The Effect of Workload on Occupational Stress. Emmanuel Segui
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Transcript of The Effect of Workload on Occupational Stress. Emmanuel Segui
WORKLOADEmmanuel SeguiIndustrial/Organizational Psychologist
Workload Overload
Underload Having work that fails to use a worker's
skills and abilities
FLOW (Csikszentmihalyi)
Yerkes-Dodson Law Inverted-U function
• Optimal level of arousal differs for experts/novices and simple/complex tasks.
• Poor performance if too low (low motivation, boredom) or too high (test anxiety)
Work Overload Time-line Model
Time-line model Workload percentage = Time required/Time
available Can have over 100% workload and handle it okay
or less than 100% and not Moderators of time requirement estimations:
Individual differences Level of automaticity Shared vs. separate resources
Work Overload Time-line Model
Definitions of Workload? Physiological and mental demands that
occur while performing a task or a combination of tasks.
Workload is defined as the physical and/or mental requirements associated with a task or a combination of tasks.
Definitions of Workload? Aspect of Interaction between an
operator and an Assigned Task The term workload refers to that portion
of the operators limited capacity actually required to perform a particular Task
Workload Strains Anxiety Physiological reactions
Fatigue Backache Headache Gastrointestinal problems.
Performance Loss
Fatigue One effect of continuous work overload is
fatigue. Fatigue is a stressor that degrades
performance and creates problems in maintaining attention.
Fatigue Fatigue studied in
military operations, long-haul truck drivers, medical workers in hospitals, pilots, ATC (overload)
Fatigue can also result from long periods of doing little (underload).
Examples of the effects of fatigue due to sleep disruption 60% of class A aircraft mishaps in the Air
Force are due to fatigue The explosion of the space shuttle
Challenger is thought to be due to poor decision making of the launch team who received very little sleep prior to their early morning decision to launch the rocket in excessively cold temperature.
Examples of the effects of fatigue due to sleep disruption Over 200,000 auto
accidents per year Medical errors Performance on the
battle field.
Fatigue, Vigilance and Underarousal
Automation may make the problem of underarousal worse.
Workload
Construct Complex phenomenon
Multiple dimensions Hard to define “There is still no universally
accepted definition for mental workload”
Why Measure Workload?
Avoid Accidents Performance limits Predict top performance and operation
failure
Why Measure Workload?
“If workload is only studied in an experimental environment and is not applied to real-life situations, then the research is useless. It is easy to get a count of eye blinks per minute, but applying that to exactly how much workload a pilot flying a bombing mission is experiencing may be quite difficult. This difficult task is essentially the most important aspect of workload because it is the reason workload is studied”
Measuring Workload 3 main classifications
Performance-based measures Physiological measures Subjective measures
Performance-based measures Primary task measures Secondary task
methods Measure the reserve
capacity left over after performing the primary task (examples: memory tasks, mental arithmetic)
Performance-based measures Advantages
Non-invasive and non-interfering
Tracks changes in workload dynamically. (i.e., as performance proceeds)
Disadvantages Unable to predict
failure
2. Physiological measures Physiological
measures Heart rate Blink rate EEG Pupil diameter
Visual Scanning Used extensively in aviation research
gaze characteristics on cockpit instruments mean dwell time of each fixation on the pilot's primary
instrument Tole, et al. (1982)
Visual scanning behavior and mental workload in aircraft pilots scanning behavior was also a function of the estimated
skill level of the pilots, with novices being affected by the loading task much more than experts.
Visual scanning of instruments in a controlled task may be an indicator of both workload and skill
ECG Bonner & Wilson
(2001) Monitored pilots
throughout test and evaluation of an aircraft
Note differences between subjective workload and HR
Physiological Measures Advantage
Discreet Disadvantage
Expensive
3. Subjective measures The NASA Task Load Index
(NASA-TLX) multidimensional assessment tool that rates perceived workload
Temporal Demand, Effort, Stress, Own Performance, Frustration, Physical Demand (6 sources of workload)
3. Subjective measures SWAT Developed by US
Air Force (Subjective Workload Assessment Technique) Time, effort, stress
(sources of worlkload)
3. Subjective measures Advantage
Easy to do High Face validity
Disadvantage Bias
Recap
Remediation Task redesign or assignment to multiple workers Automate Develop display design that highlights the most
important information. Training for high time-stress workload situations. Training of task management skills
https://www.youtube.com/watch?v=4HWYVrTbnw0
ANY QUESTIONS?