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See detailSelectivity of Face Perception to Horizontal Information over Lifespan (from 6 to 74 Year Old).
Goffaux, Valerie; Poncin, Aude; Schiltz, Christine UL

in PloS one (2015), 10(9), 0138812

Face recognition in young human adults preferentially relies on the processing of horizontally-oriented visual information. We addressed whether the horizontal tuning of face perception is modulated by ... [more ▼]

Face recognition in young human adults preferentially relies on the processing of horizontally-oriented visual information. We addressed whether the horizontal tuning of face perception is modulated by the extensive experience humans acquire with faces over the lifespan, or whether it reflects an invariable processing bias for this visual category. We tested 296 subjects aged from 6 to 74 years in a face matching task. Stimuli were upright and inverted faces filtered to preserve information in the horizontal or vertical orientation, or both (HV) ranges. The reliance on face-specific processing was inferred based on the face inversion effect (FIE). FIE size increased linearly until young adulthood in the horizontal but not the vertical orientation range of face information. These findings indicate that the protracted specialization of the face processing system relies on the extensive experience humans acquire at encoding the horizontal information conveyed by upright faces. [less ▲]

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See detailHorizontal tuning for faces originates in high-level Fusiform Face Area.
Goffaux, Valerie; Duecker, Felix; Hausfeld, Lars et al

in Neuropsychologia (2015), 81

Recent work indicates that the specialization of face visual perception relies on the privileged processing of horizontal angles of facial information. This suggests that stimulus properties assumed to be ... [more ▼]

Recent work indicates that the specialization of face visual perception relies on the privileged processing of horizontal angles of facial information. This suggests that stimulus properties assumed to be fully resolved in primary visual cortex (V1; e.g., orientation) in fact determine human vision until high-level stages of processing. To address this hypothesis, the present fMRI study explored the orientation sensitivity of V1 and high-level face-specialized ventral regions such as the Occipital Face Area (OFA) and Fusiform Face Area (FFA) to different angles of face information. Participants viewed face images filtered to retain information at horizontal, vertical or oblique angles. Filtered images were viewed upright, inverted and (phase-)scrambled. FFA responded most strongly to the horizontal range of upright face information; its activation pattern reliably separated horizontal from oblique ranges, but only when faces were upright. Moreover, activation patterns induced in the right FFA and the OFA by upright and inverted faces could only be separated based on horizontal information. This indicates that the specialized processing of upright face information in the OFA and FFA essentially relies on the encoding of horizontal facial cues. This pattern was not passively inherited from V1, which was found to respond less strongly to horizontal than other orientations likely due to adaptive whitening. Moreover, we found that orientation decoding accuracy in V1 was impaired for stimuli containing no meaningful shape. By showing that primary coding in V1 is influenced by high-order stimulus structure and that high-level processing is tuned to selective ranges of primary information, the present work suggests that primary and high-level levels of the visual system interact in order to modulate the processing of certain ranges of primary information depending on their relevance with respect to the stimulus and task at hand. [less ▲]

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See detailHorizontal tuning of face-specific processing from childhood to elderly adulthood.
Goffaux, Valerie; Poncin, Aude; Schiltz, Christine UL

Poster (2015)

Face recognition in adults recruits specialised mechanisms that are selectively driven by horizontal information. This range indeed conveys the most optimal and stable cues to identity. Whether the ... [more ▼]

