976 resultados para Perception-action


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Perception is linked to action via two routes: a direct route based on affordance information in the environment and an indirect route based on semantic knowledge about objects. The present study explored the factors modulating the recruitment of the two routes, in particular which factors affecting the selection of paired objects. In Experiment 1, we presented real objects among semantically related or unrelated distracters. Participants had to select two objects that can interact. The presence of distracters affected selection times, but not the semantic relations of the objects with the distracters. Furthermore, participants first selected the active object (e.g. teaspoon) with their right hand, followed by the passive object (e.g. mug), often with their left hand. In Experiment 2, we presented pictures of the same objects with no hand grip, congruent or incongruent hand grip. Participants had to decide whether the two objects can interact. Action decisions were faster when the presentation of the active object preceded the presentation of the passive object, and when the grip was congruent. Interestingly, participants were slower when the objects were semantically but not functionally related; this effect increased with congruently gripped objects. Our data showed that action decisions in the presence of strong affordance cues (real objects, pictures of congruently gripped objects) relied on sensory-motor representation, supporting the direct route from perception-to-action that bypasses semantic knowledge. However, in the case of weak affordance cues (pictures), semantic information interfered with action decisions, indicating that semantic knowledge impacts action decisions. The data support the dual-route account from perception-to-action.

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Dance is a rich source of material for researchers interested in the integration of movement and cognition. The multiple aspects of embodied cognition involved in performing and perceiving dance have inspired scientists to use dance as a means for studying motor control, expertise, and action-perception links. The aim of this review is to present basic research on cognitive and neural processes implicated in the execution, expression, and observation of dance, and to bring into relief contemporary issues and open research questions. The review addresses six topics: 1) dancers’ exemplary motor control, in terms of postural control, equilibrium maintenance, and stabilization; 2) how dancers’ timing and on-line synchronization are influenced by attention demands and motor experience; 3) the critical roles played by sequence learning and memory; 4) how dancers make strategic use of visual and motor imagery; 5) the insights into the neural coupling between action and perception yielded through exploration of the brain architecture mediating dance observation; and 6) a neuroaesthetics perspective that sheds new light on the way audiences perceive and evaluate dance expression. Current and emerging issues are presented regarding future directions that will facilitate the ongoing dialogue between science and dance.

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Objective. To evaluate the perception of eating practices and the stages of change among adolescents. Methods. Cross-sectional study involving a representative sample of 390 adolescents from 11 public schools in the city of Piracicaba, Brazil, in 2004. Food consumption was identified by a food frequency questionnaire and the perception of eating practices evaluation was conducted by comparing food consumption and individual classification of healthy aspects of the diet. The participants were classified within stages of change by means of a specific algorithm. A reclassification within new stages of change was proposed to identify adolescents with similar characteristics regarding food consumption and perception. Results. Low consumption of fruit and vegetables and high consumption of sweets and fats were identified. More than 44% of the adolescents had a mistaken perception of their diet. A significant relationship between the stages of change and food consumption was observed. The reclassification among stages of change, through including the pseudo-maintenance and non-reflective action stages was necessary, considering the high proportion of adolescents who erroneously classified their diets as healthy. Conclusion. Classification of the adolescents into stages of change, together with consumption and perception data, enabled identification of groups at risk, in accordance with their inadequate dietary habits and non-recognition of such habits. (C) 2009 Elsevier Inc. All rights reserved.

