Ergonomics - Human Factors (4) Flashcards
1
Q
What is the concept of cognitive overload?
A
- claims there are limits to the number of stimuli that people can handle at any one time
2
Q
What are the four factors of environmental overload suggested by Bell (1996)?
A
- capacity of humans to process incoming stimuli is limited
- information overload occurs when our capacity to process information is exceeded by the amount of information - the normal reaction to this is to block out those inputs that are less relevant or distracting and focus harder on the task at hand
- we pay most attention to stimuli that are intense, predictable or uncontrollable and that may require some sort of adaptive response
- capacity for attention can be temporarily depleted by prolonged demands on it that leave it overloaded
3
Q
What is ergonomics?
A
- applied science of equipment design based on the study of efficiency or productivity of its use
- a piece of equipment is considered to be highly ergonomic if it’s both comfortable and easy for the user, and highly efficient in terms of outcomes
- cognitive ergonomics applies this to the demands that it places on our working memory
4
Q
How have ergonomic strategies in the workplace been successful in the past?
A
- Taylor (1911) observed workers at a steel company, particularly those shovelling materials
- he focussed on observing those who were highly effective and noticed that they were very particular about the shovel they selected
- he then orchestrated a large shovel tool room being built, with 8-10 different types of shovel so workers could select the best shovel for the material they were working with
- output increased dramatically, with 140 men producing the same amount of work as had been done by 400-600 men previously
5
Q
What is the working memory model?
A
- describes short term memory as a system with multiple components
- these include the phonological loop, the visuo-spatial sketchpad and a central executive
- every component has limited capacity and duration
6
Q
What evidence supports the working memory model?
A
- Caird et al. conducted a meta-analysis involving 33 studies on the use of mobile phones whilst driving
- sample size around 2000
- found cognitive tasks led to a slower reaction time and slightly slower driving speeds
- this shows cognitive overload from having to perform multiple tasks can lead to reductions in performance, as predicted by the WMM
7
Q
What is social facilitation and what research evidence supports it?
A
- when our performance on a task is improved just because other people are present
- Bond and Titus conducted meta-analysis of 241 studies involving almost 24,000 people
- found being observed whilst undertaking simple tasks improves speed and performance, however whilst undertaking complex tasks accuracy and speed decreases
8
Q
What was the background to Drews and Doig’s study?
A
- in ICUs, nurses have to constantly monitor critically ill patients, using display units that show info such as blood pressure, oxygen levels and heart rate
- traditionally shown numerically, however this may not be the most effective way to present this info
- ICU nurses may be monitoring these displays in a number of different ways and monitoring is likely to be intermittent
9
Q
What was the aim of Drews and Doig’s study?
A
- they wanted to develop an ICU monitoring display that could present info that shows when patients’ vital signs have changed and what the nature of that change is to enable nurses to detect acute physiological change
- wanted to test whether this decreases the mental demands places on nurses
- believed it would, as would reduce requirements on nurses to calculate extent of change in vital signs
10
Q
How did Drews and Doig design the CVS (configural vital signs) display?
A
- interviewed nurses, conducted literature reviews and interviewed data visualisation experts
- as part of design, visual clutter minimised and colour coding/geometric shapes used to visually convey vital signs
- three experienced ICU nurses asked to review each successive prototype, resulting in the final version (effectiveness of which tested in the main study)
11
Q
What design did Drews and Doig use?
A
- 42 registered nurses who had critical care training and minimum of 1yr experience in the ICU
- randomly assigned to CVS display group or control group
- exposed to simplified version displaying just numerical info without the trend data - those in the control group could access trend data by pressing a button in a similar way to that of traditional displays
- four patient scenarios tested whether the CVS display led to better decision making than traditional displays and whether it led to quicker identification of a “stable” patient
- each nurse participated in all four scenarios in a random order
12
Q
What procedure did Drews and Doig carry out?
A
- participants given standardised 20min training session in the use and functions of the display
- participants then received specific patient information
- presented with scenario-specific clinical information for four patients (early sepsis, septic shock, pulmonary embolism and one in a stable state)
- told to verbally evaluate the patients’ status, interpret the data and recommend appropriate interventions as quickly and accurately as possible
- given five minutes to complete each scenario
- once completed all scenarios, asked to complete 7 point likert scale about the desirability of the CVS display and realism of the scenarios
- key data was the speed of the response and the accuracy of the data interpretation
- other factors such as amount of experience each nurse had was taken into account in the analysis
13
Q
What were the results of Drews and Doig’s study?
A
- nurses able to respond significantly more quickly with the CVS display (30% improvement) because they could interpret the data significantly faster (43% faster on average)
- nurses also able to identify the correct condition significantly more often with the CVS display - significant overall, particularly in the septic shock and pulmonary embolism scenarios
- nurses rated the desirability of the CVS 6/7 and rated the scenarios 6/7 for realism
14
Q
What were the conclusions of Drews and Doig’s study?
A
- data suggests this type of display (integrating vital signs info with trend data in a simple visual display) can improve nurses’ assessment of a patient in at least some clinical conditions
- the scenario in which there was no difference (early sepsis) is likely to be become some relevant data (temperature) was not included on the display, suggesting it could be further improved
15
Q
What research provides evidence that feng shui improves work place design?
A
- Dazkir and Read (2011) compared the effects of curvilinear (rounded) and rectilinear (straight edged) furniture on participants
- curvilinear furniture rated more positively in terms of happiness and approachability
