Measurement and evidence of computer-based task switching and multitasking by ‘Net Generation’ students

Logs of on-campus computer and Internet usage were used to conduct a study of computer-based task switching and multitasking by undergraduate medical students. A detailed analysis of over 6000 individual sessions revealed that while a majority of students engaged in both task switching and multitasking behaviours, they did so less frequently than ‘Net Generation’ rhetoric implies. The incidence and intensity of task switching and multitasking among students ranged from low to very high but infrequent and low-level multitaskers easily outnumbered inveterate multitaskers. Male and international students were significantly more likely to task switch and multitask than their female and local counterparts. Students who entered University directly from secondary school were significantly more likely to multitask than graduate students, as were first year compared to second year students, suggesting that post-secondary experiences may temper students’ propensity or inclination to multitask.     

A comparison of human and near-optimal task management behavior

OBJECTIVE: The primary contribution of this work is the development of an abstract framework to which a variety of multitasking scenarios can be mapped. The metaphor of a juggler spinning plates was introduced to represent an operator performing multiple concurrent tasks. BACKGROUND: This allowed seeking a quantitative model for management of multiple continuous tasks instead of a model for completing multiple discrete tasks, which was considered in previous studies. METHODS: The multitasking performance of 10 participants in five scenarios was measured in a low-fidelity simulator (named Tardast), which was developed based on the concept of the juggler metaphor. This performance was then compared with a normative model, which was a near-optimal solution to a mathematical programming problem found by tabu search heuristics. RESULTS: Tabu outperformed the participants overall, although the best individual performance nearly equaled that of tabu. It was also observed that participants initially tended to manage numerous tasks poorly but that they gradually learned to handle fewer tasks and excel in them. CONCLUSION: This suggests that they initially overreacted to the penalization associated with poor performance in the software. Participants' strategic task management (e.g., what tasks to handle) was more significant in obtaining a good score than their tactical task management (e.g., how often to switch between two tasks). APPLICATION: Potential applications include better design of equipment, procedures, and training of operators of complex systems.     

Media multitasking predicts video-recorded lecture learning performance through mind wandering tendencies

Media multitasking behaviors are on the rise globally. This phenomenon extends to academic settings, and has implications for education that is predicated on computer-assisted technology, which may be a source of distractibility for, especially, heavy media multitaskers. We hypothesized that habitual media multitasking correlates negatively with video-recorded lecture learning performance, with mind wandering mediating this association. Eighty-one participants from the National University of Singapore first completed a media multitasking survey (Loh & Kanai, 2014; Ophir et al., 2009). They then studied Coursera video-recorded lectures, during which their mind wandering tendencies were assessed using direct probes. Finally, participants attempted a test relating to what they have studied. Four regression models were built to analyse the data, and revealed evidence that supported the present hypothesis, even after we controlled for phenomenological variables relating to learning (i.e., anxiety, mental fatigue, and prior subject knowledge). Implications and future directions are discussed.     

If I choose when to switch: Heavy multitaskers remember online content better than light multitaskers when they have the freedom to multitask

The present study explored the effects of switching between reading an online article and checking Facebook on recognition memory, moderated by polychronicity, or preference for multitasking. The results of the study indicated that participants recognized online information less efficiently when they were required to check Facebook (forced multitasking) and when they could choose to check Facebook if and when they wanted (voluntary multitasking) compared with the control, non-multitasking, condition. I.e., the opportunity to multitask interfered with the efficiency of online information processing as much as actual multitasking. Polychronicity was a significant moderator of the multitasking effects. Low polychronics were negatively affected by multitasking to a greater extent than high polychronics. Their article recognition levels were lower than those of high polychronics. Two recognition measures derived from the signal detection theory: recognition sensitivity and criterion bias, were used. The study indicated that forced and voluntary multitasking affected high and low polychronics differently. Low polychronics showed greater cognitive effort than high polychronics when they engaged in voluntary media multitasking, while the amount of cognitive resources allocated to processing increased in high polychronics in the non-multitasking (control) condition. When high polychronics did not have control over switching to Facebook (forced multitasking), their recognition of the online article content decreased. Theoretical, methodological, and managerial implications of the study are discussed.     

