Visual Perception of Dynamic Properties and Events: Collisions and Throws

The central topic of this dissertation is visual perception of dynamic events. The topic is worth of interest, as witnessed by its long tradition in the history of Experimental Psychology, starting with the seminal work of Albert Michotte (1881 - 1965) on phenomenal causality. Thus, the topic I chose is not original in itself. However, a distinctive element of novelty in my dissertation is the use of Computer Graphics techniques as a means for creating realistic experimental stimuli in psychological experiments. Besides the advantage of reducing the gap between laboratory experiments and everyday experience, this may reveal the importance of experimental variables which traditionally have been ignored in research on visual perception of dynamic events. The reader should be informed that this dissertation is characterized by various lines of research, which are intrinsically connected with the central topic of visual perception of dynamic events. In some of the experiments, I investigate visual perception of dynamic events, whereas in others I investigate cognition of the same events. Two distinct dynamic events will be especially studied: horizontal collisions and throws. Moreover, the results of the experiments will be discussed not only in relation to their theoretical implications for psychological models, but also in relation to their potential applications to Physics education and Computer Graphics. As a result, the content of the dissertation is quite heterogeneous, but I hope to provide the reader with a broad and multidisciplinary perspective on the subject at hand. The dissertation is composed of five chapters, which may be divided into three groups. (i) In Chapters 1-3, after a presentation of the theoretical background of visual perception of dynamic events, I investigate the influence of dynamic properties of virtual objects on visual perception of horizontal collisions. The results of this research are important for the old and still active debate on phenomenal causality. (ii) In Chapter 4 I present a research on Naïve Physics of horizontal collisions between virtual spheres differing in simulated mass and velocity. In this chapter I take a more cognitive (rather than perceptual) perspective on dynamic events, investigating how people reason about the proposed physical event. (iii) In Chapter 5, I present a research on visual perception of virtual throwing animations, which are complex and rarely studied dynamic events. This chapter stands out for its multidisciplinary nature, as in it I discuss how the results can be applied to Computer Graphics. The research presented in this last chapter has been conducted as a part of my doctorate studies when I was a visiting PhD student at the Graphics, Vision, and Visualisation Group at Trinity College Dublin, where I collaborated with Professor Carol O’Sullivan and Doctor Ludovic Hoyet, who are computer scientists working on applications of visual perception to Computer Graphics. In more detail, in Chapter 1 I discuss the theoretical background of visual perception of dynamic events and phenomenal causality. Firstly, I focus on Michotte’s classical work. Secondly, I discuss some prominent issues which have been debated for a long time in this field of research. Lastly, I present White’s schema-matching model of visual perception of dynamic events, discussing its differences and similarities as compared with Michotte’s model. This chapter is intended to serve as a theoretical point of reference for the entire dissertation. In Chapter 2 I discuss the hypothesis that visually perceived dynamic properties of objects involved in dynamic events do influence visual perception of the dynamic events themselves. Firstly, I try to confute two popular arguments against this hypothesis. Then, I highlight the evolutionary advantage of visual perception of dynamic properties, discussing their possible influence on visual perception of dynamic events. Lastly, I discuss Runeson’s KSD model in relation to the presented hypothesis. In Chapter 3 I present three experiments which confirm the hypothesis discussed in Chapter 2. In particular, I show that simulated material (Experiment 1) and size (Experiments 2 and 3) of virtual objects involved in horizontal collisions strongly influence how observers perceive the event. I also discuss the theoretical implications of these findings by referring to Michotte’s and White’s models. In Chapter 4 I present a research on Naïve Physics of horizontal collisions. Firstly, I discuss the general importance of studying Naïve Physics for improving basic education in Physics. Secondly, I present Information Integration Theory and Functional Measurement methodology as suitable tools for the assessment of students’ intuitive knowledge of physical events, evidencing their advantages over multiple-choice surveys. Lastly, I present two experiments (conducted using Information Integration Theory and Functional Measurement) on Naïve Physics of horizontal collisions between simulated spheres differing in size, velocity, and material. The importance of the results for Physics instruction will also be discussed. Finally, in Chapter 5 I present a research on visual perception of edited virtual throwing animations. First I discuss the relations between visual perception of dynamic events (human motion in particular) and Computer Graphics. Then, I present two experiments on observers’ sensitivity to anomalies in realistic virtual throwing animations, discussing the importance of the results for videogames and movies industry

