855 resultados para Perception and action


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Presents the results of the study on the perceptions and views of children, fathers and mothers in relation to the services and products Children's Library "Miriam Alvarez Brenes" National University, developed by the Institute of Social Studies Population (IDESP), in collaboration with the Library staff Pretend that provided inputs to become key elements in making decisions and setting policies emanating from the authorities responsible for the proper development and expansion of activities and services that are to be implemented in selected communities will benefit of this project.

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This thesis proposes a generic visual perception architecture for robotic clothes perception and manipulation. This proposed architecture is fully integrated with a stereo vision system and a dual-arm robot and is able to perform a number of autonomous laundering tasks. Clothes perception and manipulation is a novel research topic in robotics and has experienced rapid development in recent years. Compared to the task of perceiving and manipulating rigid objects, clothes perception and manipulation poses a greater challenge. This can be attributed to two reasons: firstly, deformable clothing requires precise (high-acuity) visual perception and dexterous manipulation; secondly, as clothing approximates a non-rigid 2-manifold in 3-space, that can adopt a quasi-infinite configuration space, the potential variability in the appearance of clothing items makes them difficult to understand, identify uniquely, and interact with by machine. From an applications perspective, and as part of EU CloPeMa project, the integrated visual perception architecture refines a pre-existing clothing manipulation pipeline by completing pre-wash clothes (category) sorting (using single-shot or interactive perception for garment categorisation and manipulation) and post-wash dual-arm flattening. To the best of the author’s knowledge, as investigated in this thesis, the autonomous clothing perception and manipulation solutions presented here were first proposed and reported by the author. All of the reported robot demonstrations in this work follow a perception-manipulation method- ology where visual and tactile feedback (in the form of surface wrinkledness captured by the high accuracy depth sensor i.e. CloPeMa stereo head or the predictive confidence modelled by Gaussian Processing) serve as the halting criteria in the flattening and sorting tasks, respectively. From scientific perspective, the proposed visual perception architecture addresses the above challenges by parsing and grouping 3D clothing configurations hierarchically from low-level curvatures, through mid-level surface shape representations (providing topological descriptions and 3D texture representations), to high-level semantic structures and statistical descriptions. A range of visual features such as Shape Index, Surface Topologies Analysis and Local Binary Patterns have been adapted within this work to parse clothing surfaces and textures and several novel features have been devised, including B-Spline Patches with Locality-Constrained Linear coding, and Topology Spatial Distance to describe and quantify generic landmarks (wrinkles and folds). The essence of this proposed architecture comprises 3D generic surface parsing and interpretation, which is critical to underpinning a number of laundering tasks and has the potential to be extended to other rigid and non-rigid object perception and manipulation tasks. The experimental results presented in this thesis demonstrate that: firstly, the proposed grasp- ing approach achieves on-average 84.7% accuracy; secondly, the proposed flattening approach is able to flatten towels, t-shirts and pants (shorts) within 9 iterations on-average; thirdly, the proposed clothes recognition pipeline can recognise clothes categories from highly wrinkled configurations and advances the state-of-the-art by 36% in terms of classification accuracy, achieving an 83.2% true-positive classification rate when discriminating between five categories of clothes; finally the Gaussian Process based interactive perception approach exhibits a substantial improvement over single-shot perception. Accordingly, this thesis has advanced the state-of-the-art of robot clothes perception and manipulation.

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Background and Aim: The prevalence of alcohol use has increased globally. Out-of-school youth are a vulnerable group who might have missed opportunities for learning healthy behaviours in a formal school environment. The purpose of this study was to determine the risk perception, pattern of use, and correlates of alcohol use among out-of-school youth in Lagos, Nigeria. Methods: A cross-sectional study was conducted among 380 out-of-school youth in motor parks in Lagos State, Nigeria, using interviewer administered questionnaires. Results: The lifetime prevalence of alcohol use was 61.1%, while 55.5% were current drinkers. Beer (57.3%) was the most consumed type of alcohol, followed by distilled spirits (29.8%). Using the CAGE scoring system, more than half (57.8%) of the current drinkers had a drinking problem. Almost three quarters (70.1%) had experienced at least one episode of alcohol intoxication within the past month. A considerable number of current drinkers (63.5%) desired to reduce their alcohol intake or stop drinking, while 45.5% had made unsuccessful attempts to do so within the past year. Only 28.9% had received assistance to quit or reduce their drinking and of these less than half (39.3%) received assistance from a professional or healthcare worker. Males were more likely to be current drinkers and to have experienced episodes of alcohol intoxication. Parental and peer drinking were associated with alcohol use but not with intoxication. Conclusions: It is important to design specific programmes to reduce alcohol use among out-of-school youth in these settings.

