; (c) There was no significant correlation between recalibration and selective adaptation. These results suggest that recalibration of phonemic boundaries does not play a central role in natural accent accommodation. Instead, there is some evidence suggesting that natural accent accommodation involves a relaxation of phonemic categorization criteria. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Trauma or Drama: A Predictive Processing Perspective on the Continuum of Stress.

The notion of psychological trauma has been liberally used both in clinical literature and general discourse. However, no consensus exists on its exact meaning and definition. Whereas traditionally trauma has been mostly associated with criterion A of acute and posttraumatic stress disorders (PTSDs) as defined in the Diagnostic and Statistical Manual of Mental Disorders, many researchers find this definition too constraining and not accounting for the complexity and many aspects of trauma. This touched off a quest for a broader more accommodating trauma concept, and a dimensional view of trauma with PTSD as its extreme manifestation has been suggested. The dimensional view also has its detractors arguing that “conceptual bracket creep” may undermine the category’s utility. Both categorical and dimensional views mostly rely on trauma’s clinical phenomenology and lack a unified theoretical basis. In an attempt to reconcile this contradiction, a hybrid categorical–dimensional model of trauma based on the general theory of stress has been recently proposed (Krupnik, 2019). Herein, I explore the categorical boundary of the trauma concept, as posited by the model, within the predictive processing framework (PPF). I integrate the PPF view with the theory of stress. In conclusion, I briefly discuss how the proposed model of trauma may guide clinical practice.

Variation in carotenoid-containing retinal oil droplets correlates with variation in perception of carotenoid coloration

In the context of mate choice, males may vary continuously in their expression of assessment signals, typically reflecting information about variation in mate quality. Similarly, females may exhibit variation in mate preference, which could be due to differences in how individual females perceive signals. The extent to which perception varies across individuals, however, and whether differences in sensory physiology underlie perceptual differences is poorly understood. Carotenoid pigments create the orange-red coloration of many assessment signals, and they also play a role in color discrimination in many vertebrates via their presence in retinal oil droplets. Here, we link variation in oil droplet carotenoid concentration with the ability of female zebra finches (Taeniopygia guttata) to discriminate an orange-red color continuum that parallels variation in male beak color, a mate assessment signal. We have shown previously that zebra finch females perceive this color range categorically, meaning they label color stimuli from this continuum as belonging to two categories and exhibit better discrimination between colors from different categories as compared with equally different colors from within a category. We quantified behavioral color discrimination and R-type (red) cone oil droplet spectral absorption, a proxy for carotenoid concentration. Oil droplet absorption was strongly predictive of variation in behavioral color discrimination ability. In particular, higher carotenoid concentration in oil droplets correlated with increased discrimination of colors from different sides of the previously identified category boundary. These data show that differences in the sensory periphery can correlate with individual variation in perception of a signal-relevant color range.Significance statementSignal receivers vary in their preferences for signaling traits, but whether this is due to variation in how different receivers perceive signals is not well-understood. We show that variation between individual zebra finch females in perception of an orange-red continuum range correlates with the carotenoid concentration of retinal oil droplets. These data provide the first direct evidence that individual variation in oil droplet carotenoid concentration can lead to variation in color discrimination ability. Linking variation in signal-relevant color discrimination ability with variation in retinal physiology suggests a potential mechanism contributing to individual variation in signal assessment.

Effect of Music Training on Categorical Perception of Speech and Music.

Background and ObjectivesThe aim of this study is to evaluate the effect of music training on the characteristics of auditory perception of speech and music. The perception of speech and music stimuli was assessed across their respective stimulus continuum and the resultant plots were compared between musicians and non-musicians.Subjects and MethodsThirty musicians with formal music training and twenty-seven non-musicians participated in the study (age: 20 to 30 years). They were assessed for identification of consonant-vowel syllables (/da/ to /ga/), vowels (/u/ to /a/), vocal music note (/ri/ to /ga/), and instrumental music note (/ri/ to /ga/) across their respective stimulus continuum. The continua contained 15 tokens with equal step size between any adjacent tokens. The resultant identification scores were plotted against each token and were analyzed for presence of categorical boundary. If the categorical boundary was found, the plots were analyzed by six parameters of categorical perception; for the point of 50% crossover, lower edge of categorical boundary, upper edge of categorical boundary, phoneme boundary width, slope, and intercepts.ResultsOverall, the results showed that both speech and music are perceived differently in musicians and non-musicians. In musicians, both speech and music are categorically perceived, while in non-musicians, only speech is perceived categorically.ConclusionsThe findings of the present study indicate that music is perceived categorically by musicians, even if the stimulus is devoid of vocal tract features. The findings support that the categorical perception is strongly influenced by training and results are discussed in light of notions of motor theory of speech perception.

