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Compatibility between alternative valence and task influences the decision time, difficulty, attribute recall, and effort of consumers when making decisions. The role of the task of choosing in studying attribute conflict is highlighted.

While prior research has found that familiarity is beneficial to team performance, it is not clear whether different kinds of familiarity are more or less beneficial when the work has [...]

Cognitive flexibility can be studied using the task-switching paradigm. This paradigm requires subjects to adapt behaviour to changing contexts as indicated by a cue. In our study, we addressed the question of how cue-based implementation of mental 'task sets' occurs. We assumed that cues build up associations to the tasks that they indicate. These associations lead to retrieval of the associated task set once the cue shows up again. In three experiments, we tested this assumption using a negative transfer paradigm. First participants were exposed to one cue-task mapping. After a training phase, the cue-task mapping changed in either of two ways. Whereas one group of participants got new cues, the other experienced a reversal of the learnt cue-task mapping. Our results show that participants build up cue-task associations and that these formerly learnt associations can hamper the implementation of new cue-task mappings (particular with mapping reversal). Prolonged preparation time decreased the cost of changing the cue-task mapping but did not change the overall pattern of results.

Various models of representational theory of measurement to analyze observable or non-directly observable properties of an object or operation are presented.

Abstract This paper introduces a systematic constraint-based approach to specify complex tasks of general sensor-based robot systems consisting of rigid links and joints. The approach integrates both instantaneous task specification [...]

In this article, we present a usability experiment in which participants were asked to make intensive use of information on an intranet in order to execute job-related tasks. Participants had to work with one of two versions of an intranet: one with an organization-based hyperlink structure, and one with a task-based hyperlink structure. Efficiency and effectiveness were measured in terms of execution time and task accuracy, respectively. After the task execution, participants were asked to evaluate the task as well as the intranet. The results show that participants perform more efficiently with the organization-based structure, which is probably due to their familiarity with this structure. A post hoc analysis revealed, however, a learning effect in the task condition, which suggests that once users are acquainted with it, a task structure is at least as efficient.

Recent research (e.g., Siegler, 1996) has discovered the important and vital role that variability plays among strategy use and development over time. However, as many researchers have pointed out (e.g., Miller, 1993), the majority of the research addressing this issue has focused on the outcomes, rather than on the potentially more informative aspects of variability, strategy development, and the process of adaptation. In this study, we examined the role of variability during strategy development, utilizing a longitudinal method. Thirteen participants were studied over 3 months as they coached a simulated football team. The results suggest that variability plays a major role in adaptive skill acquisition in a dynamic environment--in the direction, however, opposite to that predicted by previous research done with simple static tasks.

The explicit task-cuing procedure involves presenting a cue that indicates which task to perform on a target. Responses are typically faster when tasks repeat than when they alternate, and this difference is often interpreted as a measure of the time required for executive control processes to change task set. This article suggests that the difference reflects priming of cue encoding when successive cues are identical or associatively related. Subjects responded to task repetitions more quickly when the cue on the current trial was associatively related to the cue on the previous trial (e.g., day [right arrow] night) than when the cues were unrelated (e.g., verb [right arrow] night). Models applied to the time course function--generated by manipulating the interval between the onsets of the cue and the target--showed that the facilitation was due to cue encoding, a process that does not require online executive control.

The article describes a simulated 'cooking breakfast' task in which participants must remember to start and stop cooking five foods so that all the foods are 'ready' at the same time. In between starting and stopping operations, the participants also carried out a 'table-setting' task as a filler activity. The breakfast task yields various measures of multitasking and executive control. Groups of younger and older adults performed the task; half of the participants in each group were bilinguals and the other half were monolinguals. The results showed substantial age-related decrements in most measures of executive control. Additionally, older bilinguals showed some advantages in task management over their monolingual peers.

This study examined how task switching is affected by hierarchical task organization. Traditional task-switching studies, which use a constant temporal and spatial distance between each task element (defined as a stimulus requiring a response), promote a flat task structure. Using this approach, Experiment 1 revealed a large switch cost of 238 ms. In Experiments 2-5, adjacent task elements were grouped temporally and/or spatially (forming an ensemble) to create a hierarchical task organization. Results indicate that the effect of switching at the ensemble level dominated the effect of switching at the element level. Experiments 6 and 7, using an ensemble of 3 task elements, revealed that the element-level switch cost was virtually absent between ensembles but was large within an ensemble. The authors conclude that the element-level task repetition benefit is fragile and can be eliminated in a hierarchical task organization.