Face recognition in adults recruits specialised mechanisms that are selectively driven by horizontal information. This range indeed conveys the most optimal and stable cues to identity. Whether the horizontal tuning of adult face recognition reflects horizontal bias already active at infancy and/or whether it also results from the extensive experience acquired with faces over the lifespan is elusive. Answering these questions is crucial to determine the information constraining the developmental specialisation of core visual functions such as face perception. Participants aged between 6 and 74 years matched unfamiliar faces that were filtered to retain information in narrow ranges centred on horizontal (H), vertical (V), or both orientation ranges (HV). H and V ranges respectively maximize and minimize the recruitment of face-specific mechanisms (Goffaux and Dakin, 2010). Stimuli were presented at upright and inverted planar orientations and the face inversion effect (FIE; i.e., better performance for upright than inverted faces) was taken as a marker of face-specific processing. In H and HV conditions, FIE size increased linearly from childhood to adulthood, manifesting the progressive specialization of face perception. FIE emerged earlier when processing HV than H faces (FIE onset: 6 and 12 years, respectively) indicating that until 12 years horizontal information is necessary but not sufficient to trigger face-specialised processing. Partial correlations further showed that FIE development in HV condition was not fully explained by FIE development in H condition. Besides a progressive maturation of horizontal processing, the specialization of the face processing system thus also depends on the improved integration of horizontal range with other orientations. In contrast, FIE size was small and stable when processing V information. These results show that the face processing system matures over the life span based on the refined encoding of horizontally-oriented (upright) face cues. Meeting abstract presented at VSS 2015. [less ▲]

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See detailInhibition of return and attentional facilitation: Numbers can be counted in, letters tell a different story.
Hoffmann, Danielle UL; Goffaux, Valerie; Schuller, Anne-Marie UL et al

in Acta psychologica (2015), 163

Prior research has provided strong evidence for spatial-numerical associations. Single digits can for instance act as attentional cues, orienting visuo-spatial attention to the left or right hemifield ... [more ▼]

Prior research has provided strong evidence for spatial-numerical associations. Single digits can for instance act as attentional cues, orienting visuo-spatial attention to the left or right hemifield depending on the digit's magnitude, thus facilitating target detection in the cued hemifield (left/right hemifield after small/large digits, respectively). Studies using other types of behaviourally or biologically relevant central cues known to elicit automated symbolic attention orienting effects such as arrows or gaze have shown that the initial facilitation of cued target detection can turn into inhibition at longer stimulus onset asynchronies (SOAs). However, no studies so far investigated whether inhibition of return (IOR) is also observed using digits as uninformative central cues. To address this issue we designed an attentional cueing paradigm using SOAs ranging from 500ms to 1650ms. As expected, the results showed a facilitation effect at the relatively short 650ms SOA, replicating previous findings. At the long 1650ms SOA, however, participants were faster to detect targets in the uncued hemifield compared to the cued hemifield, showing an IOR effect. A control experiment with letters showed no such congruency effects at any SOA. These findings provide the first evidence that digits not only produce facilitation effects at shorter intervals, but also induce inhibitory effects at longer intervals, confirming that Arabic digits engage automated symbolic orienting of attention. [less ▲]

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See detailDifferent number-processing tasks entail qualitatively different SNARC effects
Georges, Carrie UL; Hoffmann, Danielle UL; Schiltz, Christine UL

Poster (2014, October)

Evidence for number-space associations comes from the spatial-numerical association of response-codes (SNARC) effect, consisting in faster reaction times to small/large digits with the left/right hand ... [more ▼]

Evidence for number-space associations comes from the spatial-numerical association of response-codes (SNARC) effect, consisting in faster reaction times to small/large digits with the left/right hand respectively. Although the SNARC effect has been extensively replicated, it is characterized by high inter-individual variability (e.g. Hoffmann et al., 2014). Moreover, even though number-space associations have been observed when numerical magnitude is both relevant (e.g. magnitude comparison) and irrelevant (e.g. parity and color judgment) for successful task completion, their strengths and underlying cognitive processes seem to vary depending on whether explicit reference to numerical magnitude is drawn or not (Fias et al., 2001; Mitchell et al., 2012). To further evaluate this hypothesis, we examined whether the SNARC effects observed in a single individual during distinct number-processing tasks were systematically linked. We computed correlations between the SNARC effects measured during a parity, magnitude and color judgment task in a population of 85 healthy university students (39 females, mean age=23.44 years). Interestingly, no relation could be observed between the color (slope=-6.79) and magnitude SNARC effects (slope=-6.98; r=0.18, p=0.11), indicating that number-space associations potentially underlie different cognitive operations in tasks with and without explicit numerical magnitude processing. Conversely, the parity SNARC effect (slope=-11.58) correlated with both the color (r=0.36, p=0.001) and magnitude SNARC effects (r=0.36, p=0.001). This suggests that although no explicit numerical magnitude treatment is required in the parity task – explaining its relationship with the color task – the involvement of number semantics is sufficient to position it in line with the magnitude judgment task. [less ▲]

