Thesis (Ph. D)--UCLA, 2004. / Vita. Description based on print version record. Includes bibliographical references (leaves 213-222).

有研究發現過度的媒界多任務處理者(HMMs)在多種認知任務上較輕度的媒界多任務處理者(LMMs)表現得遜色。這表示HMMs的多種認知功能，包括工作記憶的更新及維持、選擇性的注意力及作業轉換的能力，皆次於LMMs。有研究採用有線索的作業轉換典範時，為每一個作業設置了兩個線索，從而將總的作業轉換成本拆分為與作業轉換過程中兩個連續而不同的階段相關的部份。第一部份的成本由線索的改變導致，代表使用線索把作業心向從長期記憶抽出放於工作記憶這一階段所需要的成本。第二部份的成本由作業的改變導致，代表將作業規則應用於刺激這一階段所需的成本。第二階段的成本被大多數研究者視為真正的作業轉換成本。本研究想探討的問題是過度的媒界多任務處理所影響的是哪一階段的作業轉換能力。我們採用一份網上的媒界使用問卷選出二十名HMMs及二十名LMMs來參加實驗。實驗中，被試必須完成一個雙線索對單作業的作業轉換典範，當中的兩個作業分別為一個打字作業及一個性別判斷作業。反應時上的總作業轉換成本被拆成兩個部份: (甲)作業不變而線索改變所引起的線索轉換成本，及(乙)線索轉換成本所不能解釋的剩下的作業轉換成本。我們發現HMMs的線索轉換成本顯著地高於LMMs的線索轉換成本。然而，兩組人之間的作業轉換成本並沒有顯著差異。結果表明，HMMs只在使用線索把作業心向從長期記憶拿出來放在工作記憶這一階段遜色於LMMs。 / Heavy media multitaskers (HMMs) are found to be inferior to light media multitaskers (LMMs) in cognitive functions such as updating and maintenance of working memory representations, selectively attention, and surprisingly, the ability to switch between tasks. Research on task-switching paradigm using a 2:1 mapping between cues and tasks separates the total switch cost into costs related to two distinct, serial processing stages. The first type of cost, relating to the stage of cue-driven retrieval of task-set from long-term memory into working memory, is caused by a change in the task-indicating cue. The second type of cost, relating to the stage of application of task-rules onto the stimuli, is caused by a change of the task-set and has been regarded by some as the actual task-switch cost. In the current study, we examine which stage(s) are affected by media multitasking experience. Twenty HMMs and twenty LMMs identified using an online media-use questionnaire participated in a cued task-switching experiment involving a word typing task and a face gender classification task. The overall switch cost in response time was decomposed into two components: (a) the cue-switch cost as a result of a change of the cue with the task unchanged; and (b) the task-switch cost, which represent the switch cost not accountable by the cue-switch cost. HMMs showed a significantly larger cue-switch cost than LMMs, while the task-switch cost was similar for the two groups. Results suggest that HMMs may only be inferior in the cue-driven retrieval process of task set but not in the task-rule application stage. / Detailed summary in vernacular field only. / Lui, Fai Hong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 25-28). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / Chapter Chapter 1: --- Introduction --- p.1 / Media multitasking and its chronic effects --- p.1 / Effects of media multitasking on task switching ability --- p.4 / The typical task-switching paradigm --- p.5 / Task-switching paradigm using a 2:1 mapping between cues and tasks --- p.7 / Design of the current study --- p.10 / Hypotheses of the current study --- p.11 / Chapter Chapter 2: --- 2: Experiment 1: Method --- p.15 / Participants --- p.15 / Apparatus --- p.15 / Stimuli and procedure --- p.16 / Chapter Chapter 3: --- Experiment 1: Results --- p.19 / Chapter Chapter 4: --- Experiment 2 --- p.22 / Chapter Chapter 5: --- Experiment 2: Method --- p.24 / Participants --- p.24 / Apparatus --- p.24 / Stimuli and procedure --- p.24 / Chapter Chapter 6: --- Experiment 2: Results --- p.26 / Chapter Chapter 7: --- Discussions --- p.28

