225 research outputs found
In primum librum Regum expositionum libri VI
No full textThe paper traces the misunderstandings of the commentary on the first book of Regum attributed to Gregory the Great. The history of the editions is analyzed till the discovery of the only manuscript known of the work, Cava dei Tirreni, Biblioteca dell'Abbazia 9. The criteria of the last edition by Patrick Verbraken are discussed as he uncritically favored the manuscript on the constitutio textus. The problem of the authorship of the work is investigated: although recent studies date the commentary to the twelfth century and ascribe it to Peter of Venosa on the basis of the Chronicon Venusinum, it is possible that the author used texts authentically gregorian
Individualised rating-scale procedure: a means of reducing response style contamination in survey data?
No full textResponse style bias has been shown to seriously contaminate the substantive results drawn from survey data; particularly those conducted using cross-cultural samples. As a consequence, identification of response formats that suffer least from response style bias has been called for. Previous studies show that respondents’ personal characteristics, such as age, education level and culture, are connected with response style manifestation.Differences in the way respondents interpret and utilise researcher-defined fixed rating-scales (e.g. Likert formats), poses a problem for survey researchers. Techniques that are currently used to remove response bias from survey data are inadequate as they cannot accurately determine the level of contamination present and frequently blur true score variance. Inappropriate rating-scales can impact on the level of response style bias manifested, insofar as they may not represent respondents’ cognitions. Rating-scale lengths that are too long present respondents with some response categories that are not ‘meaningful’, whereas rating-scales that are too short force respondents into compressing their cognitive rating-scales into the number of response categories provided (this can cause ERS contamination – extreme responding). We are therefore not able to guard against two respondents, who share the same cognitive position on a continuum, reporting their stance using different numbers on the rating-scale provided. This is especially problematic where a standard fixed rating-scale is used in cross-cultural surveys.This paper details the development of the Individualised Rating-Scale Procedure (IRSP), a means of extracting a respondent’s ‘ideal’ rating-scale length, and as such ‘designing out’ response bias, for use as the measurement instrument in a survey. Whilst the fundamental ideas for self-anchoring rating-scales have been posited in the literature, the IRSP was developed using a series of qualitative interviews with participants. Finally, we discuss how the IRSP’s reliability and validity can be quantitatively assessed and compared to typical fixed researcher-defined rating-scales, such as the Likert format
Supramodal agnosia for oblique mirror orientation in patients with periventricular leukomalacia
No full textPeriventricular leukomalacia (PVL) is characterized by focal necrosis at the level of the periventricular white matter, often observed in preterm infants. PVL is frequently associated with motor impairment and with visual deficits affecting primary stages of visual processes as well as higher visual cognitive abilities. Here we describe six PVL subjects, with normal verbal IQ, showing orientation perception deficits in both the haptic and visual domains. Subjects were asked to compare the orientation of two stimuli presented simultaneously or sequentially, using both a two alternative forced choice (2AFC) orientation-discrimination and a matching procedure. Visual stimuli were oriented gratings or bars or collinear short lines embedded within a random pattern. Haptic stimuli comprised two rotatable wooden sticks. PVL patients performed at chance in discriminating the oblique orientation, both for visual and haptic stimuli. Moreover when asked to reproduce the oblique orientation, they often oriented the stimulus along the symmetric mirror orientation. The deficit generalized to stimuli varying in many low level features, was invariant for spatiotopic object orientation, and also occurred for sequential presentations. The deficit was specific to oblique orientations, and not for horizontal or vertical stimuli. These findings show that PVL can affect a specific network involved with the supramodal perception of mirror symmetry orientation
Excessive visual crowding effects in developmental dyscalculia
No full textVisual crowding refers to the inability to identify objects when surrounded by other similar items. Crowding-like mechanisms are thought to play a key role in numerical perception by determining the sensory mechanisms through which ensembles are perceived. Enhanced visual crowding might hence prevent the normal development of a system involved in segregating and perceiving discrete numbers of items and ultimately the acquisition of more abstract numerical skills. Here, we investigated whether excessive crowding occurs in developmental dyscalculia (DD), a neurodevelopmental disorder characterized by difficulty in learning the most basic numerical and arithmetical concepts, and whether it is found independently of associated major reading and attentional difficulties. We measured spatial crowding in two groups of adult individuals with DD and control subjects. In separate experiments, participants were asked to discriminate the orientation of a Gabor patch either in isolation or under spatial crowding. Orientation discrimination thresholds were comparable across groups when stimuli were shown in isolation, yet they were much higher for the DD group with respect to the control group when the target was crowded by closely neighbouring flanking gratings. The difficulty in discriminating orientation (as reflected by the combination of accuracy and reaction times) in the DD compared to the control group persisted over several larger target flanker distances. Finally, we found that the degree of such spatial crowding correlated with impairments in mathematical abilities even when controlling for visual attention and reading skills. These results suggest that excessive crowding effects might be a characteristic of DD, independent of other associated neurodevelopmental disorders
Time and numerosity estimation in peripersonal and extrapersonal space
