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Multitasking and monotasking: The effects of mental workload on deferred task interruptions

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Abstract

Recent research has found that forced interruptions at points of higher mental workload are more disruptive than at points of lower workload. This paper investigates a complementary idea: when users experience deferrable interruptions at points of higher workload, they may tend to defer processing of the interruption until times of lower workload. In an experiment, users performed a mail-browser primary task while being occasionally interrupted by a secondary chat task, evenly distributed between points of higher and lower workload. Analysis showed that 94% of the time, users switched to the interrupting task during periods of lower workload, versus only 6% during periods of higher workload. The results suggest that when interruptions can be deferred, users have a strong tendency to ''monotask'' until primary-task mental workload has been minimized.

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... A common strategy is to wait for 'natural breakpoints' in the task to switch attention [11,12,26,27,28,48]; for example, Iqbal et al. showed that drivers chunked a task of providing directions while driving into multiple steps and reoriented to driving at the boundaries between chunks [26]. There are many advantages of interleaving at natural breakpoints: it reduces mental workload [3,49] as it reduces information that needs to be maintained in memory [7], it frees mental resources such as visual attention for other tasks [50,55], it reduces stress [4], it reduces the time needed for later task resumption (cf. [2]), and it can offer speed-accuracy trade-offs in dynamic environments such as driving [28]. ...
... Moreover, gradually disengaging from the task and waiting for a natural breakpoint can also benefit the driving task. If interleaving at a more opportune task reduces workload [3,49] and stress [4], then people are in a better mental state to resume driving. ...
... A recent review showed that drivers distract themselves more with other tasks as automation in the car increases, and that this impacts their situational awareness and ability to respond correctly [16]. Based on theory, we expect that a pre-alert has four benefits (1) it allows a driver the necessary time to disengage from a secondary task [6], (2) this can reduce mental workload [3,49] and stress [4] and leave drivers in a better state to manage the handover, (3) this allows drivers more time to reorient to the driving task and gain relevant situational awareness, and (4) with sufficient time distracting effects from the non-driving tasks may be reduced (cf. [52]). ...
Conference Paper
Semi-autonomous vehicles occasionally require control to be handed over to the driver in situations where the vehicle is unable to operate safely. Currently, such handover requests require the driver to take control almost instantaneously. We investigate how auditory pre-alerts that occur well before the handover request impact the success of the handover in a dual task scenario. In a study with a driving simulator, drivers perform tasks on their phone while the car is in an autonomous mode. They receive a repeated burst audio pre-alert or an increasing pulse audio pre-alert preceding the standard warning for immediate handover. Results show that pre-alerts caused people to look more at the road before the handover occurred, and to disengage from the secondary task earlier, compared to when there was no pre-alert. This resulted in safer handover situations. Increasing pulse pre-alerts show particular promise due to their communication of urgency. Our detailed analysis informs the design and evaluation of alerts in safety-critical systems with automation.
... Resumption lag is increased when the duration of the interrupting task increases (Hodgetts & Jones, 2006;Monk et al., 2008). While a resumption lag is lessened if an interruption occurs at the completion of a task rather than during one (Tanaka et al., 2014;Adamczyk & Bailey, 2004;Czerwinski, Cutrell, & Horvitz, 2000;Salvucci & Bogunovich, 2010;Iqbal & Bailey, 2005). ...
... These include the type of task being performed when an interruption occurs (Bailey, Konstan, & Carlis, 2000;Zijlstra, Roe, Leonora, & Krediet, 1999), the mental workload (defined as the resources required to perform the task [Hoedemacker, 2002; as cited in Silva, 2014], Adamczyk & Bailey, 2004;Salvucci & Bogunovich, 2010), arousal (Adler & Benbunan-Fich, 2012;Altmann & Trafton, 2002;Speier, Valacich, & Vessey, 1999;Speier, Vessey, & Valacich, 2003) and the opportunity to practice or prepare for the interruption (Trafton, Altmann, Brock, & Mintz, 2003). Though logically independent, these factors can interact (Liu, Wadeson, Kim, & Nam, 2016;Wickens, 2008;Speier, Vessey, & Valacich, 2003). ...
... The impact of workload on task switching is also largely dependent on whether the individual is able to choose when to be interrupted. With research demonstrating that individuals are more likely to voluntarily switch between tasks during a period of lower workload (Iqbal & Bailey, 2005;Salvucci & Bogunovich, 2010). Salvucci and Bogunovich (2010) demonstrated that when individuals experienced interruptions that did not require immediate attention during periods of high workload, they were strongly inclined to delay the processing of the interruption until a period of lower workload or until the mental workload on the primary task had been lessened. ...
Thesis
Sleep disruption literature has largely focused on exploring sleep disruptions effects on relatively simple tasks with less attention given to how it impacts more complex tasks. Further, research has given very little attention on how performance fairs when participants also have to switch between tasks, in both a voluntary and forced state. The goal of this thesis was, therefore, to expand on previous investigations of sleep loss and its effects on performance of complex visuo-cognitive tasks whilst either voluntarily or forcibly task switching. Over the course of four experiments this was examined. Experiment 1 and 2 explored the effects of both sleep restriction and sleep deprivation and the cost they have on voluntary task switching performance. These experiments revealed that individuals can largely compensate for the negative effects of sleep restriction especially when they spend longer preparing for an upcoming switch in tasks. However, when they have experienced sleep deprivation these effects become more severe, causing fewer words to be generated and an increase in the number of switches made. Experiment 3, explored how the removal of control over the task in terms of forcing them when to switch, impacted performance between sleep conditions, while also seeing how it compares to voluntary switching. Results highlighted that once control of the task was removed a larger profile of errors emerged. Specifically, with the reduction in the number of words in both the sleep deprived condition and the forced switching condition, as well as, sleep deprived participants having a longer resumption lag. Finally, Experiment 4 addressed two key components. The first component addressed the sensitivity of subjective measures of sleepiness versus objective measures of sleepiness. Results highlighted that subjective measures of sleepiness are more sensitive to the feelings of fatigue and are resilient against individual differences unlike the objective measures. The second component aimed to address the differences between voluntary versus forced switching and sleep deprived versus Control while switching between two tasks that contained two different types of cognitive task goals. Issues arose during data collection that hindered collection of a full dataset and subsequently no firm conclusions can be drawn. Based on the results from these experiments, this thesis demonstrates that the negative effects of sleep loss are dependent on the task constraints and the amount of sleep lost. However, it is clear the harder the task becomes the more difficult it is for individuals to compensate for the negative effects of fatigue when performing complex visuo-cognitive tasks. The implication of this research is that both fatigue and task switching are an important consideration when managing small daily tasks whilst also addressing the potential impact it poses on safety concerns in many industries. <br/
... For instance, interruptions have been shown to be more disruptive if they happen in the middle of a subtask compared to when they happen between subtasks, because people have a higher workload of remembering where they are in the middle of the subtask Iqbal & Bailey, 2005). Salvucci & Bogunovich (2010) conducted an experiment investigating how people manage interruptions that are deferrable, and found people deferred interruptions until moments of low workload. This suggests that people may be fairly good at focusing on a task and postponing interruptions, though the study only looked at external interruptions, which were triggered by notifications. ...
... For example, it is less disruptive to interrupt a task at a low-workload than high-workload moment Iqbal & Bailey, 2005). Prior studies have shown that people choose to defer interruptions until low workload moments if given the option to do so, and if they do not have to hold the intention to interrupt in memory (Gilbert, 2015;Salvucci & Bogunovich, 2010). Gilbert (2015) looked at people's off-loading behaviour of future tasks in both an experimental and naturalistic setting. ...
... Most experimental studies on self-interruptions have used an artificial distraction, such as chat messages, to measure how people self-interrupt to attend to this distracting task (Katidioti & Taatgen, 2013;Salvucci & Bogunovich, 2010). The current study makes a methodological contribution by using participants' own personal email inbox, based on the assumption that email provides a natural source of distraction (Hanrahan & Pérez-Qu, 2015;Mark et al., 2016a). ...
Conference Paper
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Computer-based work often involves looking up information from different sources. Though these interruptions are required to progress with work, switching away from a task can be disruptive: it slows people down, increases errors and it is challenging to remain focused on work. This thesis investigates how interruption management tools can better support people in managing these types of work-required interruptions in the context of data entry work. The first part of the thesis reports two qualitative studies looking at understanding data entry in an office setting. They demonstrate that physical interruptions are postponed until a convenient moment in the task if they are expected to take time, but digital interruptions are addressed immediately as these are presumed to be quick to deal with. The second part of the thesis reports three controlled experiments to test the hypothesis that people manage interruptions by avoiding time costs. Results show that if people are able to learn the expected time costs of digital interruptions, they avoid interruptions with a high time cost. They reduce the number of these interruptions and postpone them until later in the task, and address interruptions with low time costs first. The third part of the thesis reports an online experiment and a field study that evaluate a design intervention showing people the duration of their interruptions. These studies demonstrate that making people aware of the time costs of digital interruptions makes people reflect on what they were doing during an interruption, reduces the duration of interruptions, and makes people faster and more accurate in completing data entry tasks. Taken together, this thesis demonstrates that people manage interruptions based on expected time costs, and that giving people feedback on the time they spend on interruptions can help them manage their interruptions better. It makes a theoretical contribution by showing how people adapt to small changes in time costs by reducing the number and duration of interruptions, and postponing them until later in a task. It makes a practical contribution by showing that giving people feedback on time costs can help them to reduce the duration of interruptions, and improve their focus on the task at hand.
... Although the timing of the task switches was not recorded, the fact that it led to the best performance suggests that people waited for an opportune time to respond to interruptions. Salvucci and Bogunovich (2010) determined that people tended to respond to interruptions at a moment of lower workload when given a choice. A time of lower workload is a point in the primary task when the participant would not need to remember any information about the primary task when returning after an interruption. ...
... When given a choice about when to respond to an interruption, people tend to choose a time in between subtasks when they will not need to remember information about the primary task (Salvucci & Bogunovich, 2010). People also experience frustration when forced to task switch during a subtask instead of in between subtasks (Adamczyk & Bailey, 2004). ...
