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The term workload can refer to several different yet related entities.
| | This article needs additional citations for verification .(February 2013) |
The term workload can refer to several different yet related entities.
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An old definition refers to workload as the amount of work an individual has to do. [1] There is a distinction between the actual amount of work and the individual's perception of the workload. [1] To distinguish the two types, the term 'mental workload' (MWL) is often preferred, clearly indicating the latter type, which refers to the workload experienced by a human, regardless of the task's difficulty. This is because the same underlying task might generate two distinct mental responses and experiences, thus, different cognitive load amounts, even if executed by the same person. Many definitions of mental workload have been proposed in the years. [2]
A more recent and operational definition is that "Mental workload (MWL) represents the degree of activation of a finite pool of resources, limited in capacity, while cognitively processing a primary task over time, mediated by external stochastic environmental and situational factors, as well as affected by definite internal characteristics of a human operator, for coping with static task demands, by devoted effort and attention". [2] This definition has emerged from a systematic review of the construct of mental workload by analysing many published research works and all the ad-hoc definitions that have emerged in the last 60 years. It has also been influenced by the Multiple Resource Theory, described below, and the notion of human, multiple resources. [3]
The assessment of operator workload has a strong impact on new human-machine systems design. By evaluating operator workload during the design of a new system, or iteration of an existing system, problems such as workload bottlenecks and overload can be identified. As the human operator is a central part of a human-machine system, correcting these problems is necessary to operate safe and efficient systems. An operating budget may include estimates of the expected workload for a specific activity. 'Workload' or 'cognitive load' is often confused with 'cognitive load theory'. The latter is referred to as the actual construct of Cognitive Load (CL), or mental workload (MWL). In contrast, the former is referred to a specific cognitivist learning theory within the larger field of pedagogy and instructional design.
Workload can also refer to the total energy output of a system, particularly of a person or animal performing a strenuous task over time. One particular application of this is weight lifting/weights training, where both anecdotal evidence and scientific research have shown that it is the total "workload" that is important to muscle growth, as opposed to just the load, just the volume, or "time under tension". In these and related uses, "workload" can be broken up into "work+load", referring to the work done with a given load. In terms of weights training, the "load" refers to the heaviness of the weight being lifted (20 kg is a more significant load than 10 kg), and "work" refers to the volume, or the total number of reps and sets done with that weight (20 reps are more work than ten reps, but two sets of 10 reps are the same work as 1 set of 20 reps, its just that the human body cannot do 20reps of heavy weight without a rest, so its best to think of 2x10 as being 20 reps, with a rest in the middle).
This theory was also used to determine horse power (hp), which was defined as the amount of work a horse could do with a given load over time. The wheel that the horse turned in Watt's original experiment put a specific load on the horse's muscles, and the horse could do a certain amount of work with this load in a minute. Provided the horse was a perfect machine, it would be capable of a constant maximum workload. Increasing the load by a given percentage would decrease the possible work done by the same percentage so that it would still equal "1 hp". Horses are not perfect machines and, over short periods, are capable of as much as 14 hp, and over long periods of exertion, output an average of less than 1 hp.
The theory can also be applied to automobiles or other machines, which are slightly more "perfect" than animals. Making a car heavier, for instance, increases the load that the engine must pull. Likewise, making it more aerodynamic decreases drag, which also acts as a load on the car. Torque can be considered the ability to move a load, and the revs are how much work it can do with that load in a given amount of time. Therefore, torque and revs together create kilowatts or total power output. Total output can be related to the "workload" of the engine/car or how much work it can do with a given load. As engines are more mechanically perfect than animals' muscles and do not fatigue similarly, they will conform much more closely to the formula that if you apply more load, they will do less work, and vice versa.
In an occupational setting, workload can be stressful and serve as a stressor for employees. Three aspects of workload can be stressful.
