1,721,062 research outputs found
Habituation to abrupt onset distractors with different spatial occurrence probability
No full textDataset and experimental scripts related to the publication "Habituation to abrupt onset distractors with different spatial occurrence probability", by Matteo Valsecchi and Massimo Turatto, published in Attention, Perception & Psychophysics.
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Habituation to onsets is controlled by spatially selective distractor expectation
Full text linkHabituation to onset distractors has been shown to be stronger the higher the distractor probability. However, since in previous studies distractor probability covaried with distractor numerosity, it was unclear whether habituation was controlled by a mechanism that relies on distractor expectation (Sokolov, 1963), or by a mechanism that is merely driven by the number of stimulations delivered to the nervous system (Groves & Thompson, 1970). To address this issue, we manipulated the probability of distractor occurrence at a fixed location, without varying the number of distractors being presented. The results of Experiment 1 clearly favored the Sokolov model of habituation, showing that habituation of capture is controlled by the level of distractor expectation for the same distractors number. Experiment 2 excluded that the pattern of habituation was determined by the difference in the temporal frequency of the distractor between higher and lower distractor rates. Furthermore, the results of Experiment 3 suggested that the amount of habituation of capture is mainly controlled by the local rather than by the global rate of the onset distractor occurrence, thus indicating that habituation of capture is largely spatially specific
Context matters: Domestic chicks’ short- and long-term habituation of freezing to a sudden acoustic stimulus
No full textHabituation, a response decrement to an irrelevant stimulus across repeated presentations, is often described as the simplest form of non-associative learning, and it is often considered to be stimulus-specific1. However, associative models of habituation have been proposed, according to which a stimulus-context association is established in long-term memory when a stimulus is presented repeatedly2. If habituation is context-specific, the habituated response to the same stimulus should not transfer from one context to another3-5.
We reared 51 chicks (Gallus gallus) in cages with an imprinting object as social companion for 2 days. On the next 2 days, all chicks underwent 2 daily sequences, 1 hour apart, of 5 sudden burst of white noise (250 ms), one every 30-60 seconds. Chicks could be administered the stimulation in the following conditions: a) always within a running wheel; b) one day in the home-cage and the next in the wheel; c) in a cage-replica placed in the same experimental room of the wheel and the next day in the wheel. Number and duration of stops of running in the wheel were the measures of chicks’ freezing response.
When tested in the wheel, chicks stimulated in their home-cage froze significantly more than those stimulated always in the wheel, and those stimulated in the cage-replica before being moved in the wheel. Chicks stimulated in the same environment (the experimental room) but in different contexts (wheel vs. cage-replica), showed a comparable level of habituation overall. However, a higher proportion of stops revealed a modulation of context when chicks were moved from the cage-replica to the wheel as compared to those stimulated only in the wheel.
We documented in newborn chickens the presence of a sophisticated mechanism of associative learning that cannot be accounted for by classic non-associative models of habituation. Our data show that habituation relies both on local contextual and broader environmental information, which are not necessarily based on visual cues, and that probably involve other sensory information
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
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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