Response bias in judging deceptive movements

Two not mutually exclusive explanations, perceptual and motor expertise, account for the finding that experts outperform novices in recognizing deceptive actions from bodily (kinematic) cues. The aim of the present study was twofold: First, we sought to examine the impact of motor and perceptual expertise on distinguishing deceptive and non-deceptive actions. Second, we tested the hypothesis that differences in perceptual judgments on deceptive movements vs. non-deceptive movements do not necessarily need to be caused by either perceptual or motor expertise differences, but can also be a result of response bias. Skilled handball players (field players and goalkeepers) and novices had to detect whether a penalty-taker shot or faked a shot at the goal. Signal detection theory (SDT) analysis revealed that skilled handball players outperformed novices in discriminating shots from fakes. No differences in perceptual sensitivity were found between the goalkeepers and the field players. However, SDT analysis showed that goalkeepers were significantly biased to judge movements as deceptive, while neither field players nor novices showed this response bias.     

The effect of local kinematic changes on anticipation judgments

Skilled tennis players rely on a more global than local perceptual strategy when anticipating an opponent’s shot direction in tennis (Williams, Huys, Cañal-Bruland, & Hagemann, 2009). Global perceptual strategy refers to the pick-up of dynamic information across different body areas rather than from a single source such as the arm or racket. We extend previous work by examining the spatiotemporal characteristics of visual information pick-up when anticipating shot direction in tennis. We perturbed information from various body locations by interchanging the dynamics of selected areas with those from strokes played to the opposite side of the court. In addition, we presented each manipulation under four different temporal occlusion conditions (from 240 ms prior to racket-ball contact) to examine the time course of information extraction. Skilled tennis players outperformed less skilled counterparts in predicting shot direction, even at early phases of the opponent’s motion. Moreover, skilled players showed significant decrements in performance when the arms and racket were perturbed, highlighting the relevance of distal information when anticipating opponents’ intentions.     

Skilled anticipation in real-world tasks: measurement of attentional demands in the domain of tennis

Anticipatory skills are characteristic of expert performance in a range of dynamic domains. However, models of the processes underlying such skilled anticipation remain limited. This study describes the construction and validation of a video-based test of anticipation in tennis and examined whether video test performance is less attentionally demanding for expert tennis players than for novices. Expert players performed the anticipation test more effectively than novices and were less vulnerable to dual-task decrement. This article discusses these findings in relation to models of skilled anticipation. The video test could be used for both selection and identification of training needs.     

The use of anticipatory visual cues by highly skilled tennis players

The authors examined 13 skilled and 12 novice tennis performers' ability to use visual information of an opponent's movement pattern to anticipate and respond. In Experiment 1, skilled and novice players anticipated the type of stroke and the direction in which the ball was hit in a highly coupled perception-action environment. Both groups of players correctly anticipated at greater than chance levels. Skilled players were significantly more accurate than novices with live and video displays but not with point-light displays. In Experiment 2, the reaction latencies of 10 expert performers were significantly faster when they returned balls hit by a live opponent than when they returned balls projected from a cloaked ball machine. The findings indicate that experts are able to use movement-pattern information to determine shot selection and to use that information to significantly reduce their response delay times. The findings are discussed in terms of perception-action coupling in time-stress activities.     

Visual span and change detection in soccer: An expertise study

There is evidence to suggest that sports experts are able to extract more perceptual information from a single fixation than novices when exposed to meaningful tasks that are specific to their field of expertise. In particular, Reingold et al. (2001) showed that chess experts use a larger visual span including fewer fixations when compared to their less skilled counterparts. The aim of the present study was to examine whether also in a more complex environment, namely soccer, skilled players use a larger visual span and fewer fixations than less skilled players when attempting to recognise players’ positions. To this end, we combined the gaze-contingent window technique with the change detection paradigm. Results seem to suggest that skilled soccer players do not use a larger visual span than less skilled players. However, skilled soccer players showed significantly fewer fixations of longer duration than their less skilled counterparts, supporting the notion that experts may extract more information from a single glance.     

