从一心一意到三心二意：青少年的媒体多任务行为

计算机时代的到来带来了青少年媒体使用行为的变化,其中媒体多任务现象尤为显著。为全面了解在青少年群体中日渐普及的媒体多任务行为,本文首先介绍该现象的概念界定,其次概括研究中的理论基础和测量方式,并总结了青少年媒体多任务的影响因素和影响后果。未来应加强对智能手机等新兴媒体对媒体多任务行为的影响、媒体多任务行为的性别差异、媒体多任务行为的生态化测量以及媒体多任务行为积极影响的研究。     

Does multitasking mediate the relationships between episodic memory,attention, executive functions and apathetic manifestations in traumatic brain injury?

Apathy is frequently described in patients with traumatic brain injury (TBI); its negative consequences particularly affect functional independence. Among apathetic manifestations, lack of initiative and lack of interest have mainly been associated with cognitive impairments. However, few studies have been conducted to precisely identify the underlying cognitive processes. Our aims were (1) to determine the best predictor of apathy from among several cognitive processes, including episodic memory and attention/executive mechanisms and multitasking, and (2) to examine to what extent multitasking could mediate the relationships between specific cognitive processes and lack of initiative/interest. Seventy participants (34 patients with TBI matched with 36 control participants) were given a questionnaire to assess anxio‐depressive symptoms, four tasks to assess specific cognitive processes, and one task to assess real‐life multitasking. Participants’ relatives completed an apathy questionnaire. Multitasking, as assessed by the number of goals not achieved, was the only significant predictor of apathetic manifestations. In addition, the mediation analyses revealed that multitasking performance mediated the relationships between verbal episodic memory and lack of initiative/interest, whereas executive and attentional functions were only indirectly related to lack of initiative/interest due to their significant impacts on multitasking. These results shed new light on the aetiology of apathetic manifestations in patients with TBI, indicating how specific cognitive deficits are expressed in real‐life multitasking, and consequently, how they may lead to the development and/or maintenance of apathetic manifestations.     

Doing It All At Once: Multitasking as a predictor of call center agents’ performance and performance‐based dismissal

Multitasking has become an important skill in many jobs. Still, the predictive validity of job‐applicants’ multitasking abilities has rarely been tested empirically. The current study focuses on the multitasking ability of call center applicants. Results from a Dutch call center show that applicants’ multitasking ability as assessed during personnel selection indeed predicts their later job performance as call center agents as well as their likelihood of losing their job for poor performance. While some of these relationships could be explained via applicants’ fluid intelligence, results also support the usefulness of including measures of multitasking ability in the current selection procedure.     

Media multitasking and memory: Differences in working memory and long-term memory

Increasing access to media in the 21st century has led to a rapid rise in the prevalence of media multitasking (simultaneous use of multiple media streams). Such behavior is associated with various cognitive differences, such as difficulty filtering distracting information and increased trait impulsivity. Given the rise in media multitasking by children, adolescents, and adults, a full understanding of the cognitive profile of media multitaskers is imperative. Here we investigated the relationship between chronic media multitasking and working memory (WM) and long-term memory (LTM) performance. Four key findings are reported (1) heavy media multitaskers (HMMs) exhibited lower WM performance, regardless of whether external distraction was present or absent; (2) lower performance on multiple WM tasks predicted lower LTM performance; (3) media multitasking-related differences in memory reflected differences in discriminability rather than decision bias; and (4) attentional impulsivity correlated with media multitasking behavior and reduced WM performance. These findings suggest that chronic media multitasking is associated with a wider attentional scope/higher attentional impulsivity, which may allow goal-irrelevant information to compete with goal-relevant information. As a consequence, heavy media multitaskers are able to hold fewer or less precise goal-relevant representations in WM. HMMs’ wider attentional scope, combined with their diminished WM performance, propagates forward to yield lower LTM performance. As such, chronic media multitasking is associated with a reduced ability to draw on the past—be it very recent or more remote—to inform present behavior.     

Media Multitasking Effects on Cognitive vs. Attitudinal Outcomes: A Meta‐Analysis

Despite the recent proliferation of research on media multitasking, a comprehensive meta‐analytic review of its effects has not been available. Based on a review of 49 media multitasking studies, this meta‐analysis showed that multitasking has negative effects on cognitive outcomes, whereas it has positive effects on attitudinal (or persuasion‐related) outcomes. Moderator analyses suggested that the negative effects of multitasking on cognitive outcomes varied by (a) user control, (b) task relevance, and (c) task contiguity. Specifically, multitasking had greater effects (a) when media users had less control over the media, (b) for tasks that were unrelated, and (c) for tasks that were physically distant. Implications for future multitasking research are further discussed.     