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Background. Teachers’ legitimacy is central to school functioning. Teachers’ justice, whether distributive or procedural, predicts teachers’ legitimacy. Aims. What is still do be found, and constitutes the goal of this paper, is whether unjust treatment by a teacher affects the legitimacy of the teacher differently when the student knows that the teacher was fair to a peer (comparative judgement) or when the student does not have that information (autonomous judgement). Samples. A total of 79 high school students participated in Study 1; 75 high school students participated in Study 2. Methods. Two experimental studies with a 2 justice valence (just, unjust) 9 2 social comparison processes (autonomous judgements, comparative judgements) betweenparticipants design were conducted. Study 1 addressed distributive justice and Study 2 addressed procedural justice. The dependent variable was teachers’ legitimacy. Results. In both studies, situations perceived as just led to higher teachers’ legitimacy than situations perceived as unjust. For the distributive injustice conditions, teachers’ legitimacy was equally lower for autonomous judgement and comparative judgement conditions. For procedural injustice, teachers’ legitimacy was lower when the peer was treated justly and the participant was treated unfairly, compared with the condition when the participants did not know how the teacher treated the peer. Conclusions. We conclude that teachers’ injustice affects teachers’ legitimacy, but it does it differently according to the social comparisons involved and the type of justice involved. Moreover, these results highlight that social comparisons are an important psychological process and, therefore, they should be taken into account in models of justice.

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Technological advances at the level of mobile devices are transforming the world. Banking users are able to conduct banking services at any place, and at any time, with m-banking. The purpose of this research is to analyse intention and action in m-banking services. A research model was developed and PLS was used to test the causalities in the proposed model. Our proposal extends the existing models with an assessment of the actual usage of m-banking and of how behavioural intention translates into action. This study found that the main determinants of behavioural intention for m-banking are social influence and relative advantage. Furthermore, perceived risk, lack of information and usage barriers have a negative effect on m- banking behavioural intention. Perceived risks, e-banking use, and behaviour intention are found to be significant antecedents of m-banking use. Gender has a positive and significant influence on m-banking usage, but not on the construction of behavioural intention.

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Background: Premature infants, who have to spend the first week of their lives in neonatal intensive care units (NICUs), experience pain and stress in numerous cases, and they are exposed to many invasive interventions. The studies have shown that uncontrolled pain experienced during early life has negative and long-term side effects, such as distress, and such experiences negatively affect the development of the central nervous system Objectives: The purpose of the study was to examine the effects of touching on infant pain perception and the effects of eutectic mixture of local anesthetic (EMLA) on the reduction of pain. Patients and Methods: Data for the study were collected between March and August 2012 from the neonatal clinic of a university hospital located in eastern Turkey. The population of the study consisted of premature infants who were undergoing treatment, completed the first month and who were approved for Hepatitis B vaccine. The study consisted of two experimental groups and one control group. Information forms, intervention follow-up forms, and Premature Infant Pain Profile (PIPP) were used to collect the data. EMLA cream was applied on the vastus lateralis muscles of the first experimental group before the vaccination. The second experimental group was vaccinated by imitation (placebo), without a needle tip or medicine. Vaccination was carried out using instrumental touch in this group. A routine vaccination was applied in the control group. Results: Mean pain scores of the group to which EMLA was applied were lower in a statistically significant way (P < 0.05) compared to the pain scores of the other groups. Moreover, it was determined that even though invasive intervention was not applied to the newborns, the touching caused them to feel pain just as in the placebo group (P < 0.005). Conclusions: The results demonstrated that EMLA was an effective method for reducing pain in premature newborns, and the use of instrumental touch for invasive intervention stimulated the pain perception in the newborns.

