373 research outputs found

    Mantra: an open method for object and movement tracking

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    Mantra is a free and open-source software package for object tracking. It is specifically designed to be used as a tool for response collection in psychological experiments and requires only a computer and a camera (a webcam is sufficient). Mantra is compatible with widely used software for creating psychological experiments. In Experiments 1 and 2, we validated the spatial and temporal precision of Mantra in realistic experimental settings. In Experiments 3 and 4, we validated the spatial precision and accuracy of Mantra more rigorously by tracking a computer controlled physical stimulus and stimuli presented on a computer screen

    Individual Recognition in Domestic Cattle (Bos taurus): Evidence from 2D-Images of Heads from Different Breeds

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    BACKGROUND: In order to maintain cohesion of groups, social animals need to process social information efficiently. Visual individual recognition, which is distinguished from mere visual discrimination, has been studied in only few mammalian species. In addition, most previous studies used either a small number of subjects or a few various views as test stimuli. Dairy cattle, as a domestic species allow the testing of a good sample size and provide a large variety of test stimuli due to the morphological diversity of breeds. Hence cattle are a suitable model for studying individual visual recognition. This study demonstrates that cattle display visual individual recognition and shows the effect of both familiarity and coat diversity in discrimination. [br/]METHODOLOGY/PRINCIPAL FINDINGS: We tested whether 8 Prim'Holstein heifers could recognize 2D-images of heads of one cow (face, profiles, (3/4) views) from those of other cows. Experiments were based on a simultaneous discrimination paradigm through instrumental conditioning using food rewards. In Experiment 1, all images represented familiar cows (belonging to the same social group) from the Prim'Holstein breed. In Experiments 2, 3 and 4, images were from unfamiliar (unknown) individuals either from the same breed or other breeds. All heifers displayed individual recognition of familiar and unfamiliar individuals from their own breed. Subjects reached criterion sooner when recognizing a familiar individual than when recognizing an unfamiliar one (Exp 1: 3.1+/-0.7 vs. Exp 2: 5.2+/-1.2 sessions; Z = 1.99, N = 8, P = 0.046). In addition almost all subjects recognized unknown individuals from different breeds, however with greater difficulty. [br/] CONCLUSIONS/SIGNIFICANCE: Our results demonstrated that cattle have efficient individual recognition based on categorization capacities. Social familiarity improved their performance. The recognition of individuals with very different coat characteristics from the subjects was the most difficult task. These results call for studies exploring the mechanisms involved in face recognition allowing interspecies comparisons, including humans

    Paradoxical effects of Worrisome Thoughts Suppression: the influence of depressive mood

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    Thought suppression increases the persistence of unwanted idiosyncratic worries thoughts when individuals try to suppress them. The failure of suppression may contribute to the development and maintenance of emotional disorders. Depressive people seem particulary prone to engage in unsuccessful mental control strategies such as thought suppression. Worry has been reported to be elevated in depressed individuals and a dysphoric mood may also contribute for the failure of suppression. No studies examine, however, the suppression of worisome thoughts in individuals with depressive symptoms. To investigate the suppression effects of worrisome thoughts, 46 participants were selected according to the cut-off score of a depressive symptomatology scale and they were divided in two groups (subclinical and nonclinical group). All the individuals took part in an experimental paradigm of thought suppression. The results of the mixed factorial analysis of variance revealed an increased frequency of worrisome thoughts during the suppression phase on depending of the depressive symptoms. These findings confirm that depressive mood can reduce the success of suppression.info:eu-repo/semantics/publishedVersio

    Assessing Levels of Attention Using Low Cost Eye Tracking

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    The emergence of mobile eye trackers embedded in next generation smartphones or VR displays will make it possible to trace not only what objects we look at but also the level of attention in a given situation. Exploring whether we can quantify the engagement of a user interacting with a laptop, we apply mobile eye tracking in an in-depth study over 2 weeks with nearly 10.000 observations to assess pupil size changes, related to attentional aspects of alertness, orientation and conflict resolution. Visually presenting conflicting cues and targets we hypothesize that it's feasible to measure the allocated effort when responding to confusing stimuli. Although such experiments are normally carried out in a lab, we are able to differentiate between sustained alertness and complex decision making even with low cost eye tracking "in the wild". From a quantified self perspective of individual behavioral adaptation, the correlations between the pupil size and the task dependent reaction time and error rates may longer term provide a foundation for modifying smartphone content and interaction to the users perceived level of attention.Comment: 12 pages, 6 figures, 2 tables. The final publication will be available at Springer via http://dx.doi.org/DOIxxx, when published as part of the HCI International 2016 Conference Proceeding

    Using Evolutionary Algorithms for Fitting High-Dimensional Models to Neuronal Data

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    In the study of neurosciences, and of complex biological systems in general, there is frequently a need to fit mathematical models with large numbers of parameters to highly complex datasets. Here we consider algorithms of two different classes, gradient following (GF) methods and evolutionary algorithms (EA) and examine their performance in fitting a 9-parameter model of a filter-based visual neuron to real data recorded from a sample of 107 neurons in macaque primary visual cortex (V1). Although the GF method converged very rapidly on a solution, it was highly susceptible to the effects of local minima in the error surface and produced relatively poor fits unless the initial estimates of the parameters were already very good. Conversely, although the EA required many more iterations of evaluating the model neuron’s response to a series of stimuli, it ultimately found better solutions in nearly all cases and its performance was independent of the starting parameters of the model. Thus, although the fitting process was lengthy in terms of processing time, the relative lack of human intervention in the evolutionary algorithm, and its ability ultimately to generate model fits that could be trusted as being close to optimal, made it far superior in this particular application than the gradient following methods. This is likely to be the case in many further complex systems, as are often found in neuroscience

    Comparing angular and curved shapes in terms of implicit associations and approach/avoidance responses.