... In this experiment, there were no significant differences between the number of people who had more During Switches and the number of people who had more Between Switches. This seems to contradict previous studies that have determined that people prefer to task switch at breakpoints (Payne et al., 2007) and that when given a choice about when to respond to an interruption, people prefer to wait for a break between subtasks (Salvucci & Bogunovich, 2010). Similarly, Katidioti et al. (2014) found that participants preferred to switch at a moment of lower workload even in situations where they were able to switch completely at their own discretion. ...
Conference Paper
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Research has shown that people use smartphones in a way that encourages constant multitasking. While previous studies have determined that multitasking with technology has a negative impact on performance of a primary task, we examine how constant task switching specifically with mobile devices affects users. Our experiment examines discretionary task interleaving with smartphones and the effects this has on performance. The results demonstrate that while any amount of multitasking negatively affects performance on a primary task, these effects are lessened when switching at a breakpoint between subtasks rather than during a subtask.
... As is known from other studies (e.g. Salvucci & Bogunovich, 2010), people are rational when they self-interrupt and do so mostly on low-workload moments. As a result, participants self-interrupted on low-workload moments but were externally interrupted on highworkload moments. ...
... Design. The main and the interrupting task of this experiment were based on the ones used by Salvucci and Bogunovich (2010) and . The experimental setup resembles a client service work environment of an electronics company. ...
... Furthermore, people are known to self-interrupt on low-workload moments (e.g. Salvucci & Bogunovich, 2010;). Therefore it would not be fair to say that all external interruptions are less disruptive than self-interruptions. ...
Article
Interruptions are part of everyday life and are known to be disruptive. With the current study we investigated which kind of interruption is more disruptive: external interruptions or self-interruptions. We conducted two experiments, one behavioral experiment (28 participants) and one in which pupil dilation was measured (21 participants). In both experiments, self-interruptions made participants complete the main task slower than external interruptions (occurring at similar moments in the task as the self-interruptions). However, there was no difference between the two kinds of interruptions in the time needed to resume the main task (resumption lag). Instead, the pupil dilation data revealed that the decision to self-interrupt takes about 1 s, resulting in slower performance overall.
... Further support for the notion of better and worse moments for interruption comes from the way that people themselves manage interruptions. Salvucci and Bogunovich (2010) investigated how people managed interruptions in a simple task. Participants were asked to manage an email inbox of incoming requests. ...
... They also had to attend to instant messages. Salvucci and Bogunovich (2010) found that people tended to wait until they were not storing product information in their head before they switched to the instant messaging task. They suggested that maintaining representations of product information in working memory (they refer to it as the problem-state) required significant cognitive resources. ...
... Given that previous research has suggested that subtask boundaries might be the best place to interrupt people (Iqbal & Bailey, 2010) and that people will defer switching tasks until subtask boundaries (Janssen et al., 2012;Bogunovich & Salvucci, 2011;Salvucci & Bogunovich, 2010), why was resumption faster after within-subtask interruptions in Experiment 5? The simple answer is that people make tradeoffs when dealing with interruptions. When working through a task, goals are created in working memory to represent information about a task and progress through it. ...
Thesis
Interruptions disrupt activity, hindering performance and provoking errors. They present an obvious challenge in safety-critical environments where momentary slips can have fatal consequences. Interruptions are also a problem in more workaday settings, like offices, where they can reduce productivity and increase stress levels. To be able to systematically manage the negative effects of interruptions, we first need to understand the factors that influence their disruptiveness. This thesis explores how the disruptiveness of interruptions is influenced by their relevance and timing. Seven experimental studies investigate these properties in the context of a routine data-entry task. The first three experiments explore how relevance and timing interact. They demonstrate that the relevance of interruptions depends on the contents of working memory at the moment of interruption. Next, a pair of experiments distinguish the oft-conflated concepts of interruption relevance and relatedness. They show that interruptions with similar content to the task at hand can negatively affect performance if they do not contribute toward the rehearsal of goals in working memory. By causing active interference, seemingly useful interruptions that are related to the task at hand have the potential to be more disruptive than entirely unrelated, irrelevant interruptions. The final two experiments in this thesis test the reliability of the effects observed in the first five experiments through alternative experimental paradigms. They show that relevance and timing effects are consistent even when participants are given control over interruptions and that these effects are robust even in an online setting where experimental control is compromised. The work presented in this thesis enhances our understanding of the factors influencing the disruptiveness of interruptions. Its primary contribution is to show that when we talk about interruptions, ‘relevance’, ‘irrelevance’ and ‘relatedness’ must be considered in the context of the contents of working memory at the moment of interruption. This finding has implications for experimental investigations of interrupted performance, efforts to under- stand the effects of interruptions in the workplace, and the development of systems that help users manage interruptions.
... We developed an IMS that uses real-time changes in pupil dilation to identify the low-workload moments of a task. We then tested it on the email task that is interrupted by chat messages Salvucci & Bogunovich, 2010) with minor adjustments to fit the current setup. As the task progresses, the IMS calculates a workload identifier value (WIV). ...
... The main and the interrupting task of the experiment were based on Salvucci and Bogunovich (2010). The experiment simulates the working environment of an employee of an electronics company who has to answer clients' emails while being interrupted by chat messages. ...
... When the price of the product loads, there are again high-workload moments, since participants have to keep the price in their working memory until the answer is sent. A similar task analysis has been used at Salvucci and Bogunovich (2010) and . Both these papers have used the same e-mail task (with some small differences in Salvucci & Bogunovich, 2010). ...
Article
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Interruptions are prevalent in everyday life and can be very disruptive. An important factor that affects the level of disruptiveness is the timing of the interruption: Interruptions at low-workload moments are known to be less disruptive than interruptions at high-workload moments. In this study, we developed a task-independent interruption management system (IMS) that interrupts users at low-workload moments in order to minimize the disruptiveness of interruptions. The IMS identifies low-workload moments in real time by measuring users’ pupil dilation, which is a well-known indicator of workload. Using an experimental setup we showed that the IMS succeeded in finding the optimal moments for interruptions and marginally improved performance. Because our IMS is task-independent—it does not require a task analysis—it can be broadly applied.
... The second proposed method is a standing and lying (SL) approach. According to the multitasking theory [35], a user is more at risk of falling when performing a secondary task in addition to a primary task. Those behaviors include when elderly people use mobile phones, although the risk is varied depending on whether the user performs the second action while holding the phone or while in the act of putting it down [34,35]. ...
... According to the multitasking theory [35], a user is more at risk of falling when performing a secondary task in addition to a primary task. Those behaviors include when elderly people use mobile phones, although the risk is varied depending on whether the user performs the second action while holding the phone or while in the act of putting it down [34,35]. Consequently, it is important to know whether a user is holding onto or putting down their mobile device. ...
Article
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There are many healthcare possibilities for the elderly, such as hospitals, nursing homes, and home-based care. However, in times of COVID-19, most home-based elderly people did not have sufficient supplies or healthcare as usual. Fulfilling their desire for an independent lifestyle while protecting them from falls, sudden illness, or accidents is difficult. This study represents a smart system for coping with this problem in public healthcare. The existing methods for residential aged care (RAC), such as fall detection, focus on personal profiles and physical symptoms records or use a collaborative filtering method to notify caregivers or family members that the elderly person may be at a high level of risk. However, these methods have many limitations in times of COVID-19, including insufficient risk factors, problems gathering information from mobile sensors, and issues with handling human variability. This study proposes a new method for RAC in times of COVID-19 called the Intelligent Healthcare Agent System (IHAS), which, unlike the old system, incorporates context information, such as indoor and outdoor (IO), standing and lying (SL), and resting and moving (RM). IHAS integrates diverse mobile sensor data and utilizes artificial intelligence (AI) technologies into the research model and learning-oriented prototype system that can manage human variability. Ultimately, this study’s findings should contribute to the existing research and industrial applications of RAC, as well as offer new avenues of study in future research.
... Additionally, participants were asked to deal with interrupter tasks. Interrupter tasks were modeled after those used in other studies (e.g., Adamczyk & Bailey, 2004;Iqbal & Bailey, 2005;Salvucci & Bogunovich, 2010) and took the form of pop-up windows with additional tasks that appeared on the screen while participants were performing ongoing tasks. They were presented at pre-defined moments unknown to participants. ...
... Once the interrupter window has been displayed, the task in the background was frozen up to a point a participant reacted (the pop-up window with the interrupter task was presented in the middle of the screen and the rest of the screen turned dark grey to indicate the task in the background is inactive). Participants could either go to the task (by clicking the "Answer" button) or ignore it (by clicking the "Ignore" button), that is, they were not forced to perform the task (as in Salvucci & Bogunovich, 2010). They were also told that it depended on them whether or not to engage in these additional tasks. ...
Article
In two studies we test the role motivational rigidity, i.e., need for cognitive closure (NFC), plays in handling task irrelevant interruptions and multitasking performance. We assumed that, although related to rigid cognitive style, NFC may enhance multitasking performance thanks to better focalization on the main task goal. We thus predicted that NFC would be related to lower engagement in tasks unrelated to the main task goal and thereby to a better performance on multiple tasks. The results supported our hypotheses as it turned out that NFC was negatively related to the number of responses to task irrelevant interruptions and positively to multitasking performance in Study 1. Study 2 additionally showed that there was a positive indirect effect of NFC on multitasking performance mediated by lower engagement in interruption tasks. This effect was significant for difficult but not easy tasks supporting previous findings that interruptions are more disruptive for complex rather than simple tasks. The results suggest that better focalization on the main task goal and lower engagement in interruptions might be the mechanism responsible for enhanced multitasking performance exhibited at times by highly rigid individuals.
... This is because this type of notification is expected to be less disruptive of the primary task (e.g., visual query formulation) in comparison to its intrusive counterpart. Furthermore, recent research has suggested that users typically delay processing of a nonintrusive interruption, when it is sent to them at points of higher mental workload, until they have reached a point of lower mental workload [26]. On the other hand, acceptability of high-urgency messages (e.g., empty results, syntax error) is expected to be low when presented non-intrusively as immediate user response is expected for such notifications. ...