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Ethylene is a plant hormone that is of fundamental importance to in vitro morphogenesis, but in many species, it has not been thoroughly studied. Its relationship with polyamines has been studied mainly because the two classes of hormones share a common biosynthetic precursor, S-adenosylmethionine (SAM). In order to clarify whether competition between polyamines and ethylene influences in vitro morphogenetic responses of Passiflora cincinnata Mast., a climacteric species, different compounds were used that act on ethylene biosynthesis and action, or as ethylene scavengers. Treatment with the ethylene inhibitor, aminoethoxyvinylglycine (AVG) caused a greater regeneration frequency in P. cincinnata, whereas treatment with the ethylene precursor, 1-aminocyclopropane-1-carboxylic-acid (ACC) lessened regeneration frequencies. The data suggested that levels of polyamines and ethylene are not correlated with morphogenic responses in P. cincinnata. It was ascertained that neither the absolute ethylene and polyamine levels, nor competition between the compounds, correlated to the obtained morphogenic responses. However, sensitivity to, and signaling by, ethylene appears to play an important role in differentiation. This study reinforces previous reports regarding the requirement of critical concentrations and temporal regulation of ethylene levels for morphogenic responses. Temporal regulation also appeared to be a key factor in competition between the two biosynthetic pathways, without having any effects on morphogenesis. Further studies investigating the silencing or overexpression of genes related to ethylene perception, under the influence of polyamines in cell differentiation are extremely important for the complete understanding of this process.

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Previous studies have documented temporal attraction in perceived times of actions and their effects. While some authors argue that voluntary action is a necessary condition for this phenomenon, others claim that the causal relationship between action and effect is the crucial ingredient. In the present study, we investigate voluntary action and causality as the necessary and sufficient conditions for temporal binding. We used a variation of the launching effect proposed by Michotte, in which participants controlled the launch stimulus in some blocks. Volunteers reported causality ratings and estimated the interval between the two events. Our results show dissociations between causality ratings and temporal estimation. While causality ratings are not affected by voluntary action, temporal bindings were only found in the presence of both voluntary action and high causality. Our results indicate that voluntary action and causality are both necessary for the emergence of temporal binding.

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Previous studies have documented a subjective temporal attraction between actions and their effects. This finding, named intentional binding, is thought to be the result of a cognitive function that links actions to their consequences. Although several studies have tried to outline the necessary and sufficient conditions for intentional binding, a quantitative comparison between the roles of temporal contiguity, predictability and voluntary action and the evaluation of their interactions is difficult due to the high variability of the temporal binding measurements. In the present study, we used a novel methodology to investigate the properties of intentional binding. Subjects judged whether an auditory stimulus, which could either be triggered by a voluntary finger lift or be presented after a visual temporal marker unrelated to any action, was presented synchronously with a reference stimulus. In three experiments, the predictability, the interval between action and consequence and the presence of action itself were manipulated. The results indicate that (1) action is a necessary condition for temporal binding; (2) a fixed interval between the two events is not sufficient to cause the effect and (3) only in the presence of voluntary action do temporal predictability and contiguity play a significant role in modulating the effect.These findings are discussed in the context of the relationship between intentional binding and temporal expectation. (C) 2010 Elsevier B.V. All rights reserved.