Dedicated workspaces: Faster resumption times and reduced cognitive load in sequential multitasking

Studies show that virtual desktops have become a widespread approach to window management within desktop environments. However, despite their success, there is no experimental evidence of their effect on multitasking. In this paper, we present an experimental study incorporating 16 participants in which a traditional Windows 7 environment is compared to one augmented by virtual desktops. Within the experimental condition, each virtual desktop acts as a dedicated workspace devoted to an independent goal-oriented task, as opposed to the control condition where only one single workspace is available to perform the same tasks. Results show that adopting virtual desktops as dedicated workspaces allows for faster task resumption (10 s faster on average) and reduced cognitive load during sequential multitasking. Within our experiment the majority of users already benefited from using dedicated workspaces after three switches to a previously suspended task, as the time lost on setting up workspaces was compensated for by faster subsequent task resumption. These results provide a strong argument for supporting goal-oriented dedicated workspaces within desktop environments.     

The effects of multitasking on quality inspection in advanced manufacturing systems

Although the industrial quality inspection task has been extensively studied, the effect of multitasking on the performance of the operator in a hybrid inspection system is still unknown. The experiment described in this article compared the quality inspection performance for participants performing a single task, 3 multiple tasks, and 5 multiple tasks. The results of this research indicate that the performance of the operator in the quality inspection task while multitasking in an advanced manufacturing system will be determined by the interaction between the number of different types of defects that can be presented at the same time in the inspected parts and multitasking. The best performance will be obtained when the load created by additional tasks minimizes the monotony of the quality inspection task without interfering with the processing resources needed for the memorized quality criteria. © 2001 John Wiley & Sons, Inc.     

Effects of tactile cueing on concurrent performance of military and robotics tasks in a simulated multitasking environment

This study examined the concurrent performance of military gunnery, robotics control and communication tasks in a simulated environment. More specifically, the study investigated how aided target recognition (AiTR) capabilities (delivered either through tactile or tactile + visual cueing) for the gunnery task might benefit overall performance. Results showed that AiTR benefited not only the gunnery task, but also the concurrent robotics and communication tasks. The participants' spatial ability was found to be a good indicator of their gunnery and robotics task performance. However, when AiTR was available to assist their gunnery task, those participants of lower spatial ability were able to perform their robotics tasks as well as those of higher spatial ability. Finally, participants' workload assessment was significantly higher when they teleoperated (i.e. remotely operated) a robot and when their gunnery task was unassisted. These results will further understanding of multitasking performance in military tasking environments. These results will also facilitate the implementation of robots in military settings and will provide useful data to military system designs.     

Effects of tactile cueing on concurrent performance of military and robotics tasks in a simulated multitasking environment

This study examined the concurrent performance of military gunnery, robotics control and communication tasks in a simulated environment. More specifically, the study investigated how aided target recognition (AiTR) capabilities (delivered either through tactile or tactile + visual cueing) for the gunnery task might benefit overall performance. Results showed that AiTR benefited not only the gunnery task, but also the concurrent robotics and communication tasks. The participants' spatial ability was found to be a good indicator of their gunnery and robotics task performance. However, when AiTR was available to assist their gunnery task, those participants of lower spatial ability were able to perform their robotics tasks as well as those of higher spatial ability. Finally, participants' workload assessment was significantly higher when they teleoperated (i.e. remotely operated) a robot and when their gunnery task was unassisted. These results will further understanding of multitasking performance in military tasking environments. These results will also facilitate the implementation of robots in military settings and will provide useful data to military system designs.     