... Output: Notification N 1 Initialize canInterrupt = false; 2 while canInterrupt is false do 3 if !hasCourseBreakpoint() then 4 moveDir ← getCursorDirection() ; 5 if moveDir is true then 6 T m ← movementTime(D, W , H, a, b, η) cursor is in Schema Panel then 11 if an item is not dragged then 12 p ← getPosition(); 13 T s ← selectionTime(m, n, p) cursor is in Query Panel and selected item is dropped then 19 canInterrupt = true; 20 else 21 canInterrupt = false; 22 if NullCond is true then 23 Display N = "The condition C ∅ will return an empty result."; 24 else 25if NullCond is false ∧ AllCond is true then26 Display N = "The conditions C ∅ will return an empty result."; ...
Conference Paper
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The usability of visual querying schemes for tree and graph-structured data can be greatly enhanced by providing feedback during query construction, but feedback at inopportune times can hamper query construction. In this paper, we rethink the traditional way of providing feedback. We describe a novel vision of interruption-sensitive query feedback where relevant notifications are delivered quickly but at an appropriate moment when the mental workload of the user is low. Though we focus on one class of query feedback, namely empty result detection, where a user is notified when a partially constructed visual query yields an empty result, our new paradigm is applicable to other kinds of feedback. We present a framework called iSERF that bridges the classical database problem of empty-result detection with intelligent notification management from the domains of HCI and psychology. Instead of immediate notification, iSERF considers the structure of query formulation tasks and breakpoints when reasoning about when to notify the user. We present an HCI-inspired model to quantify the performance bounds that iSERF must abide by for checking for an empty result in order to ensure interruption-sensitive notification at optimal breakpoints. We implement this framework in the context of visual XML query formulation and highlight its effectiveness empirically.
... Previous research has focused on factors that make interruptions disruptive [e.g., interrupting task complexity, duration; 13,14,18,20,22,23,34,35,46], on when users can best be interrupted [1,25,27,32], as well as on how users manage interruptions themselves [7,19,29,30,42,45,46]. To improve our understanding of interruptions, the results of these studies should be integrated into a cognitive theory. ...
... To test whether users are aware that they should switch at low-workload moments, in [42] users were asked to perform a mail-and-internet task, which was interrupted by a chat task. Users were free to respond to the chat messages whenever they thought was best. ...
Conference Paper
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In this paper we present a computational cognitive model of task interruption and resumption, focusing on the effects of the problem state bottleneck. Previous studies have shown that the disruptiveness of interruptions is for an important part determined by three factors: interruption duration, interrupting-task complexity, and moment of interruption. However, an integrated theory of these effects is still missing. Based on previous research into multitasking, we propose a first step towards such a theory in the form of a process model that attributes these effects to problem state requirements of both the interrupted and the interrupting task. Subsequently, we tested two predictions of this model in two experiments. The experiments confirmed that problem state requirements are an important predictor for the disruptiveness of interruptions. This suggests that interfaces should be designed to a) interrupt users at low-problem state moments and b) maintain the problem state for the user when interrupted.
... Reasonable workload with increased efficiency enables the handoff process to be lean. Maintaining a reasonable level of workload is crucial because it is related to interruption management, 36 performance, 37 and quality and safety of care. 38 In addition, handoff duration is important because time is often limited, and the ever-present time demands unfortunately impact cognitive workload, decision-making, and multitasking. ...
Article
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Background and objectives: Handoff protocols are often developed by brainstorming and consensus, and few are directly compared. We hypothesized that a handoff protocol (Flex 11) developed using a rigorous methodology would be more favorable in terms of clinicians' attitudes, behaviors, cognitions, or time-on-task when performing handoffs compared with a prevalent protocol (Situation Background Assessment Recommendation [SBAR]). Methods: Using a between-groups, randomized control trial design (Flex 11 versus SBAR) during a pilot study in a simulated environment, 20 clinicians (13 attending physicians and 7 residents) received 3 patient handoffs from a standardized physician, managed the patients, and handed off the patients to the same standardized physician. Participants completed surveys assessing their attitudes and cognitions, and behaviors and handoff duration were assessed through observations. Results: All data were analyzed using independent samples t tests. For attitudes, "ease of use" ratings were lower for SBAR participants than Flex 11 participants (P < .01), and "being helpful" ratings were lower for SBAR participants than Flex 11 participants (P = .02). For behaviors, results indicate no significant difference in the information acquired between the SBAR and Flex 11 protocols. However, SBAR participants gave significantly less information than Flex 11 participants (P < .01). For cognitions, SBAR and Flex 11 participants reported similar workload except for frustration. For handoff duration, there were no significant differences between the protocols (P = .36). Conclusions: The results suggest that Flex 11 is an efficient, beneficial tool in a simulated environment with pediatric clinicians. Future studies should evaluate this protocol in the inpatient setting.
... Multitasking is usually explained from the perspective of sequential execution as a type of task switching where all tasks are performed in succession (Salvucci & Bogunovich, 2010). In mobile environments, users often multitask by task switching among various features to achieve related sequential tasks or events. ...
Article
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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.
... The negative impact of interruptions can be either reinforced or countered, depending on whether they contain irrelevant or relevant information about the primary activities. On one hand, with every exposure to incongruent interruptions, individuals are compelled to create a new problem state that distracts attention from primary activities (Salvucci and Bogunovich 2010). Performance will therefore likely suffer. ...
Article
Interruption of work by e-mail and other communication technologies has become widespread and ubiquitous. However, our understanding of how such interruptions influence individual performance is limited. This paper distinguishes between two types of e-mail interruptions (incongruent and congruent) and draws upon action regulation theory and the computer-mediated communication literature to examine their direct and indirect effects on individual performance. Two empirical studies of sales professionals were conducted spanning different time frames: a survey study with 365 respondents and a diary study with 212 respondents. The results were consistent across the two studies, showing a negative indirect effect of exposure to incongruent interruptions (interruptions containing information that is not relevant to primary activities) through subjective workload, and a positive indirect effect of exposure to congruent interruptions (interruptions containing information that is relevant to primary activities) through mindfulness. The results differed across the two studies in terms of whether the effects were fully or partially mediated, and we discuss these differences using meta-inferences. Technology capabilities used during interruption episodes also had significant effects: rehearsing (fine-tuning responses to incoming messages) and reprocessing (reexamining received messages) were positively related to mindfulness, parallel communication (engaging in multiple e-mail conversations simultaneously) and leaving messages in the inbox were positively related to subjective workload, and deleting messages was negatively related to subjective workload. This study contributes to research by providing insights on the different paths that link e-mail interruptions to individual performance and by examining the effects of using capabilities of the interrupting technology (IT artifact) during interruption episodes. It also complements the experimental tradition that focuses on isolated interruptions. By shifting the level of analysis from specific interruption events to overall exposure to interruptions over time and from the laboratory to the workplace, our study provides realism and ecological validity.
... The average professional software development experience of participants is 3.5 (range 1 to 8) at Arcurve and 9.5 (range 4 to 25) in their total career. Task level (v 3 )[10]–[12]: The parentId column of our database Interrupting task's type (v 4 )[2],[8],[13],[14]: We conducted a manual analysis on the meta data associated to each task to identify the type of both interrupted and interrupting tasks. Interruption type (v 5 )[2],[12],[15]–[17]: We used the meta data associated to each task. ...
Conference Paper
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Task switching and interruptions are a daily reality in software development projects: developers switch between Requirements Engineering (RE), coding, testing, daily meetings, and other tasks. Task switching may increase productivity through increased information flow and effective time management. However, it might also cause a cognitive load to reorient the primary task, which accounts for the decrease in developers' productivity and increases in errors. This cognitive load is even greater in cases of cognitively demanding tasks as the ones typical for RE activities. In this paper, to compare the reality of task switching in RE with the perception of developers, we conducted two studies: (i) a case study analysis on 5,076 recorded tasks of 19 developers and (ii) a survey of 25 developers. The results of our retrospective analysis show that in 98% of cases that the disruptiveness of RE interruptions is statistically different from other software development tasks, RE related tasks are more vulnerable to interruptions compared to other task types. Moreover, we found that context switching, the priority of the interrupting task, and the interruption source and timing are key factors that impact RE interruptions. We also provided a set of RE task switching patterns along with recommendations for both practitioners and researchers. While the results of our retrospective analysis show that self-interruptions are more disruptive than external interruptions, developers have different perceptions about the disruptiveness of various sources of interruptions.
... People may avoid combining tasks of similar modalities in order to prevent interference between them (Salvucci & Taatgen, 2008Wickens, 2002Wickens, , 2008. A task can have "natural breakpoints" (Janssen, Brumby, & Garnett, 2012), where interleaving is particularly beneficial, for example, because workload is low at those points (Bailey & Iqbal, 2008;Salvucci & Bogunovich, 2010) or because these natural breakpoints incur shorter resumption costs after an interruption (Altmann & Trafton, 2002;Borst, Taatgen, & van Rijn, 2010). Other researchers debate people's ability to multitask optimally (e.g., Nijboer, Taatgen, Brands, Borst, & van Rijn, 2013;Ophir, Nass, & Wagner, 2009;Stoet, O'Connor, Conner, & Laws, 2013;Watson & Strayer, 2010), focusing on the interplay between cognitive characteristics and task performance (e.g., "do people perform worse when they are faced with two challenging tasks?") and on performance decrements in multitask compared to single-task settings. ...
Article
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We test people's ability to optimize performance across two concurrent tasks. Participants performed a number entry task while controlling a randomly moving cursor with a joystick. Participants received explicit feedback on their performance on these tasks in the form of a single combined score. This payoff function was varied between conditions to change the value of one task relative to the other. We found that participants adapted their strategy for interleaving the two tasks, by varying how long they spent on one task before switching to the other, in order to achieve the near maximum payoff available in each condition. In a second experiment, we show that this behavior is learned quickly (within 2-3 min over several discrete trials) and remained stable for as long as the payoff function did not change. The results of this work show that people are adaptive and flexible in how they prioritize and allocate attention in a dual-task setting. However, it also demonstrates some of the limits regarding people's ability to optimize payoff functions.
... The average professional software development experience of participants is 3.5 (range 1 to 8) at Arcurve and 9.5 (range 4 to 25) in their total career. Task level (v 3 )[10]–[12]: The parentId column of our database Interrupting task's type (v 4 )[2],[8],[13],[14]: We conducted a manual analysis on the meta data associated to each task to identify the type of both interrupted and interrupting tasks. Interruption type (v 5 )[2],[12],[15]–[17]: We used the meta data associated to each task. ...