Experimental Analysis of Protective Headgear Used in Defensive Softball Play

Every year in the United States, an estimated 1.6 to 3.8 million people sustain sports-related traumatic brain injuries (TBIs), with an appreciable number of these injuries coming from the sport of softball. Several studies have analyzed the impact performance of catcher’s masks within the context of baseball; however, virtually no studies have been performed on fielder’s masks within the context of softball. Thus, the main objective of the present work was to evaluate the protective capabilities of softball fielder’s masks. To better understand the injury mechanisms and frequency associated with softball head/facial injuries, epidemiological data from a national database was reviewed first. Results displayed “struck-by-ball” as the most frequent injury mechanism (74.3%) for all head/facial injuries with a large majority occurring to defensive players (83.7%). With further motivation, the present work focused on testing the impact attenuation and facial protection capabilities of fielder’s masks from softball impacts. Testing with an instrumented Hybrid III headform was conducted at two speeds and four impact locations for several protective conditions: six fielder’s masks, one catcher’s mask, and unprotected (no mask). The results showed that most fielder’s masks reduced head accelerations, but not to the standard of catcher’s masks. On average, they reduced peak linear and angular acceleration from 40-mph impacts by 36-49% and 14-45%, respectively, while for 60-mph impacts they were reduced by 25-42% and 13-46%, respectively. Plastic-frame fielder’s masks were observed to allow facial contact when struck at the nose region at high speed. Observed differences in impact attenuation across fielder’s mask designs further suggested influence from specific design features such as foam padding and frame properties. Overall, the results clearly demonstrate that head/facial injuries may be mitigated through the broader use of masks, while further optimization of impact attenuation for fielder’s masks is pursued

Proceedings of the 11th International Conference on Kinanthropology

The 11th International Conference on Kinantropology was held on the Nov 29 – Dec 1, 2017 in Brno and was organized by the Faculty of Sports Studies, Masaryk University and the Faculty of Kinesiology, University of Zagreb. This year was divided into several themes: sports medicine, sport and social science, sport training, healthy lifestyle and healthy ageing, sports management, analysis of human movement. Part of the conference was also a symposium Atletika and Ortoreha that gathered specialists in physiotherapy

Eye quietness and quiet eye in expert and novice golf performance: an electrooculographic analysis

Quiet eye (QE) is the final ocular fixation on the target of an action (e.g., the ball in golf putting). Camerabased eye-tracking studies have consistently found longer QE durations in experts than novices; however, mechanisms underlying QE are not known. To offer a new perspective we examined the feasibility of measuring the QE using electrooculography (EOG) and developed an index to assess ocular activity across time: eye quietness (EQ). Ten expert and ten novice golfers putted 60 balls to a 2.4 m distant hole. Horizontal EOG (2ms resolution) was recorded from two electrodes placed on the outer sides of the eyes. QE duration was measured using a EOG voltage threshold and comprised the sum of the pre-movement and post-movement initiation components. EQ was computed as the standard deviation of the EOG in 0.5 s bins from –4 to +2 s, relative to backswing initiation: lower values indicate less movement of the eyes, hence greater quietness. Finally, we measured club-ball address and swing durations. T-tests showed that total QE did not differ between groups (p = .31); however, experts had marginally shorter pre-movement QE (p = .08) and longer post-movement QE (p < .001) than novices. A group × time ANOVA revealed that experts had less EQ before backswing initiation and greater EQ after backswing initiation (p = .002). QE durations were inversely correlated with EQ from –1.5 to 1 s (rs = –.48 - –.90, ps = .03 - .001). Experts had longer swing durations than novices (p = .01) and, importantly, swing durations correlated positively with post-movement QE (r = .52, p = .02) and negatively with EQ from 0.5 to 1s (r = –.63, p = .003). This study demonstrates the feasibility of measuring ocular activity using EOG and validates EQ as an index of ocular activity. Its findings challenge the dominant perspective on QE and provide new evidence that expert-novice differences in ocular activity may reflect differences in the kinematics of how experts and novices execute skills

19th Conference of The Associations of Christians In The Mathematical Sciences

Association of Christians in the Mathematical Sciences 19th Biennial Conference Proceedings, May 29 - June 1, 2011, Bethel University

Detailing the Genetic and Environmental Influences Shared between Conventional and Electronic Cigarette Use Across Measures of Initiation and Past 12-Month Use

Introduction. Tobacco use is a public health crisis with nearly 500,000 Americans suffering premature mortality attributable to tobacco use in 2014. New development efforts have created new nicotine delivery systems whose health consequences are not yet fully understood such as electronic cigarettes (ECIG). It is possible there are shared genetic and environmental factors that influence an individual’s liability to initiate cigarette (CIG) or ECIG use, as both systems are designed to deliver nicotine. Methods. Four study designs were used to resolve the genetic and environmental influences that underlie CIG and ECIG initiation. A twin study, scoping review, genome-wide association study (GWAS), and moderation model examined these potential sources of variation. Results. The twin study suggested there were shared genetic factors between CIG and ECIG initiation. Univariate GWAS analysis of ECIG found no genome-wide significant hits among self-identified white participants. Genome-wide polygenic scores also showed no association between CIG and ECIG initiation. Statistical evidence of a weak interaction between ECIG coupon receipt, income level, and CIG use was reported. A review of tobacco use measures in genetically informative samples found that how individual studies measured different aspects of tobacco use lead to different genome-wide significant results. Conclusions. These analyses suggest there are shared genetic and environmental influences between CIG and ECIG. Low sample sizes may have contributed to non-significant findings of measured molecular genetic effects, though genome-wide suggestive findings indicate further research is needed. Further, aggregating genome-wide association study results by biological function may increase the consistency of findings