Multitasking: multiple,domain-specific cognitive functions in a virtual environment

Multitasking among three or more different tasks is a ubiquitous requirement of everyday cognition, yet rarely is it addressed in research on healthy adults who have had no specific training in multitasking skills. Participants completed a set of diverse subtasks within a simulated shopping mall and office environment, the Edinburgh Virtual Errands Test (EVET). The aim was to investigate how different cognitive functions, such as planning, retrospective and prospective memory, and visuospatial and verbal working memory, contribute to everyday multitasking. Subtasks were chosen to be diverse, and predictions were derived from a statistical model of everyday multitasking impairments associated with frontal-lobe lesions (Burgess, Veitch, de Lacy Costello, & Shallice, 2000b). Multiple regression indicated significant independent contributions from measures of retrospective memory, visuospatial working memory, and online planning, but not from independent measures of prospective memory or verbal working memory. Structural equation modelling showed that the best fit to the data arose from three underlying constructs, with Memory and Planning having a weak link, but with both having a strong directional pathway to an Intent construct that reflected implementation of intentions. Participants who followed their preprepared plan achieved higher scores than those who altered their plan during multitask performance. This was true regardless of whether the plan was efficient or poor. These results substantially develop and extend the Burgess et al. (2000b) model to healthy adults and yield new insight into the poorly understood area of everyday multitasking. The findings also point to the utility of using virtual environments for investigating this form of complex human cognition.     

Multitasking as a Predictor of Pilot Performance: Validity Beyond Serial Single-Task Assessments

Although multitasking has been identified as an important competency for many jobs, standardized preemployment tests of multitasking are uncommon, and their validity beyond separate single-task assessments is unclear. To address this gap, this study compared the validity of a preemployment multitasking assessment (with math, memorization, and monitoring tasks presented concurrently) to an assessment in which the same constituent tasks were assessed separately. Among military pilot applicants, concurrent multitasking predicted both flying and academic performance, whereas serial single-task scores and their combination predicted only academic performance. Larger multitasking decrements (i.e., operationalized as the difference between single-task and multiple-task performance of the same constituent tasks) were associated with poorer flying performance. Results suggest the potential utility of multitasking assessments in selection for military jobs requiring competing, concurrent task demands.     

Working Memory,Fluid Intelligence,and Attention Are Predictors of Multitasking Performance,but Polychronicity and Extraversion Are Not

This study explored predictors of multitasking performance. Based on cognitive psychology research, attention and working memory were assumed to be predictors. Fluid intelligence, polychronicity (as the preference for multitasking and the belief that their preference is the best way to handle things), and Extraversion were argued to be additional predictors. Multitasking performance was measured with the scenario "Simultaneous capacity/Multi-tasking (SIMKAP)" (n = 122). Hierarchical multiple regression analyses revealed that working memory was the most important predictor in addition to attention and fluid intelligence. The latter two constructs contributed significantly to the explained variance, but to a lesser extent. Polychronicity was not a significant predictor, nor was Extraversion. Implications for personnel selection and for time management are discussed.     

The effects of exercise at different temperatures on cognitive function: A systematic review

To date, no review has focused specifically on the potential modulating role of environmental temperature on the effects of exercise on cognitive function. Despite this, a range of occupations and performance contexts exist (e.g., military personnel, emergency services, sport) where the maintenance of cognitive function in environmentally challenging environments is crucial. Therefore, this systematic review aimed to evaluate the experimental research investigating how manipulating environmental temperature influenced the effects of acute bouts exercise on cognitive functioning from pre-to-post exercise, or during exercise. Studies to be included were assessed by two authors reviewing title, abstract, and then full-text. From the searches conducted, twenty articles were identified which met the inclusion criteria. For the purpose of this review, exercise involved in each study was categorised into low, moderate, and vigorous dosages (dependent on intensity and duration). The results indicate that moderate dosages of exercise help stimulate improved cognitive performance from pre-to-post exercise in temperate conditions, where cold exposure appears to blunt these effects. In addition, hot environments led to cognitive decrements during and post exercise which were often identified in studies that implemented prolonged moderate or vigorous exercise protocols. Therefore, suggesting a combination of heightened physiological strain from increased dose of exercise, alongside heat exposure, can be detrimental to optimal cognitive functioning, whereby executive functioning tasks appeared to be most affected. The findings from this systematic review highlight the potential modulating role of environmental temperature on the effects of exercise on cognitive function. Thus, highlighting the importance of considering the role of environmental temperature for individuals either exercising to elicit desired cognitive benefits or for those involved in physically demanding occupations or performance domains.     