Article
Full-text available
Task switching and interruptions are a daily reality in software development projects: developers switch between Requirements Engineering (RE), coding, testing, daily meetings, and other tasks. Task switching may increase productivity through increased information flow and effective time management. However, it might also cause a cognitive load to reorient the primary task, which accounts for the decrease in developers' productivity and increases in errors. This cognitive load is even greater in cases of cognitively demanding tasks as the ones typical for RE activities. In this paper, to compare the reality of task switching in RE with the perception of developers, we conducted two studies: (i) a case study analysis on 5,076 recorded tasks of 19 developers and (ii) a survey of 25 developers. The results of our retrospective analysis show that in ALL of the cases that the disruptiveness of RE interruptions is statistically different from other software development tasks, RE related tasks are more vulnerable to interruptions compared to other task types. Moreover, we found that context switching, the priority of the interrupting task, and the interruption source and timing are key factors that impact RE interruptions. We also provided a set of RE task switching patterns along with recommendations for both practitioners and researchers. While the results of our retrospective analysis show that self-interruptions are more disruptive than external interruptions, developers have different perceptions about the disruptiveness of various sources of interruptions.
... A model by Senders et al. (1967) accounted for the environmental demands: drivers switch attention when the uncertainty about the road and vehicle state exceeds a threshold, to reduce the discomfort of high uncertainty. Other studies have proposed that task characteristics influence the switching behavior (e.g., Janssen, Brumby, & Garnett, 2012): a task can be decomposed into multiple subtasks, and drivers tend to switch at the boundaries of subtasks rather than in the middle of the subtask, because switching at subtask boundary benefits people by reducing workload (Salvucci & Bogunovich, 2010). ...
Studies of multitasking while driving have shown that drivers tend to switch attention at subtask boundaries. It is also known that the uncertainty of roadway information plays a significant role in attention switching. Yet, these two approaches have not been modeled together. In this study, we create an attention switching model that accounts for both subtask boundaries and uncertainty, and use Approximate Bayesian Computation-Markov Chain Monte Carlo (ABC- MCMC) to determine the weight between the two factors, based on the empirical data. The weight was calculated for each of two different types of tasks, text reading and entry, that have subtask boundaries with different characteristics. We found that the subtask boundary in the text reading task nudged drivers to discontinue the distracting task and switch attention back to the road more than the subtask boundary in the text entry task. This study suggests that task structure may play a role in generating long glances.
... Students attempting to complete parts of their coursework were similarly affected by instant messages, and spent up to 50% longer reading a passage from a textbook than individuals who did not IM during reading (Bowman et al., 2010). A recent study of students performing two tasks on the computer found that individuals showed a strong preference to complete one task until the workload of the primary task had been minimised (Salvucci and Bogunovich, 2010). This evidence suggests that individuals use strategies to mitigate the effects of multitasking on performance. ...
Article
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Multi-tasking is an important skill for clinical work which has received limited research attention. Its impacts on clinical work are poorly understood. In contrast, there is substantial multi-tasking research in cognitive psychology, driver distraction, and human-computer interaction. This review synthesises evidence of the extent and impacts of multi-tasking on efficiency and task performance from health and non-healthcare literature, to compare and contrast approaches, identify implications for clinical work, and to develop an evidence-informed framework for guiding the measurement of multi-tasking in future healthcare studies. The results showed healthcare studies using direct observation have focused on descriptive studies to quantify concurrent multi-tasking and its frequency in different contexts, with limited study of impact. In comparison, non-healthcare studies have applied predominantly experimental and simulation designs, focusing on interleaved and concurrent multi-tasking, and testing theories of the mechanisms by which multi-tasking impacts task efficiency and performance. We propose a framework to guide the measurement of multi-tasking in clinical settings that draws together lessons from these siloed research efforts.
... Finally, the negative impact of attending to HMI messages on ongoing NDRTs could be further limited by supporting their re-uptake after the HMI message has been processed by the driver (thereby lowering the resumption lag, see Figure 1). For example, interrupting the driver in the middle of an ongoing NDRT will cause longer resumption lags compared to interruptions after a sub-task was completed [1,34,60] and increase workload associated with the task switch [87]. Thus, non-urgent status messages could be delayed until the NDRT can be interrupted at a suitable step [32,33]. ...
Conference Paper
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To increase the safety in use of automated vehicles, Human Factors research has focused primarily on driver performance during takeover situations. However, surveys on public opinion on automated vehicles still report a lack of acceptance of the technology. In this review, we give an overview on how taking the changed role of the driver into account when designing Human-Machine Interfaces (HMI) of automated vehicles could increase the usefulness of the technology, which might in turn result in increased public acceptance. We propose that balancing the driver's need of being informed about the automated vehicle's status, actions and intentions with the desire to engage in non-driving related tasks (NDRTs) is likely to play an important role in this process.
... Task-switching on a single device, however, is different because the sequence of attention over time is more important than divided attention at one point in time. That is, engaging in multiple tasks on a single display is more likely to be characterized as sequential switching between activities, rather than the splitting of attention between simultaneous, competing information streams-a distinction supported by rich literatures on the cognitive processes and effects of engaging multiple tasks serially versus concurrently (Pashler, 2000;Monsell, 2003;Salvucci et al., 2010). People actively make choices to pause one interaction and replace it with another, a consolidation of experience that is encouraged by computer operating systems and interfaces that enable people to switch quickly between radically different content. ...
Article
Personal computers allow multitasking among a greater variety of content than has ever been possible on a single device. We logged all switches made for 4 days for 30 people on personal computers used in natural environments. The median time before a switch occurred was 11 sec, shorter than previously observed. We also measured individual differences in appetitive versus defensive motivations to switch. Those people high on both motivations (Coactives) had the most switches per session. Risk takers had the shortest content segment lengths; risk avoiders and inactives were lower on the number of switches and anticipated arousal. Different patterns of content selection, in addition to switching behavior, were also observed for the different motivation activation groups. Results highlight how threads of experience that mix radically different short media segments may better define how people now search, process, and evaluate information. Implications in light of technological trends and individual differences are discussed.
... Some studies also include an option to defer interruptions (postpone them so they can be answered later, e.g., Salvucci & Bogunovich, 2010). In some situations, this might be the most efficient way to handle interruptions because deferred interruptions do not disrupt the focus on the current task to a great extent, but neither are they entirely ignored. ...
Chapter
This case is devoted to multitasking (performing two or more simultaneous tasks) in the face of task-irrelevant interruptions. I first briefly present how multitasking performance is typically measured in an experimental setting and introduce dual-tasking and task-switching paradigms. Next, I present how handling interruptions is measured in laboratory experiments. Finally, I present two experimental methods that combine both multitasking and dealing with interruptions. I focus on task-irrelevant interruptions, which are differentiated from task-relevant interruptions. I also show that ignoring interruptions might lead to better multitasking performance, especially when task-irrelevant interruptions are involved. Possible method modifications for future studies are discussed.
... This reengagement process will afford cognitive and motoric re-configurations of the driver's state to meet the demands of the driving situation (Marberger et al., 2017). Typically, such task switches have been shown to go along with increased reaction times, mental effort and error rates in cognitive psychology (so-called "switch costs", Altmann and Trafton, 2004;Salvucci and Bogunovich, 2010;Trafton et al., 2003), which can be reflected in worsened vehicle control directly after a transfer of control event (Merat et al., 2014;Naujoks et al., 2017a). ...
Article
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Automated driving systems are getting pushed into the consumer market, with varying degrees of automation. Most often the driver's task will consist of being available as a fall-back level when the automation reaches its limits. These so-called takeover situations have attracted a great body of research, focusing on various human factors aspects (e.g., sleepiness) that could undermine the safety of control transitions between automated and manual driving. However, a major source of accidents in manual driving, alcohol consumption, has been a non-issue so far, although a false understanding of the driver's responsibility (i.e., being available as a fallback level) might promote driving under its influence. In this experiment, N = 36 drivers were exposed to different levels of blood alcohol concentrations (BACs: placebo vs. 0.05% vs. 0.08%) in a high fidelity driving simulator, and the effect on takeover time and quality was assessed. The results point out that a 0.08% BAC increases the time needed to re-engage in the driving task and impairs several aspects of longitudinal and lateral vehicle control, whereas 0.05% BAC did only go along with descriptive impairments in fewer parameters.
... However, it is difficult to measure how workers become overloaded when they work beyond what they are capable of independently. Various ways have been developed to measure and predict the workload changes in a multitasking environment (Salvucci & Bogunovich, 2010;Svensson, Angelborg-Thanderez, Sjöberg, & Olsson, 1997;Xie & Salvendy, 2000). However, no previous works have investigated the relationship between the fractal dimension of pupil dilation and the human workload in a multitasking environment. ...
Article
The purpose of this study is to investigate the usefulness of the fractal dimension of pupil dilation as a measure of workload in a multitasking environment. Researchers have found that pupil dilation can reveal the underlying mechanism of the cognitive workload in a dynamic task environment. However, the workload metrics by using pupillary responses in a multitasking environment are not well studied in the literature. In this study, the participants' pupil dilation was collected and analyzed by using a fractal analysis technique to assess the participants' workload during the experiment. During the experiment, each participant performed a process monitoring task and Multi-Attribute Task Battery (MATB) task together. The process monitoring task simulated the responsibilities of process operators in the control room of oil and gas refinery plants. The MATB task consisted of system monitoring, target tracking, and dynamic resource management. To validate the outcome of this new metric, NASA-TLX questionnaires were used to measure the subjective workload, and the result of NASA-TLX was compared to the fractal dimension result. The findings from this study showed that the fractal dimension of pupil dilation could be used as a new physiological index to measure the workload in a multitasking environment.
... Salvucci et al. [9] explored differing types of lags that can be induced by an interruption. Both Interruption Lag (where a notification can cause the user to switch to a secondary task) and Resumption Lag (where the person returns to their primary task after completing the secondary task) both contributed to inefficiencies compared to performing tasks sequentially. ...