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See detailShifts of spatial attention cued by irrelevant numbers: Electrophysiological evidence from a target discrimination task
Schuller, Anne-Marie UL; Hoffmann, Danielle UL; Goffaux, Valérie et al

in Journal of cognitive pychology (2014)

Fischer et al. demonstrated that a centrally presented number can shift attention to the left/right when its magnitude is small/large. Two electrophysiological studies described these attentional effects ... [more ▼]

Fischer et al. demonstrated that a centrally presented number can shift attention to the left/right when its magnitude is small/large. Two electrophysiological studies described these attentional effects as eventrelated potentials (ERPs) at centro-parietal sites. Since both studies used target detection tasks, it remains currently unknown whether similar results would be obtained with a discrimination task. We used ERPs to test whether digit cues also induce attention shifts when participants perform a feature discrimination task on targets. ERPs were recorded whereas subjects discriminated the colour of lateral targets that were preceded by a central non-predictive digit. Analysis of cue-locked controlateral vs. ipsilateral ERP activity showed the emergence of early preparatory attention-directing components in parietal and frontal regions. Moreover, target-locked P1 components at occipito-parietal sites were significantly modulated by digit magnitude-target side congruency. These results demonstrate that irrelevant digit cues also bias sensory processing when embedded in a feature-discrimination task. [less ▲]

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See detailQue fait un professeur d’université qui travaille dans le domaine des neurosciences cognitives?
Schiltz, Christine UL

Conference given outside the academic context (2014)

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See detailWaat as Dyscalculie?
Schiltz, Christine UL

Conference given outside the academic context (2014)

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See detailCognitive style influences number-space associations
Georges, Carrie UL; Hoffmann, Danielle UL; Schiltz, Christine UL

Poster (2014, May)

Evidence for number-space associations comes from the spatial-numerical association of response-codes (SNARC) effect, consisting in faster reaction times to small/large digits with the left/right hand ... [more ▼]