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The research topic of this paper is focused on the analysis of how trade associations perceive lobbying in Brussels and in Brasília. The analysis will be centered on business associations located in Brasília and Brussels as the two core centers of decision-making and as an attraction for the lobbying practice. The underlying principles behind the comparison between Brussels and Brasilia are two. Firstof all because the European Union and Brazil have maintained diplomatic relations since 1960. Through these relations they have built up close historical, cultural, economic and political ties. Their bilateral political relations culminated in 2007 with the establishment of a Strategic Partnership (EEAS website,n.d.). Over the years, Brazil has become a key interlocutor for the EU and it is the most important market for the EU in Latin America (European Commission, 2007). Taking into account the relations between EU and Brazil, this research could contribute to the reciprocal knowledge about the perception of lobby in the respective systems and the importance of the non-market strategy when conducting business. Second both EU and Brazilian systems have a multi-level governance structure: 28 Member States in the EU and 26 Member States in Brazil; in both systems there are three main institutions targeted by lobbying practice. The objective is to compare how differences in the institutional environments affect the perception and practice of lobbying, where institutions are defined as ‘‘regulative, normative, and cognitive structures and activities that provide stability and meaning to social behavior’’ (Peng et al., 2009). Brussels, the self-proclaimed "Capital of Europe”, is the headquarters of the European Union and has one of the highest concentrations of political power in the world. Four of the seven Institutions of the European Union are based in Brussels: the European Parliament, the European Council, the Council and the European Commission (EU website, n.d.). As the power of the EU institutions has grown, Brussels has become a magnet for lobbyists, with the latest estimates ranging from between 15,000 and 30,000 professionals representing companies, industry sectors, farmers, civil society groups, unions etc. (Burson Marsteller, 2013). Brasília is the capital of Brazil and the seat of government of the Federal District and the three branches of the federal government of Brazilian legislative, executive and judiciary. The 4 city also hosts 124 foreign embassies. The presence of the formal representations of companies and trade associations in Brasília is very limited, but the governmental interests remain there and the professionals dealing with government affairs commute there. In the European Union, Brussels has established a Transparency Register that allows the interactions between the European institutions and citizen’s associations, NGOs, businesses, trade and professional organizations, trade unions and think tanks. The register provides citizens with a direct and single access to information about who is engaged in This process is important for the quality of democracy, and for its capacity to deliver adequate policies, matching activities aimed at influencing the EU decision-making process, which interests are being pursued and what level of resources are invested in these activities (Celgene, n.d). It offers a single code of conduct, binding all organizations and self-employed individuals who accept to “play by the rules” in full respect of ethical principles (EC website, n.d). A complaints and sanctions mechanism ensures the enforcement of the rules and addresses suspected breaches of the code. In Brazil, there is no specific legislation regulating lobbying. The National Congress is currently discussing dozens of bills that address regulation of lobbying and the action of interest groups (De Aragão, 2012), but none of them has been enacted for the moment. This work will focus on class lobbying (Oliveira, 2004), which refers to the performance of the federation of national labour or industrial unions, like CNI (National Industry Confederation) in Brazil and the European Banking Federation (EBF) in Brussels. Their performance aims to influence the Executive and Legislative branches in order to defend the interests of their affiliates. When representing unions and federations, class entities cover a wide range of different and, more often than not, conflicting interests. That is why they are limited to defending the consensual and majority interest of their affiliates (Oliveira, 2004). The basic assumption of this work is that institutions matter (Peng et al, 2009) and that the trade associations and their affiliates, when doing business, have to take into account the institutional and regulatory framework where they do business.

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Background: Angola is one of the African countries with the highest morbidity and mortality rates and a devastating lack of human resources for health, including nursing. The World Health Organization stimulates and takes technical cooperation initiatives for human resource education and training in health and education, with a view to the development of countries in the region. The aim in this study was to identify how nurses affiliated with nursing education institutions perceive the challenges nursing education is facing in Angola. Methods: After consulting the National Directory of Human Resources in Angola, the nurse leaders affiliated with professional nursing education institutions in Angola were invited to participate in the study by email. Data were collected in February 2009 through the focus group technique. The group of participants was focused on the central question: what are the challenges faced for nursing education in your country? To register and understand the information, besides the use of a recorder, the reporters elaborated an interpretative report. Data were coded using content analysis. Results: Fourteen nurses participated in the meeting, most of whom were affiliated with technical nursing education institutions. It was verified that the nurse leaders at technical and higher nursing education institutions in Angola face many challenges, mainly related to the lack of infrastructure, absence of trained human resources, bureaucratic problems to regularize the schools and lack of material resources. On the opposite, the solutions they present are predominantly centered on the valuation of nursing professionals, which implies cultural and attitude changes. Conclusions: Public health education policies need to be established in Angola, including action guidelines that permit effective nursing activities. Professional education institutions need further regularizations and nurses need to be acknowledged as key elements for the qualitative enhancement of health services in the country.