On the advantage of being left-handed in volleyball: further evidence of the specificity of skilled visual perception

High ball speeds and close distances between competitors require athletes in interactive sports to correctly anticipate an opponent's intentions in order to render appropriate reactions. Although it is considered crucial for successful performance, such skill appears impaired when athletes are confronted with a left-handed opponent, possibly because of athletes' reduced perceptual familiarity with rarely encountered left-handed actions. To test this negative perceptual frequency effect hypothesis, we invited 18 skilled and 18 novice volleyball players to predict shot directions of left- and right-handed attacks in a video-based visual anticipation task. In accordance with our predictions, and with recent reports on laterality differences in visual perception, the outcome of left-handed actions was significantly less accurately predicted than the outcome of right-handed attacks. In addition, this left-right bias was most distinct when predictions had to be based on preimpact (i.e., before hand-ball contact) kinematic cues, and skilled players were generally more affected by the opponents' handedness than were novices. The study's findings corroborate the assumption that skilled visual perception is attuned to more frequently encountered actions.     

Anticipation skill in a real-world task: measurement,training, and transfer in tennis

Anticipation skill in tennis was examined using realistic film simulations, movement-based response measures, and a portable eye movement recording system. Skilled players were faster than their less skilled counterparts in anticipating the direction of opponents' tennis strokes, with this superior performance being based, at least in part, on more effective visual search behaviors. The processes mediating superior performance were then modeled in groups of recreational tennis players using video simulation, instruction, and feedback. Players who received perceptual training improved their performance on laboratory- and field-based tests of anticipation when compared with matched placebo and control groups that did not receive any instruction regarding expert performance strategies. The approach used may have practical utility in a variety of performance contexts.     

On the dynamic information underlying visual anticipation skill

What information underwrites visual anticipation skill in dynamic sport situations? We examined this question on the premise that the optical information used for anticipation resides in the dynamic motion structures, or modes, that are inherent in the observed kinematic patterns. In Experiment 1, we analyzed whole-body movements involved in tennis shots to different directions and distances by means of principal component analysis. The shots differed in the few modes that captured most of the variance, especially as a function of shot direction. In Experiments 2 and 3, skilled and less skilled tennis players were asked to anticipate the direction of simulated shots on the basis of kinematic patterns in which only the constituent dynamic structures were manipulated. The results indicated that players predicted shot direction by picking up the information contained in multiple low-dimensional dynamic modes, suggesting that anticipation skill in tennis entails the extraction of this dynamic information from high-dimensional displays.     

Expertise, visual search, and information pick-up in squash

The visual search characteristics of expert and novice squash players were compared in two experiments. In the first experiment subjects were required to predict the forthcoming direction and force of an opponent's stroke from a film display. This film display was designed to simulate the normal display available to the defending player in squash and involved the use of variable temporal cut-offs to force the subjects to use advance cues in their prediction. Systematic differences in the information pick-up of the experts and novices were observed on the film task but these differences were achieved with only relatively minor between-group variations in visual search strategy. In the second experiment, set in the natural field setting, no expert-novice differences in either fixation distribution, order, or duration were observed on a comparable prediction task. This provided further support for the conclusion that the limiting factor in the perceptual performance of the novices is not an inappropriate search strategy but rather an inability to make full use of the information available from fixated display features. Some practical implications of these findings for the squash coach and player are considered.     