Evidence for number-space associations comes from the spatial-numerical association of response-codes (SNARC) effect, consisting in faster reaction times to small/large digits with the left/right hand respectively. The cognitive processes underlying the SNARC effect are suggested to be task-dependent, such that number-space interactions result from verbal-spatial and visual-spatial number coding in parity and magnitude judgment tasks respectively (van Dijck et al., 2009). Moreover, the SNARC effect is characterized by high inter-individual variability (Hoffmann et al., 2014). Here we aimed to determine whether differences between the cognitive styles of individuals could influence the SNARC effect in a parity and magnitude judgment task. To distinguish between verbal and visual cognitive styles and between object- and spatial-visualizers, participants (n=74, 36 females, mean age=23.45 years) completed a modified version of Kirby et al.’s (1988) Verbalizer-Visualizer Questionnaire (VVQ, as in Mendelson & Thorson, 2004) and the Object-Spatial Imagery Questionnaire (OSIQ, Blajenkova et al., 2006, purchased from MM Virtual Design, LLC) respectively. Each item was placed on a five-point rating scale between strongly agree and strongly disagree, allowing us to compute verbal, visual, object and spatial scores for each participant. Participants that featured visual/verbal and spatial/object score ratios that were either both below or above the respective median ratio (visual/verbal ratio: M=1.09; spatial/object ratio: M=0.87) were classified as verbalizers (n=25, 16 females) and spatial-visualizers (n=25, 10 females) respectively. Participants subsequently performed the classical parity and magnitude judgment tasks. In verbalizers, the SNARC effect was significantly negative in the parity (slope=-11.2, p=0.001), but not the magnitude judgment task (slope=-1.2, p=0.53). Their verbal cognitive style might thus have induced a strong number-space association in tasks that supposedly draw on these cognitive processes, while it prevented spatial-numerical interactions in tasks that activate visuo-spatial number coding. Conversely, spatial-visualizers featured a significantly negative magnitude SNARC effect (slope=-4.8, p=0.04), indicating that a visuo-spatial style is not only necessary but sufficient to generate a number-space association in tasks that favour visuo-spatial number coding. Interestingly, they also manifested a significantly negative parity SNARC effect (slope=-9.9, p<0.001). It is likely that the spatial-visualizers switched strategy for the parity judgment task and - despite their visuo-spatial preferences - adopted the better-suited verbal strategy. Indeed, in contrast to verbalizers, their parity and magnitude SNARC effects did not correlate (spatial-visualizers: r=0.14, p=0.5; verbalizers: r=0.4, p=0.05). All in all, differences in cognitive styles might provide an additional explanation for the high inter-individual variability of the SNARC effect. Moreover, we provided further evidence for the verbal-spatial and visuo-spatial nature of the parity and magnitude SNARC effects respectively. [less ▲]

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See detailArithmetic in the Bilingual Brain: an fMRI study
Van Rinsveld, Amandine UL; Dricot, Laurence; Guillaume, Mathieu UL et al

Scientific Conference (2014, May)

How do bilinguals solve arithmetic problems in their different languages? We investigated this question with functional magnetic resonance imaging (fMRI) by exploring the neural substrates of arithmetic ... [more ▼]

How do bilinguals solve arithmetic problems in their different languages? We investigated this question with functional magnetic resonance imaging (fMRI) by exploring the neural substrates of arithmetic processing in bilinguals in comparison to monolinguals. Bilingual participants were highly proficient both in German and French as they attended primary school in German and secondary school and higher education in French. This bilingual combination is particularly interesting because the order of two-digit number words is inversed in these languages: decade-unit in French but unit-decade in German. 21 German-French bilinguals and 12 French-speaking monolinguals were scanned while performing different types of arithmetic problems: additions of different complexity levels (from simple to complex additions) and multiplication facts. We presented different types of operations in order to disentangle arithmetic computation from pure memory retrieval that occurs in very simple additions or multiplications. Arithmetic problems were presented via headsets in a verification paradigm and bilinguals performed the tasks in both languages. Results showed that all arithmetic tasks elicited a broad fronto-parietal network in both groups and for both of bilinguals’ language sessions. However, we observed that complex additions involved more left frontal activity (i.e. inferior frontal gyrus, anterior cingulate gyrus) in bilinguals than in monolinguals. It is important to notice that these frontal activation differences occurred both for the arithmetic acquisition language (i.e. German) and the second language (i.e. French). These BOLD differences between bilingual and monolingual participants were observed despite the fact that both groups solved the arithmetic problems with equivalent accuracy rates. Moreover, localization of the regions activated by complex additions in bilinguals differed from the typical activation pattern reported for mental arithmetic in recent meta-analyses (Arsalidou & Taylor, 2011). Taken together, our results indicate that highly proficient bilinguals rely on differential activation patterns than monolinguals to solve complex additions. The differences in left frontal activations might reflect different degrees of language-related automaticity when computing complex arithmetic problems. Executive functions that are necessary to control language context and access for bilinguals’ respective languages might also play a role. Further insights about the role of language in arithmetic solving process in bilingual and non-bilingual individuals will be discussed. [less ▲]