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    Most people prefer smoothly curved shapes over more angular shapes. We investigated the origin of this effect using abstract shapes and implicit measures of semantic association and preference. In Experiment 1 we used a multidimensional Implicit Association Test (IAT) to verify the strength of the association of curved and angular polygons with danger (safe vs. danger words), valence (positive vs. negative words) and gender (female vs. male names). Results showed that curved polygons were associated with safe and positive concepts and with female names, whereas angular polygons were associated with danger and negative concepts and with male names. Experiment 2 used a different implicit measure, which avoided any need to categorise the stimuli. Using a revised version of the Stimulus Response Compatibility (SRC) task we tested with a stick figure (i.e., the manikin) approach and avoidance reactions to curved and angular polygons. We found that RTs for approaching vs. avoiding angular polygons did not differ, even in the condition where the angles were more pronounced. By contrast participants were faster and more accurate when moving the manikin towards curved shapes. Experiment 2 suggests that preference for curvature cannot derive entirely from an association of angles with threat. We conclude that smoothly curved contours make these abstract shapes more pleasant. Further studies are needed to clarify the nature of such a preference

    Hypnotic analgesia reduces brain responses to pain seen in others.

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    Brain responses to pain experienced by oneself or seen in other people show consistent overlap in the pain processing network, particularly anterior insula, supporting the view that pain empathy partly relies on neural processes engaged by self-nociception. However, it remains unresolved whether changes in one's own pain sensation may affect empathic responding to others' pain. Here we show that inducing analgesia through hypnosis leads to decreased responses to both self and vicarious experience of pain. Activations in the right anterior insula and amygdala were markedly reduced when participants received painful thermal stimuli following hypnotic analgesia on their own hand, but also when they viewed pictures of others' hand in pain. Functional connectivity analysis indicated that this hypnotic modulation of pain responses was associated with differential recruitment of right prefrontal regions implicated in selective attention and inhibitory control. Our results provide novel support to the view that self-nociception is involved during empathy for pain, and demonstrate the possibility to use hypnotic procedures to modulate higher-level emotional and social processes

    Sensorimotor adaptation as a behavioural biomarker of early spinocerebellar ataxia type 6.

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    Early detection of the behavioural deficits of neurodegenerative diseases may help to describe the pathogenesis of such diseases and establish important biomarkers of disease progression. The aim of this study was to identify how sensorimotor adaptation of the upper limb, a cerebellar-dependent process restoring movement accuracy after introduction of a perturbation, is affected at the pre-clinical and clinical stages of spinocerebellar ataxia type 6 (SCA6), an inherited neurodegenerative disease. We demonstrate that initial adaptation to the perturbation was significantly impaired in the eighteen individuals with clinical motor symptoms but mostly preserved in the five pre-clinical individuals. Moreover, the amount of error reduction correlated with the clinical symptoms, with the most symptomatic patients adapting the least. Finally both pre-clinical and clinical individuals showed significantly reduced de-adaptation performance after the perturbation was removed in comparison to the control participants. Thus, in this large study of motor features in SCA6, we provide novel evidence for the existence of subclinical motor dysfunction at a pre-clinical stage of SCA6. Our findings show that testing sensorimotor de-adaptation could provide a potential predictor of future motor deficits in SCA6

    Attempting to reduce susceptibility to fraudulent computer pop-ups using malevolence cue identification training

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    People accept a high number of computer pop-ups containing cues that indicate malevolence when they occur as interrupting tasks during a cognitively demanding memory-based task [1, 2], with younger adults spending only 5.5–6-s before making an accept or decline decision [2]. These findings may be explained by at least three factors: pressure to return to the suspended task to minimize forgetting; adopting non-cognitively demanding inspection strategies; and, having low levels of suspicion [3]. Consequences of such behavior could be potentially catastrophic for individuals and organizations (e.g., in the event of a successful cyber breach), and thus it is crucial to develop effective interventions to reduce susceptibility. The current experiment (N = 50) tested the effectiveness of malevolence cue identification training (MCIT) interventions. During phase 1, participants performed a serial recall task with some trials interrupted by pop-up messages with accept or cancel options that either contained cues (e.g., missing company name, misspelt word) to malevolence (malevolent condition) or no cues (non-malevolent condition). In phase 2, participants were allocated to one of three groups: no MCIT/Control, non-incentivized MCIT/N-IMCIT, or incentivized MCIT/IMCIT. Control group participants only had to identify category-related words (e.g., colors). Participants in intervention conditions were explicitly made aware of the malevolence cues in Phase 1 pop-ups before performing trying to identify malevolence cues within adapted passages of text. The N-IMCIT group were told that their detection accuracy was being ranked against other participants, to induce social comparison. Phase 3 was similar to phase 1, although 50% of malevolent pop-ups contained new cues. MCIT did lead to a significant reduction in the number of malevolent pop-ups accepted under some conditions. Incentivized training did not (statistically) improve performance compared to non-incentivized training. Cue novelty had no effect. Ways of further improving the MCIT training protocol used, as well as theoretical implications, are discussed
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