A kinematic comparison of successful and unsuccessful tennis serves across the elite development pathway

While velocity generation is an obvious prerequisite to proficient tennis serve performance, it is also the only stroke where players are obliged to negotiate a unique target constraint. Therefore, the dearth of research attending to the accuracy component of the serve is surprising. This study compared the body, racquet and ball kinematics characterising successful serves and service faults, missed into the net, in two groups of elite junior female players and one professional female tennis player. Three-dimensional body, racquet and ball kinematics were recorded using a 22-camera VICON motion analysis system. There were no differences in body kinematics between successful serves and service faults, suggesting that service faults cannot be attributed to a single source of biomechanical error. However, service faults missing into the net are characterized by projection angles significantly further below the horizontal, implying that consistency in this end-point parameter is critical to successful performance. Regulation of this parameter appears dependent on compensatory adjustments in the distal elbow and wrist joints immediately prior to impact and also perceptual feedback. Accordingly, coordination of the distal degrees of freedom and a refined perception-action coupling appear more important to success than any isolated mechanical component of the service action.     

Musical experts recruit action-related neural structures in harmonic anomaly detection: Evidence for embodied cognition in expertise

Humans are extremely good at detecting anomalies in sensory input. For example, while listening to a piece of Western-style music, an anomalous key change or an out-of-key pitch is readily apparent, even to the non-musician. In this paper we investigate differences between musical experts and non-experts during musical anomaly detection. Specifically, we analyzed the electroencephalograms (EEG) of five expert cello players and five non-musicians while they listened to excerpts of J.S. Bach’s Prelude from Cello Suite No. 1. All subjects were familiar with the piece, though experts also had extensive experience playing the piece. Subjects were told that anomalous musical events (AMEs) could occur at random within the excerpts of the piece and were told to report the number of AMEs after each excerpt. Furthermore, subjects were instructed to remain still while listening to the excerpts and their lack of movement was verified via visual and EEG monitoring. Experts had significantly better behavioral performance (i.e. correctly reporting AME counts) than non-experts, though both groups had mean accuracies greater than 80%. These group differences were also reflected in the EEG correlates of key-change detection post-stimulus, with experts showing more significant, greater magnitude, longer periods of, and earlier peaks in condition-discriminating EEG activity than novices. Using the timing of the maximum discriminating neural correlates, we performed source reconstruction and compared significant differences between cellists and non-musicians. We found significant differences that included a slightly right lateralized motor and frontal source distribution. The right lateralized motor activation is consistent with the cortical representation of the left hand – i.e. the hand a cellist would use, while playing, to generate the anomalous key-changes. In general, these results suggest that sensory anomalies detected by experts may in fact be partially a result of an embodied cognition, with a model of the action for generating the anomaly playing a role in its detection.     

Source misattributions and false recognition errors: Examining the role of perceptual resemblance and imagery generation processes

In three experiments, we examine the extent to which participants’ memory errors are affected by the perceptual features of an encoding series and imagery generation processes. Perceptual features were examined by manipulating the features associated with individual items as well as the relationships among items. An encoding instruction manipulation was included to examine the effects of explicit requests to generate images. In all three experiments, participants falsely claimed to have seen pictures of items presented as words, committing picture misattribution errors. These misattribution errors were exaggerated when the perceptual resemblance between pictures and images was relatively high (Experiment 1) and when explicit requests to generate images were omitted from encoding instructions (Experiments 1 and 2). When perceptual cues made the thematic relationships among items salient, the level and pattern of misattribution errors were also affected (Experiments 2 and 3). Results address alternative views about the nature of internal representations resulting in misattribution errors and refute the idea that these errors reflect only participants’ general impressions or beliefs about what was seen.     

Visual learning of statistical relations among nonadjacent features: Evidence for structural encoding

Recent results suggest that observers can learn, unsupervised, the co-occurrence of independent shape features in viewed patterns (e.g., Fiser & Aslin, 2001). A critical question with regard to these findings is whether learning is driven by a structural, rule-based encoding of spatial relations between distinct features or by a pictorial, template-like encoding, in which spatial configurations of features are embedded in a “holistic” fashion. In two experiments, we test whether observers can learn combinations of features when the paired features are separated by an intervening spatial “gap”, in which other, unrelated features can appear. This manipulation both increases task difficulty and makes it less likely that the feature combinations are encoded simply as larger unitary features. Observers exhibited learning consistent with earlier studies, suggesting that unsupervised learning of compositional structure is based on the explicit encoding of spatial relations between separable visual features. More generally, these results provide support for compositional structure in visual representation.     

Characterizing typographic expertise: Do we process typefaces like faces?