Workload has been linked to a number of strains, including anxiety, physiological reactions such as cortisol, fatigue, [5] backache, headache, and gastrointestinal problems. [6]
Workload as a work demand is a major component of the demand-control model of stress. [7] This model suggests that jobs with high demands can be stressful, especially when the individual has low control over the job. In other words, control serves as a buffer or protective factor when demands or workload is high. This model was expanded into the demand-control-support model, which suggests that the combination of high control and high social support at work buffers the effects of high demands. [8] A 2019 survey by Cartridge People identified workload as the main cause of occupational stress. [9]
As a work demand, workload is also relevant to the job demands-resources model of stress that suggests that jobs are stressful when demands (e.g., workload) exceed the individual's resources to deal with them. [10] [11]
There is no one agreed definition of mental workload and consequently not one agreed method of assessing or modelling it. [2] One example definition by Hart and Staveland (1988) describes workload as "the perceived relationship between the amount of mental processing capability or resources and the amount required by the task". A more generally applicable operational definition of workload is that "Mental workload (MWL) represents the degree of activation of a finite pool of resources, limited in capacity, while cognitively processing a primary task over time, mediated by external stochastic environmental and situational factors, as well as affected by definite internal characteristics of a human operator, for coping with static task demands, by devoted effort and attention". [2]
Workload modelling is the analytical technique used to measure and predict workload. The main objective of assessing and predicting cognitive workload is to achieve an evenly distributed, manageable workload and to avoid overload or underload. Another aspect of workload is the mathematical predictive models used in human factors analysis to support the design and assessment of safety-critical systems.
Wickens' (1984) multiple resource theory (MRT) model [12] is illustrated in figure 1:
Wickens' MRT proposes that the human operator does not have one single information processing source that can be tapped but several different pools of resources that can be tapped simultaneously. Each box in figure 1 indicates one cognitive resource. Depending on the nature of the task, these resources may have to process information sequentially if the different tasks require the same pool of resources or can be processed in parallel if the task requires different resources.
Wickens' theory views performance decrement as a shortage of these different resources and describes humans as having limited capability for processing information. Cognitive resources are limited, and a supply and demand problem occurs when the individual performs two or more tasks that require a single resource (as indicated by one box on the diagram). Excess workload caused by a task using the same resource can cause problems, errors, or slower performance. For example, if the task is to dial the phone, then no excess demands are placed on any component. However, if another task is being performed simultaneously that demands the same component(s), the result may be an excess workload.
The relationship between workload and performance is complex. It is not always the case that as workload increases, performance decreases. Performance can be affected by workload being too high or too low (Nachreiner, 1995). A sustained low workload (underload) can lead to boredom, loss of situation awareness and reduced alertness. Also, as workload increases, performance may not decrease as the operator may have a strategy for handling task demands.
Wickens' theory allows system designers to predict when:
Like Wickens, McCracken and Aldrich (1984) describe the processing, not as one central resource but as several processing resources: visual, cognitive, auditory, and psychomotor (VCAP). All tasks can be decomposed into these components.
They developed rating scales for each VCAP component, which provide a relative rating of the degree to which each resource component is used.
Joseph Hopkins (unpublished) developed a training methodology. The background to his training theory is that complex skills are, in essence, resource conflicts where training has removed or reduced the conflicting workload demands, either by higher-level processing or by predictive time sequencing. His work is based on Gallwey (1974) and Morehouse (1977). The theory postulates that the training allows the different task functions to be integrated into one new skill. An example of this is learning to drive a car. Changing gear and steering are two conflicting tasks (i.e. both require the same resources) before they are integrated into the new skill of "driving". An experienced driver will not need to think about what to do when turning a corner (higher level processing) or may change gear earlier than required to give sufficient resources for steering around the corner (predictive time sequencing).
With any attempt at creating a workload model, the process begins with understanding the tasks to be modelled. This is done by creating a task analysis that defines:
Each task must be defined to a sufficient level to allow realistic physical and mental workload values to be estimated and to determine which resources (or combination of resources) are required for each task – visual, auditory, cognitive and psychomotor. A numerical value can be assigned to each based on the scales developed by McCracken and Aldrich.
