0HM310 - Automotive Human Factors Flashcards
What tasks does the driver perform in a multitask environment?
- Strategic tasks
- Tactical tasks
- Control tasks
The driving task is also defined by a series of component tasks
What are strategic tasks?
Focus on the purpose of the trip and the driver’s overall goals.
Many strategic tasks happen before the drivers gets into the car
* E.g. route planning, deciding when to go
What are tactical tasks?
Focus on the choice of maneuvers and immediate goals in getting to the destination.
They include speed selection, whether to pass another vehicle, and the choice of lanes.
What is PVAL
Primary Visual Attention Lobe
tracking control tasks has 2 dimensions:
Lateral tracking: the roadway curvature
* best performance measure is the time-to-line crossing (TLC)
* average amount of time before crossing the line given the current heading and distance from the
lane edge.
Longitudinal tracking: different channels
1. Flow of motion along the roadway
2. Location or distance of hazards
3. Traffic control devices
* Performance measure: Time-to-contact (2 s rule)
* distance divided by speed difference
Control tasks of driving
The lateral task of maintaining lane position can be thought of as a second-order control task.
* With preview (the roadway ahead).
* A predictor (the heading of the vehicle).
* constrained by the roadway curvature.
The longitudinal task is a first-order tracking task of speed keeping.
* The command input coming from internal goals (e.g., travel fast, but do not lose control; do not
get a ticket for speeding)
* or, external factors (behavior of other vehicles, hazards, traffic control signals in front)
What is automation
Automation refers to situations where a machine assumes a task that is otherwise performed by a human operator
Reasons for automation?
- Impossible or hazardous tasks (e.g., special needs population)
- Difficult or unpleasant tasks (e.g., vigilant monitoring)
- Extending human capabilities (e.g., memory aids)
- Cost reduction (e.g., automated phone menus
How to represent automation?
One way of representing automation is by the amount of human information processing it replaces (Parasuraman et al. 2000)
4 stages of automation:
- Information acquisition, selection and filtering
* Detection/monitoring (e.g., oil light) - Information integration (e.g., route planning)
- Action selection and choice (e.g., collision avoidance system)
- Control and action execution (e.g., cruise control)
Levels of car automation
5
Human Factors issues pt1
- Relation Driver/User – Vehicle:
* Trust (Reliability), Control, Convenience/Usability
* (“Do I still need to do something?”), Experience,
* Acceptance of behaviour - Relation Vehicle – Environment
* Trust (Reliability), Predictability of behaviour,
* Acceptance of behaviour - Societal level
* Technology acceptance - Reliability
* System may be at fault (i.e., actually unreliable)
* Automation may be inappropriate for certain situations (e.g., cruise control while driving downhill)
* User may incorrectly set up or use the system
* Poor understanding of automation by users
* automation induced surprises - Calibration of trust in automation
* Mistrust - not related to reliability
* Distrust – related to reliability
* Overtrust/ complacency – overreliance on automation
* Detection (vigilance)
* Situation awareness
* Skill loss
Human factor issues pt2
- Workload and situation awareness
- Loss of arousal (e.g., driving at night)
- Lack of appropriate training and certification
- Loss of human cooperation
- Driving satisfaction (book: job satisfaction)
What is workload underload?
Vigilance (=waakzaamheid) and Underarousal
Sustained attention in low-arousal environments can be just as fatiguing as high-workload situations
causes of vigilance decrement
- Time: long duration increases miss rate
- Event salience: subtle events show larger
miss rate - Signal rate: infrequent events are more
effortful to monitor - Arousal level: infrequent events are less
stimulating and arousal falls- Enhanced by sleep deprivation
Vigilance remediation
- Watches should not be too long
- Frequent breaks
- Enhance salience of signals (signal enhancement)
- Alter detection criteria by providing large rewards
- Increasing signal expectancy
* Deliberately include false signals - Increase level of arousal
* Coffee
* Concurrent non-interfering tasks (music, conversation)
* Prevent sleepiness
* Movements (chewing gum)
What is bad automation
- Automates easy tasks, but makes complicated tasks more difficult
- It negatively impacts human performance (skill loss)
- It fails in difficult situations, not easy ones
- It is not either/or between human and system (function allocation)
What is Human-centred automation?