The Extraordinary Ordinary: Re‐engineering Multilingualism as a Natural Category

AbstractThis article addresses different ways scholars conceptualize the multilingual repertoire. Formal and functional approaches investigate crosslinguistic influence across clearly demarcated languages, while dynamic systems theory and translanguaging approaches question countability and boundedness of languages. Problems with both perspectives are discussed, and a unified approach that relies on the idea of languages as natural categories is presented as a form of conceptual reengineering. It embraces the possibility and the meaningfulness of the identification of languages in the repertoire while also accounting for their continuous, graded nature and the lack of clear boundaries of language categories. The proposal accounts for seemingly inconsistent findings on the effects of bi‐ and multilingualism on cognition and on language learning. Multilingualism as a field of inquiry is the investigation of an ordinary phenomenon; what is special about multilingualism is that multilingual speakers may have an extraordinary amount of language and linguistic variability at their disposal.

Earlier age of second language learning induces more robust speech encoding in the auditory brainstem in adults, independent of amount of language exposure during early childhood

Learning a second language (L2) at a young age is a driving factor of functional neuroplasticity in the auditory brainstem. To date, it remains unclear whether these effects remain stable until adulthood and to what degree the amount of exposure to the L2 in early childhood might affect their outcome.We compared three groups of adult English-French bilinguals in their ability to categorize English vowels in relation to their frequency following responses (FFR) evoked by the same vowels. At the time of testing, cognitive abilities as well as fluency in both languages were matched between the (1) simultaneous bilinguals (SIM, N = 18); (2) sequential bilinguals with L1-English (N = 14); and (3) sequential bilinguals with L1-French (N = 11).Our results show that the L1-English group show sharper category boundaries in identification of the vowels compared to the L1-French group. Furthermore, the same pattern was reflected in the FFRs (i.e., larger FFR responses in L1-English > SIM > L1-French), while again only the difference between the L1-English and the L1-French group was statistically significant; nonetheless, there was a trend towards larger FFR in SIM compared to L1-French.Our data extends previous literature showing that exposure to a language during the first years of life induces functional neuroplasticity in the auditory brainstem that remains stable until at least young adulthood. Furthermore, the findings suggest that amount of exposure (i.e., 100% vs. 50%) to that language does not differentially shape the robustness of the perceptual abilities or the auditory brainstem encoding of phonetic categories of the language.Statement of significance:Previous studies have indicated that early age of L2 acquisition induces functional neuroplasticity in the auditory brainstem during processing of the L2. This study compared three groups of adult bilinguals who differed in their age of L2 acquisition as well as the amount of exposure to the L2 during early childhood. We demonstrate for the first time that the neuroplastic effect in the brainstem remains stable until young adulthood and that the amount of L2 exposure does not influence behavioral or brainstem plasticity. Our study provides novel insights into low-level auditory plasticity as a function of varying bilingual experience.

Integration and segmentation conflict during ensemble coding of shape.