Self-interruptions in discretionary multitasking

Human multitasking is often the result of self-initiated interruptions in the performance of an ongoing task. These self-interruptions occur in the absence of external triggers such as electronic alerts or email notifications. Compared to externally induced interruptions, self-interruptions have not received enough research attention. To address this gap, this paper develops a typology of self-interruptions based on the integration of Flow Theory and Self-regulation Theory. In this new typology, the two major categories stem from positive and negative feelings of task progress and prospects of goal attainment. The proposed classification is validated in an experimental multitasking environment with pre-defined tasks. Empirical findings indicate that negative feelings trigger more self-interruptions than positive feelings. In general, more self-interruptions result in lower accuracy in all tasks. The results suggest that negative internal triggers of self-interruptions unleash a downward spiral that may degrade performance.     

The Effects of Hover Interface on Users’ Behavioral Multitasking Intention

As the number of features with smartphones is increasing, user interfaces have been advanced considerably with innovative ways for providing useful, multitasking interfaces. In particular, the z-axis of the user interface has been considered to help multitaskers control their smartphone more easily. However, relatively little research has been conducted on the significance of the z-axis on task switching. The main research goal of this study is to explain how a z-axis can affect the experience of multitasking on a mobile device. In particular, the authors focused on a hover interface because of its high functional relevance to multitasking as a form of task switching. Theoretically, the authors provide a conceptual model based on the concept of spatial presence. Systemically, they suggest the important system factors for implementing z-axis interface technology: controllability and naturalness. With regards to users, the authors assume that if the experience with the z-axis interface is increased, users’ intention to multitask is also increased, even when the task complexity is high. The influence of controllability on perceived spatial presence by the hover interface was negatively validated, and the influence of naturalness was positively validated. In addition, the influence of perceived spatial presence on users’ behavioral multitasking intention was positively validated. Finally, the influence from perceived spatial presence to users’ behavioral multitasking intention in the high level of task complexity was significantly stronger than in the low level. Implications and limitations of the study results are discussed in the final section of the article.     

Multitasking across generations: Multitasking choices and difficulty ratings in three generations of Americans

This study investigated whether changes in the technological/social environment in the United States over time have resulted in concomitant changes in the multitasking skills of younger generations. One thousand, three hundred and nineteen Americans from three generations were queried to determine their at-home multitasking behaviors. An anonymous online questionnaire asked respondents to indicate which everyday and technology-based tasks they choose to combine for multitasking and to indicate how difficult it is to multitask when combining the tasks. Combining tasks occurred frequently, especially while listening to music or eating. Members of the “Net Generation” reported more multitasking than members of “Generation X,” who reported more multitasking than members of the “Baby Boomer” generation. The choices of which tasks to combine for multitasking were highly correlated across generations, as were difficulty ratings of specific multitasking combinations. The results are consistent with a greater amount of general multitasking resources in younger generations, but similar mental limitations in the types of tasks that can be multitasked.     

基于VxWorks的多任务程序设计

VxWorks是一种嵌入式实时多任务操作系统,以其良好的可靠性和卓越的实时性被广泛地应用在航天、航空、通信等领域中。随着嵌入式系统功能的不断复杂和性能需求的不断提高,多任务程序的合理设计对嵌入式系统软件的稳定、可靠运行起着重要的作用。文中对VxWorks下的多任务调度机制进行分析,然后介绍多任务程序设计过程中任务优先级的设置、多任务间通信、中断处理等关键要点,结合FC通信的应用实例给出多任务程序设计的步骤和方法,在实际应用中验证了设计的合理性和可靠性,为基于VxWorks的多任务程序设计提供一定的参考。     

Media multitasking between two conversational tasks

Communication multitasking was examined in three conditions: IM conversation with one partner, two IM conversations at the same time, and IM and phone conversation at the same time. Participants in the multitasking conditions reported higher task demand and a small loss in task performance was evident. Single-task partners assigned to a task the required discussion and deliberation preferred to interact with the multitasking participant via phone, rather than IM. But interactions via phone with one partner led to poorer assessment by a second partner who was shortchanged during the interaction. Multitasking participants who were focused on helping both partners seemed blind to these perceived differences by their single-task partners. The results suggest a strategic model of multitasking, with IM being the preferred choice for tasks that require fewer, shorter exchanges and voice being the preferred choice for tasks that required more discussion and deliberation.     