- Automation to support and complement humans
- Shared roles and responsibilities
- Keeping the human informed
* Relevant and timely information
* Keep human up-to-date as to the automated actions - Keeping the human trained
* Train for system failure - Keeping the operator in the loop
* Some level of involvement (e.g. veto) will keep human involved and appraised - Selecting appropriate stages and levels of automation when automation is imperfect
* Imperfection at higher stages more likely to be harmful - Making automation flexible and adaptive
* Dynamic automation, tailored to task demands and operator load
What is situation awareness? & how to measure it
– Perception, comprehension & future projection of elements in environment
– SAGAT questionnaire (Endsley, 1998a), RT, time-to-learn a system …
What happens at night?
- Rod vision
- loss of colour
- loss of contrast sensitivity
- Loss of spatial acuity
Visibility Issues - Signage
- Minimize visual clutter from unnecessary signs.
- Locate signs consistently.
- Visibility issues can become amplified by deficiencies in the eyesight of the viewer.
Human visual system
- Visual acuity and visual search are important for reading. Human performance mostly depends on the optics and retina of the human eye
- Spatial vision & Contrast sensitivity explains reasons for glare and night vision.
- Depth perception explains mechanisms underlying estimates of distance
Optics of the eye
- Light enters the Cornea
* strong refraction (48D) - Balance intensity/focus regulated by iris
* pupil diameter
* emotional state - Image is focused by Lens
* Accomodation - ciliary muscles change the shape of the lens - Photosensitive layer is called the Retina
The retina exists out of….?
120 Million rods
* High sensitivity (night vision)
* Rods: no colour
* Parafovea/Periphery
* Scotopic (night vision)
* very sensitive for blue/green light
* blue LEDS are blinding the rods at dusk/night !!!
* insensitive to red light
* red print will look black at dusk !!!
6 Million Cones
* Lower sensitivity (daylight vision)
* L, M and S cones: Colour vision
* Fovea
* Photopic (daylight vision)
Visual search - Saccadic eye movements
Saccadic eye movements
* Fast, jerky eye movements (up to 900 deg/s!)
* Very stereotypic velocity profile
* Brings fovea to region of interest
serial search
parallel search
Limitation of eyes
Fovea: High acuity in small (5 deg) region
* Displays that require high acuity draw attention away from Primary Visual Attention Lobe
(PVAL)
Eye movements to scan large areas with high acuity
* Search time increases with # items (serial search)
* Colour/Shape can make items pop out (parallel search)
michelson contrast (contrast sensitivity)
C = Lmax-Lmin/Lmax+Lmin
Spatial acuity is crucial for reading print
- 3 cycles/degree
- stroke width > 1/6 degree visual angle
- Maximise lightness contrast
- Avoid isoluminant colours
* black on red (red looks black at low light levels) - Avoid negative contrast
- Avoid unusual shapes, orientations etc.
Depth Cues
- Occlusion (interposition)
- Retinal Size
- Perspective
- Familiarity
- Height in picture
- Blur
- Brightness
- Colour
- Shadow
- Motion parallax
- Stereo vision (disparity)
Limitations of judging depth
- Robust; monocular and binocular
- Binocular vision not very effective beyond 5m
It is natural for the brain to combine multiple cues - Displays using multiple cues are easier to
* Detect
* Discriminate
Accommodation
* Cannot see sharp both at nearby and far distances
* Very important for display design!
* Age > 50 : eye no longer accommodates
* Bifocal or multifocal glasses
Motion on the retina can be due to:
- Object motion
- Self-motion (Eye, Head, Body)
What is optic flow
Self-motion evokes different whole-field retinal motion
patterns
* Translation (left/right)
* Expansion (forward)
* Compression (backward)
This is called optic flow
Limitations of motion detectors/optic flow and velocity perception
Motion detectors in the visual system detect motion
* Motion After Effect (MAE) when motion stops
Optic flow is the motion pattern on the retina due to self-motion
* used to extract heading information
* Used for distinguishing self-motion from object motion
Velocity perception
* Is detected directly (not derived from distance estimates)
* People adapt to high speeds
* Underestimation of velocity due to adaptation
* MAE makes it worse: for example, when leaving high-way!
