Week 9 - attention and workload Flashcards
define workload
Mental workload (referred to as just workload) is a general term used to describe the cost of accomplishing task requirements
what does workload depend on?
1- Workload varies as a function of the task demands
placed on the human operator
2- The operator’s capacity to meet those demands
what are three task demands
1- task difficulty
2- task priority
3- situation
define operator capacity
- each operator has a supply of mental resources
- mental resources are limited in supply eg memory, planning, decision making
- Task performance generally improves as resources are directed to it
- Resources that are unused are referred to as ‘spare
capacity’
overload vs underload
- Generally, the focus is on the detrimental effects of overload (e.g. excessive workload)
- However underload (e.g. sustained low workload) is
just as much of a problem
what does underload cause
(1) Increased fatigue
(2) Lower task engagement
(3) Lower vigilance
(4) Generally reduces operators capacity to deal
with the unexpected (spare capacity)
what are three reasons to why you measure workload
Workload prediction • To maintain workload within acceptable limits Equipment assessment • Optimize the system to suit operator Choose the right operators • Employee selection or further training
explain workload prediciton
Safety • Often relies on predicting workload ahead of time • When will an operator struggle? Change management: • Know in advance what effect changes will have
explain equitment assessment
Designers may want to know what workload will be at
the design, production, or usage stages
• Identify problem areas where performance may
decline
• Compare workload between multiple systems
explain choosing the right operators
- Equipment design focuses on controlling task demands, but operator selection focuses on controlling operator capacity
• Can train to improve some capacity, but only up to a
point (and it may not be cost effective)
what are three major categories of workload measures?
- Performance
- Subjective
- Physiological
what are two ways performance can be divided into?
- primary task measures
- secoundary task measures
what is primary task performance advantages
• Workload reflected directly by performance outcome
• Non-invasive and non-interfering
• Tracks changes in workload dynamically. (i.e., as
performance proceeds)
• Uncontaminated by memory issues
what is primary task performance disadvantages
• Mental workload is not the only thing that can
influence performance
• Doesn’t take effort into account
• Might not always have the technology or interface
available to monitor performance
what is a secondary task purpose and what does it measure?
- To measure the spare capacity not being
used by the primary task
• Usually, an increase in primary task workload is
associated with a decrease in secondary task perf.
• Potential measures including: Rhythmic tapping task, Probe reaction tasks, Auditory monitoring
what is secoundary task performance advantages
• The same secondary task can be used with very
different primary tasks
• There are a collection of available (and validated)
secondary tasks
• Provide a measure of space capacity
• Useful when there is little primary task data available
(e.g. monitoring jobs, baggage scanner)
what is secoundary task performance disadvantages
• Only relevant when secondary task taps into the
same resources as the primary task
• It adds in another task to the work environment (could increase workload)
• Can interfere/interrupt primary task