During ensemble coding, the visual system extracts summary information from input that has been integrated, facilitating gist-level judgments about objects and features that belong together. In contrast, input can be segmented, allowing for quick categorical distinctions between objects. Integration and segmentation usually work in parallel but may sometimes conflict in the context of ensemble coding. To investigate this possibility, we examined summary perception of aspect ratio (i.e., "tallness/flatness"). Aspect ratio has a category boundary (e.g., a circle), and individual aspect ratios may be perceptually exaggerated-segmented-away from this boundary. We predicted that summary perception of multiple aspect ratios would be disrupted when, as a set, they spanned the category boundary, since integration and segmentation would then be at odds. We found that when observers reported the average aspect ratio of a set of ellipses, they were less sensitive to the mean of sets that included both tall and flat ellipses, compared to sets comprised of tall or flat ellipses. Follow-up experiments suggest this occurred because segmentation distorted the appearance of ellipses away from the category boundary, exaggerating set heterogeneity. These experiments advance understanding of how the visual system summarizes information by showing that integration and segmentation can conflict. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Categorical face perception in fish: How a fish brain warps reality to dissociate "same" from "different".

Categorical perception (CP) is the phenomenon by which a smoothly varying stimulus property undergoes a nonlinear transformation during processing in the brain. Consequently, the stimuli are perceived as belonging to distinct categories separated by a sharp boundary. Originally thought to be largely innate, the discovery of CP in tasks such as novel image discrimination has piqued the interest of cognitive scientists because it provides compelling evidence that learning can shape a category's perceptual boundaries. CP has been particularly closely studied in human face perception. In nonprimates, there is evidence for CP for sound and color discrimination, but not for image or face discrimination. Here, we investigate the potential for learned CP in a lower vertebrate, the damselfish Pomacentrus amboinensis. Specifically, we tested whether the ability of these fish to discriminate complex facial patterns tracked categorical rather than metric differences in the stimuli. We first trained the fish to discriminate sets of two facial patterns. Next, we morphed between these patterns and determined the just noticeable difference (JND) between a morph and original image. Finally, we tested for CP by analyzing the discrimination ability of the fish for pairs of JND stimuli along the spectrum of morphs between two original images. Discrimination performance was significant for the image pair straddling the boundary between categories, and chance for equivalent stimulus pairs on either side, thus producing the classic "category boundary" effect. Our results reveal how perception can be influenced in a top-down manner even in the absence of a visual cortex.

Cortical Auditory Event-Related Potentials and Categorical Perception of Voice Onset Time in Children With an Auditory Neuropathy Spectrum Disorder.

Objective: This study evaluated cortical encoding of voice onset time (VOT) in quiet and noise, and their potential associations with the behavioral categorical perception of VOT in children with auditory neuropathy spectrum disorder (ANSD).Design: Subjects were 11 children with ANSD ranging in age between 6.4 and 16.2 years. The stimulus was an /aba/-/apa/ vowel-consonant-vowel continuum comprising eight tokens with VOTs ranging from 0 ms (voiced endpoint) to 88 ms (voiceless endpoint). For speech in noise, speech tokens were mixed with the speech-shaped noise from the Hearing In Noise Test at a signal-to-noise ratio (SNR) of +5 dB. Speech-evoked auditory event-related potentials (ERPs) and behavioral categorization perception of VOT were measured in quiet in all subjects, and at an SNR of +5 dB in seven subjects. The stimuli were presented at 35 dB SL (re: pure tone average) or 115 dB SPL if this limit was less than 35 dB SL. In addition to the onset response, the auditory change complex (ACC) elicited by VOT was recorded in eight subjects.Results: Speech evoked ERPs recorded in all subjects consisted of a vertex positive peak (i.e., P1), followed by a trough occurring approximately 100 ms later (i.e., N2). For results measured in quiet, there was no significant difference in categorical boundaries estimated using ERP measures and behavioral procedures. Categorical boundaries estimated in quiet using both ERP and behavioral measures closely correlated with the most-recently measured Phonetically Balanced Kindergarten (PBK) scores. Adding a competing background noise did not affect categorical boundaries estimated using either behavioral or ERP procedures in three subjects. For the other four subjects, categorical boundaries estimated in noise using behavioral measures were prolonged. However, adding background noise only increased categorical boundaries measured using ERPs in three out of these four subjects.Conclusions: VCV continuum can be used to evaluate behavioral identification and the neural encoding of VOT in children with ANSD. In quiet, categorical boundaries of VOT estimated using behavioral measures and ERP recordings are closely associated with speech recognition performance in children with ANSD. Underlying mechanisms for excessive speech perception deficits in noise may vary for individual patients with ANSD.