What is haptics
Haptics literally determines the “feel” of the car.
Haptics is also useful for displaying information
* Haptic displays (e.g. vibrating car seat, force-feedback accelerator pedal
what is Anthropometry?
the scientific study of the measurements and proportions of the human body.
Seating: range of body postures, adequate eye position (visibility)
Reachability: controls
Designing for the “mean” is not appropriate
* provide flexible options for seating adjustment, etc
What is haptic perception?
Haptic perception is to sense an object’s properties trough touch, proprioception and
kinesthesis
* They are all part of the somatosensory system
Haptics can detect many features of objects like shape, texture, hardness, mass, weight,
temperature, etc.
Design issues:
* Touchscreens do not provide haptic feedback of keypresses
* In virtual reality it is extremely hard to provide realistic haptic feedback
* Tactile feedback can help discriminate controls
* Tactile feedback can off-load visually demanding tasks
What is the Somatosensory System
Touch:
* physical properties of surfaces, such as texture, warmth, and softness
Nociception:
* Pain, tingling sensation, heat and cold
Proprioception:
* position of body parts
Kinesthesis:
* movement of body parts
Two-point acuity
Spatial accuracy
The two-point threshold for any part of
the body is determined by the size of the
receptive fields and the extent of overlap
Vestibular system
Concerned with equilibrium
Provides information about position of head in space, angular acceleration and linear acceleration
Sensory receptors located in inner ear
Damage may result in imbalance, circling, head tilt, vertigo and nausea
Physiology of the vestibular system
Otolith organs
* Linear acceleration
* Gravitation
Semicircular canals
* Angular acceleration
* One canal for rotation axis
Main functions
* Maintain balance
* Stabilise retinal image
* Compensate for head movements
Motion sickness + remedies
It is caused by the mismatch between visual and vestibular signals.
Remedies: prevent cue conflict by:
* Reducing linear and angular accelerations
* Look outside in the direction of movement
Artifacts should be designed to support
- Perception of relevant system variables (situation awareness)
- Cognition: Facilitate further processing of information
- Facilitate formation of task and context appropriate abstractions and concepts
- Facilitate integration of information
Type of displays
- static, eg road signs
- multimodal:
- visual, eg “idiot lights” in cars
- auditory, eg siren of ambulance
- haptic (touch), eg vibrate mode
- smell, eg added smell to natural gas
- etc.
Principles of display design
- Perceptual operations
- Make displays legible and audible
- Avoid absolute judgement limits
- Facilitate top down processing by providing context
- Redundancy gain
- Discriminability
- Mental model
- Principle of pictorial realism
- Principle of moving parts
- Human attention
- Minimizing information access cost
- Proximity compatibility principle
- Principle of multiple resources:
- Human memory
- Replace memory with visual information
- Predictive aiding:
- Consistency
(dis)advantages of head-up displays
- Advantages:
– Parallel processing of far-domain (environment) and near-domain (instrumentation) information
– Conformal displays allow mapping onto environment (e.g., schematic runway, or horizon) – supports divided attention
– Collimated imagery allows eyes to maintain accommodation at optical infinity – more relaxed viewing - Disadvantage
– Creation of visual clutter
* Legibility of image
* Visibility of environment
Function of displays
- Explain identity or function
- e.g. text labels
- Alerting
- e.g. lane departure warning
- Monitoring displays
- e.g. speedometer
How should you design Alerting displays?