网球运动专长对深度运动知觉影响的ERP研究

结合专家-新手范式与ERP技术,研究网球运动专长对个体深度运动知觉产生的影响。通过记录网球专家和新手各19名进行深度运动模式判断时的行为和ERP数据,比较两组个体深度运动知觉的行为反应差异和脑电特征。结果显示,网球专家组深度运动知觉的判断准确率高于新手组;新手组在球体靠近时P1(PO7点)的潜伏期比球体远离时的潜伏期长,专家组无显著性差异;专家组在球体靠近时的P2(Oz点)成分潜伏期长于球体远离时的潜伏期。结果表明,网球运动专家的深度运动知觉能力在准确性上较新手高;运动专长效应与选择性注意资源的调用以及模式识别有关;枕区P2成分可作为深度运动知觉的评价指标。     

Expertise and the perception of kinematic and situational probability information

Two experiments were conducted on the nature of expert perception in the sport of squash. In the first experiment, ten expert and fifteen novice players attempted to predict the direction and force of squash strokes from either a film display (occluded at variable time periods before and after the opposing player had struck the ball) or a matched point-light display (containing only the basic kinematic features of the opponent's movement pattern). Experts out-performed the novices under both display conditions, and the same basic time windows that characterised expert and novice pick-up of information in the film task also persisted in the point-light task. This suggests that the experts' perceptual advantage is directly related to their superior pick-up of essential kinematic information. In the second experiment, the vision of six expert and six less skilled players was occluded by remotely triggered liquid-crystal spectacles at quasi-random intervals during simulated match play. Players were required to complete their current stroke even when the display was occluded and their prediction performance was assessed with respect to whether they moved to the correct half of the court to match the direction and depth of the opponent's stroke. Consistent with experiment 1, experts were found to be superior in their advance pick-up of both directional and depth information when the display was occluded during the opponent's hitting action. However, experts also remained better than chance, and clearly superior to less skilled players, in their prediction performance under conditions where occlusion occurred before any significant pre-contact preparatory movement by the opposing player was visible. This additional source of expert superiority is attributable to their superior attunement to the information contained in the situational probabilities and sequential dependences within their opponent's pattern of play.     

中国象棋经验棋手与新手的知觉差异:来自眼动的证据

为探讨中国象棋领域内的专长效应及象棋专长的知觉编码优势,研究采用中国象棋棋局为实验材料,对比了经验棋手和新手在观看象棋棋局时视觉搜索、变化觉察和对棋盘的记忆。实验1呈现真实棋局和随机棋局,要求被试观看5秒后复盘,结果发现经验棋手的复盘正确率高于新手;经验棋手注视棋盘的眼跳幅度和瞳孔直径更大;经验棋手更多注视棋子间而不是棋子本身。实验2采用移动窗口范式控制了观看棋盘时视野大小,结果发现经验棋手在副中央凹呈现时复盘正确率更高,而新手不受视野大小的影响。实验3采用闪烁范式要求棋手觉察变化的棋子,结果发现经验棋手的觉察速度和正确率都优于新手;而且经验棋手在报告变化前就利用中央凹和副中央凹注视到了变化的棋子。结论认为:中国象棋与国际象棋类似,也存在专长的知觉编码优势效应;经验棋手不仅对棋盘记忆更好,而且可以利用存贮的组块和长期练习经验选择性加工棋盘结构信息,利用副中央凹提取信息,具有更大的知觉广度。研究为象棋专家可以利用副中央凹加工棋盘及具有更强的知觉编码能力提供了直接的证据。     

On-court position and handedness in visual anticipation of stroke direction in tennis

ObjectivesIn racket sports, players integrate information picked up from their opponent's kinematics and contextual cues like on-court position into shot outcome anticipation. In view of suggested difficulties with anticipating left-handed opponents' action intentions, here we examined whether an opponent's handedness interacts with position-dependency in visual anticipation.Design and methodFollowing a 2 (Group) x 2 (Handedness) x 2 (Position) x 3 (Temporal Occlusion) factorial design, 20 tennis players and 20 non-players predicted directional outcome of temporally manipulated point-light animations of identical left- and right-handed forehand groundstrokes performed near vs. far from the court's midline.ResultsTennis players' response selection was mostly affected by an opponent's on-court position, particularly at an early stage of a hitting movement. Opponents' handedness affected response selection similarly in both groups (i.e., bias towards down-the-line predictions against left-handed strokes occluded at racket-ball-contact), but it did not interact with on-court position.ConclusionsFindings highlight that on-court position, and opponents' handedness to some extent as well, appears relevant for skilled visual anticipation in tennis.     