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See detailAre patients with Parkinson’s disease blind to blindsight?
Diederich, Nico UL; Stebbins, Glenn; Schiltz, Christine UL et al

in Brain : A Journal of Neurology (2014)

In Parkinson’s disease, visual dysfunction is prominent. Visual hallucinations can be a major hallmark of late stage disease, but numerous visual deficits also occur in early stage Parkinson’s disease ... [more ▼]

In Parkinson’s disease, visual dysfunction is prominent. Visual hallucinations can be a major hallmark of late stage disease, but numerous visual deficits also occur in early stage Parkinson’s disease. Specific retinopathy, deficits in the primary visual pathway and the secondary ventral and dorsal pathways, as well as dysfunction of the attention pathways have all been posited as causes of hallucinations in Parkinson’s disease. We present data from patients with Parkinson’s disease that contrast with a known neuro-ophthalmological syndrome, termed ‘blindsight’. In this syndrome, there is an absence of conscious object identification, but preserved ‘guess’ of the location of a stimulus, preserved reflexive saccades and motion perception and preserved autonomical and expressive reactions to negative emotional facial expressions. We propose that patients with Parkinson’s disease have the converse of blindsight, being ‘blind to blindsight’. As such they preserve conscious vision, but show erroneous ‘guess’ localization of visual stimuli, poor saccades and motion perception, and poor emotional face perception with blunted autonomic reaction. Although a large data set on these deficits in Parkinson’s disease has been accumulated, consolidation into one specific syndrome has not been proposed. Focusing on neuropathological and physiological data from two phylogenetically old and subconscious pathways, the retino-colliculo-thalamo-amygdala and the retino-geniculo-extrastriate pathways, we propose that aberrant function of these systems, including pathologically inhibited superior colliculus activity, deficient corollary discharges to the frontal eye fields, dysfunctional pulvinar, claustrum and amygdaloid subnuclei of the amygdala, the latter progressively burdened with Lewy bodies, underlie this syndrome. These network impairments are further corroborated by the concept of the ‘silent amygdala’. Functionally being ‘blind to blindsight’ may facilitate the highly distinctive ‘presence’ or ‘passage’ hallucinations of Parkinson’s disease and can help to explain handicaps in driving capacities and dysfunctional ‘theory of mind’. We propose this synthesis to prompt refined neuropathological and neuroimaging studies on the pivotal nuclei in these pathways in order to better understand the networks underpinning this newly conceptualized syndrome in Parkinson’s disease. [less ▲]

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See detailCanonical finger numeral configurations are perceived holistically
Di Luca, Samuel UL; Pesenti, Mauro; Schiltz, Christine UL et al

Poster (2014, April 04)

Sooner or later human beings represent or see numerosities represented by hands. This handling of small numerosities by prototypical finger configurations has been the focus of many experiments ... [more ▼]

Sooner or later human beings represent or see numerosities represented by hands. This handling of small numerosities by prototypical finger configurations has been the focus of many experiments investigating the possibility that semantic representations of numbers are motor-rooted. Canonical finger configurations (i.e. the culturally determined way to express numerosity with fingers) are for instance recognized faster (Di Luca et al., 2006), and give direct access to number semantics (Di Luca et Pesenti, 2008). It is also known that these effects are not due to a visual facilitation of canonical configurations (Di Luca et Pesenti, 2010), but to a different inner representation (Di Luca, Lefèvre and Pesenti, 2010). However, a precise characterization of their visual processing is currently lacking. We addressed this shortcoming by using an eye-tracking method based on gaze-contingent stimulus presentation (Van Belle et al., 2010). While participants named numerosities expressed by canonical and non-canonical finger numeral configurations presented in upright or inverted orientations, we selectively impaired analytical or holistic visual perception by respectively masking (in real time) peripheral or focal vision. Our data confirm the results found in literature: canonical configurations are processed faster than non-canonical ones, upright configurations are processed faster than inverted ones and holistic perception is faster than analytical one. Most importantly, we also demonstrate that canonical configurations are impaired by the peripheral mask (i.e. holistic vision hindered) whereas non-canonical ones are impaired by the foveal mask (i.e. analytical vision hindered). These results confirm that the practice of finger numeral configurations modifies not only the way human beings process and represent numerosities but especially the way to visually perceive them. [less ▲]