Critical alerts: omnidirectional audio signal (e.g., fire alarm)
Levels of criticality
* Warnings: salient auditory alert
* Cautions: softer auditory alert
* Advisories: purely visual
Redundancy principle: vision + audition
Discriminability: e.g., color coding
4 key design criteria of Labels
label = Static displays signaling the identity or function of an entity
Four key design criteria:
– Visibility/ legibility
– Discriminability
* Avoid negatives (e.g., “no exit”)
– Meaningfulness
* Foreign language
* Unknown abbreviations or icons
– Location: close to the entity they label
Display layout: design guidelines
- Frequency of use
- Importance of use
- Display relatedness / sequence of use
- Consistency
- Organisational Groupings
- Stimulus-response compatibility
- Clutter avoidance
four main tasks of navigation displays and maps
- Provide guidance to destination
- Facilitate planning
- Help recovery when becoming lost
- Maintain situation awareness
Different types of displays
– Route lists and command displays
– Maps
–Static or dynamic
–2D or 3D
Requirements for maps
- Legibility
- Clutter and overlay
– Tradeoff between clarity and detail
* Smart color coding
* Highlighting
* Declutter: higher mental load - Position representation
– location and orientation of traveler - Map orientation
– North up: facilitates planning and communication
– Viewer direction up: pictorial realism facilitates situation awareness
Scale & 3D in maps
Scale
– Adjustable scale (electronic maps)
– Dual maps
– 3D Perspective maps: more detail nearby than far away
“3D” maps (perspective maps)
– Enhanced pictorial realism: landmarks, terrain
– Facilitates situation awareness
– Not very useful for planning
Sound Properties
Physical properties
* Sound pressure level
* Amplitude
* Frequency
Perceptual properties
* Pitch
* Loudness
* Duration
* Timbre
Harmonic sounds
Complex tones consisting of the sum of sinusoids with frequencies that are integer multiples
of the fundamental frequency f0
pitch
Pitch is a property of a harmonic, more or less periodic signal, i.e. the sound consists of pure sinusoids with frequencies that are all integral multiples of a common fundamental frequency.
aka high freq -> high pitch, vice versa
Loudness
Loudness is a perceptual property which we attribute to a perceived sound source.
Loudness is perceived as an attribute that can be ordered from soft to hard.
The presence of other sounds can affect the loudness of a sound source. This is called masking
Restauration
The intensities of only a few partials must be 15 to 20 dB above masking level.
Pitch is one of the most robust perceptual attributes of a sound.
But there is more, if the auditory system has evidence that information of the sound signal is masked, it can restore the information
Human factors issues of auditory displays
- Detectability, audibility
- Identifiability
- Discriminability
- Localizability
- Perceived urgency
- Annoyance
- Startle responses
- Interference with human communication
- Timing
- False alarm
- Number
Audibility
The level of a frequency component of a warning signal does not have to be much higher than 15 dB above its masking level.
Selective attention - Four factors determine what we attend to:
Attention is limited. Four factors determine what we attend to:
– Salience (colors, warning signals)
– Effort
– Expectancy
– Value
What is effort wrt attention?
Effort is modelled as moving attention from one Area of Interest to another, assuming that such effort is monotonically related to the distance between AOIs, in Wickens’ Attention-Situation Awareness Model.
what is expectancy wrt attention?
The frequency with which events or changes occurred to information contained within the
Area of Interest.
Certain cues are expected by a mental model of a given situation.
what is Vigilance
Vigilance, a state of readiness to respond despite long intervals of empty waiting.
The focus is more strongly on lapses of attention.
Most common paradigm is the Psychomotor Vigilance Task (PVT).
what is phonological loop
represents verbal information in an acoustical form
What is visuospatial sketchpad ?
The visuospatial sketchpad holds information in an analog spatial form (e.g., visual imagery)
What is The episodic buffer?
The episodic buffer orders and sequences events and communicates with long-term memory to provide meaning to the information held in the phonological loop and visuospatial sketchpad.
enables a meaningful sequence of events—a story—to be remembered much more easily than an unordered sequence
What is the difference between Schemas and scripts
The knowledge structure about a particular topic is often termed a schema.
Schemas that describe a typical sequence of activities, are called scripts.
why is the concept of a mental model useful?
(a) guiding attention to relevant aspects of the situation,
(b) a means of integrating information perceived to form an understanding of its meaning, and
(c) a mechanism for projecting future states of the system based on its current state and an understanding of its dynamics.
steps of decision making
- Acquire and integrate a number of cues, or pieces of information, which are received from the environment and go into working memory.