The use of portable digital devices in the United States is increasing. With this increase in digital technology use comes an increase in interruptions between digital users. This study explores whether interruptions caused by a digital device evoke an emotion from members of the Millennial generation. In addition, this research aims to determine whether an interruption during a task causes a reduction in task efficiency amongst Millennials. The findings from this study can provide corporations and educational institutions with information about how portable digital technologies might affect the productivity of Millennial employees and students. / Department of Telecommunications

Individuals are required to manage multiple tasks which require strategic allocation of time and effort to ensure goals are reached efficiently. By providing the worker with autonomy over their work, performance and worker well-being have improved. This increased control allows individuals to organize work according to the needs of the body, which prevents fatigue leading to improved productivity. When given the option, humans tend to switch between tasks frequently. This behaviour can be used to determine the change in self-regulation strategies. An understanding of human task-switching behaviour is important for the design of job rotation systems. However, there is a lack of evidence explaining the factors motivating the need to switch between tasks. This study aims to use physiological, subjective and behavioural measures to explain the factors influencing selfregulation through the act of task-switching. Three primary hypotheses were developed to explain the factors underlying taskswitching behaviour. It was hypothesized that the degree of boredom experienced, the effort required to perform the task and the resource usage induced by the task are factors responsible in deciding task switching behaviour. Participants (17 males and 17 females) switched freely between five different information-processing tasks for the 45 minutes. Participants were allowed to switch back and forth between tasks and did not have to conduct all five tasks. The following measures were recorded during the experiment: subjective measures of boredom, mental effort, task frustration and perceived performance of the tasks; energy consumption and physiological measures of effort (HR, HRV and body temperature) and behavioural measures, including duration and frequency of task. Perceived boredom was found to differ among the tasks and before and after the experiment. The average boredom rating at each task transition for all tasks exceeded a score of 2.5 out of a possible 4. There were no significant changes in physiological measures between the beginning and end of the task trials. However, changes in physiological measures showed a decrease in effort investment following task transition. Heart rate variability was lower for externally-paced tasks than for self-paced tasks, despite the differences in cognitive demands. The most frequent task-switch combination occurred between tasks of high and low cognitive demand. The least frequent task-switching combination occurred between tasks of similar characteristics, which produced no differences in physiological responses. Task-switching behaviour was influenced by the degree of boredom, and therefore more time was spent on less monotonous tasks. The level of physiological effort required for the task affected task-switching behaviour. Task switches were made before any changes in effort took place in an attempt to maintain task efficiency. It appears plausible that a task switch was made to reduce effort investment and activation levels. The type of information processing resources used by different tasks affected the task-switching combinations. Individuals tended to switch between tasks of differing resources so that those in limited supply were able to replenish. Therefore the findings from this study can potentially be used to improve the design of job rotation systems. Such improvements may enhance productivity and worker well-being by inhibiting the onset of down regulation and fatigue processes. This study showed that autonomy is necessary for individuals to regulate behaviour to suit human needs. / Microsoft� Office Word 2007 / Adobe Acrobat 9.54 Paper Capture Plug-in