Purpose: Development of strategies to optimize the functional performance of older adults requires understanding the behavior of older people doing tasks in real-world settings and capturing these interactions in research protocols. This is a major challenge as there is some degree of tension between capturing the contextual variables and constraints that operate in the real world and the scale of research that can be realistically conducted within controlled experimental settings. This article presents a research approach that can be used to help ensure the ecological validity of research protocols. The intent is to demonstrate how an ecologically valid approach affords greater insight into the performance of older adults in real world settings. Methods: The approach involves techniques such as task analysis and simulation. Examples from two research projects examining aging and the performance of real-world computer-based work tasks are used to demonstrate the application of this approach. Results: The article demonstrates how an ecologically valid research approach yields information about human performance that can be translated into solutions for real-world problems. Implications: Ecologically valid research protocols offer the potential for providing answers to real-world problems and advancing theory regarding aging and functional performance. Key Words: Ecological validity, Real-world tasks, Task analysis

The intention superiority effect (ISE) is characterized by faster response time to task material intended for future performance than to neutral material with no associated intention or material that is linked to a canceled intention. The existence of the ISE has been explored here under naturalistic conditions in which participants self-initiate an intention that is of personal relevance to them. Participants were required to remember prospective tasks that were presented under the guise of preparatory tasks for the next participant. After encoding a pair of tasks, they were informed that one task no longer needed to be performed. Subsequent lexical decision data exhibited the expected effect of faster response time for intended items than for canceled items (experimental groups in Experiments 1A and 1B). No differences in response time were observed between two sets of canceled items (control group in Experiment 1A). When an intention coexisted with the expectation that a written description of the task would be available, no reliable difference in latencies for these items and canceled items was observed (control group in Experiment 1B). The results are discussed in terms of facilitatory and inhibitory processes that may allow us to contend with many intentions in everyday scenarios.

This paper examines the optimal structure of hierarchies when workers differ in the range of tasks they can perform. A hierarchical system may reduce costs by allowing most tasks to be handled by unskilled workers. This may however increase delay for those tasks which must pass through several layers before reaching the appropriate level. The paper characterises an optimal hierarchy when such a trade-off exists.

The delay between choosing to switch tasks is caused by several essential components. These include reflection, dissipation of the previous task parameters, preparation for the new task, and a residual component.

A new study examines the interaction between different map displays and spatial task using two commonly used aircraft display systems.

This paper examines the utility of prospective memory as a secondary task. For this purpose, the results of seven experiments were analysed to evaluate the sensitivity of prospective memory, making a direct comparison with another secondary task (reaction time). Both tasks were used as subsidiary elements in a complex task environment, the design of which was based on the micro-world research paradigm. The results indicated that prospective memory was slightly more vulnerable to variations in experimental conditions than was reaction time. The paper concludes that, overall, prospective memory appears to be a suitable secondary task. This is partly attributed to the element of self-initiation, which is a feature of some prospective memory tasks. It is recommended to use time-based and pulse-based prospective memory tasks since they seem to be the more sensitive.

This article examines two approaches to speed up the execution of the secondary task performed in the redundant robot manipulators using standard task-priority algorithm. Optimizing the null space projection matrix facilitates choice of weight of the pseudoinverse matrix.

The aim of the study was to document the nature and incidence of surgical errors enacted during laparoscopic surgery in order to direct future research and surgical training. A modified Human Reliability Analysis (HRA) approach, based on direct observation, was adopted to categorise and record errors encountered during the practice of laparoscopic cholecystectomy. This study confirmed the applicability and usefulness of an observational methodology in the assessment of human error in endoscopic surgical performance. The study identified aspects of the design and usage of instruments, surgical training and the differences between tasks which needed further directed research in order to identify underlying performance shaping factors (PSFs) and so reduce error rates. Keywords: human error, laparoscopic cholecystectomy, observational methodology

Two new studies investigate whether an accurate task-switching model could be identified and to determine if it was related to adult age and measures of higher order cognition. Both studies show that there was moderate correlation of task switching across various combinations of tasks and distinguished between a model reflecting processing speed and a switching construct. The second study shows that age is linked to the task-switching construct and to spatial visualization, episodic memory and inductive reasoning, although they are not independent of other variables.

