273 research outputs found

    Scalar-tensor theories of gravity, neutrino physics, and the H0 tension

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    We use Planck 2018 data to constrain the simplest models of scalar-tensor theories characterized by a coupling to the Ricci scalar of the type F(σ)R with F(σ) = N2 pl + ξσ2 . We update our results with previous Planck and BAO data releases obtaining the tightest constraints to date on the coupling parameters, that is ξ < 5.5 × 10−4 for Npl = 0 (induced gravity or equivalently extended Jordan-Brans-Dicke) and (Npl √ 8πG) − 1 < 1.8 × 10−5 for ξ = −1/6 (conformal coupling), both at 95% CL. Because of a modified expansion history after radiation-matter equality compared to the ΛCDM model, all these dynamical models accommodate a higher value for H0 and therefore alleviate the tension between Planck/BAO and distance-ladder measurement from SNe Ia data from 4.4σ at best to 2.7-3.2σ with CMB alone and 3.5-3.6σ including BAO data

    Conceptual knowledge for understanding other’s actions is organized primarily around action goals

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    Semantic knowledge about objects entails both knowing how to grasp an object (grip-related knowledge) and what to do with an object (goal-related knowledge). Considerable evidence suggests a hierarchical organization in which specific hand-grips in action execution are most often selected to accomplish a remote action goal. The present study aimed to investigate whether a comparable hierarchical organization of semantic knowledge applies to the recognition of other’s object-directed actions as well. Correctness of either the Grip (hand grip applied to the object) or the Goal (end-location at which an object was directed) were manipulated independently in two experiments. In Experiment 1, subjects were required to attend selectively to either the correctness of the grip or the goal of the observed action. Subjects were faster when attending to the goal of the action and a strong interference of goal-violations was observed when subjects attended to the grip of the action. Importantly, observation of irrelevant goal- or grip-related violations interfered with making decisions about the correctness of the relevant dimension only when the relevant dimension was correct. In contrast, in Experiment 2, when subjects attended to an action-irrelevant stimulus dimension (i.e. orientation of the object), no interference of goal- or grip-related violations was found, ruling out the possibility that interference-effects result from perceptual differences between stimuli. These findings suggest that understanding the correctness of an action selectively recruits specialized, but interacting networks, processing the correctness of goal- and grip-specific information during action observation

    Empathy, engagement, entrainment: the interaction dynamics of aesthetic experience

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    A recent version of the view that aesthetic experience is based in empathy as inner imitation explains aesthetic experience as the automatic simulation of actions, emotions, and bodily sensations depicted in an artwork by motor neurons in the brain. Criticizing the simulation theory for committing to an erroneous concept of empathy and failing to distinguish regular from aesthetic experiences of art, I advance an alternative, dynamic approach and claim that aesthetic experience is enacted and skillful, based in the recognition of others’ experiences as distinct from one’s own. In combining insights from mainly psychology, phenomenology, and cognitive science, the dynamic approach aims to explain the emergence of aesthetic experience in terms of the reciprocal interaction between viewer and artwork. I argue that aesthetic experience emerges by participatory sense-making and revolves around movement as a means for creating meaning. While entrainment merely plays a preparatory part in this, aesthetic engagement constitutes the phenomenological side of coupling to an artwork and provides the context for exploration, and eventually for moving, seeing, and feeling with art. I submit that aesthetic experience emerges from bodily and emotional engagement with works of art via the complementary processes of the perception–action and motion–emotion loops. The former involves the embodied visual exploration of an artwork in physical space, and progressively structures and organizes visual experience by way of perceptual feedback from body movements made in response to the artwork. The latter concerns the movement qualities and shapes of implicit and explicit bodily responses to an artwork that cue emotion and thereby modulate over-all affect and attitude. The two processes cause the viewer to bodily and emotionally move with and be moved by individual works of art, and consequently to recognize another psychological orientation than her own, which explains how art can cause feelings of insight or awe and disclose aspects of life that are unfamiliar or novel to the viewer

    Grasping the Intentions of Others with One's Own Mirror Neuron System

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    Understanding the intentions of others while watching their actions is a fundamental building block of social behavior. The neural and functional mechanisms underlying this ability are still poorly understood. To investigate these mechanisms we used functional magnetic resonance imaging. Twenty-three subjects watched three kinds of stimuli: grasping hand actions without a context, context only (scenes containing objects), and grasping hand actions performed in two different contexts. In the latter condition the context suggested the intention associated with the grasping action (either drinking or cleaning). Actions embedded in contexts, compared with the other two conditions, yielded a significant signal increase in the posterior part of the inferior frontal gyrus and the adjacent sector of the ventral premotor cortex where hand actions are represented. Thus, premotor mirror neuron areas—areas active during the execution and the observation of an action—previously thought to be involved only in action recognition are actually also involved in understanding the intentions of others. To ascribe an intention is to infer a forthcoming new goal, and this is an operation that the motor system does automatically

    fMRI Supports the Sensorimotor Theory of Motor Resonance

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    The neural mechanisms mediating the activation of the motor system during action observation, also known as motor resonance, are of major interest to the field of motor control. It has been proposed that motor resonance develops in infants through Hebbian plasticity of pathways connecting sensory and motor regions that fire simultaneously during imitation or self movement observation. A fundamental problem when testing this theory in adults is that most experimental paradigms involve actions that have been overpracticed throughout life. Here, we directly tested the sensorimotor theory of motor resonance by creating new visuomotor representations using abstract stimuli (motor symbols) and identifying the neural networks recruited through fMRI. We predicted that the network recruited during action observation and execution would overlap with that recruited during observation of new motor symbols. Our results indicate that a network consisting of premotor and posterior parietal cortex, the supplementary motor area, the inferior frontal gyrus and cerebellum was activated both by new motor symbols and by direct observation of the corresponding action. This tight spatial overlap underscores the importance of sensorimotor learning for motor resonance and further indicates that the physical characteristics of the perceived stimulus are irrelevant to the evoked response in the observer
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