These numerical values against each resource type are then entered into the workload model. The model sums the workload ratings within each resource and across concurrent tasks. The critical points within the task are therefore identified. When proposals are made for introducing new devices onto the current baseline activities, this impact can then be compared to the baseline. One of the most advanced workload models was possibly developed by K Tara Smith (2007). This model integrated the theories of Wickens, McCracken and Aldrich and Hopkins to produce a model that not only predicts the workload for an individual task but also indicates how that workload may change given the experience and training level of the individuals carrying out that task. Workload assessment techniques are typically used to answer the following types of questions: Eisen, P.S and Hendy, K.C. (1987):
It is well accepted that there is a relationship between the media by which information is transferred and presented to a decision maker and their cognitive workload. During times of concentrated activity, single-mode information exchange is a limiting factor. Therefore, the balance between the different information channels (most commonly considered visual processing and auditory, but could also include haptic, etc.) directly affects cognitive workload (Wickens 1984). In a time-critical decision situation, this workload can lead to human error or delayed decisions to accommodate the processing of the relevant information. (Smith, K.T. & Mistry, B. 2009). [13] Work conducted by K Tara Smith has defined some terms relating to the workload in this area. The two main concepts relating to workload are:
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This article incorporates textfrom this source, which is available under the CC BY 4.0 license.{{cite journal}}: CS1 maint: multiple names: authors list (link){{cite journal}}: CS1 maint: multiple names: authors list (link)In software quality assurance, performance testing is in general a testing practice performed to determine how a system performs in terms of responsiveness and stability under a particular workload. It can also serve to investigate, measure, validate or verify other quality attributes of the system, such as scalability, reliability and resource usage.
Scalability is the property of a system to handle a growing amount of work. One definition for software systems specifies that this may be done by adding resources to the system.
Work design is an area of research and practice within industrial and organizational psychology, and is concerned with the "content and organization of one's work tasks, activities, relationships, and responsibilities" (p. 662). Research has demonstrated that work design has important implications for individual employees, teams, organisations, and society.
Job satisfaction, employee satisfaction or work satisfaction is a measure of workers' contentment with their job, whether they like the job or individual aspects or facets of jobs, such as nature of work or supervision. Job satisfaction can be measured in cognitive (evaluative), affective, and behavioral components. Researchers have also noted that job satisfaction measures vary in the extent to which they measure feelings about the job. or cognitions about the job.
In cognitive psychology, cognitive load refers to the amount of working memory resources used. However, it is essential to distinguish it from the actual construct of Cognitive Load (CL) or Mental Workload (MWL), which is studied widely in many disciplines. According to work conducted in the field of instructional design and pedagogy, broadly, there are three types of cognitive load: intrinsic cognitive load is the effort associated with a specific topic; extraneous cognitive load refers to the way information or tasks are presented to a learner; and germane cognitive load refers to the work put into creating a permanent store of knowledge. However, over the years, the additivity of these types of cognitive load has been investigated and questioned. Now it is believed that they circularly influence each other.
Self-regulation theory (SRT) is a system of conscious, personal management that involves the process of guiding one's own thoughts, behaviors and feelings to reach goals. Self-regulation consists of several stages. In the stages individuals must function as contributors to their own motivation, behavior, and development within a network of reciprocally interacting influences.
Situational awareness or situation awareness (SA) is the understanding of an environment, its elements, and how it changes with respect to time or other factors. Situational awareness is important for effective decision making in many environments. It is formally defined as:
“the perception of the elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future”.
Ecological interface design (EID) is an approach to interface design that was introduced specifically for complex sociotechnical, real-time, and dynamic systems. It has been applied in a variety of domains including process control, aviation, and medicine.
Cognitive ergonomics is a scientific discipline that studies, evaluates, and designs tasks, jobs, products, environments and systems and how they interact with humans and their cognitive abilities. It is defined by the International Ergonomics Association as "concerned with mental processes, such as perception, memory, reasoning, and motor response, as they affect interactions among humans and other elements of a system. Cognitive ergonomics is responsible for how work is done in the mind, meaning, the quality of work is dependent on the persons understanding of situations. Situations could include the goals, means, and constraints of work. The relevant topics include mental workload, decision-making, skilled performance, human-computer interaction, human reliability, work stress and training as these may relate to human-system design." Cognitive ergonomics studies cognition in work and operational settings, in order to optimize human well-being and system performance. It is a subset of the larger field of human factors and ergonomics.
Job performance assesses whether a person performs a job well. Job performance, studied academically as part of industrial and organizational psychology, also forms a part of human resources management. Performance is an important criterion for organizational outcomes and success. John P. Campbell describes job performance as an individual-level variable, or something a single person does. This differentiates it from more encompassing constructs such as organizational performance or national performance, which are higher-level variables.