In three experiments that used levels of processing and study time manipulations as independent variables in a word fragment completion task, the validity of the assumption of independence between recollection and automatic influences of memory was assessed. This assumption underlies the use of the process dissociation procedure (Jacoby, 1991), a tool suggested for distinguishing the different contributions of recollection and automatic influences of memory. Overall, it appeared that semantic processing, as compared with physical processing at study, positively affected recollection but negatively affected automatic influences of memory in word fragment completion. This negative effect on the automatic influences was reduced when the available study time decreased. The incompatibility of these results with the assumption of independence between recollection and automatic influences of memory and their impact on the applicability of the process dissociation procedure are discussed.

The present study was a replication and expansion of Eisenberger's 1992 model of learned industriousness which states that task persistence is determined by one's prior history with effort and reinforcement on previous tasks. He predicted a linear relationship between these factors. College students (32 women and 22 men) participated in this study which examined the relationship among seven levels of difficulty on a digit-array task and persistence on an unsolvable anagram task. Analysis indicated a quadratic relationship; at intermediate levels of difficulty and reinforcement, persistence was highest, and at low and high levels of difficulty and reinforcement, persistence declined. We attribute these findings to the effects of both learned industriousness and learned helplessness.

Byline: Levan Lira (1), Diane M. Browder (2), Jeff Sigafoos (3) Keywords: functional equivalence; task designs; alternatives; response effort; motion study Abstract: We evaluated the effects of functionally equivalent task designs and alternatives, as validated by motion study procedures, on dependent variables (nonadaptive responses, use of alternative, attempts at task, and completed attempts at task) relevant to performing a selected task. First, we evaluated the effects of functionally equivalent task designs on the dependent variables. Second, we evaluated the effects of an efficient functionally equivalent alternative on the variables. Third, we compared the effects of the efficient functionally equivalent alternative with a less efficient functionally equivalent alternative on the same variables. The results showed that the inefficient functionally equivalent task design occasioned higher rates of nonadaptive responses than the efficient functionally equivalent task design. The results also showed that the functionally equivalent task designs and alternatives competed within and across response classes to reduce nonadaptive responses. Mixed results were obtained in comparing the effects of the efficient versus the less efficient functionally equivalent alternatives. We provide evidence for extending the current concept of functional equivalence to include task design responses as well as alternative responses in functional equivalence training. Author Affiliation: (1) Division of Specialised Education, National Institute of Education, Nanyang Technological University, Singapore (2) Department of Education and Human Services, College of Education, Lehigh University, PA, USA (3) Schonell Special Education Research Centre, University of Queensland, Queensland, Australia Article History: Registration Date: 28/09/2004

Participation has an indirect relationship with task performance through goal acceptance. A sample taken from a goal-setting program participated in by 200 employees reveals that participation also has a positive effect on task performance and procedural justice perceptions. The procedural justice perceptions of the goal-setting program, however, does not have any effect on task performance.

The redistribution and assignment of staff and physician tasks resulted in the decrease in the number of days that passed between the time of examination and the day the eyeglasses are given. The strategy also leads to the increase in the number of appointments and the daily revenue obtained by the physicians. Task redundancy, integration of independent individual assignments and accountability of the staff and the physicians are addressed by the task-manipulation condition.

Performance by the participants improved after their task was clarified. The results indicated that the need to define responsibilities is needed to maximize efficiency. On the other hand, feedback intervention and positive reinforcement suffered setbacks due to several factors, one of which is the ineffectiveness of positive reinforcement from outsiders. Participants value more their supervisor's feedback. It was concluded that it would be harder to implement performance improvements in the police force due to the varying situations they are subjected to.

The ability of an optimum duration of inter-task system response times (SRT) to aid users in achieving a perfect readiness for task execution is systematically investigated. Three SRT duration conditions, namely, short, medium and long, were applied in a balanced repeated measures design. Medium SRTs are observed to enable the attainment of optimum readiness for task execution.