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See detailPredicting first-grade mathematics achievement: the contributions of domain-general cognitive abilities, nonverbal number sense, and early number competence
Hornung, Caroline UL; Schiltz, Christine UL; Brunner, Martin UL et al

in Frontiers in Psychology [=FPSYG] (2014), 5

Early number competence, grounded in number-specific and domain-general abilities, is supposed to lay the foundation for later math achievement. Few longitudinal studies tested a comprehensive model for ... [more ▼]

Early number competence, grounded in number-specific and domain-general abilities, is supposed to lay the foundation for later math achievement. Few longitudinal studies tested a comprehensive model for early math development. Using structural equation modeling and mediation analyses, we studied the influence of kindergarteners’ basic cognitive abilities (i.e., nonverbal number sense, working memory, fluid intelligence, and receptive vocabulary) and their early number competence (i.e., symbolic number skills) on first grade math achievement (arithmetic, shape and space, and number line estimation) assessed one year later. Latent regression models revealed that nonverbal number sense and working memory are central building blocks for developing early number competence in kindergarten and that early number competence is key for first grade math achievement. Fluid intelligence significantly predicted arithmetic and number line estimation while receptive vocabulary significantly predicted shape and space after controlling for early number competence. In sum we suggest that early math achievement draws on different constellations of number-specific and domain-general mechanisms. [less ▲]

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See detailTask instructions determine the visuo-spatial and verbal-spatial nature of number-space associations
Georges, Carrie UL; Schiltz, Christine UL; Hoffmann, Danielle UL

Poster (2014, April)

Evidence for number-space associations comes from the spatial-numerical association of response-codes (SNARC) effect, consisting in faster reaction times (RTs) to small/large digits with the left/right ... [more ▼]

Evidence for number-space associations comes from the spatial-numerical association of response-codes (SNARC) effect, consisting in faster reaction times (RTs) to small/large digits with the left/right hand respectively. Classically, they are thought to result from numerical coding along a left-to-right-oriented mental number line (visuo-spatial account; Dehaene et al., 1993). Recently, an association between the verbal concepts “small”/“left” and “large”/“right” has been suggested as an alternative explanation (verbal-spatial account; Gevers et al., 2010). Since the predominance of these accounts remains debated, we aimed to determine whether task instructions influence their extent of explaining the SNARC effect. A magnitude comparison task where the verbal labels “left”/“right” were displayed on the left/right response side alternatively allowed us to directly contrast the two accounts by comparing verbal SNARC slopes (based on differences in RTs to the labels “left” and “right”) with classical spatial SNARC slopes (based on differences in RTs to the left and right response side). In the verbal condition, participants (41 students, 20 female, mean age=21.6) responded to the assigned labels irrespective of their side of appearance, whereas the spatial condition required responding to the left or right response side irrespective of the displayed label. Under verbal instructions, only the verbal slope was significantly negative (verbal slope=-67.54, spatial slope=-4.82). Conversely, no significant difference was observed between verbal and spatial slopes under spatial instructions – both slopes being significantly negative (verbal slope=-15.12, spatial slope=-29.39). Taken together, number-space associations arise from verbal coding regardless of task instructions, while spatial coding only occurs under spatial instructions. [less ▲]

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See detailThe effect of languages on the production and recognition of numbers in German-French bilinguals
Van Rinsveld, Amandine UL; Schiltz, Christine UL; Ugen, Sonja UL

Poster (2014, April)

How do bilinguals produce and recognize two-digit number words? We investigated this question at different language proficiency levels in German-French bilinguals. German two-digit number words indeed ... [more ▼]

