1,721,003 research outputs found
The Simon effect with saccadic eye movements
No full textIn the Simon effect performance is faster and more accurate when the task-irrelevant spatial dimension of the stimulus corresponds to the location of the response, compared to when they do not correspond. In the prosaccade-antisaccade effect the latencies of saccades away from the stimulus location (i.e., antisaccades) are slower than latencies of saccades toward the stimulus location (i.e., prosaccades). Because these two effects share a similar basis, the study of the Simon effect with saccadic eye movements needs to be decoupled from the prosaccade-antisaccade effect. A standard Simon task (Experiment 1) and a Simon task in which a distractor stimulus was also presented (Experiment 2) were implemented. In Experiment 1, results showed an effect likely attributable to the sum of the Simon effect and the prosaccade-antisaccade effect. In Experiment 2, in which the difference between the prosaccade and antisaccade was eliminated, only a Simon effect, cognitive in nature, manifested itself
Visual search during motion perception
No full textEye movements during motion tracking or smooth pursuit have been widely investigated. However, it is still unclear how eye movements and motion perception system are related. We aim to analyze the pattern of gaze during coherent motion perception in absence of tracking at the very early stage of the motion perception process. Moreover, we would measure if good performances in motion perception are guided by specific gaze pattern. We measured the gaze in twenty-five healthy subjects using eye tracker system (SMI500) during motion perception tasks (coherent motion test), and during visual search of static elements (i.e. searching coloured dots within a group of white dots). The subjects are divided in two groups: good motion perception performers (scoring above the 50% of the total trials) and bad motion performers. The gaze is analyzed by means of specific parameters obtained from the eye movements recordings: the length of the eye movement track plotted on a bidimensional plane, the area of the confidence ellipse of the eye position, the standardized length (obtained by the ratio between the length and the area of the confidence ellipse), the flattening and the slope of the confidence ellipse. Significant differences in gaze patterns are found between motion perception and static visual search tasks. The gaze during motion perception is characterized by stronger flattening of confidence ellipse and longer length of eye movement track. The good performers have significantly longer length and standardized length of the eye movements track as compared to bad performers. These results show that the motion detection requires longer gaze path with respect to static visual search and that the path length is longer in good than in bad performers. In conclusion, the efficiency in motion detection is related to longer length of the gaze path (i.e. mean velocity) more than to the area scanned by the different gaze positions
L'effetto Simon: il suo decorso temporale con stimoli visivi e risposte oculo-motorie
No full textL’effetto Simon consiste in una prestazione più veloce ed accurata quando
la posizione della risposta corrisponde alla posizione dello stimolo anche se questa
non è rilevante per il compito. Il presente lavoro ha studiato l’emergere dell’effetto Simon
e il suo decorso temporale con stimoli visivi e risposte oculo-motorie utilizzando
un paradigma di tipo standard: stimoli e risposte condividevano infatti una relazione
anatomico-spaziale. I risultati hanno mostrato un effetto (1) ampio e significativo sia
nei tempi di reazione saccadici che negli errori e (2) con un decorso temporale descrescente,
supportando l’ipotesi che esso sia dovuto ad un meccanismo visuomotorio
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
La direzione del movimento del corpo si riflette sulle operazioni di calcolo numerico?
No full textQuesto studio indaga la relazione tra i movimenti del nostro corpo e l’elaborazione numerica andando a studiare l’asse di movimento circolare. I partecipanti dovevano contare aggiungendo o sottraendo ‘tre’ mentre eseguivano dei movimenti circolari, in direzione oraria o antioraria, in modalità attiva (camminando) oppure in modalità passiva (venivano spinti su una sedia a rotelle). I risultati hanno messo in luce la presenza di una relazione tra l’elaborazione numerica e la direzione del movimento circolare, sia in condizioni di movimento attivo che passivo, ma solo per le addizioni e limitatamente ai partecipanti maschi.This study investigates the relationship between the movements of the whole body and numerical calculation, such as additions and subtractions. Starting from previous evidence on the horizontal and vertical axes, in the present study participants were required to count by adding or subtracting 'three' while performing a motion on the circular axis (i.e., a clockwise or counterclockwise movement), in an active (i.e., walking) or passive mode (i.e., being pushed on a wheelchair). Results showed the presence of a relationship between numerical processing and the direction of the circular movement, both in an active and passive movement condition, but only for additions and only for male participants. Implications of the results for theories of embodied cognition are discussed
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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