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INFLUENCE OF ANCHORING ON MISCARRIAGE RISK PERCEPTION ASSOCIATED WITH AMNIOCENTESIS Publication No. ___________ Regina Nuccio, BS Supervisory Professor: Claire N. Singletary, MS, CGC Amniocentesis is the most common invasive procedure performed during pregnancy (Eddleman, et al., 2006). One important factor that women consider when making a decision about amniocentesis is the risk of miscarriage associated with the procedure. People use heuristics such as anchoring, the action of using a prior belief regarding the magnitude of risk as a frame of reference for new information to be synthesized, to better understand risks that they encounter in their lives. This study aimed to determine a woman’s perception of miscarriage risk associated with amniocentesis before and after a genetic counseling session and to determine what factors are most likely to anchor a woman’s perception of miscarriage risk associated with amniocentesis. Most women perceived the risk as low or average pre-counseling and were likely to indicate the numeric risk of amniocentesis as <1% risk. A higher percentage of patients correctly identified the numeric risk as <1% post-counseling when compared to pre-counseling. However, the majority of patients’ feeling about the risk perception did not change after the genetic counseling session (60%), regardless of how they perceived the risk before discussing amniocentesis with a genetic counselor. Those whose risk perception did change after discussing amniocentesis with a genetic counselor showed a decreased risk perception (p<0.0001). Of the multitude of factors studied, only two showed significance: having a friend or relative with a personal or family history of a genetic disorder was associated with a lower risk perception (p=0.001) and having a child already was associated with a lower risk perception (p=0.038). The lack of significant factors may reflect the uniqueness of each patient’s heuristic framework and reinforces the importance of genetic counseling to elucidate individual concerns.

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Title: The perception of critical situations involving football fans – how conflicts escalate or de-escalate Authors: Brechbühl, A.1, Schumacher, A.1 & Seiler, R.1 1Institute of Sport Science, University of Bern, Switzerland Abstract: Introduction: Fan violence in the context of football matches is a prominent issue in today’s western societies and Switzerland presents no exception. A lot of research has been conducted on reasons for fan violence, mostly with fans of national teams. A prominent model is the Elaborated Social Identity Model (ESIM; Drury & Reicher, 2000): ESIM highlights the importance of interactions between the involved groups and their effect on the development of social identities. Another model is the aggravation mitigation model (AM model; Hylander & Guvå, 2010) which illustrates factors that can contribute towards an escalation or non-escalation of group violence, such as the “categorization” of the opponent group. Despite these models, research about the individual perceptions, and in particular, what factors distinguish between an escalation versus a non-escalation of a potentially violent situation in domestic football, is as yet scarce. This explorative study examines perceptions of critical situations in the domestic football fan context in Switzerland. Methods: An explorative qualitative design was employed to gather data about critical situations (CS) around football matches of two clubs of the Raiffeisen Super League. A CS is defined as a setting in or around the football stadium where violence between football fans and another group could occur. Eight CS were identified and analysed. Fifty-nine narrative interviews with individuals involved in a CS, e.g. fans, police officers or security personnel, were conducted. Interviews were analysed using interpretative phenomenological analysis (IPA). Results: The involved opposing groups expressed group-specific perceptions. Furthermore a strong tendency to negatively stereotype the opponent group was observed. Provocative symbols, such as balaclavas or riot-gear uniforms, were considered as highly relevant for the interpretation of the situation. Successful communication and sufficient distance between opponent groups supported the appeasement of a CS. These findings also underline the importance of knowledge about the local fan culture. This culture serves as basis for the perception of legitimacy, which was assessed to be essential for a de-escalation of a CS by fans. Discussion/Conclusion: This study improves the understanding of fan violence in the domestic football context in Switzerland. Based on the results it is suggested to deploy security or police forces without riot gear but with the goal of seeking dialogue with the fans to increase the likelihood of a peaceful ending in a CS. The findings also support the applicability of the ESIM (Drury & Reicher, 2000) and the AM model (Hylander & Guvå, 2010) in the context of domestic fan violence. Due to possible differences in the local fan cultures in Switzerland, research in this area should be continued. References: Drury, J., & Reicher, S. (2000). Collective action and psychological change: The emergence of new social identities. British Journal of Social Psychology, 39, 579-604. Hylander, I., & Guvå, G. (2010). Misunderstanding of out-group behaviour: Different interpretations of the same crowd events among police officers and demonstrators. Nordic Psychology, 62, 25-47.