Studies of face recognition and discrimination provide a rich source of data and debate on the nature of their processing, in particular through using inverted faces. This study draws parallels between the features of typefaces and faces, as letters share a basic configuration, regardless of typeface, that could be seen as similar to faces. Typeface discrimination is compared using paragraphs of upright letters and inverted letters at three viewing durations. Based on previously reported effects of expertise, the prediction that designers would be less accurate when letters are inverted, whereas nondesigners would have similar performance in both orientations, was confirmed. A proposal is made as to which spatial relations between typeface components constitute holistic and configural processing, posited as the basis for better discrimination of the typefaces of upright letters. Such processing may characterize designers' perceptual abilities, acquired through training.     

Similarity grouping as feature-based selection

Our visual system groups objects with similar features, such as colour, orientation, or shape. We argue that similarity grouping is nothing more than global selection of a certain feature value, such as red, horizontal, or circular. This account makes the striking prediction that only one feature group can be created at a time. Here we provide the most direct evidence yet for this proposal, using a number estimation task that forces simultaneous processing of all objects. Multiple similarity cues failed to produce grouping in this task, in contrast to proximity, connectivity, and common region, which all showed strong grouping effects.     

The relation of discrete stimuli can be integrated despite the failure of conscious identification

ABSTRACT

The integration of the sameness or difference of two unconscious stimuli occurs and affects behaviour without subjective visual consciousness. Yet, intermittent stimulus awareness or a process simpler than integration could also account for these results. In a masked go/no-go task, participants provided or withheld a response based on the same/different relation of two stimuli. Post-trial performance on a discrimination task was used to classify invisible stimuli, providing an objective criterion of awareness. Stimulus pairs with a No-go-associated relation showed reduced and slower responding even when those stimuli were incorrectly discriminated and presumably unconscious. Due to the large set of stimuli, this effect is unlikely to be due to response mapping or action triggers. The integration of the relation of discrete stimuli is a cognitive function that is not dependent upon visual awareness, in the form of conscious identification, to occur.     

More of myself: Manipulating interoceptive awareness by heightened attention to bodily and narrative aspects of the self

Psychology distinguishes between a bodily and a narrative self. Within neuroscience, models of the bodily self are based on exteroceptive sensorimotor processes or on the integration of interoceptive sensations. Recent research has revealed interactions between interoceptive and exteroceptive processing of self-related information, for example that mirror self-observation can improve interoceptive awareness. Using heartbeat perception, we measured the effect on interoceptive awareness of two experimental manipulations, designed to heighten attention to bodily and narrative aspects of the self. Participants gazed at a photograph of their own face or at self-relevant words. In both experimental conditions interoceptive awareness was significantly increased, compared to baseline. Results show that attention to narrative aspects of self, previously regarded as relying on higher-order processes, has an effect similar to self-face stimuli in improving interoceptive awareness. Our findings extend the previously observed interaction between the bodily self and interoception to more abstract amodal representations of the self.     

Attending to what matters: Flexibility in adults’ and infants’ action perception

Action perception is selective in that observers attend to and encode certain dimensions of action over others. But how flexible is action perception in its selection of perceptual information? One possibility is that observers consistently attend to particular dimensions of action over others across different contexts. Another possibility, tested here, is that observers flexibly vary their attention to different dimensions of action based on the context in which action occurs. We investigated 9.5-month-old infants’ and adults’ ability to attend to drop height under varying contexts—aiming to drop an object into a narrow container versus a wide container. We predicted differential attention to increases in aiming height for the narrow container versus the wide container because an increase in aiming height has a differential effect on success (i.e., getting the object into the container) depending on the width of the container. Both adults and infants showed an asymmetry in their attention to aiming height as a function of context; in the wide container condition increases and decreases in aiming height were equally detectable, whereas in the narrow container condition observers more readily discriminated increases over decreases in aiming height. These results indicate that action perception is both selective and flexible according to context, aiding in action prediction and infants’ social–cognitive development more broadly.     

噪音背景对二语语音感知的影响

日常言语交流常常会遇到各种噪音的干扰。研究表明, 噪音所产生的能量掩蔽和信息掩蔽会给语音感知带来较大影响。在感知地道的二语语音时, 二语者在各种噪音条件下所受干扰通常比母语者更大, 其表现随噪音类型、水平和目标音位特征的不同而变化; 同时, 二语者的感知也存在较大个体差异, 这是多种因素影响的结果。在噪音下感知带有各种外国腔的二语口音时, 母语者的表现差于其对地道母语语音的感知; 二语经历贫乏的二语者则对与自己口音类似的外国腔感知较好, 但二语经历较长的二语者在感知中却表现出较大灵活性。