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In this article, the authors propose a theory of the truth value of propositions from a logic-mathematical point of view. The work that the authors present is an attempt to address this question from an epistemological, linguistic, and logical-mathematical point of view. What is it to exist and how do we define existence? The main objective of this work is an approach to the first of these questions. We leave a more thorough treatment of the problem of existence for future works.

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Knowledge organization (KO) research is a field of scholarship concerned with the design, study and critique of the processes of organizing and representing documents that societies see as worthy of preserving (Tennis, 2008). In this context we are concerned with the relationship between language and action.On the one hand, we are concerned with what language can and does do for our knowledge organization systems (KOS). For example, how do the words NEGRO or INDIAN work in historical and contemporary indexing languages? In relation to this, we are also concerned with how we know about knowledge organization (KO) and its languages. On the other hand, we are concerned with how to act given this knowledge. That is, how do we carry out research and how do we design, implement, and evaluate KO systems?It is important to consider these questions in the context of our work because we are delegated by society to disseminate cultural memory. We are endowed with a perspective, prepared by an education, and granted positions whereby society asks us to ensure that documentary material is accessible to future generations. There is a social value in our work, and as such there is a social imperative to our work. We must act with good conscience, and use language judiciously, for the memory of the world is a heavy burden.In this paper, I explore these two weights of language and action that bear down on KO researchers. I first summarize what extant literature says about the knowledge claims we make with regard to KO practices and systems. To make it clear what it is that I think we know, I create a schematic that will link claims (language) to actions in advising, implementing, or evaluating information practices and systems.I will then contrast this with what we do not know, that is, what the unanswered questions might be (Gnoli, 2008 ; Dahlberg, 2011), and I will discuss them in relation to the two weights in our field of KO.Further, I will try to provide a systematic overview of possible ways to address these open questions in KO research. I will draw on the concept of elenchus - the forms of epistemology, theory, and methodology in KO (Tennis, 2008), and framework analysis which are structures, work practice, and discourses of KO systems (Tennis, 2006). In so doing, I will argue for a Neopragmatic stance on the weight of language and action in KO (Rorty, 1982 ; 2000). I will close by addressing the lacuna left in Neopragmatic thought – the ethical imperative to use language and action in a particular good and moral way. That is, I will address the ethical imperative of KO given its weights, epistemologies, theories, and methods. To do this, I will review a sample of relevant work on deontology in both western and eastern philosophical schools (e.g., Harvey, 1995).The perspective I want to communicate in this section is that the good in carrying out KO research may begin with epistemic stances (cf., language), but ultimately stands on ethical actions. I will present an analysis describing the micro and the macro ethical concerns in relation to KO research and its advice on practice. I hope this demonstrates that the direction of epistemology, theory, and methodology in KO, while burdened with the dual weights of language and action, is clear when provided an ethical sounding board. We know how to proceed when we understand how our work can benefit the world.KO is an important, if not always understood, division of labor in a society that values its documentary heritage and memory institutions. Being able to do good requires us to understand how to balance the weights of language and action. We must understand where we stand and be able to chart a path forward, one that does not cause harm, but adds value to the world and those that want to access recorded knowledge.

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Polyphenols are widely present in fruits, vegetables, cereals and beverages. Their study gained scientific interest because of their beneficial effects on health. Although there is currently no official dietary recommendation for polyphenol intake, health professionals recommend the consumption of 5-8 daily portions of fruits and vegetables. This is not always achieved and, despite possible causes associated to practical schedule difficulties, the aversive bitter and astringent sensations associated to polyphenols may also lead to avoidance. As such, a better understanding on mechanisms responsible for differences among people, in polyphenol oral perception, is needed for promoting healthier choices. Saliva has been linked to polyphenol consumption. We have previously observed, in animal models, changes in salivary proteome induced by tannin-enriched diets. Moreover, differences in astringency perception were attributed to differences in salivary protein composition. In a recent experiment, we observed differences among individuals with dissimilar tannic-acid perception: people with high sensitivity for the oral sensations elicited by tannins have higher amounts of salivary cystatins and lower capacity to maintain their levels after tannic-acid ingestion. Additionally, and similarly to previous studies, salivary amylase was observed to be involved in tannin perception. In this presentation, oral cavity characteristics influencing the perception of polyphenol-containing foods will be discussed.