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So far, most research attempts to explain the mechanism of the action of acupuncture have focused mostly on mechanically-triggered active factors and have produced inconclusive findings. In this study, we investigate whether acupuncture might also involve nonmechanical, nonpsychological active factors originating in the therapist. In 30 individuals, an acupuncture needle was inserted in the acupoint PC6 using a special device without touching the needle. A second device was used to fix the needle rigidly in place, excluding any mechanical transmission of movement from the handle to the needle's tip. Each participant was exposed in random order to a control and a stimulation phase. During the stimulation phase, the free needle's end was held by the therapist to allow the transmission of Qi; during the control phase, it was left untouched. Participants' subjective sensations during the stimulation phase and the control phase were recorded using a questionnaire. Twenty-two of 28 (79%; p = 0.003) test participants believed that they had received stimulation when it had actually been performed, and 26 (93%; p < 0.001) sensed differences between the two experimental phases. Thus, participants were able to sense the transmission of therapeutic Qi in the absence of mechanical or psychological factors.

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La medida de calidad de vídeo sigue siendo necesaria para definir los criterios que caracterizan una señal que cumpla los requisitos de visionado impuestos por el usuario. Las nuevas tecnologías, como el vídeo 3D estereoscópico o formatos más allá de la alta definición, imponen nuevos criterios que deben ser analizadas para obtener la mayor satisfacción posible del usuario. Entre los problemas detectados durante el desarrollo de esta tesis doctoral se han determinado fenómenos que afectan a distintas fases de la cadena de producción audiovisual y tipo de contenido variado. En primer lugar, el proceso de generación de contenidos debe encontrarse controlado mediante parámetros que eviten que se produzca el disconfort visual y, consecuentemente, fatiga visual, especialmente en lo relativo a contenidos de 3D estereoscópico, tanto de animación como de acción real. Por otro lado, la medida de calidad relativa a la fase de compresión de vídeo emplea métricas que en ocasiones no se encuentran adaptadas a la percepción del usuario. El empleo de modelos psicovisuales y diagramas de atención visual permitirían ponderar las áreas de la imagen de manera que se preste mayor importancia a los píxeles que el usuario enfocará con mayor probabilidad. Estos dos bloques se relacionan a través de la definición del término saliencia. Saliencia es la capacidad del sistema visual para caracterizar una imagen visualizada ponderando las áreas que más atractivas resultan al ojo humano. La saliencia en generación de contenidos estereoscópicos se refiere principalmente a la profundidad simulada mediante la ilusión óptica, medida en términos de distancia del objeto virtual al ojo humano. Sin embargo, en vídeo bidimensional, la saliencia no se basa en la profundidad, sino en otros elementos adicionales, como el movimiento, el nivel de detalle, la posición de los píxeles o la aparición de caras, que serán los factores básicos que compondrán el modelo de atención visual desarrollado. Con el objetivo de detectar las características de una secuencia de vídeo estereoscópico que, con mayor probabilidad, pueden generar disconfort visual, se consultó la extensa literatura relativa a este tema y se realizaron unas pruebas subjetivas preliminares con usuarios. De esta forma, se llegó a la conclusión de que se producía disconfort en los casos en que se producía un cambio abrupto en la distribución de profundidades simuladas de la imagen, aparte de otras degradaciones como la denominada “violación de ventana”. A través de nuevas pruebas subjetivas centradas en analizar estos efectos con diferentes distribuciones de profundidades, se trataron de concretar los parámetros que definían esta imagen. Los resultados de las pruebas demuestran que los cambios abruptos en imágenes se producen en entornos con movimientos y disparidades negativas elevadas que producen interferencias en los procesos de acomodación y vergencia del ojo humano, así como una necesidad en el aumento de los tiempos de enfoque del cristalino. En la mejora de las métricas de calidad a través de modelos que se adaptan al sistema visual humano, se realizaron también pruebas subjetivas que ayudaron a determinar la importancia de cada uno de los factores a la hora de enmascarar una determinada degradación. Los resultados demuestran una ligera mejora en los resultados obtenidos al aplicar máscaras de ponderación y atención visual, los cuales aproximan los parámetros de calidad objetiva a la respuesta del ojo humano. ABSTRACT Video quality assessment is still a necessary tool for defining the criteria to characterize a signal with the viewing requirements imposed by the final user. New technologies, such as 3D stereoscopic video and formats of HD and beyond HD oblige to develop new analysis of video features for obtaining the highest user’s satisfaction. Among the problems detected during the process of this doctoral thesis, it has been determined that some phenomena affect to different phases in the audiovisual production chain, apart from the type of content. On first instance, the generation of contents process should be enough controlled through parameters that avoid the occurrence of visual discomfort in observer’s eye, and consequently, visual fatigue. It is especially necessary controlling sequences of stereoscopic 3D, with both animation and live-action contents. On the other hand, video quality assessment, related to compression processes, should be improved because some objective metrics are adapted to user’s perception. The use of psychovisual models and visual attention diagrams allow the weighting of image regions of interest, giving more importance to the areas which the user will focus most probably. These two work fields are related together through the definition of the term saliency. Saliency is the capacity of human visual system for characterizing an image, highlighting the areas which result more attractive to the human eye. Saliency in generation of 3DTV contents refers mainly to the simulated depth of the optic illusion, i.e. the distance from the virtual object to the human eye. On the other hand, saliency is not based on virtual depth, but on other features, such as motion, level of detail, position of pixels in the frame or face detection, which are the basic features that are part of the developed visual attention model, as demonstrated with tests. Extensive literature involving visual comfort assessment was looked up, and the development of new preliminary subjective assessment with users was performed, in order to detect the features that increase the probability of discomfort to occur. With this methodology, the conclusions drawn confirmed that one common source of visual discomfort was when an abrupt change of disparity happened in video transitions, apart from other degradations, such as window violation. New quality assessment was performed to quantify the distribution of disparities over different sequences. The results confirmed that abrupt changes in negative parallax environment produce accommodation-vergence mismatches derived from the increasing time for human crystalline to focus the virtual objects. On the other side, for developing metrics that adapt to human visual system, additional subjective tests were developed to determine the importance of each factor, which masks a concrete distortion. Results demonstrated slight improvement after applying visual attention to objective metrics. This process of weighing pixels approximates the quality results to human eye’s response.