Conference Paper
One of the primary ways that people interact with applications on their mobile phones is through notifications. However, Android and iOS treat notifications differently, one being opt-in and the other being opt-out. We explore, through two identical survey studies spaced 2.5 years apart, changing practices in choosing to enable or disable notifications for certain types of mobile applications and how the power of defaults has lessened over time. We conclude with implications for apps that wish to use notifications to increase engagement.
... Multiple studies have shown that the less disruptive moment to present an interrupting task is between tasks rather than in the middle of a task. These moments are low workload moments and are considered less costly than high workload moments Monk, Boehm-Davis, Mason, & Trafton, 2004;Salvucci & Bogunovich, 2010). In contrast, interruptions during high workload periods increase the time to return to the primary task (Altmann & Trafton, 2007;Altmann, Trafton, & Hambrick, 2014;Mark, Gonzalez, & Harris, 2005), and reduce response time and increase errors (Iqbal & Bailey, 2007). ...
Article
Interruptions in the middle of a task have considerable costs. The objective of this study was to develop a system that postpones interruptions when they occur in periods of high workload. In Experiment 1, an air traffic control (ATC) simulator was presented with varying working memory demands. Pupil data were used to train a range of machine-learning classifiers to distinguish between high and low workload moments. The Gradient Boosted Tree (GBT) provided the best predictions. In Experiment 2, this classifier was used to develop a real-time interruption management system (IMS). The role of the IMS was to predict high and low workload and to postpone interruptions to the next low workload moment. To examine the IMS’s performance, its interruptions were compared to random interruptions. Results showed that the IMS successfully identified high and low workload moments with 76% accuracy, and postponed interruptions to the next low workload moment.
... For example, queuing in the consulting room is chaotic, and doctors suspend work tasks to maintain visit order. Or, in order to improve the work efficiency, doctors will actively choose to be interrupted when dealing with documentation, and perform multitasking simultaneously (35). Task of differing modalities, in this case verbal and nonverbal, can more easily be performed in parallel than tasks of the same modality (26). ...
Article
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Background: Workflow interruptions are frequent in hospital outpatient clinics. Eventually, not only reducing the work efficiency and quality, but also further threatening patient safety. Over the last 10-15 years, research on workflow interruptions in inpatient care has increased, but there is a lack of research on the interruptions in outpatient clinics. The present study aimed to study the differences in physicians' workflow interruptions among outpatient departments in the tertiary hospital in China. Methods: In a tertiary hospital, a standardized observational study of 32 doctors' workflow in outpatient department of four typical clinical specialties was conducted. The record of workflow interruptions was based on a self-made observation instrument after verifying its reliability and validity. Linear regression methods were used to assess outpatient characteristics as predictors of the number of interruptions. The Kruskal-Wallis test was used to analyze the difference about the duration of interruptions among specialties, and the Chi-Square Test was used to examine the sources of interruptions among different specialties, to determine whether interruption source is associated with specialty. Results: The number of patients was the significant independent predictor of the number of interruptions (p < 0.001). In terms of work tasks being interrupted, the highest interruption rate occurred when physicians were asking health history: 19.95 interruptions per hour. The distribution of interruption sources among the four clinical specialties were statistically different (X 2 = 16.988, p = 0.049). Conclusion: The findings indicate that physicians' workflow interruptions are connected with many contents in the work system. Further emphasis should be placed on the effective application of hospital management measures in an interrupted environment to promote a safe and efficiency outpatient care.
... For example, queuing in the consulting room is chaotic, and doctors suspend work tasks to maintain visit order. Or, in order to improve the work e ciency, doctors will actively choose to be interrupted when dealing with documentation, and perform multitasking simultaneously [50]. Task of differing modalities, in this case verbal and nonverbal, can more easily be performed in parallel than tasks of the same modality [24]. ...
Preprint
Full-text available
Background: Workflow interruptions are frequent in hospital outpatient clinics. Eventually, not only reducing the work efficiency and quality, but also further threatening patient safety. Over the last 10–15 years, research on workflow interruptions in inpatient care has increased, but there is a lack of research on the interruptions in outpatient clinics. The present study aimed to study the differences in physicians' workflow interruptions among outpatient departments in the tertiary hospital in China. Methods: In a tertiary hospital, a standardized observational study of 32 doctors' workflow in outpatient department of four typical clinical specialties was conducted. The record of workflow interruptions was based on a self-made observation instrument after verifying its reliability and validity. Linear regression methods were used to assess outpatient characteristics as predictors of the number of interruptions. The Kruskal-Wallis test was used to analyze the difference about the duration of interruptions among specialties, and the Chi-Square Test was used to examine the sources of interruptions among different specialties, to determine whether interruption source is associated with specialty. Results: The number of patients was the significant independent predictor of the number of interruptions(p<0.001). In terms of work tasks being interrupted, the highest interruption rate occurred when physicians were asking health history: 19.95 interruptions per hour. The distribution of interruption sources among the four clinical specialties were statistically different (Χ² =16.988, p = 0.049). Conclusion: The findings indicate that physicians' workflow interruptions are connected with many contents in the work system. Further emphasis should be placed on the effective application of hospital management measures in an interrupted environment to promote a safe and efficiency outpatient care.
... Unterbrechungen bis zu Momenten mit geringerem Workload hinaus (Salvucci & Bogunovich, 2010). Grenzen von Teilaufgaben stellen in der Regel Situationen mit geringem Workload dar, weswegen sich diese besonders für eine Unterbrechung eignen (Bailey & Iqbal, 2008). ...
Thesis
Fahrzeughersteller haben die Verfügbarkeit sogenannter hochautomatisierter Fahrfunktionen (SAE Level 3; SAE, 2018) in ihren Modellen angekündigt. Hierdurch wird der Fahrer in der Lage sein, sich permanent von der Fahraufgabe abzuwenden und fahrfremden Tätigkeiten nachzugehen. Allerdings muss er immer noch als Rückfallebene zur Verfügung stehen, um im Fall von Systemgrenzen oder -fehlern (siehe Gold, Naujoks, Radlmayr, Bellem & Jarosch, 2017), die Fahrzeugkontrolle zu übernehmen. Das Übernahmeerfordernis wird dem Fahrer durch die Ausgabe einer Übernameaufforderung vermittelt. Die Übernahme der manuellen Fahrzeugführung aus dem hochautomatisierten Fahren stellt aus psychologischer Sicht einen Aufgabenwechsel dar. Bei der Untersuchung von Aufgabenwechseln im Bereich der kognitiven und angewandten Psychologie zeigte sich vielfach, dass Aufgabenwechsel mit verlängerten Reaktionszeiten und erhöhten Fehlerraten assoziiert sind. Für den Anwendungsfall des automatisierten Fahrens liegen ebenfalls eine Reihe empirischer Studien vor, die darauf hinweisen, dass der Wechsel zum manuellen Fahren mit einer Verschlechterung der Fahrleistung gegenüber dem manuellen Fahren verbunden ist. Da Erkenntnisse vorliegen, dass eine Vorbereitung auf den Aufgabenwechsel die zu erwartenden Kosten verringern kann, ist das Ziel dieser Arbeit die Konzeption und empirische Evaluation einer Mensch-Maschine-Schnittstelle, die Nutzer hochautomatisierter Fahrzeuge durch frühzeitige Vorinformationen über Systemgrenzen auf die Kontrollübernahme vorbereitet. Drei Experimente im Fahrsimulator mit Bewegungssystem betrachteten jeweils unterschiedliche Aspekte frühzeitiger Vorinformationen über bevorstehende Übernahmen. Das erste Experiment untersuchte, ob Fahrer überhaupt von frühzeitigen Situationsankündigungen, beispielsweise im Sinne einer verbesserten Übernahmeleistung, profitieren. Das zweite Experiment befasste sich mit der Frage, wie solche Ankündigungen zeitlich und inhaltlich zu gestalten sind (d. h. wann sie präsentiert werden und welche Informationen sie enthalten sollten), und welchen Einfluss deren Gestaltung auf die Aufgabenbearbeitung (insbesondere deren Unterbrechung und spätere Wiederaufnahme) während der automatisierten Fahrt hat. Um herauszufinden, wie ein Anzeigekonzept zur längerfristigen Planung von fahrfremden Tätigkeiten während des automatisierten Fahrens beitragen könnte, fand im dritten Experiment ein Vergleich von Situationsankündigungen, die vor dem Erreichen einer Übernahmesituation ausgegeben wurden, mit kontinuierlich präsentierten Informationen über die verbleibende Distanz zur nächsten Systemgrenze statt. In allen Studien wurde neben den Auswirkungen frühzeitiger Vorinformationen auf die Übernahmeleistung und Bearbeitung von fahrfremden Tätigkeiten auch untersucht, welche Auswirkungen ein erweitertes Übernahmekonzept auf die Fahrerreaktion in Grenz- und Fehlerfällen, in denen Vorinformationen entweder nicht oder fehlerhaft angezeigt wurden, hat. Für die Gestaltung zukünftiger Übernahmekonzepte für hochautomatisierte Fahrzeuge kann basierend auf den Ergebnissen empfohlen werden, frühzeitige Anzeigen von Systemgrenzen zur Ermöglichung eines sicheren und komfortablen Wechsels zwischen dem manuellen und dem automatisierten Fahren in die Mensch-Maschine-Schnittstelle zu integrieren. Basierend auf den Ergebnissen dieser Arbeit liegt der empfohlene Zeitpunkt für diskrete Ankündigungen bei einer Reisegeschwindigkeit von 120 km/h bei etwa 1000 Meter (d. h. ca. 30 Sekunden) vor der Ausgabe der Übernahmeaufforderung. Zudem wird empfohlen zur Abschätzung der verbleibenden Zeit im automatisierten Modus eine Anzeige der Entfernung zur nächsten Systemgrenze in das Konzept zu integrieren, die dem Fahrer eine längerfristige Aufgabenplanung ermöglicht. Neben der reinen Anzeige des Übernahmeerfordernisses sollten dem Fahrer auch Informationen über das erforderliche Fahrmanöver nach der Kontrollübernahme übermittelt werden.