The Multitasking Preference Inventory: Toward an Improved Measure of Individual Differences in Polychronicity

This article describes the initial development of a new measure of individual polychronicity, a construct indicating a preference for multitasking as opposed to performing only one task at a time. Following a brief review of past definitional issues, a revised definition is offered and a new measure of polychronicity—the Multitasking Preference Inventory (MPI)—is created based on this definition. Three studies describe the creation, pilot testing, and psychometric refinement of an initial pool of items (Study 1); a convergent and discriminant validity analysis (Study 2); and initial findings with respect to the criterion-related validity of scores on the MPI (Study 3). Together, these findings provide preliminary evidence for the reliability of scores on the MPI and the validity of the MPI in predicting variables relevant to multitasking.     

Exploring the nature of cognitive flexibility

Cognitive flexibility is an important characteristic that helps humans pursue complex tasks, such as multitasking and finding novel, adaptable solutions to changing demands. Yet it is still a poorly understood construct. After briefly reviewing several investigations of this construct in cognitive science, I propose a unified account that considers cognitive flexibility a property of the cognitive system, rather than a cognitive skill. The emergence of cognitive flexibility is dependent on two kinds of interactions: the interaction of several cognitive mechanisms, and the interaction of sensorimotor mechanisms, cognition, and context in developmental time. The quest for a comprehensive and unified account of cognitive flexibility is highly justified given its potential usefulness in fostering efficient problem solving and creativity.     

Decision-making,cognitive functions,impulsivity, and media multitasking expectancies in high versus low media multitaskers

In several studies, individuals who reported to frequently multitask with different media displayed reduced cognitive performance, for example in fluid intelligence and executive functioning. These cognitive functions are relevant for making advantageous decisions under both objective risk (requiring reflection and strategical planning) and ambiguous risk (requiring learning from feedback). Thus, compared to low media multitaskers (LMMs), high media multitaskers (HMMs) may perform worse in both types of decision situations. The current study investigated HMMs and LMMs in a laboratory setting with the Game of Dice Task (GDT; objective risk), the Iowa Gambling Task (IGT; ambiguous risk), various tests quantifying cognitive functions (logical reasoning, working memory, information processing, general executive functions), and self-report measures of impulsivity, media multitasking expectancies, and problematic Internet use. From 182 participants, 25 HMMs and 19 LMMs were identified using the Media Multitasking Index. Results show that HMMs compared to LMMs performed weaker on the IGT but not on the GDT. Furthermore, HMMs had slightly decreased performance in tests of logical reasoning and working memory capacity. HMMs tended to increased information processing speed but this difference was not significant. Furthermore, HMMs have more positive expectancies regarding media multitasking and reported higher tendencies toward problematic Internet use. HMMs and LMMs did not differ significantly with respect to impulsivity and executive functions. The results give a first hint that HMMs may have difficulties in decision-making under ambiguous but not under objective risk. HMMs may be more prone to errors in tasks that require feedback processing. However, HMMs appear not to be impaired in aspects of long-term strategic decision-making.

     

The role of saccades in multitasking: towards an output-related view of eye movements

The present paper presents an overview of research on the role of saccades in multitasking. Multitasking is known to cause performance costs in terms of increased response times and/or error rates. However, most of the previous research on multitasking was focused on manual and vocal action demands, and the role of eye movements has been largely neglected. As a consequence, saccade execution was mainly considered with respect to its functional role in gathering new visual information (input side of information processing). However, several more recent experiments confirmed that saccades both exhibit and cause dual-task costs in the context of other actions and should thus also be regarded as a response modality (output side of information processing). Theoretical implications as well as several open issues for future research will be outlined.     

Predictors of media multitasking in Chinese adolescents

We examined predictors of media multitasking in Chinese adolescents from 3 contexts: characteristics of the media user, types of media use and family media contexts. Three hundred and twenty adolescents, 11–18 years of age, completed questionnaires to measure media use, impulsivity, sensation seeking, time management disposition and family media environment. The results showed that media multitasking was positively correlated with age and total media use time. Participants with high levels of impulsivity and sensation seeking reported more multitasking behaviour. Multitasking was negatively correlated with time management. Children from media‐oriented families often engage in more multitasking. What's more, social networking sites use and music use can mediate the effect of individual and family factors on media multitasking.     