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The primate visual system offers unprecedented opportunities for investigating the neural basis of cognition. Even the simplest visual discrimination task requires processing of sensory signals, formation of a decision, and orchestration of a motor response. With our extensive knowledge of the primate visual and oculomotor systems as a base, it is now possible to investigate the neural basis of simple visual decisions that link sensation to action. Here we describe an initial study of neural responses in the lateral intraparietal area (LIP) of the cerebral cortex while alert monkeys discriminated the direction of motion in a visual display. A subset of LIP neurons carried high-level signals that may comprise a neural correlate of the decision process in our task. These signals are neither sensory nor motor in the strictest sense; rather they appear to reflect integration of sensory signals toward a decision appropriate for guiding movement. If this ultimately proves to be the case, several fascinating issues in cognitive neuroscience will be brought under rigorous physiological scrutiny.

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The duration of movements made to intercept moving targets decreases and movement speed increases when interception requires greater temporal precision. Changes in target size and target speed can have the same effect on required temporal precision, but the response to these changes differs: changes in target speed elicit larger changes in response speed. A possible explanation is that people attempt to strike the target in a central zone that does not vary much with variation in physical target size: the effective size of the target is relatively constant over changes in physical size. Three experiments are reported that test this idea. Participants performed two tasks: (1) strike a moving target with a bat moved perpendicular to the path of the target; (2) press on a force transducer when the target was in a location where it could be struck by the bat. Target speed was varied and target size held constant in experiment 1. Target speed and size were co-varied in experiment 2, keeping the required temporal precision constant. Target size was varied and target speed held constant in experiment 3 to give the same temporal precision as experiment 1. Duration of hitting movements decreased and maximum movement speed increased with increases in target speed and/or temporal precision requirements in all experiments. The effects were largest in experiment 1 and smallest in experiment 3. Analysis of a measure of effective target size (standard deviation of strike locations on the target) failed to support the hypothesis that performance differences could be explained in terms of effective size rather than actual physical size. In the pressing task, participants produced greater peak forces and shorter force pulses when the temporal precision required was greater, showing that the response to increasing temporal precision generalizes to different responses. It is concluded that target size and target speed have independent effects on performance.