... It was however important to evaluate the notification in a setting where there was a potential to get distracted, making people more likely to be unaware of the time they spent away from a task. Designing a controlled study of self-initiated interruptions is fiendishly difficult: prior research suggests that participants tend to ignore experimenter-generated interruptions whenever they can [ 40 ]. We therefore conducted an online study, as participants get interrupted in online studies at a rate consistent with workplace observations [ 14 ]. ...
Article
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Many computer tasks involve looking up information from different sources, and these self-interruptions can be disruptive. In this article, we investigate whether giving people feedback on how long they are away from their task influences their self-interruption behaviour. We conducted a contextual inquiry on self-interruption behaviour in an office workplace. Participants were observed to postpone physical interruptions until a convenient moment in the task if they were expected to take time. In contrast, observations revealed that digital interruptions were addressed immediately; participants reported these were presumed to be quick to deal with. To increase awareness of time spent on digital interruptions, we developed TimeToFocus, a notification tool showing people the duration of their interruptions while working on a task. A field study deployment of TimeToFocus in an office workplace found that feedback on the duration of interruptions made participants reflect on what they were doing during interruptions. They reported that they used this insight to avoid task-irrelevant activities. To confirm whether participants’ perceptions of the benefit of the tool could be measured, we conducted an online experiment, where participants had to retrieve information from an email sent to their personal email addresses and enter it into a spreadsheet. Participants who used our tool made shorter interruptions, completed the spreadsheet task faster and made fewer data entry errors. We conclude that feedback on the length of interruptions can assist users in focusing on their primary task and thus improve productivity.
... On the one hand, with repeated exposure to incongruent IT-mediated information interruption, individuals are likely to transfer to a new work state that distracts their attention from the current work state (Salvucci & Bogunovich, 2010), thus increase their level of overload of the interruptions. For example, one of our participants mentioned: ...
Article
Full-text available
Information technology-mediated interruptions have become widespread and ubiquitous in the workplace. However, our understanding of how these interruptions and individuals’ interruption processing mechanism impact individuals’ performance, especially psychological performance, is still limited. Leveraging Conservation of Resources Theory, this study focused on two types of IT-mediated information interruptions (congruent and incongruent) and examined the moderating effects of different process mechanisms on the relationship between information interruptions and individuals’ interruption overload. A multi-methods research design was conducted in this study: a qualitative study with 20 interviews in Study 1 and a quantitative study with 345 surveys in Study 2. The results show a positive indirect effect of IT-mediated information interruption on emotional exhaustion through interruption overload. Results also review the moderation effects of different processing mechanisms. The findings of this study advance the current understanding of the “dark side” of online information behavior. Additionally, this study provides practical and theoretical implications for both employers and employees on how to process IT-mediated information interruptions in the workplace.
... Task-scheduling and switching research has primarily focused on dual-task experiments with interruptions using relatively simple tasks with undergraduate (nonexpert) subjects (e.g., Trafton & Monk, 2007). This research has generated a large body of knowledge concerning the relationship between different variables and outcomes as well as models to describe the task-scheduling process (e.g., Freed, 2000;Latorella, 1998;McFarlane & Latorella, 2002;Salvucci & Bogunovich, 2010). Although these models and their empirical data have described and elaborated on the process of task scheduling, the models generally do not address the specific task attributes that interact with this process. ...
Article
Objective This study evaluated task-scheduling decisions in the context of emergency departments by comparing patterns of emergency physicians’ task-scheduling models across levels of experience. Background Task attributes (priority, difficulty, salience, and engagement) influence task-scheduling decisions. However, it is unclear how attributes interact to affect decisions, especially in complex contexts. An existing model of task scheduling, strategic task overload management-no priority (STOM-NP), found that an equal weighting of attributes can predict task-scheduling behavior. Alternatively, mathematical modeling estimated that priority alone could make similar predictions as STOM-NP in a parsimonious manner. Experience level may also influence scheduling decisions. Method An experimental design methodology shortened a judgment analysis approach to compare a priori task-scheduling decision strategies. Emergency physicians with two levels of experience rank-ordered 10 sets of 3 tasks varying on 4 task attributes in this complex environment. Results Bayesian statistics were used to identify best-fit decision strategies. STOM-NP and priority-only provided the best model fits. STOM-NP fit the lower-experienced physicians best, whereas priority-only—using only one cue—fit the higher-experienced physicians best. Conclusion Models of decision strategies for task-scheduling decisions were extended to complex environments. Experts’ level of experience influenced task-scheduling decisions, where the scheduling decisions of more-experienced experts was consistent with a more frugal decision process. Findings have implications for training and evaluation. Application We assessed models of cues that influence task-scheduling decisions, including a parsimonious model for task priority only. We provided a sample approach for shortening methods for understanding decisions.
... Disruptions are a noteworthy problem in the workplace, and most of the interruptions at all stages were associated with ontask business activities. Authors in [45] investigated the idea of users deferring interruptions at points of higher workload until times of lower workload. Their study showed that during periods of lower workload, users swapped to the interrupting task 94% of the time. ...
Article
Full-text available
Interruptions are unexpected breaks that introduce new tasks on top of ongoing activities. In work environments, interruptions occur when operators and decision-makers have to deal simultaneously with several stimuli and information sources and have to make decisions so as to maintain the flow of activities at a satisfactory level of performance or quality of service. The causes and effects of interruptions and their subsequent management strategies in workplace environments have been researched in the past, however, only a few review articles are available to report on current advances in this area, to analyze contributions, and to highlight open research directions. This paper offers an up-to-date review and a framework for interruptions and interruption management strategies. The current approaches to identify, report, and manage interruptions in a variety of workplace environments are reviewed and a description of environmental characteristics that favor the occurrence of interruptions and influence interruption management in workplace environments is provided. Various approaches to classify and model the different types of interruptions and their cause-consequence relationships are discussed and the strategies to manage interruptions and approaches to measure human performance when dealing with interruptions are analyzed. Based on these insights, several guidelines to manage interruptions in workplace environments are provided, and future research directions are highlighted.
... Such moments often occur at natural task breakpoints [20]. Many driving studies have leveraged this notion of using natural breakpoints for task switching (e.g., [7,25,38]). More recently, the concept of microtasks has introduced an alternate form of tasking where a complex task can be decomposed into smaller units which can be completed in short bursts of time [10,13,42]. ...
Conference Paper
Full-text available
In-car intelligent assistants offer the opportunity to help drivers productively use previously unclaimed time during their commute. However, engaging in secondary tasks can reduce attention on driving and thus may affect road safety. Any interface used while driving, even if speech-based, cannot consider non-driving tasks in isolation of driving---alerts for safer driving and timing of the non-driving tasks are crucial to maintaining safety. In this work, we explore experiences with a speech-based assistant that attempts to help drivers safely complete complex productivity tasks. Via a controlled simulator study, we look at how level of support and road context alerts from the assistant influence a driver's ability to drive safely while writing a document or creating slides via speech. Our results suggest ways to support speech-based productivity interactions and how speech-based road context alerts may influence driver behavior.
... With regard to reducing cognitive load, it has been established that the human cognitive architecture is not well-equipped for dealing with multiple things simultaneously (Salvucci and Taatgen 2008;Courage et al. 2015). As a result, people develop different strategies to deal with interferences induced by multitasking (see for examples, Adler and Benbunan-Fich 2012;Salvucci and Bogunovich 2010). One of such strategies is to select media pairs which induce lower cognitive demands. ...
Article
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Many researchers have used the Media Multitasking Index (MMI) for investigating media multitasking behaviour. While useful as a means to compare inter-individual multitasking levels, the MMI disregards the variability in media multitasking choice behaviour: certain media combinations are more likely to be selected than others, and these patterns might differ from one population to another. The aim of the present study was to examine media multitasking choices in different populations. For this means, we employed a social network approach to render MMI responses collected in eight different populations into networks. The networks showed that the level of media multitasking as measured by the network densities differed across populations, yet, the pattern of media multitasking behaviour was similar. Specifically, media combinations which involved texting/IMing, listening to music, browsing, and social media were prominent in most datasets. Overall the findings indicate that media multitasking behaviours might be confined within a smaller set of media activities. Accordingly, instead of assessing a large number of media combinations, future studies might consider focusing on a more limited set of media types.
... While they still have the option to send a STANDBY, which is also a matter of two seconds, to double the time allowed to reply, this pilot still preferred to take a risk and finish her current task, and ended up replying in extremis. The act of postponing an incoming activity while busy on one involving a high cognitive process seems to be a default in human behaviour, as shown in [48], while a task switch can be expected if the current task does not involve a high workload. In the couple of cases mentioned the task they were performing was the most deferrable of all, but it seems that what made them reluctant to answer was facing the flight swap; having to load in your mind the situation of the other flight and then come back to the current one. ...
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The concept of operations proposed here pursues the feasibility, from a human factors perspective, of having a single pilot/aircrew controlling several remotely piloted aircraft systems at once in non-segregated airspace. To meet such feasibility, this multitasking must be safe and not interfere with the job of the air traffic controllers due to delays or errors associated with parallel piloting. To that end, a set of measures at several levels is suggested, which includes workload prediction and balance, pilot activity monitoring, and a special emphasis on interface usability and the pilot’s situational awareness. The concept relies greatly on the exploitation of the potential of Controller-Pilot Data Link Communications, anticipating future widespread implementation and full use. Experiments comparing the performance of the same pseudo-pilots before and after the implementation of part of the measures showed a decrease in the number of errors, oversights and subjective stress.
... Although, if we are interested in testing whether the means of more than two variables are equal, the appropriate statistical deduction will depend on the underlying distributions [102]. Both tests, the parametric Analysis of Variance (ANOVA) [103] test and the non-parametric Kruskal-Wallis [104] test, are adequate for testing differences between more than two condition samples from the same population of radiologists. ...
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Breast cancer is one of the most commonly occurring types of cancer among women. The primary strategy to reduce mortality is early detection and treatment based on medical imaging technologies. The current workflow applied in breast cancer diagnosis involves several imaging multimodalities. The fact that no single modality has high enough sensitivity for a reliable diagnosis supports the need for multi-modal imaging in breast cancer diagnosis. Nevertheless, their combination can significantly increase diagnostic accuracy. It also reduces the number of unnecessary biopsies, leading to better patient care and lower healthcare costs. In this work, we used interaction techniques to build a user interface adapted to the standard needs of a radiology room. This user interface allows the combination of MG, US, MRI and Text Data to assist the clinician in establishing the diagnosis. The work involves the development and design of a user interface for automatic detection, segmentation and classification from breast MG, US and MRI, as well as, textual data notations and information visualisation. We conclude, through user analysis and evaluation, that our methods, techniques and developments are satisfactory. Moreover, this work provides a framework that can be applied to new medical interaction systems.