Participants performed choice reaction time (RT) tasks on 2-dimensional stimuli such that each task was based on 1 stimulus dimension. A cue preceded the target stimulus and instructed the participant about which (randomly selected) task to perform. Shifting between tasks was associated with an RT cost, which was larger when the (randomly varying) cue-target interval was short as opposed to when it was long. Cue-target interval was not confounded with the remoteness from the previous trial. Hence, it affected the task-shift cost through preparation rather than by allowing carryover effects to dissipate. Similar results were obtained for 2 location tasks and for the object-based tasks (color and shape discrimination). They indicate a time-effort consuming process that operates after a task shift, precedes task execution, and presumably reflects the advance reconfiguration of processing mode.

The purpose of this research was to develop a new model to describe and predict a computerized task. AutoCAD was utilized as the experimental tool to collect operating procedure and time data at a keystroke level for a computer aided design (CAD) task. Six undergraduate students participated in the experiment. They were required to complete one simple and one complex engineering drawing. A model which characterized the task performance by software commands and predicted task execution time using keystroke-level model operators was proposed and applied to the analysis of the dialogue data. This task parameter model adopted software commands, e.g. LINE, OFFSET in AutoCAD, to describe the function of a task unit and used up to five parameters to indicate the number of keystrokes, chosen function for a command, and ways of starting and ending a command. Each task unit in the task parameter model can be replaced by a number of primitive operators as in the keystroke level model to predict the task execution time. The observed task execution times of all task units were found to be highly correlated with the task execution times predicted by the keystroke level model. Therefore, the task parameter model was proved to be a usable analytical tool for evaluating the human-computer interface (HCI). Keywords: task analysis, GOMS model, computer-aided design (CAD)

The steps of a task-analytic research program designed to identify the in-session performances involved in resolving lingering bad feelings toward a significant other are described. A rational-empirical methodology of repeatedly cycling between rational conjecture and empirical observations is demonstrated as a method of developing an intervention manual and the components of client processes of resolution. A refined model of the change process developed by these procedures is validated by comparing 11 successful and 11 unsuccessful performances. Four performance components - intense expression of feeling, expression of need, shift in representation of other, and self-validation or understanding of the other - were found to discriminate between resolution and nonresolution performances. These components were measured on 4 process measures: the Structural Analysis of Social Behavior, the Experiencing Scale, the Client's Emotional Arousal Scale, and a need scale.

INTRODUCTION The beneficial effects of spacing practice are well established even when the interval between practice opportunities is filled with other activities (Carlson & Yaure, 1990; Glenberg, 1979). Accordingly, a […], We compared an alternating task modules (ATM) protocol - which alternated sessions on Space Fortress, Phoenix (video-game-like tasks), and algebra word problems - with a massed protocol, which blocked sessions on the tasks. The protocols were isochronal (equal in duration), each entailing one week of training and testing. ATM gave the men and women an advantage in learning and retention on Space Fortress and algebra word problems; it did not change their performance on Phoenix. Arousal, not confidence or motivation, was implicated in the ATM advantage. The practical implication of demonstrating and describing ATM benefits is that real-world training often requires minimal durations. This pragmatic constraint favors ATM over frequently investigated anisochronal schedules, in which spacing practice over long durations is more effective than massing practice in short durations. Evaluations of retention, arousal, motivation, and confidence began the process of testing theories that might be expanded to explain and enhance ATM benefits.

INTRODUCTION Automation is ubiquitous in many modern work settings, but perhaps most so in aviation. Automation in aviation, as in other domains, has increased demands on the pilot to monitor […], The present study examined the effects of task complexity and time on task on the monitoring of a single automation failure during performance of a complex flight simulation task involving tracking, fuel management, and engine-status monitoring. Two groups of participants performed either all three flight simulation tasks simultaneously (multicomplex task) or the monitoring task alone (single-complex task); a third group performed a simple visual vigilance task (simple task). For the multicomplex task, monitoring for a single failure of automation control was poorer than when participants monitored engine malfunctions under manual control. Furthermore, more participants detected the automation failure in the first 10 min of a 30-min session than in the last 10 min of the session, for both the simple and the multicomplex task. Participants in the single-complex condition detected the automation failure equally well in both periods. The results support previous findings of inefficiency in monitoring automation and show that automation-related monitoring inefficiency occurs even when there is a single automation failure. Implications for theories of vigilance and automation design are discussed.