Anticipation of ball location in low and high-skill performers: a developmental perspective

Objectives: To study how visual anticipatory capabilities develop in high and low-skill tennis players and the role of years of practice (i.e. experience). It was expected that with accumulated experience differences will increase with skill-level, in particular under conditions of fast visual exposure which results in minimal environmental information exposure.Method: Eighty tennis players divided into 4 age categories and 2 skill levels (high and low) were selected according to 4 criterion which ensured appropriate representation of skill-level and experience in tennis. Age categories were 8–11, 11–14, 14–18, and >18. Years of experience in the game were 2.12, 4.17, 6.5, and 12.4 years respectively. Players observed filmed segments of tennis strokes on a monitor, which varied in temporal occlusion conditions from −480 ms prior to ball-racquet contact to 320 ms after contact. After each exposure they were asked to indicate the final ball location. The radial, lateral, and depth distances were averaged for age and skill level.Design: A temporal occlusion paradigm was used in this study. The film was prepared with a camera positioned in the receiver's court. Eight strokes which best represent the game of tennis were chosen. Forty-eight segments were viewed and errors were calculated for each exposure.Result: High-skill tennis players gained more from practice and experience in developing visual anticipatory skills, but their perceptual advantage was not consistent across all stroke conditions, being at its greatest number in conditions of maximal temporal constraints.Conclusions: Differences in visual anticipatory capabilities exist between different skill levels at the outset of their development. These differences increase with experience, mainly after 6–7 years. Greater knowledge base does not always guarantee a superior anticipation of upcoming events and choosing the best decision.     

Skilled players’ and novices’ difficulty anticipating left- vs. right-handed opponents’ action intentions varies across different points in time

A left-handers’ performance advantage in interactive sports is assumed to result from their relative rarity compared to right-handers. Part of this advantage may be explained by athletes facing difficulties anticipating left-handers’ action intentions, particularly when anticipation is based on kinematic cues available at an early stage of an opponent’s movement. Here we tested whether the type of volleyball attack is predicted better against right- vs. left-handed opponents’ movements and whether such handedness effects are evident at earlier time points in skilled players than novices. In a video-based experiment volleyball players and novices predicted the type of shot (i.e., smash vs. lob) of left- and right-handed volleyball attacks occluded at six different time points. Overall, right-handed attacks were better anticipated than left-handed attacks, volleyball players outperformed novices, and performance improved in later occlusion conditions. Moreover, in skilled players the handedness effect was most pronounced when attacks were occluded 480 ms prior to hand-ball-contact, whereas in novices it was most evident 240 ms prior to hand-ball-contact. Our findings provide further evidence of the effect of an opponent’s handedness on action outcome anticipation and suggest that its occurrence in the course of an opponent’s unfolding action likely depends on an observers’ domain-specific skill.     

The advantage of being left-handed in interactive sports

As compared with their prevalence in the general population, left-handers are overrepresented in the expert domain of many interactive sports. This study examined to what extent this is due to negative perceptual frequency effects—that is, whether the greater frequency of tennis matches with right-handed opponents makes it possible to discriminate the stroke movements of right-handed players more precisely. Fifty-four right-handed and 54 left-handed males in three equal-sized groups of varying levels of tennis expertise (national league experts, local league intermediates, and novices) completed a tennis anticipation test in which they had to predict the subsequent direction of an opponent’s temporally occluded tennis strokes on a computer screen. The results showed that all three groups were better at predicting the direction of strokes by right-handed players. This supports the hypothesis that the overrepresentation of left-handers in the expert domain is partly due to perceptual frequency effects.     