Can students really multitask? An experimental study of instant messaging while reading

Students often “multitask” with electronic media while doing schoolwork. We examined the effects of one form of media often used in such multitasking, instant messaging (IM). We predicted that students who engaged in IMing while reading a typical academic psychology passage online would take longer to read the passage and would perform more poorly on a test of comprehension of the passage. Participants were randomly assigned to one of three conditions (IM before reading, IM during reading, or no IM). We found that students took significantly longer to read the passage when they IMed during reading (not including time taken to IM) than in other conditions. However, test performance did not differ by condition. Students who are managing busy lives may think they are accomplishing more by multitasking, but our findings suggest they will actually need more time to achieve the same level of performance on an academic task.     

Visual search in vibration environments: Effects of spatial ability,stimulus size and stimulus density

Visual search is one type of common encountered human-computer interaction tasks, but it has less been examined in vibration environments. The aim of this study was to examine the effects of one user characteristic (spatial ability) and two stimulus characteristics (i.e., stimulus size and stimulus density) on visual search performance during single- and double-target tasks in simulated vibration environments. Twenty-four participants attended an experiment where they were instructed to perform single- and double-target visual search tasks with varied levels of stimulus size and stimulus density under static, slight and moderate vibration environments, respectively. Results indicated that the two vibration conditions achieved comparable visual search performance, perceived visual fatigue, and perceived comfort with static condition across task types. Stimuli size and stimulus density yielded significant effects on visual search time in both single- and double-target tasks (p's < 0.001). Participants with high spatial ability were faster than those with low spatial ability in double-target tasks (p = 0.042). Users preferred interface design with medium-to-large stimulus size and low-to-medium stimulus density in visual search.     

Performance bounds for concurrent software with rendezvous

Synchronous message-passing communication, or rendezvous, occurring between software tasks can have a significant effect on system performance. The rendezvous style of communication is coming into wider use in programming languages and operating systems for parallel and distributed environments. Understanding the performance implications of this style of inter-task communication is becoming a matter of practical importance. The dual nature of a task which acts both like a customer as well as a server, makes the performance analysis of rendezvous-based multitasking systems quite different from the analysis of the other queueing systems with known results. This research focuses on rendezvous-based systems in which the execution behavior of the software has a nondeterministic component of a very general nature which may for example be the manifestation of a data dependent behavior. Based on a model called the Stochastic Rendezvous Network the computation of bounds on task throughputs for multitasking systems characterized by rendezvous style communication is presented. Although the behavior of tasks is called stochastic, it is very general and the results are valid for general distributions of computation times and the number of messages generated by tasks. The inter-relationship among task throughputs, however, makes it difficult to extract the bounds in closed analytic form. The notion of a feasible throughput region which encloses the set of feasible tasks throughputs and captures the inter-relationship among the behavior of tasks is introduced. Variations of this basic bounding approach that are useful in the context of different types of multitasking systems are considered in the article. For example, a novel technique based on interval arithmetic is proposed for the computation of numerical values for the bounds. The applicability of the bounds and their tightness are analyzed through case studies. Issues such as the inter-relationship between the software architecture and system performance, and the effect of processor contention on the performance bounds are discussed.     