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Introduction: Why we need to base childrens’ sport and physical education on the principles of dynamical systems theory and ecological psychology As the childhood years are crucial for developing many physical skills as well as establishing the groundwork leading to lifelong participation in sport and physical activities, (Orlick & Botterill, 1977, p. 11) it is essential to examine current practice to make sure it is meeting the needs of children. In recent papers (e.g. Renshaw, Davids, Chow & Shuttleworth, in press; Renshaw, Davids, Chow & Hammond, in review; Chow et al., 2009) we have highlighted that a guiding theoretical framework is needed to provide a principled approach to teaching and coaching and that the approach must be evidence- based and focused on mechanism and not just on operational issues such as practice, competition and programme management (Lyle, 2002). There is a need to demonstrate how nonlinear pedagogy underpins teaching and coaching practice for children given that some of the current approaches underpinning children’s sport and P.E. may not be leading to optimal results. For example, little time is spent undertaking physical activities (Tinning, 2006) and much of this practice is not representative of the competition demands of the performance environment (Kirk & McPhail, 2002; Renshaw et al., 2008). Proponents of a non- linear pedagogy advocate the design of practice by applying key concepts such as the mutuality of the performer and environment, the tight coupling of perception and action, and the emergence of movement solutions due to self organisation under constraints (see Renshaw, et al., in press). As skills are shaped by the unique interacting individual, task and environmental constraints in these learning environments, small changes to individual structural (e.g. factors such as height or limb length) or functional constraints (e.g. factors such as motivation, perceptual skills, strength that can be acquired), task rules, equipment, or environmental constraints can lead to dramatic changes in movement patterns adopted by learners to solve performance problems. The aim of this chapter is to provide real life examples for teachers and coaches who wish to adopt the ideas of non- linear pedagogy in their practice. Specifically, I will provide examples related to specific issues related to individual constraints in children and in particular the unique challenges facing coaches when individual constraints are changing due to growth and development. Part two focuses on understanding how cultural environmental constraints impact on children’s sport. This is an area that has received very little attention but plays a very important part in the long- term development of sporting expertise. Finally, I will look at how coaches can manipulate task constraints to create effective learning environments for young children.

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This study examined the perceptual attunement of relatively skilled individuals to physical properties of striking implements in the sport of cricket. We also sought to assess whether utilising bats of different physical properties influenced performance of a specific striking action: the front foot straight drive. Eleven, skilled male cricketers (mean age = 16.6 ± 0.3 years) from an elite school cricket development programme consented to participate in the study. Whist blindfolded, participants wielded six bats exhibiting different mass and moment of inertia (MOI) characteristics and were asked to identify their three most preferred bats for hitting a ball to a maximum distance by performing a front foot straight drive (a common shot in cricket). Next, participants actually attempted to hit balls projected from a ball machine using each of the six bat configurations to enable kinematic analysis of front foot straight drive performance with each implement. Results revealed that, on first choice, the two bats with the smallest mass and MOI values (1 and 2) were most preferred by almost two-thirds (63.7%) of the participants. Kinematic analysis of movement patterns revealed that bat velocity, step length and bat-ball contact position measures significantly differed between bats. Data revealed how skilled youth cricketers were attuned to the different bat characteristics and harnessed movement system degeneracy to perform this complex interceptive action.