The signals and category boundaries that enable categorical perception: a comment on Green et al.

The signals and category boundaries that enable categorical perception: a comment on Green et al.

An explicit investigation of the roles that feature distributions play in rapid visual categorization.

Ensemble representations are often described as efficient tools when summarizing features of multiple similar objects as a group. However, it can sometimes be more useful not to compute a single summary description for all of the objects if they are substantially different, for example when they belong to entirely different categories. It was proposed that the visual system can efficiently use the distributional information of ensembles to decide whether simultaneously displayed items belong to single or several different categories. Here we directly tested how the feature distribution of items in a visual array affects an ability to discriminate individual items (Experiment 1) and sets (Experiments 2-3) when participants were instructed explicitly to categorize individual objects based on the median of size distribution. We varied the width (narrow or fat) as well as the shape (smooth or two-peaked) of distributions in order to manipulate the ease of ensemble extraction from the items. We found that observers unintentionally relied on the grand mean as a natural categorical boundary and that their categorization accuracy increased as a function of the size differences among individual items and a function of their separation from the grand mean. For ensembles drawn from two-peaked size distributions, participants showed better categorization performance. They were more accurate at judging within-category ensemble properties in other dimensions (centroid and orientation) and less biased by superset statistics. This finding corroborates the idea that the two-peaked feature distributions support the "segmentability" of spatially intermixed sets of objects. Our results emphasize important roles of ensemble statistics (mean, range, distribution shape) in explicit visual categorization.

Using immersive virtual reality to modify body image

We tested the efficacy of a training programme, delivered in virtual reality (VR), to modify the perceptual boundary between what participants classify as a fat versus a thin body. Three cohorts of 20 female volunteers with high body image concerns were recruited to two intervention groups and one control group. All participants completed a 4-day training programme in VR where they categorised a series of 3D models as either thin or fat; one intervention group was presented with the stimuli briefly, while the other group had no time limits imposed. Both intervention groups were given inflationary feedback to shift their categorisations of the stimulus models towards higher BMIs. Our results show that, compared to controls, both intervention groups shifted their categorical boundaries between Day 1 and follow-up on Day 14. Unlimited stimulus presentation times were associated with a larger training effect. Furthermore, both intervention groups experienced statistically significant reductions in their concerns about their own body shape, weight and eating habits. However, only in the group with longer stimulus presentation times were these reductions consistent with a clinically meaningful effect. These findings suggest that manipulating categorical perception in VR might provide a complementary addition to existing treatments for eating disorders.

The perception of caricatured emotion in voice

Affective vocalisations such as screams and laughs can convey strong emotional content without verbal information. Previous research using morphed vocalisations (e.g. 25% fear/75% anger) has revealed categorical perception of emotion in voices, showing sudden shifts at emotion category boundaries. However, it is currently unknown how further modulation of vocalisations beyond the veridical emotion (e.g. 125% fear) affects perception. Caricatured facial expressions produce emotions that are perceived as more intense and distinctive, with faster recognition relative to the original and anti-caricatured (e.g. 75% fear) emotions, but a similar effect using vocal caricatures has not been previously examined. Furthermore, caricatures can play a key role in assessing how distinctiveness is identified, in particular by evaluating accounts of emotion perception with reference to prototypes (distance from the central stimulus) and exemplars (density of the stimulus space). Stimuli consisted of four emotions (anger, disgust, fear, and pleasure) morphed at 25% intervals between a neutral expression and each emotion from 25% to 125%, and between each pair of emotions. Emotion perception was assessed using emotion intensity ratings, valence and arousal ratings, speeded categorisation and paired similarity ratings. We report two key findings: 1) across tasks, there was a strongly linear effect of caricaturing, with caricatured emotions (125%) perceived as higher in emotion intensity and arousal, and recognised faster compared to the original emotion (100%) and anti-caricatures (25%–75%); 2) our results reveal evidence for a unique contribution of a prototype-based account in emotion recognition. We show for the first time that vocal caricature effects are comparable to those found previously with facial caricatures. The set of caricatured vocalisations provided open a promising line of research for investigating vocal affect perception and emotion processing deficits in clinical populations.