... Behavioral research by Lebbon and Hurley (2013) appear to support Coker's findings that individuals who spend less than 15% of total work hours on leisure do experience an increase in productivity. Others have conducted simulations and found that IM-ing is greatly restricted to lower workload tasks (Salvucci & Bogunovich, 2010) and those who are interrupted demonstrate higher levels of work output in comparison to those who are not interrupted (Speier, Valacich, & Vessey, 1999;Zijlstra, Roe, Leonora, & Krediet, 1999). Interestingly, 60% of recent survey respondents report performance improvements after Internet use (Salary.com, ...
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At this moment of the COVID-19 epidemic, it is difficult for caregivers to be fully aware of the elderly by closing care to prevent accidents at home. Existing research, home-based self-health management strategies, by using contextual tools and a lack of empirical procedures or technological components in internet monitoring, home accidents from individualized patterns has not been achieved. We use vision detecting through the internet monitoring method in a smart lighting materials house to fill this research gap. We examined the impact of physical transitions and visibility on fall detection and compared the accuracies of fall prediction based on combinations of related factors. The results indicated that including both physical transitions and visibility would enable older people to avoid falls. We evaluated the impact of physical transitions and visibility on fall detection and compared the accuracy of falls based on combinations of related factors. The accuracy of predictions using both physical transition and visibility was higher than 81%, which is a high forecasting accuracy rate. Those are significant contributions to the elderly in applied economics. Keywords: COVID-19, Home-based, Physical transition, Visibility, Fall detection.
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Spontaneous communication is an integral part of any workplace as well as everyday life. In workplaces that use computer or similar devices, most of the spontaneous conversations happen over email or chat. Frequent use of chat application or email disrupts a recipient’s workflow and leads to constant interruptions causing task fragmentation. In this paper, we present a receiver oriented Interruption-Information Management (IIM) chat which incorporates automated agents to prevent receivers from getting a plethora of messages. This framework manages both interruption and forthcoming information in the chat interface. It is a novel approach in the area of interruption management. It not only considers interruption management, but also manages the information based on the users’ behavior and preferences. It is a cooperative approach where both the message sender and the receiver work together to deliver messages during the receiver’s most favorable times. The receiver contributes to manage interruption whereas the sender contributes to manage information, together forming an interruption-information management mechanism to decide the least interruptible time for message delivery.
Chapter
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Les interruptions sont l’un des phénomènes les plus perturbants pour la concentration au travail. Alors que leur nombre ne cesse d’augmenter avec la multiplication des notifications et l’ouverture des espaces de travail, le milieu professionnel commence à se rendre compte qu’elles nuisent à la productivité, mais aussi au bien-être en entreprise. C’est pourquoi un grand nombre de scientifiques ont cherché à comprendre les causes et les conséquences spécifiques des interruptions, en étudiant les différentes situations possibles. De nombreuses questions restent toutefois sans réponses.Dans ce travail de thèse, nous nous sommes focalisés sur l’effet de quatre types d’interruption, pour lesquels soit les causes ne sont pas ou mal connues, soit les conséquences n’avaient encore jamais été étudiées : (i) la complexité de la tâche interruptrice (ii) le moment de survenue de l’interruption (iii) la source de l’interruption et (iv) le caractère agréable de la tâche interruptrice. Nous nous sommes également intéressés à deux contextes de travail bien spécifiques, à savoir le tri d’emails et la détection d’armes dissimulées dans des valises.Avec 6 études, nous avons pu en apprendre davantage sur les effets de chacune des caractéristiques des interruptions précédemment citées, ainsi que l’effet des interruptions en fonction de la tâche qu’elles suspendent. Nous avons également pu identifier précisément les processus cognitifs impliqués dans la suspension de la tâche interrompue, en fonction de sa caractéristique manipulée.Ce travail de thèse a ainsi apporté un certain nombre de découvertes empiriques, que nous avons discuté à la lumière de la littérature et de différents modèles théoriques, auxquels nous avons proposé quelques améliorations. Ces travaux ont également un intérêt pratique, car ils nous ont permis de proposer des recommandations sur l’organisation des espaces de travail et sur l’utilisation des moyens de communication en entreprise.
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Anti-malware software must be frequently updated in order to protect the system and the user from attack. Makers of this software must choose between interrupting the user to update immediately or allowing them to update later. In either case, assessing the content of the interruption may still require cognitive investment. However, by allowing the user to negotiate a delayed response to these interruptions, users can instead focus on their work. This paper experimentally examines the effect of immediate and negotiated interruptions on user decision time and decision accuracy in multiple stage tasks. For complex tasks, decision performance is higher when the user can negotiate the onset of and response to interruptions. The option to defer response also results in greater subjective perceptions of control, improved task resumption and reduced feelings of interruption and distraction on the part of the user, even within a short period of time. These findings have practical implications for endpoint security and where there is a need to mitigate the effects of user interruptions from computer-mediated communication in complex task situations.
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Chapter
This chapter presents and discusses the concept of presence in online dialogues and interactions. The point of departure in this discussion is that of multitasking and social presence. Then, the chapter frames different e-learning scenarios that give participants the impression of being-or not being-present in the same room although geographically dispersed. On the basis of theoretical inspiration from symbolic interactionism and ethnomethodology, educators' new roles in e-learning are discussed in the context of empirical material collected from an e-learning program in a physiotherapy school. In addition, the concept of multi-presence is presented. This chapter argues that multi-presence occurs in both online and offline interactions and that, as a result of technology, is utilized in both professional and learning situations.
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In the present day, the need and ability to multitask in or across devices is growing. However, these multitasking abilities are being introduced to devices without considering the effect they have on the cognitive workload of a user and its impact on one's productivity. Through our study described in this paper, we attempt to understand multitasking from a qualitative perspective by exploring the difference in multitasking behaviour of users when they deal with active and passive tasks. We also identify workarounds devised by users in order to minimize their cognitive workload while multitasking across apps on their mobile devices. Finally, we suggest certain guidelines that could be adopted by technology companies to aid users in effectively handling interruptions and switching across applications.
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A computational model is created to simulate drivers’ task switching behavior, or dynamic allocation of visual attention, while they are driving and engaging in a secondary task. The model takes the following into account: uncertainty about the roadway, task structure, and individual differences. The first factor, uncertainty, means a lack of information about the roadway that plays a significant role in switching attention back to the roadway. The second factor, task structure, reflects the driver's tendency to switch visual attention from the secondary task to the roadway at subtask boundaries as well as the tendency to continue to perform task to reach subtask boundaries. Lastly, the model considers the variability of performance speed across the driver population. The factors jointly influence the probability of switching attention in the model. We use the ABC-MCMC (Approximate Bayesian Computation – Markov Chain Monte Carlo) method to estimate model parameters that produce the microstructure of task switching. The fitted model generates glance patterns at a micro level that are consistent with those generated by participants in an experiment.
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Data entry often involves looking up information from email. Task switching to email can be disruptive, and people can get distracted and forget to return to their primary task. In this paper, we investigate whether giving people feedback on how long they are away from their task has any effect on the duration and number of their switches. An online experiment was conducted in which participants had to enter numeric codes into an online spreadsheet. They had to look up these codes in an email sent to their personal email address upon starting the experiment. People who were shown how long they were away for made shorter switches, were faster to complete the task and made fewer data entry errors. This suggests feedback on switching duration may make people more aware of their switching behaviour, and assist users in maintaining focus on their main task.
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The significance of Attentional User Interfaces that help create computing and communication systems to sense and reason about human attention by fusing together information from multiple streams, is discussed. Attentional cues are central in decisions about when to initiate or to make an effective contribution to a conversation or project. Computers with an ability to track and to understand attentional patterns among people engaged in conversations can provide new kinds of services and facilities. It is noted that continuing refinement of methods for recognizing, reasoning and communicating about attention will change in a qualitative manner the way working with computing systems is perceived.
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This work investigates the use of workload-aligned task models for predicting opportune moments for interruption. From models for several tasks, we selected boundaries with the lowest (Best) and highest (Worst) mental workload. We compared effects of interrupting primary tasks at these and Random moments on resumption lag, annoyance, and social attribution. Results show that interrupting at the Best moments consistently caused less resumption lag and annoyance, and fostered more social attribution. Results demonstrate that use of workload-aligned models offers a systematic method for predicting opportune moments.
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Most current designs of information technology are based on the notion of supporting distinct tasks such as document production, email usage, and voice communication. In this paper we present empirical results that suggest that people organize their work in terms of much larger and thematically connected units of work. We present results of fieldwork observation of information workers in three different roles: analysts, software developers, and managers. We discovered that all of these types of workers experience a high level of discontinuity in the execution of their activities. People average about three minutes on a task and somewhat more than two minutes using any electronic tool or paper document before switching tasks. We introduce the concept of working spheres to explain the inherent way in which individuals conceptualize and organize their basic units of work. People worked in an average of ten different working spheres. Working spheres are also fragmented; people spend about 12 minutes in a working sphere before they switch to another. We argue that design of information technology needs to support people's continual switching between working spheres.
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Current systems often create socially awkward interruptions or unduly demand attention because they have no way of knowing if a person is busy and should not be interrupted. Previous work has examined the feasibility of using sensors and statistical models to estimate human interruptibility in an office environment, but left open some questions about the robustness of such an approach. This paper examines several dimensions of robustness in sensor-based statistical models of human interruptibility. We show that real sensors can be constructed with sufficient accuracy to drive the predictive models. We also create statistical models for a much broader group of people than was studied in prior work. Finally, we examine the effects of training data quantity on the accuracy of these models and consider tradeoffs associated with different combinations of sensors. As a whole, our analyses demonstrate that sensor-based statistical models of human interruptibility can provide robust estimates for a variety of office workers in a range of circumstances, and can do so with accuracy as good as or better than people. Integrating these models into systems could support a variety of advances in human computer interaction and computer-mediated communication.