How do bilinguals produce and recognize two-digit number words? We investigated this question at different language proficiency levels in German-French bilinguals. German two-digit number words indeed follow the unit-decade order, whereas in French the order is decade-unit. Our study was conducted in Luxembourg where pupils learn both languages at primary school. Moreover mathematics are taught in German at primary school but in French at secondary school. Pupils from grades 5 (primary school), 8 (beginning of secondary school) and 11 (middle of secondary school) performed two numerical tasks: In the number recognition task, participants were presented a spoken number word that they had to recognize among four visually presented Arabic numbers. In the number production task, participants had to pronounce visually presented Arabic numbers. Both tasks were performed in German and in French and we compared language-related performance differences for the 3 levels of language proficiencies. Participants of all levels recognized and produced number-words more efficiently in their dominant language (i.e. German). However, this advantage for the dominant language was especially prominent at the lowest level of language proficiency when mathematics education was implemented in the dominant language (i.e. German). Furthermore, performance levels decreased with increasing number size, but over and above this general trend, participants of all proficiency levels showed specific difficulties with the complex structure of French number words over 60. Taken together, these results support the view that number and language processing are tightly associated, since language proficiency and language structure influence very simple and basic numerical tasks. [less ▲]

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See detailFace perception is tuned to horizontal orientation in the N170 time window
Jacques, Corentin; Schiltz, Christine UL; Goffaux, Valerie

in Journal of Vision (2014), 14(2), 1-18

The specificity of face perception is thought to reside both in its dramatic vulnerability to picture-plane inversion and its strong reliance on horizontally oriented image content. Here we asked when in ... [more ▼]

The specificity of face perception is thought to reside both in its dramatic vulnerability to picture-plane inversion and its strong reliance on horizontally oriented image content. Here we asked when in the visual processing stream face-specific perception is tuned to horizontal information. We measured the behavioral performance and scalp event-related potentials (ERP) when participants viewed upright and inverted images of faces and cars (and natural scenes) that were phase- randomized in a narrow orientation band centered either on vertical or horizontal orientation. For faces, the magnitude of the inversion effect (IE) on behavioral discrimination performance was significantly reduced for horizontally randomized compared to vertically or nonrandomized images, confirming the importance of horizontal information for the recruitment of face- specific processing. Inversion affected the processing of nonrandomized and vertically randomized faces early, in the N170 time window. In contrast, the magnitude of the N170 IE was much smaller for horizontally randomized faces. The present research indicates that the early face- specific neural representations are preferentially tuned to horizontal information and offers new perspectives for a description of the visual information feeding face- specific perception. [less ▲]

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See detailThe Impact of Mathematical Proficiency on the Number-Space Association
Hoffmann, Danielle UL; Mussolin, Christophe; Martin, Romain UL et al

in PLoS ONE (2014)

A specific instance of the association between numerical and spatial representations is the SNARC (Spatial Numerical Association of Response Codes) effect. The SNARC effect describes the finding that ... [more ▼]

A specific instance of the association between numerical and spatial representations is the SNARC (Spatial Numerical Association of Response Codes) effect. The SNARC effect describes the finding that during binary classification of numbers participants are faster to respond to small/large numbers with the left/right hand respectively. Even though it has been frequently replicated, important inter-individual variability has also been reported. Mathematical proficiency is an obvious candidate source for inter-individual variability in numerical judgments, but studies investigating its influence on the SNARC effect remain scarce. The present experiment included a total of 95 University students, divided into three groups differing significantly in their mathematical proficiency levels. Using group analyses, it appeared that the three groups differed significantly in the strength of their number-space associations in a parity judgment task. This result was further confirmed on an individual level, with higher levels in arithmetic leading to relatively weaker SNARC effects. To explain this negative relationship we propose accounts based on differences in access to qualitatively different numerical representations and also consider more domain general factors, with a focus on inhibition capacities. [less ▲]