No full textThe representation of space, time and number is believed to rely on a common encoding system developed to support action guidance. While the ecological advantage of such a shared system is evident when objects are located within the region of space we can act on (known as peri-personal space), it is less obvious in the case of objects located beyond our arms' reach. In the current study we investigated whether and to what extent the distance of the stimuli from the observer affects the perception of duration and numerosity. We first replicated Anelli et al.'s (2015) experiment by asking adult participants to perform a duration reproduction task with stimuli of different sizes displayed in the peri- or extra-personal space, and then applied the same paradigm to a non-symbolic numerosity estimation task. Results show that, independently of size, duration estimates were overestimated when visual stimuli were presented in the extra-personal space, replicating previous findings. A similar effect was also found for numerosity perception, however overestimation for far stimuli was much smaller in magnitude and was accounted by the difference in perceived size between stimuli presented in peripersonal or extrapersonal space. Overall, these results suggest that, while the processing of temporal information is robustly affected by the position of the stimuli in either the peri- or extra-personal space, numerosity perception is independent from stimulus distance. We speculate that, while time and numerosity may be encoded by a shared system in the peri-personal space (to optimize action execution), different and partially independent mechanisms may underlie the representation of time and numerosity in extra-personal space. Furthermore, these results suggest that investigating magnitude perception across spatial planes (where it is or is not possible to act) may unveil processing differences that would otherwise pass unnoticed
Le dediche di Giovanni Immonide
No full textThe flight from Rome of Formoso, bishop of Porto, on Easter night 876 and his subsequent conviction in the Roman synods are echoed in the dedication of the last two John the Deacon’s works, Vita Gregorii I papae and the rhythmic rewriting of the Cena Cypriani. The contribution reconstructs John Immonide’s figure, his role and his friendships within the cubiculum Lateranense, and analyzes the critical loci of the manuscript tradition of the dedication poem to Pope John VIII, prefacing the hagiographical text, and of the so called Epilogus and Suppositio closing the Cena. The sections analyzed show a tradition variously attested and not univocal, that is evidence of reworking and leads to suspect that the author has reviewed the dedications of his works when he was expelled from the Lateran, falled into disgrace with the pope, and he never reached a final version of them
Fast saccadic eye-movements in humans suggest that numerosity perception is automatic and direct
No full textFast saccades are rapid automatic oculomotor responses to salient and ecologically important visual stimuli such as animals and faces. Discriminating the number of friends, foe, or prey may also have an evolutionary advantage. In this study, participants were asked to saccade rapidly towards the more numerous of two arrays. Participants could discriminate numerosities with high accuracy and great speed, as fast as 190 ms. Intermediate numerosities were more likely to elicit fast saccades than very low or very high numerosities. Reaction-times for vocal responses (collected in a separate experiment) were slower, did not depend on numerical range, and correlated only with the slow not the fast saccades, pointing to different systems. The short saccadic reaction-times we observe are surprising given that discrimination using numerosity estimation is thought to require a relatively complex neural circuit, with several relays of information through the parietal and prefrontal cortex. Our results suggest that fast numerosity-driven saccades may be generated on a single feed-forward pass of information recruiting a primitive system that cuts through the cortical hierarchy and rapidly transforms the numerosity information into a saccade command
Tra Pirandello e Judith Butler:Forma e performatività nella narrativa di Marosia Castaldi
No full textThis article sets itself a number of challenges: 1. to make a daring comparison between the notions of identity and subjectivity held by Italian modernist author Luigi Pirandello and contemporary American feminist theorist Judith Butler. 2. to use the insights generated by this unusual yet entirely tenable comparison to interpret the engagement of contemporary author Marosia Castaldi with the postmodern loss of identity. 3. to bring to light some thematic lines across the oeuvre of a writer noted for her highly fragmented and repetitive anti-realist style and impenetrable plots. The article succeeds in bringing together Pirandello’s idea of identity as subjected to such dichotomies as life vs art-forma, flux vs fixity, uniqueness vs multiplicity with Butler’s account of identity and specifically gender identity as performativity. Both underscore identity/subjectivity as repetition and (re)citation, as mimetic acts subject to societal norms, and thus both ask whether and how change can be effected. Applying these problematics to Castaldi turns out to be highly productive. I first identify a question running through her novels: what happens to identity when the individual is subjected to continual change? I then attempt to answer this question by examining her characters’ struggle against the dissolution of identity they experience as consequence of a life marked by cyclical successions of wars, migrations, cyclones, genocides, telluric movements and volcanic explosions. I conclude with looking at how they find ways of filling the identitarian void in the parodic performance of gender and identity
Data from: Attentional amplification of neural codes for number independent of other quantities along the dorsal visual stream.
No full textThis is the functional imaging dataset related to the article "Attentional amplification of neural codes for number independent of other quantities along the dorsal visual stream" by Castaldi E, Piazza M, Dehaene S, Vignaud A, Eger E (2019) Elife, in press
Abstract: Humans and other animals base important decisions on estimates of number, and intraparietal cortex is thought to provide a crucial substrate of this ability. However, it remains debated whether an independent neuronal processing mechanism underlies this “number sense”, or whether number is instead judged indirectly on the basis of other quantitative features. We performed high-resolution 7 Tesla fMRI while adult human volunteers attended either to the numerosity or an orthogonal dimension (average item size) of visual dot arrays. Along the dorsal visual stream, numerosity explained a significant amount of variance in activation patterns, above and beyond non-numerical dimensions. Its representation was selectively amplified and progressively enhanced across the hierarchy when task relevant. Our results reveal a sensory extraction mechanism yielding information on numerosity separable from other dimensions already at early visual stages and suggest that later regions along the dorsal stream are most important for explicit manipulation of numerical quantity.
When using these data, please think of citing the original article
- …