Expertise in basketball modifies perceptual discrimination abilities,underlying cognitive processes,and visual behaviours

In this paper, the links between cognitive constraints, visual behaviours, and perceptual judgements are examined. Two experiments investigated the perceptual processes employed during same-different judgement tasks. In Experiment 1, experts' eye movements (i.e., number of fixations and fixation duration) were consistent across discrepant source and target conditions where the number of displaced elements was manipulated. In contrast, novices decreased the number of fixations employed as the number of elements displaced increased. The findings are consistent with the view that both experts and novices process information in a manner (relational or attributional) that constrains the type of visual search used (low or high sensitive to attributional change). In Experiment 2, manipulation of target presentation confirmed that recognition was viewpoint dependent for both expert and novice players. The degradation in performance was accompanied by a change in the visual search behaviours employed by experts, which confirmed thr strength of the search–cognition–performance links     

Visual search,anticipation, and reactive comparisons between highly-skilled and beginning tennis players

Abstract

Simulated tennis playing situations were created for the laboratory testing of visual search patterns, anticipation, reactions, and movements to compare male and female high-level and beginning players. Of particular interest was the degree to which each measure would differentiate the groups. Participants were highly-rated university players (N-30) and students enrolled in a beginning tennis class (N = 30). Under one testing condition, visual search patterns were recorded as they viewed filmed opponents serve (60 trials) and hit ground strokes (60 trials). Also recorded was anticipation accuracy and speed of the intended type and location of serves and the intended placement of ground strokes. In other testing, execution of a split step was followed by moving rapidly to the comet location for a simulated stroke in response to a series of light cues. Reaction and movement times were recorded. Discrimination analysis revealed that experts and beginners were most differentiated due to fixations on certain cues and predicting ball direction. As to visual search analysis of fixation duration for nine possible areas during the serves, only the head area was significant. Beginners directed more time toward the head region than did the highly skilled. Experts and novices had similar visual patterns with respect to ground strokes, and a few differences existed within the two female groups, in the two male groups. as well as between males and females. Anticipation measures for the serve indicated that experts were faster and more accurate than beginners, and males were faster than females. Ground stroke data revealed that the highly-skilled were faster and more accurate than novices. Finally, the simulated split-step data showed that reaction times and movement times were faster for the experts versus the beginners, and males were quicker in movement times than females.     

Expert-novice differences in cognitive and execution skills during tennis competition

This study deals with decision and execution behavior of tennis players during competition. The study is based on the expert-novice paradigm and aims to identify differences between both groups in the decision-making and execution variables in serve and shot actions in tennis. Six expert players (elite Spanish tennis players) and six novice players (grade school tennis players) took part in this study. To carry out this study, the observation protocol defined by McPherson and Thomas in 1989, in which control, decision-making and execution variables were included, was used, where it was applied to the performance of the tennis player in a real match situation. In the analysis, significant differences between experts and novices in decision-making and execution variables are found wherein it can be observed that experts display a greater ability to make the appropriate decisions, selecting the most tactical responses to put pressure on the opponent. Expert tennis players were also able to carry out forceful executions to their opponent with greater efficiency, making the opponent's response to a large extent more difficult. These findings are in accordance with those of McPherson and colleagues.     

The Effectiveness of Situational Awareness Learning in Response to Video Tennis Match Situations

The purpose of the study was to examine the effectiveness of specially designed instructions on tennis match play training on situation awareness (SA), anticipation (A), and decision-making (DM). Response speed and accuracy measures were taken in videoed match play tennis situations and the effect of perceptual skills training on these behaviors was recorded in a primary and two related tennis situations. Intermediate tennis players (N = 59, M = 21.75 years old, SD = 4.96) were randomly assigned to one of five groups. After receiving instructions, participants responded to a series of edited video clips. A 5 × 3 × 3 (Groups × Condition x Shot Type) repeated-measures multivariate analysis of variance (MANOVA) was conducted to determine differences in perceptual training and learning strategies across three conditions and multiple shot types. Findings indicated that combinational SA/A/DM perceptual training effectively improved performance; however, no difference was found between implicit and explicit learning strategies. Future research possibilities and applied implications are discussed.