Simulated motion negatively affects motor task but not neuromuscular performance

The effects of long duration simulated motion on motor task and neuromuscular performance along with time frames required to recover from these effects are relatively unknown. This study aimed to determine (1) how simulated motion affects motor task and neuromuscular performance over one hour of motion and (2) the time course of recovery from any decrements. The dependent variables that were measured included: reaction time; visuomotor accuracy tracking; maximal voluntary contractions; voluntary activation; evoked contractile properties and biceps brachii electromyography of the elbow flexors. Reaction times and error rates of the visuomotor accuracy tracking task were compromised in motion, but maximal force, voluntary activation, evoked contractile properties and rmsEMG responses of the biceps brachii were unaffected by motion. It is concluded that motion causes an increase in attention demands, which have a greater effect on motor task rather than neuromuscular performance.

Practitioner Summary: Minor delays or mistakes can separate life and death at sea. The safety and productivity of most vessels rely on error-free performance of motor tasks. This study demonstrates that human ability to perform motor tasks is compromised by ship motions and may aid in developing training and safety guidelines for seafarers.     

Windows操作系统多核CPU内核线程管理方法

Windows是采用CPU时间片轮转多任务分配机制的非实时操作系统,无法满足实时性要求比较高的任务需要。而随着CPU技术的快速发展,当前市场上双核甚至多核CPU已成为主流,这使得在Windows平台上用多核CPU的某些核独立执行任务,从而有效地提高软件的实时性成为可能。本文介绍一种在Windows内核模式下编写Windows驱动程序,有效分配多核CPU资源从而提高软件实时性的方法。     

Simulation study of multitasking in distributed server systems with variable workload

The multitasking performance of a distributed server system is considered where the workload is variable. Time varying distributions are proposed for job arrival, job parallelism, and task service demand. A simulation model is used to address performance issues associated with task scheduling. The objective is to identify conditions that produce good overall system performance, while maintaining fairness of individual job execution times. Simulated results show that all task scheduling methods have merit. In all cases, the best policy depends on performance goals. Furthermore, although the paper studies distributed multiprocessor system performance, it also addresses the performance issues of other systems where multitasking and scheduling is used, since no restrictions are imposed on the server/job/task characteristics.     

Multiple spatial sounds in hierarchical menu navigation for visually impaired computer users

This paper describes a user study on the benefits and drawbacks of simultaneous spatial sounds in auditory interfaces for visually impaired and blind computer users. Two different auditory interfaces in spatial and non-spatial condition were proposed to represent the hierarchical menu structure of a simple word processing application. In the horizontal interface, the sound sources or the menu items were located in the horizontal plane on a virtual ring surrounding the user’s head, while the sound sources in the vertical interface were aligned one above the other in front of the user. In the vertical interface, the central pitch of the sound sources at different elevations was changed in order to improve the otherwise relatively low localization performance in the vertical dimension. The interaction with the interfaces was based on a standard computer keyboard for input and a pair of studio headphones for output. Twelve blind or visually impaired test subjects were asked to perform ten different word processing tasks within four experiment conditions. Task completion times, navigation performance, overall satisfaction and cognitive workload were evaluated. The initial hypothesis, i.e. that the spatial auditory interfaces with multiple simultaneous sounds should prove to be faster and more efficient than non-spatial ones, was not confirmed. On the contrary—spatial auditory interfaces proved to be significantly slower due to the high cognitive workload and temporal demand. The majority of users did in fact finish tasks with less navigation and key pressing; however, they required much more time. They reported the spatial auditory interfaces to be hard to use for a longer period of time due to the high temporal and mental demand, especially with regards to the comprehension of multiple simultaneous sounds. The comparison between the horizontal and vertical interface showed no significant differences between the two. It is important to point out that all participants were novice users of the system; therefore it is possible that the overall performance could change with a more extensive use of the interfaces and an increased number of trials or experiments sets. Our interviews with visually impaired and blind computer users showed that they are used to sharing their auditory channel in order to perform multiple simultaneous tasks such as listening to the radio, talking to somebody, using the computer, etc. As the perception of multiple simultaneous sounds requires the entire capacity of the auditory channel and total concentration of the listener, it does therefore not enable such multitasking.