Why do people travel? Underlying most travel behavior research is the derived-demand paradigm of travel analysis, which assumes that travel demand is derived from the demand for spatially separated activities, traveling is a means to an end (reaching destinations), and travel time is a disutility to be minimized. In contrast, the "positive utility of travel" (PUT) concept suggests that travel may not be inherently disliked and could instead provide benefits or be motivated by desires for travel-based multitasking, positive emotions, or fulfillment. The PUT idea assembles several concepts relevant to travel behavior: utility maximization, motivation theory, multitasking, and subjective well-being. Despite these varied influences, empirical analyses of the PUT concept remain limited in both quantity and scope. There is a need for more fundamental development and classification of the PUT idea and its multifaceted nature. The wide variety and quality of ways to measure PUT attributes are further research challenges. Additionally, few studies investigate both major aspects of the PUT concept--travel activities and travel experiences--simultaneously. Finally, research is only beginning to examine empirical associations between PUT measures and travel behaviors such as mode choice. This dissertation addresses many of these gaps in conceptualizing, measuring, and modeling the PUT concept. First, a literature review strengthens the definition, classification, and empirical support for a PUT, defined as "any benefit(s) accruing to a traveler through the act of traveling." The two primary PUT categories are travel activities (travel-based multitasking) and travel experiences (travel subjective well-being), and the most useful PUT measures involve gathering self-reported assessments of these topics. Based on this review, an online questionnaire is designed and administered to nearly 700 commuters in the Portland, OR, region. The survey includes detailed questions about commute mode choice, activity participation, travel usefulness, positive emotions and fulfillment, and travel liking for a recent home-to-work trip. Next, these PUT measures are empirically examined using factor analyses, finding groupings of activities and common unobserved constructs of hedonic ("Distress," "Fear," "Attentiveness," "Enjoyment") and eudaimonic ("Security," "Autonomy," "Confidence," "Health") subjective well-being. Many of these factors exhibit large variations among travel modes--walking and bicycling commuters are the most satisfied and appear to value time spent exercising--and are predicted (somewhat less strongly) by other trip and traveler characteristics in ordered logit regression and structural equation models. Finally, integrated choice and latent variable models are estimated to examine relationships between measures of the PUT concept and commute mode choice. This is made possible by the unique dataset that collects PUT measures for not only the chosen mode but also modal alternatives. Measures of travel-based multitasking are significantly related to mode choice, suggesting people may be doing things more to pass the time than to be productive. A validated measure of travel subjective well-being is also a significant and positive factor, suggesting people are more likely to choose a mode that makes them happier. Overall, PUT measures greatly increase the explanatory power of the mode choice model. These findings make significant contributions to travel behavior research methods and knowledge. They also offer important implications for transportation policies around promoting nonautomobile travel and planning for autonomous vehicles.

Thesis (M.F.A.)--University of Central Florida, 2009. / Adviser: Steven Chicurel. Includes bibliographical references (p. 142-143).

Cuando las personas interactúan con los ordenadores, hay mucha información que no se proporciona a propósito. Mediante el estudio de estas interacciones implícitas es posible entender qué características de la interfaz de usuario son beneficiosas (o no), derivando así en implicaciones para el diseño de futuros sistemas interactivos. La principal ventaja de aprovechar datos implícitos del usuario en aplicaciones informáticas es que cualquier interacción con el sistema puede contribuir a mejorar su utilidad. Además, dichos datos eliminan el coste de tener que interrumpir al usuario para que envíe información explícitamente sobre un tema que en principio no tiene por qué guardar relación con la intención de utilizar el sistema. Por el contrario, en ocasiones las interacciones implícitas no proporcionan datos claros y concretos. Por ello, hay que prestar especial atención a la manera de gestionar esta fuente de información. El propósito de esta investigación es doble: 1) aplicar una nueva visión tanto al diseño como al desarrollo de aplicaciones que puedan reaccionar consecuentemente a las interacciones implícitas del usuario, y 2) proporcionar una serie de metodologías para la evaluación de dichos sistemas interactivos. Cinco escenarios sirven para ilustrar la viabilidad y la adecuación del marco de trabajo de la tesis. Resultados empíricos con usuarios reales demuestran que aprovechar la interacción implícita es un medio tanto adecuado como conveniente para mejorar de múltiples maneras los sistemas interactivos. / Leiva Torres, LA. (2012). Diverse Contributions to Implicit Human-Computer Interaction [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/17803