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See detailDiscrimination of Numerosities in children studied by means of Fast Periodic Visual Stimulation
Mejias, Sandrine; Rossion, Bruno; Schiltz, Christine UL

Poster (2014)

We are constantly dealing with quantities in our environment. This ability to process numerical magnitude is present in infants (Izard et al., 2009), a variety of animal species (Flombaum et al., 2005 ... [more ▼]

We are constantly dealing with quantities in our environment. This ability to process numerical magnitude is present in infants (Izard et al., 2009), a variety of animal species (Flombaum et al., 2005) and in tribes with small number words lexicon (Pica et al., 2004). It implies that our brain is able to extract the total number of items in a scene, regardless of perceptual interference (non-numerical properties of the stimuli). However, this ability seems to be refined through development (Halberda et al., 2012), due to visual-perception maturation and/or educational environment, e.g. when learning arithmetic. Here, we measured rapidly and objectively 6-to-12-y.o. children’s sensitivity to (non-)symbolic numerical stimuli (dots or Arabic numbers), using fast periodic visual stimulation (FVPS) as implemented in a repetition-suppression paradigm (Rossion & Boremanse, 2011). Children were presented with stimuli appearing at 3.5 items/second (fundamental frequency=3.5 Hz), for 60 seconds. Half of the sequences consisted of different stimuli at every cycle of stimulation (e.g., “10”, “18”, “12”,...), the other half of sequences were composed of same stimuli (“10”) repeated throughout the whole sequence. We observed a large increase of the EEG response at the fundamental frequency (a steady-state visual evoked potential; Regan, 1966) over the lateral parieto-occipital electrodes sites. This response was reduced when the same stimulus was repeated, especially for symbolic stimuli. These results are correlated to children’s age and visual-perception, arithmetic and non-symbolic numerical abilities (L-POST, KRT, Panamath). They indicate that FPVS of (non-)symbolic numerosities is a promising tool to study children’s sensitivity to numerical magnitude. [less ▲]

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See detailCanonical finger numeral configurations are perceived holistically
Di Luca, Samuel UL; Pesenti, Mauro; Schiltz, Christine UL et al

Poster (2014)

Sooner or later human beings represent or see numerosities represented by hands. This handling of small numerosities by prototypical finger configurations has been the focus of many experiments ... [more ▼]

Sooner or later human beings represent or see numerosities represented by hands. This handling of small numerosities by prototypical finger configurations has been the focus of many experiments investigating the possibility that semantic representations of numbers are motor-rooted. Canonical finger configurations (i.e. the culturally determined way to express numerosity with fingers) are for instance recognized faster (Di Luca et al., 2006), and give direct access to number semantics (Di Luca et Pesenti, 2008). It is also known that these effects are not due to a visual facilitation of canonical configurations (Di Luca et Pesenti, 2010), but to a different inner representation (Di Luca, Lefèvre and Pesenti, 2010). However, a precise characterization of their visual processing is currently lacking. We addressed this shortcoming by using an eye-tracking method based on gaze-contingent stimulus presentation (Van Belle et al., 2010). While participants named numerosities expressed by canonical and non-canonical finger numeral configurations presented in upright or inverted orientations, we selectively impaired analytical or holistic visual perception by respectively masking (in real time) peripheral or focal vision. Our data confirm the results found in literature: canonical configurations are processed faster than non-canonical ones, upright configurations are processed faster than inverted ones and holistic perception is faster than analytical one. Most importantly, we also demonstrate that canonical configurations are impaired by the peripheral mask (i.e. holistic vision hindered) whereas non-canonical ones are impaired by the foveal mask (i.e. analytical vision hindered). These results confirm that the practice of finger numeral configurations modifies not only the way human beings process and represent numerosities but especially the way to visually perceive them. [less ▲]

Detailed reference viewed: 61 (5 UL)