The influence of equilibrium task complexity on its selection for multi-stage games is investigated. Three task complexity measures are considered, namely, cardinality of choice space, level of iterative knowledge of rationality and level of iterative knowledge of strategies. The metrics are used to proxy for the degree of cognitive effort needed to play a game. Coordination games with multiple equilibria each being a different division of a fixed pie are analyzed. Results show that subjects consider disparity, although not as importantly as task complexity. Subject choices are also path-dependent. The three task complexity metrics prove to be effective in predicting choice behavior.

Two studies were performed to examine the effect of the complexity of a physical task on the estimation of the time required for its performance. Different paradigms for the estimation of time (prospective vs retrospective) were used with different methods of estimation (reproduction vs verbal estimation). In Study 1, 32 pairs of adults were asked to throw a ball to each other in different ways. The two groups were distinguished by the motor and cognitive changes required in moving from one task to the next. One group had to perform 10 successive repetitions on each of five kinds of ball throws, while the other had to perform the same number of ball throws but with each type being split into two different successive sets of throws so here the task consisted of changes. In Study 2, 60 children (aged 7 or 8 yr.) were asked to perform a set of basketball tasks. The two groups were distinguished by the pace at which they had to perform the task, slowly or rapidly. The results of the two studies indicated a negative relation between the complexity of the task and the group's estimation of time. The reproductive method yielded shorter estimations than the verbal method. The results indicate that for physical activity the attentional model may well be valid.

A study proposed a two-dimensional scheme for classifying observational coding on the basis of content meaning and code type. However, the systematic task-analytic approach for observational coding involves understanding of both the nature and process of change. It includes modeling of context-specific, and in-situation process since any variations in the process yields crucial information about change in psychotherapy. The focus is on the process occurring at a particular moment in a particular environment than just the nature of change mechanisms.

A fast optimal task allocation (OTA) algorithm maximizes the reliability of redundant distributed computing systems by finding an optimal and sub-optimal task-allocation. The method assigns the processing node for each module of a task or program. The algorithm is robust for a wide range of parameters such as number of modules, number of processing nodes, ratio of average execution cost to average communication cost and connectivity of modules. The performance improves on increasing the difference between the number of modules and connectivity.

This paper describes a framework for robotic task sequence planning which decomposes tasks into operations sequences for a generic robotic workcell. The approach provides robust excucution of tasks through properties of: traceability-implicit mapping of operations to task representation, and viability-retaining multiple paths for execution. Given the descriptions of the objects in the system and all feasible geometric configurations and relationships among these objects, an AND/OR net which describes the relationships of all feasible geometric states and associated feasibility criteria for net transitions is generated. This AND/OR net is mapped into a Petri net which incorporates all feasible sequences of high level operations. The resulting Petri net is then decomposed in a stepwise manner into lower level Petri nets of which each transition can be directly implemented by control commands or command sequences based on devices and objects in the system, or, by lower level planning transitions corresponding to path planning, grasp planning, fine motion planning, etc. The property analysis for different levels of decomposition is also presented, and the inheritance of properties between levels is defined. All possible task sequences could be found using a search algorithm based on feasible system states. The shortest sequence may be chosen from the lowest level decomposition and is guaranteed to be the optimal output of the hierarchical planning system to efficiently implement the desired tasks.

This article reports on a national study of entry-level job dimensions and tasks performed by school social workers. It distinguishes job dimensions and tasks that school social workers must be able to perform on entry into the school and identifies the tasks they would prefer to perform. Findings suggest that tasks school social workers prefer are more consistent with the needs of pupils and the contemporary challenges facing the school as an institution. However, barriers found within the organization of the school and the administration of school social work services prevent practitioners from focusing on preferred tasks. Implications for practice and educational preparation are discussed., Across the United States the quality of education and the need to reform schooling continue to be debated (National Commission on Excellence in Education, 1983). Many states have approached this [...]

This study investigates the effects of a GSS on the decision outcome of five-person, face-to-face groups performing two distinct but related task types. A controlled laboratory experiment with a 3 X 2 factorial design was employed. The independent variables were support level and task type. A total of 68 groups were randomly assigned to different support levels (no support, structure support, or GSS support). Half of these groups performed an intellective task while the other half performed a preference task. The empirical findings show that task type affects consensus change and influence equality. Moreover, support level and task type jointly affect decision scheme satisfaction. This paper attempts to reconcile the body of empirical findings from related GSS studies. It discusses the implications of task type for GSS design and use.