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The overarching aim of this thesis was to investigate how processes of perception and action emerge under changing informational constraints during performance of multi-articular interceptive actions. Interceptive actions provide unique opportunities to study processes of perception and action in dynamic performance environments. The movement model used to exemplify the functionally coupled relationship between perception and action, from an ecological dynamics perspective, was cricket batting. Ecological dynamics conceptualises the human body as a complex system composed of many interacting sub-systems, and perceptual and motor system degrees of freedom, which leads to the emergence of patterns of behaviour under changing task constraints during performance. The series of studies reported in the Chapters of this doctoral thesis contributed to understanding of human behaviour by providing evidence of key properties of complex systems in human movement systems including self-organisation under constraints and meta-stability. Specifically, the studies: i) demonstrated how movement organisation (action) and visual strategies (perception) of dynamic human behaviour are constrained by changing ecological (especially informational) task constraints; (ii) provided evidence for the importance of representative design in experiments on perception and action; and iii), provided a principled theoretical framework to guide learning design in acquisition of skill in interceptive actions like cricket batting.

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The overarching aim of this programme of work was to evaluate the effectiveness of the existing learning environment within the Australian Institute of Sport (AIS) elite springboard diving programme. Unique to the current research programme, is the application of ideas from an established theory of motor learning, specifically ecological dynamics, to an applied high performance training environment. In this research programme springboard diving is examined as a complex system, where individual, task, and environmental constraints are continually interacting to shape performance. As a consequence, this thesis presents some necessary and unique insights into representative learning design and movement adaptations in a sample of elite athletes. The questions examined in this programme of work relate to how best to structure practice, which is central to developing an effective learning environment in a high performance setting. Specifically, the series of studies reported in the chapters of this doctoral thesis: (i) provide evidence for the importance of designing representative practice tasks in training; (ii) establish that completed and baulked (prematurely terminated) take-offs are not different enough to justify the abortion of a planned dive; and (iii), confirm that elite athletes performing complex skills are able to adapt their movement patterns to achieve consistent performance outcomes from variable dive take-off conditions. Chapters One and Two of the thesis provide an overview of the theoretical ideas framing the programme of work, and include a review of literature pertinent to the research aims and subsequent empirical chapters. Chapter Three examined the representativeness of take-off tasks completed in the two AIS diving training facilities routinely used in springboard diving. Results highlighted differences in the preparatory phase of reverse dive take-offs completed by elite divers during normal training tasks in the dry-land and aquatic training environments. The most noticeable differences in dive take-off between environments began during the hurdle (step, jump, height and flight) where the diver generates the necessary momentum to complete the dive. Consequently, greater step lengths, jump heights and flight times, resulted in greater board depression prior to take-off in the aquatic environment where the dives required greater amounts of rotation. The differences observed between the preparatory phases of reverse dive take-offs completed in the dry-land and aquatic training environments are arguably a consequence of the constraints of the training environment. Specifically, differences in the environmental information available to the athletes, and the need to alter the landing (feet first vs. wrist first landing) from the take-off, resulted in a decoupling of important perception and action information and a decomposition of the dive take-off task. In attempting to only practise high quality dives, many athletes have followed a traditional motor learning approach (Schmidt, 1975) and tried to eliminate take-off variations during training. Chapter Four examined whether observable differences existed between the movement kinematics of elite divers in the preparation phases of baulked (prematurely terminated) and completed take-offs that might justify this approach to training. Qualitative and quantitative analyses of variability within conditions revealed greater consistency and less variability when dives were completed, and greater variability amongst baulked take-offs for all participants. Based on these findings, it is probable that athletes choose to abort a planned take-off when they detect small variations from the movement patterns (e.g., step lengths, jump height, springboard depression) of highly practiced comfortable dives. However, with no major differences in coordination patterns (topology of the angle-angle plots), and the potential for negative performance outcomes in competition, there appears to be no training advantage in baulking on unsatisfactory take-offs during training, except when a threat of injury is perceived by the athlete. Instead, it was considered that enhancing the athletes' movement adaptability would be a more functional motor learning strategy. In Chapter Five, a twelve-week training programme was conducted to determine whether a sample of elite divers were able to adapt their movement patterns and complete dives successfully, regardless of the perceived quality of their preparatory movements on the springboard. The data indeed suggested that elite divers were able to adapt their movements during the preparatory phase of the take-off and complete good quality dives under more varied take-off conditions; displaying greater consistency and stability in the key performance outcome (dive entry). These findings are in line with previous research findings from other sports (e.g., shooting, triple jump and basketball) and demonstrate how functional or compensatory movement variability can afford greater flexibility in task execution. By previously only practising dives with good quality take-offs, it can be argued that divers only developed strong couplings between information and movement under very specific performance circumstances. As a result, this sample was sometimes characterised by poor performance in competition when the athletes experienced a suboptimal take-off. Throughout this training programme, where divers were encouraged to minimise baulking and attempt to complete every dive, they demonstrated that it was possible to strengthen the information and movement coupling in a variety of performance circumstances, widening of the basin of performance solutions and providing alternative couplings to solve a performance problem even when the take-off was not ideal. The results of this programme of research provide theoretical and experimental implications for understanding representative learning design and movement pattern variability in applied sports science research. Theoretically, this PhD programme contributes empirical evidence to demonstrate the importance of representative design in the training environments of high performance sports programmes. Specifically, this thesis advocates for the design of learning environments that effectively capture and enhance functional and flexible movement responses representative of performance contexts. Further, data from this thesis showed that elite athletes performing complex tasks were able to adapt their movements in the preparatory phase and complete good quality dives under more varied take-off conditions. This finding signals some significant practical implications for athletes, coaches and sports scientists. As such, it is recommended that care should be taken by coaches when designing practice tasks since the clear implication is that athletes need to practice adapting movement patterns during ongoing regulation of multi-articular coordination tasks. For example, volleyball servers can adapt to small variations in the ball toss phase, long jumpers can visually regulate gait as they prepare for the take-off, and springboard divers need to continue to practice adapting their take-off from the hurdle step. In summary, the studies of this programme of work have confirmed that the task constraints of training environments in elite sport performance programmes need to provide a faithful simulation of a competitive performance environment in order that performance outcomes may be stabilised with practice. Further, it is apparent that training environments can be enhanced by ensuring the representative design of task constraints, which have high action fidelity with the performance context. Ultimately, this study recommends that the traditional coaching adage 'perfect practice makes perfect", be reconsidered; instead advocating that practice should be, as Bernstein (1967) suggested, "repetition without repetition".

