1,721,088 research outputs found
Individual differences in numerical skills are influenced by brain lateralization in guppies (Poecilia reticulata)
Get PDFA large number of studies showed that fish possess numerical abilities similar to those reported in mammals and birds. However, inter-individual differences in numerical performance are repeatedly found with different types of stimuli and methodological approaches. A recent study on guppies, Poecilia reticulata, suggested that strongly lateralized individuals, assayed for eye preference in a mirror test, were better than poorly lateralized ones when tested for numerical abilities in a natural shoal choice. This study, however, had a potential confound; both the mirror and the shoal choice tests exploit the higher sociality and schooling tendencies in guppies. It is therefore possible that sociality rather than lateralization per se may have been responsible for the observed differences. In the present study, guppies were selected for high or low lateralization using a non-social test, the detour test. Subjects preferentially turning rightward (RD) or leftward (LD) when facing a dummy predator visible behind a barrier proved better than those with no preference (NL) when required to choose the larger of two groups in a shoal choice test. Our study supports the notion that inter-individual differences in the numerical abilities of guppies are related to their degree of cerebral lateralization
Laterality enhances numerical skills in the guppy, Poecilia reticulata
Get PDFIt has been hypothesized that cerebral lateralization can significantly enhance cognition and that this was one of the primary selective forces shaping its wide-spread evolution amongst vertebrate taxa. Here we tested this hypothesis by examining the link between cerebral lateralization and numerical discrimination. Guppies, Poecilia reticulata, were sorted into left, right and non-lateralized groups using a standard mirror test and their numerical discrimination abilities tested in both natural shoal choice and abstract contexts. Our results show that strongly lateralized guppies have enhanced numerical abilities compared to non-lateralized guppies irrespective of context. These data provide further credence to the notion that cerebral lateralization can enhance cognitive efficienc
Brown, Culum
No full texthttps://www.wellbeingintlstudiesrepository.org/animsent_gallery/1609/thumbnail.jp
Brown, Culum
No full texthttps://www.wellbeingintlstudiesrepository.org/animsent_gallery/1609/thumbnail.jp
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Parental predator exposure affects offspring boldness and laterality in the stickleback
Get PDFParental influences on offspring phenotype occurring through pathways other than via inherited DNA sequences are known as parental effects. Parental effects profoundly influence offspring behaviour, including behaviour laterality and personality, two traits that are widespread and of fundamental importance in the animal kingdom with clear fitness consequences. However, the impact of parental effects on the interaction between behavioural laterality and personality within the same species has not been previously explored. If such a link exists, it would deepen our understanding of personality traits, extending them to brain laterality and its underlying neurobiology. In addition, if both traits are causally linked, it may constrain evolution as changing one of these traits would affect the other. The aim of this study was to examine whether offspring personality traits and behavioural laterality are related and can simultaneously be influenced by parental effects, suggesting a common underlying mechanism. Here we exposed parents of an egg-laying species, the stickleback Gasterosteus aculeatus, to a predator cue or not and examined the impact of this exposure on two behavioural traits of their offspring. Shortly after laying, clutches were split: half were reared without predator cues for 12 weeks before behavioural testing, and the other half were used for cortisol analysis. We found that both parents and offspring from predator-exposed parents were bolder, with the offspring more likely to show lateralized behaviour, and were smaller than offspring from parents that were not exposed to predation. The egg cortisol levels were too low to be detected by LC-MS/MS. To our knowledge, these results are the first to indicate that parental effects under varying predation conditions can influence laterality, personality and growth of offspring within the same individuals, although further evaluation and experiments are needed to determine the role of maternal cortisol
Variations on the Author
Get PDF“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
Get PDFWe 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
The Influence of Social Rank on Learning in a Cichlid Fish
No full textLearning allows animals to adapt to new and changing environments. Animals can learn through their own personal experiences, known as asocial or individual learning. Asocial learning produces reliable information, but it can be energetically costly and risky for the learner. So instead of learning on their own, animals can choose to learn by observing and copying the behaviours and choices of others, known as social learning. However, because individuals that socially learn are gaining second-hand information, this form of learning is often less reliable. Animals are expected to be flexible in their use of individual versus social information, and to use whatever strategy provides the greatest benefits. Not all animals or individuals have been found to employ a flexible strategy, and research shows that many have a clear preference for one type of learning over the other. This preference for social or individual learning can be influenced by their personality, their sex and even an individual’s reproductive status. Another factor that could influence learning is an individual’s rank, but this topic has received little attention. In my M.SC. research, I studied how social rank influences an individual’s performance in an asocial and in a social learning task using the cichlid fish Neolamprologus pulcher. Using this species I also tested if social rank influences information use, by providing conflicting individual and social information to the fish. I found that subordinate N. pulcher were faster at a reversal learning (suppressing a previously learned rule and learning a new one), but there were no clear differences between the social ranks in associative learning or in social learning. When presented with conflicting individual and social information, both subordinate and dominant N. pulcher relied on individual information first. However, dominant N. pulcher were more likely to also use the conflicting social information in addition to their individual information. Taken together these results help us better understand cognitive differences between social ranks, and shed light on how information and behaviours in social groups can be learned and spread.ThesisMaster of Science (MSc
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