A multitasking general executive for compound continuous tasks

As cognitive architectures move to account for increasingly complex real-world tasks, one of the most pressing challenges involves understanding and modeling human multitasking. Although a number of existing models now perform multitasking in real-world scenarios, these models typically employ customized executives that schedule tasks for the particular domain but do not generalize easily to other domains. This article outlines a general executive for the Adaptive Control of Thought–Rational (ACT–R) cognitive architecture that, given independent models of individual tasks, schedules and interleaves the models' behavior into integrated multitasking behavior. To demonstrate the power of the proposed approach, the article describes an application to the domain of driving, showing how the general executive can interleave component subtasks of the driving task (namely, control and monitoring) and interleave driving with in-vehicle secondary tasks (radio tuning and phone dialing).     

Multidimensions of Media Multitasking and Adaptive Media Selection

This study identifies 11 basic cognitive dimensions of media multitasking behaviors based upon resource theories. These dimensions provide a conceptual framework to help compare and synthesize media multitasking studies. In addition, using 2 empirical data sets, we examine how these cognitive dimensions interact with each other to predict choices of media multitasking behaviors in daily life in an adaptive manner to conserve limited mental resources. A systematic understanding of the multiple cognitive dimensions of media multitasking behaviors has the potential to foster theory‐guided designs and more mindful selection of media tasks, technologies, and environments to curb negative consequences of media multitasking and utilize its benefits.     

Predictors of multitasking performance in a synthetic work paradigm

This study investigated determinants of success in a ‘synthetic work’ task designed to reflect the requirement for multitasking that is common to many occupations. Participants were administered tests of working memory capacity (WMC) and processing speed (PS), and they reported experience with videogames, a type of activity presumed to involve multitasking. Results revealed that WMC was a strong predictor of multitasking in a ‘non‐emergency’ condition when the pace of the tasks was relatively slow, whereas PS was a weaker predictor. Additionally, there was evidence for the incremental validity of videogame experience (VGE), consistent with the possibility that multitasking is supported by a general, trainable skill. Finally, individual differences in strategy use accounted for a large proportion of the variance in multitasking, above and beyond other predictor variables, and WMC predicted use of an effective strategy. Copyright © 2009 John Wiley & Sons, Ltd.     

The effect of different distractions on remembering delayed intentions

In safety-critical domains, frequently intentions need to be delayed until an ongoing task is completed. Research using the delay-execute paradigm showed that interruptions during the delay cause forgetting. However, staff members often handle an initial distraction not by interrupting the ongoing task but by acknowledging the distraction or multitasking. In Experiments 1a and 1b, we observed that, compared to a no distraction condition, multitasking significantly decreased remembering of intentions and interrupting decreased remembering even further. In Experiment 2, interruptions with context change reduced remembering of intentions compared to uninterrupted delays, and at the same time, interruptions without context change improved memory performance compared to uninterrupted delays. However, improved memory performance resulted in decreased interrupting task performance. Theoretically, the results support the contextual cueing mechanism of delay-execute tasks. Considering safety-critical domains, multitasking, interruptions and context changes can contribute to forgetting of tasks.     

Individual differences in media multitasking and performance on the <Emphasis Type="Italic">n</Emphasis>-back

A number of studies have recently examined the link between individual differences in media multitasking (using the MMI) and performance on working memory paradigms. However, these studies have yielded mixed results. Here we examine the relation between media multitasking and one particular working memory paradigm—the n-back (2- and 3-back)—improving upon previous research by (a) treating media multitasking as a continuous variable and adopting a correlational approach as well as (b) using a large sample of participants. First, we found that higher scores on the MMI were associated with a greater proportion of omitted trials on both the 2-back and 3-back, indicating that heavier media multitaskers were more disengaged during the n-back. In line with such a claim, heavier media multitaskers were also more likely to confess to responding randomly during various portions of the experiment, and to report media multitasking during the experiment itself. Importantly, when controlling for the relation between MMI scores and omissions, higher scores on the MMI were associated with an increase in false alarms, but not with a change in hits. These findings refine the extant literature on media multitasking and working memory performance (specifically, performance on the n-back), and suggest that media multitasking may be related to the propensity to disengage from ongoing tasks.