Occupational stress is psychological stress related to one's job. Occupational stress refers to a chronic condition. Occupational stress can be managed by understanding what the stressful conditions at work are and taking steps to remediate those conditions. Occupational stress can occur when workers do not feel supported by supervisors or coworkers, feel as if they have little control over the work they perform, or find that their efforts on the job are incommensurate with the job's rewards. Occupational stress is a concern for both employees and employers because stressful job conditions are related to employees' emotional well-being, physical health, and job performance. The World Health Organization and the International Labour Organization conducted a study. The results showed that exposure to long working hours, operates through increased psycho-social occupational stress. It is the occupational risk factor with the largest attributable burden of disease, according to these official estimates causing an estimated 745,000 workers to die from ischemic heart disease and stroke events in 2016.
In modern psychology, vigilance, also termed sustained concentration, is defined as the ability to maintain concentrated attention over prolonged periods of time. During this time, the person attempts to detect the appearance of a particular target stimulus. The individual watches for a signal stimulus that may occur at an unknown time.
The P3b is a subcomponent of the P300, an event-related potential (ERP) component that can be observed in human scalp recordings of brain electrical activity. The P3b is a positive-going amplitude peaking at around 300 ms, though the peak will vary in latency from 250 to 500 ms or later depending upon the task and on the individual subject response. Amplitudes are typically highest on the scalp over parietal brain areas.
Positive psychology is defined as a method of building on what is good and what is already working instead of attempting to stimulate improvement by focusing on the weak links in an individual, a group, or in this case, a company. Implementing positive psychology in the workplace means creating an environment that is more enjoyable, productive, and values individual employees. This also means creating a work schedule that does not lead to emotional and physical distress.
Ergonomics, also known as human factors or human factors engineering (HFE), is the application of psychological and physiological principles to the engineering and design of products, processes, and systems. Primary goals of human factors engineering are to reduce human error, increase productivity and system availability, and enhance safety, health and comfort with a specific focus on the interaction between the human and equipment.
Human performance modeling (HPM) is a method of quantifying human behavior, cognition, and processes. It is a tool used by human factors researchers and practitioners for both the analysis of human function and for the development of systems designed for optimal user experience and interaction. It is a complementary approach to other usability testing methods for evaluating the impact of interface features on operator performance.
In aviation, a source of stress that comes from the environment is known as an environmental stressor. Stress is defined as a situation, variable, or circumstance that interrupts the normal functioning of an individual and, most of the time, causes a threat. It can be related not only to mental health, but also to physical health.
Stress in the aviation industry is a common phenomenon composed of three sources: physiological stressors, psychological stressors, and environmental stressors. Professional pilots can experience stress in flight, on the ground during work-related activities, and during personal time because of the influence of their occupation. An airline pilot can be an extremely stressful job due to the workload, responsibilities and safety of the thousands of passengers they transport around the world. Chronic levels of stress can negatively impact one's health, job performance and cognitive functioning. Being exposed to stress does not always negatively influence humans because it can motivate people to improve and help them adapt to a new environment. Unfortunate accidents start to occur when a pilot is under excessive stress, as it dramatically affects his or her physical, emotional, and mental conditions. Stress "jeopardizes decision-making relevance and cognitive functioning" and it is a prominent cause of pilot error. Being a pilot is considered a unique job that requires managing high workloads and good psychological and physical health. Unlike the other professional jobs, pilots are considered to be highly affected by stress levels. One study states that 70% of surgeons agreed that stress and fatigue don't impact their performance level, while only 26% of pilots denied that stress influences their performance. Pilots themselves realize how powerful stress can be, and yet many accidents and incidents continues to occur and have occurred, such as Asiana Airlines Flight 214, American Airlines Flight 1420, and Polish Air Force Tu-154.
Juan Pascual-Leone is a developmental psychologist and founder of the neo-Piagetian approach to cognitive development. He introduced this term into the literature and put forward key predictions about developmental growth of mental attention and working memory.
The Improved Performance Research Integration Tool (IMPRINT) is a discrete-event simulation and human performance modeling software tool developed by the Army Research Laboratory and Micro Analysis and Design. It is developed using the .NET Framework. IMPRINT allows users to create discrete-event simulations as visual task networks with logic defined using the C# programming language. IMPRINT is primarily used by the United States Department of Defense to simulate the cognitive workload of its personnel when interacting with new and existing technology to determine manpower requirements and evaluate human performance.