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Coordination of dynamic interceptive movements is predicated on cyclical relations between an individual's actions and information sources from the performance environment. To identify dynamic informational constraints, which are interwoven with individual and task constraints, coaches’ experiential knowledge provides a complementary source to support empirical understanding of performance in sport. In this study, 15 expert coaches from 3 sports (track and field, gymnastics and cricket) participated in a semi-structured interview process to identify potential informational constraints which they perceived to regulate action during run-up performance. Expert coaches’ experiential knowledge revealed multiple information sources which may constrain performance adaptations in such locomotor pointing tasks. In addition to the locomotor pointing target, coaches’ knowledge highlighted two other key informational constraints: vertical reference points located near the locomotor pointing target and a check mark located prior to the locomotor pointing target. This study highlights opportunities for broadening the understanding of perception and action coupling processes, and the identified information sources warrant further empirical investigation as potential constraints on athletic performance. Integration of experiential knowledge of expert coaches with theoretically driven empirical knowledge represents a promising avenue to drive future applied science research and pedagogical practice.

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Previous studies have shown that balls subjected to spin induce large errors in perceptual judgements (Craig et al, 2006; Craig et al 2009) due to the additional accelerative force that causes the ball’s flight path to deviate from a standard parabolic trajectory. A recent review however, has suggested that the findings from such experiments may be imprecise due to the decoupling of perception and action and the reliance on the ventral system (Van der Kamp et al, 2008). The aim of this study was to present the same curved free kick trajectory simulations from the perception only studies (Craig et al, 2006; Craig et al, 2009) but this time allow participants to move to intercept the ball. By using immersive, interactive virtual reality technology participants were asked to control the movement of a virtual effector presented in a virtual soccer stadium so that it would make contact with a virtual soccer ball as it crossed the goal-line. As in the perception only studies the direction of spin had a significant effect on the participants’ responses (F(2,12)=222.340; p