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We present data from detailed observation of 24 information workers that shows that they experience work fragmentation as common practice. We consider that work fragmentation has two components: length of time spent in an activity, and frequency of interruptions. We examined work fragmentation along three dimensions: effect of collocation, type of interruption, and resumption of work. We found work to be highly fragmented: people average little time in working spheres before switching and 57% of their working spheres are interrupted. Collocated people work longer before switching but have more interruptions. Most internal interruptions are due to personal work whereas most external interruptions are due to central work. Though most interrupted work is resumed on the same day, more than two intervening activities occur before it is. We discuss implications for technology design: how our results can be used to support people to maintain continuity within a larger framework of their working spheres.
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Multitasking in user behavior can be represented along a continuum in terms of the time spent on one task before switching to another. In this paper, we present a theory of behavior along the multitasking continuum, from concurrent tasks with rapid switching to sequential tasks with longer time between switching. Our theory unifies several theoretical effects — the ACT-R cognitive architecture, the threaded cognition theory of concurrent multitasking, and the memory-for-goals theory of interruption and resumption — to better understand and predict multitasking behavior. We outline the theory and discuss how it accounts for numerous phenomena in the recent empirical literature. Author Keywords Multitasking, attention, interruption, cognitive architecture.
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We report on a field study of the multitasking beha vior of computer users focused on the suspension and resumption of tasks. Data was collected with a tool that logge d users' interactions with software applications and their a ssociated windows, as well as incoming instant messaging and email alerts. We describe methods, summarize results, and discuss design guidelines suggested by the findings. Author Keywords
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Interruptions are a central aspect of working life. The prevalence of remote co-workers and the use of mobile technology mean that interruptions are more prevalent, and workers have to learn to manage availability. To understand general issues in availability management, we carried out a naturalistic study of how interruptions are handled in face-to-face situations. We found that avail- ability management requires negotiation, that it is also highly dependent on awareness about the availability of others, and that it demands cognitive effort to shift attention to the interruption. On the basis of these observations, we developed a technology, named. The Negotiator, that embodies three main design requirements: (a) support for negotiation, (b) contextual information about when a recipient is available for a call, (c) lightweightness to reduce attention overhead. We carried out an experimental study of interruption management using this technology. The interface satisfied the original design requirements, that is, people, were able to use it effectively to negotiate times to talk, while successfully carrying out an intellectually demanding activity. Contrary to our expectations, however, people preferred to take responsibility for returning calls rather than delegating them, and they preferred to schedule calls as soon as possible rather than deferring them. We suggest that there are social reasons why people do this. They feel a social obligation to return calls as soon as possible so as not to inconvenience others and also to be responsible for making these calls themselves. They also take calls sooner to avoid having to remember future conversational commitments. We discuss the theoretical and technical implications of these findings.
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Notifications can have reduced interruption cost if delivered at moments of lower mental workload during task execution. Cognitive theorists have speculated that these moments occur at subtask boundaries. In this article, we empirically test this speculation by examining how workload changes during execution of goal-directed tasks, focusing on regions between adjacent chunks within the tasks, that is, the subtask boundaries. In a controlled experiment, users performed several inter- active tasks while their pupil dilation, a reliable measure of workload, was continuously measured using an eye tracking system. The workload data was extracted from the pupil data, precisely aligned to the corresponding task models, and analyzed. Our principal findings include (i) workload changes throughout the execution of goal-directed tasks; (ii) workload exhibits transient decreases at subtask boundaries relative to the preceding subtasks; (iii) the amount of decrease tends to be greater at boundaries corresponding to the completion of larger chunks of the task; and (iv) dif- ferent types of subtasks induce different amounts of workload. We situate these findings within resource theories of attention and discuss important implications for interruption management systems.
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The time to resume task goals after an interruption varied depending on the duration and cognitive demand of interruptions, as predicted by the memory for goals model (Altmann & Trafton, 2002). Three experiments using an interleaved tasks interruption paradigm showed that longer and more demanding interruptions led to longer resumption times in a hierarchical, interactive task. The resumption time profile for durations up to 1 min supported the role of decay in defining resumption costs, and the interaction between duration and demand supported the importance of goal rehearsal in mitigating decay. These findings supported the memory for goals model, and had practical implications for context where tasks are frequently interleaved such as office settings, driving, emergency rooms, and aircraft cockpits.
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This paper describes a study that probes the cost of interrupting users with instant messages during different "phases" of a computing task. We found that interrupting users during the "evaluation phase" of the task resulted in significantly longer completion times than interruptions in other phases. We also found that interruptions that were irrelevant to the task resulted in longer times to process the message and longer task resumption times than relevant messages. These initial results have implications for the principled design of intelligent interrupters and instant messages.
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Instant messaging (IM) has grown rapidly to involve millions of users spanning a variety of platforms. This paper outlines two preliminary studies that examined the effects of IM notifications on ongoing desktop computer productivity tasks. Results from the studies show that the disruptiveness of IM to productivity tasks is reduced if the incoming message is highly relevant to the current task, or if messages are queued until certain key computing operations have been completed. User interface design principles for the control of messaging are proposed based on the results.
Chapter
full text can be downloaded from https://human-factors.arc.nasa.gov/flightcognition/Publications/Dismukes&Nowinski_06.pdf
Article
In 1991 a tower controller at Los Angeles International airport cleared a commuter aircraft to position and hold on runway 24L while she worked to clear other aircraft to cross the other end of the runway. There were several communications delays because one of the other aircraft was on the wrong radio frequency. Visibility was poor at twilight because of haze and glare. The controller's workload was considered moderate by air traffic controllers, though laypeople might consider it quite busy. The controller forgot to clear the commuter aircraft to take off and cleared another aircraft to land on 24L, which it did, destroying both aircraft and killing 34 people. Similar errors by pilots have also led to major accidents. In 1994 an airliner ran off the runway at LaGuardia airport after the crew rejected the takeoff at high-speed because they observed anomalous indications on their airspeed indicators. The NTSB determined that the anomalous indications occurred because the crew failed to turn on the pitot heat, a normal procedural step, that keeps the pitot input to the airspeed indicators from freezing in cold, wet weather. Two previous major airline accidents occurred in the 1980's when the crews forgot to extend wing flaps and slats to takeoff position, a normal procedural step required before takeoff. More recently, in 1996, an airliner landed gear- up in Houston when the landing gear failed to extend because the crew forgot to set the hydraulic pumps to the high position, which was part of the normal procedure for preparing their type of aircraft for landing. Obviously multiple factors were at play in each of these accidents, but a central aspect of each accident was the failure of the crew
Article
Interruptions can cause people to make mistakes or errors during human–com-puter interaction (HCI). Interruptions occur as an unavoidable side-effect of some important kinds of human computer-based activities, for example, (a) constantly monitor for unscheduled changes in information environments, (b) supervise background autonomous services, and (c) intermittently collaborate and commu-nicate with other people. Fortunately, people have powerful innate cognitive abil-ities that they can potentially leverage to manage multiple concurrent activities if they have specific kinds of control and interaction support. There is great oppor-tunity, therefore, for user-interface design to increase people's ability to success-fully handle interruptions, and prevent expensive errors. The literature contains very little concrete design wisdom about how to solve the interruption problems in user interfaces (UIs). Coordination support, however, is identified as a most im-portant design topic. This article presents the results of an empirical investigation to compare basic design solutions for coordinating human interruption in com-puter-based multitasks. A theory-based taxonomy of human interruption is used HUMAN-COMPUTER INTERACTION, 2002, Volume 17, pp. 63–139 Daniel McFarlane is a computer scientist with an interest in intelligent com-mand and control systems; he is a Senior Member of the Engineering Staff in the Advanced Technology Laboratories of Lockheed Martin.
Conference Paper
User attention is a scarce resource, and users are susceptible to interruption overload. Systems do not reason about the effects of interrupting a user during a task sequence. In this study, we measure effects of interrupting a user at different moments within task execution in terms of task performance, emotional state, and social attribution. Task models were developed using event perception techniques, and the resulting models were used to identify interruption timings based on a user's predicted cognitive load. Our results show that different interruption moments have different impacts on user emotional state and positive social attribution, and suggest that a system could enable a user to maintain a high level of awareness while mitigating the disruptive effects of interruption. We discuss implications of these results for the design of an attention manager.
Conference Paper
The typical information worker is interrupted every 12 minutes, and half of the time they are interrupting themselves. However, most of the research on interruption in the area of human-computer interaction has focused on understanding and managing interruptions from external sources. Internal interruptions -- user-initiated switches away from a task prior to its completion -- are not well understood. In this paper we describe a qualitative study of self-interruption on the computer. Using a grounded theory approach, we identify seven categories of self-interruptions in computer-related activities. These categories are derived from direct observations of users, and describe the motivation, potential consequences, and benefits associated with each type of self-interruption observed. Our research extends the understanding of the self-interruption phenomenon, and informs the design of systems to support discretionary task interleaving on the computer.
Book
This book takes its title from the last lecture by Allen Newell, one of the pioneers of cognitive science. He said, "The question for me is how can the human mind occur in the physical universe? We now know that the world is governed by physics. We now understand the way biology nestles comfortably within that. The issue is how will the mind do that as well?" Newell argued that the answer to his question must take the form of a cognitive architecture, and this book describes an answer that is emerging from the study of brain and behavior. Humans share the same basic cognitive architecture with all primates, but they have evolved abilities to exercise abstract control over cognition and process more complex relational patterns. The human cognitive architecture consists of a set of largely independent modules associated with different brain regions. The book discusses in detail how these various modules can combine to produce behaviors as varied as driving a car and solving an algebraic equation, but focuses principally on two of the modules: declarative and procedural. The declarative module involves a memory system that, moment by moment, attempts to give each person the most appropriate possible window into his or her past. The procedural module involves a central system that strives to develop a set of productions that will enable the most adaptive response from any state of the modules.
The Multitasking Mind
  • D D Salvucci
  • N A Taatgen
Salvucci, D. D., & Taatgen, N. A. (2010). The Multitasking Mind. New York: Oxford University Press.