Female athletes exhibit three- to six-fold greater incidence of noncontact anterior cruciate ligament (ACL) injury relative to their male counterparts. The increased risk appears to stem from interactions between several risk factors, that can roughly be categorized as anatomic, biomechanical, hormonal, and neuromuscular. Neuromuscular risk factors have recently gained a greater focus, and include differences in the timing and magnitude of activation of lower extremity and trunk musculature. In addition to neuromuscular risk factors, the incidence of ACL injury is not evenly distributed across the menstrual cycle, suggesting that hormonal fluctuations may influence neuromuscular control. Finally, it is known that even well-trained athletes experience decrements in performance and postural control when forced to attend to multiple sensory stimuli, which is common in many sports. PURPOSE: To explore neuromuscular differences in the ways healthy and ACL-injured women respond to a secondary task requiring fine motor control and sustained mental focus (typing task). Our investigation encompassed three broad aims. First, we sought to determine whether ACL-injured individuals demonstrated similar reflex profiles to healthy individuals, as well as to determine whether the ACL-involved limb was similar to its uninvolved counterpart. Our second aim was to determine whether the typing task resulted in attenuated Hoffmann (H) reflex amplitudes, and to investigate whether any observed changes were similar in healthy and ACL-injured groups. Finally, our third broad aim was to utilize more complex H reflex analysis techniques to determine whether differences in spinal excitability existed at different points in the menstrual cycle. METHODS: Thirty nine recreationally active women (20 with prior unilateral noncontact ACL injury: 24.0 ± 4.5 years; 23.8 ± 4.5 kg•m⁻²; 4.1 ± 2.6 years post-injury; 19 with no history of knee injury: 23.8 ± 4.5 years; 23.1 ± 2.3 kg•m⁻²) agreed to participate, and were tested during days 2-5 (follicular phase) of the menstrual cycle. A sub-set of this original group (n=8; 24.0 ± 4.8 years; 22.0 ± 2.1 kg•m⁻²) also agreed to return for a second testing session 24-96 hours after ovulation (early luteal phase), in order to assess H reflex differences across the menstrual cycle. During each testing session, H reflex testing was used to explore spinal-level control mechanisms of the lower extremity musculature under both Rest and Task conditions. In the control group, the dominant limb was tested (CON-D) while in the ACL group, both the uninvolved (ACL-UN) and involved (ACL-INV) limbs were assessed. Differences between groups (Control vs. ACL) and within-groups (ACL-UN vs. ACL-INV) were explored. RESULTS: At rest, H reflex parameters in ACL-INV were generally similar to ACL-UN and to CON-D. However, differences in presynaptic inhibition were apparent in ACL-INV that imply reduced reflex plasticity. During the typing task, both the Control and ACL groups experienced attenuated H reflex parameters. In the sub-set of participants who were tested twice during the menstrual cycle, a significant increase in presynaptic inhibition was observed during the early luteal phase compared to the follicular phase. CONCLUSION: While individuals with prior ACL injury display similar H reflex profiles to healthy individuals, the ACL-involved limb may demonstrate less reflex plasticity in response to environmental changes. This lack of plasticity may potentially increase the risk of re-injury. In addition, an upper extremity task requiring fine motor control and sustained mental focus attenuates the H reflex in both groups. This attenuation has implications for lower-extremity neuromuscular control in dual-task environments. Finally, the increase in presynaptic inhibition observed during the early luteal phase may provide insight into why ACL injuries are not evenly distributed across the menstrual cycle. / Graduation date: 2012

Indiana University-Purdue University Indianapolis (IUPUI) / In today’s workforce, multitasking on the job has become increasingly important. However, past research has characterized multitasking primarily as a counterproductive work strategy. Drawing from the theory of person-job (PJ) fit, in this this study it is proposed that multitasking may not always result in performance decrements but rather that people’s perceptions and experiences of multitasking may differ depending on individual differences. The theory of PJ fit suggests positive outcomes when there is a match between employee preferences, abilities and job characteristics. Using this framework, this study proposes the concept of multitasking fit and predicts that a match between multitasking preferences and multitasking job demands will result in positive work attitudes. Lastly, it is predicted that higher working memory will lead to higher job performance, especially in jobs requiring higher amounts of multitasking. This study found that PJ fit had generally positive effects on work-related outcomes such as job satisfaction, organizational commitment, turnover intentions, and strains. Due to measurement issues, the relationship between working memory and job performance could not be assessed. However, the results of this study relating to PJ fit suggest that perhaps multitasking is not always a bad strategy within the workplace and that its consequences may instead depend on the degree of fit between an individual and his or her working environment.