- Interpret and assess cues and then use this interpretation to generate one or more situation assessments, diagnoses, or inferences as to what the
cues mean. - Plan and choose one of alternative actions
- Monitor and correct the effects of decisions.
Perception – Cognition - Action
Tasks:
* Perceive the objects and events in the world
* Reason about their relevance to your goals and current activity
* Determine action and act accordingly
Information Processing System Stages of Information Transformation
Sensation: transform of physical into neural energy
Perception: comprehension of information in the environment
Central processing: transforming and remembering the information
Responding: behavior production
What is inattentional blindness
Conspicuous objects in the field-of-vision are seen but NOT perceived (i.e., sensation vs. perception)
Reason:
AQenMon is focused on something else.
Stressors
Stressors: Influences on information processing not inherent in the
information itself
Environmental (Physical) stressors
– Noise
– Vibration
– Heat
– (Dim) lighting
Psychological stressors
– Anxiety
– Fatigue
– Frustration
– Anger
Stressors can be direct or indirect
- Direct effects influence quality of information received by receptors, or the output of the response
- Indirect effects influence information processing
Stressor effects
- Psychological experience
- Change in physiology
- Efficiency of information processing
- Long-term health effects
Psychological stressors:
- analysis of likely circumstances of emergency and actions
- design of displays, controls and procedures
– easy to locate and salient
– prevent cognitive tunneling (but see HuD) - actions should not rely on working memory
– place knowledge in the world (symbols, labels, manuals, …) - explicit instructions of emergency actions
- compatibility with conventional action patterns
- avoid excessive stimulation (auditory, visual, tactile, …)
- extensive training
– long-term instead of working memory
– learning how to respond (overlearn appropriate responses)
Psychological stressors: life stress
- remove source
- implement stress management programs
- provide individual counseling
– Note that many people who suffer life stress cope extremely
well on the job
Challenging factors to derive workload estimates:
- Identification of task times
– include covert tasks: planning, diagnosis, rehearsing, … - Scheduling and prioritization
– postpone overloading tasks - Task resource demands and automaticity
– not all tasks are equally demanding
* automation
– estimate resource demands - Multiple resources
– task interference depends
on shared resources
remedies for overload working (tr/ta >0.8/1)
- task redesign: automation, reassigning tasks to others
- improve displays and controls
- Training of component tasks
- Training in task management skills
Cognitive task load methods
Level of information processing: Cognitive demands.
– skill-based level, information is processed automatically
– rule-based level, input information triggers routine solutions
– knowledge-based level, based on input information the problem is analysed and solution(s) are planned
Causes of vigilance decrement
- Time: long duration increases miss rate
- Event salience: subtle events show larger
miss rate - Signal rate: infrequent events are more
effortful to monitor - Arousal level: infrequent events are less
stimulating and arousal falls
* Enhanced by sleep deprivation
Vigilance remediation
– Watches should not be too long
– Frequent breaks
– Enhance salience of signals (signal enhancement)
Causes of Fatigue
– High mental workload
– Prolonged period of performance
(cumulative buildup)
– Prolonged period of vigilance (doing “nothing”)
– Sleep loss
Three important factors for sleep disruption
- Sleep loss (less than 7-9 hours of sleep a night)
- Performance at low point of circadian rhythm (early morning)
* 4 of the largest nuclear power plant disasters occurred in the morning shift - Disruption of circadian rhythm (jet lag, shift work)
Circadian Rhythm
Circadian Rhythm (= day-night rhythm)
– Effects of sleep loss and circadian cycle are additive
Strategies to tackle circadian rhythm
- Shift work strategies to deal with circadian disruption
– Assign workers permanently to different shifts - Not effective when some natural day-night rhythm remains
- Social acceptance is low
– Continuous rotation of shifts - No chance to fully adapt
– Infrequent rotation of shifts - Particularly vulnerable on first (night) shift after a change
- Delayed shifts are more effective than the other way around
- Longer shifts (10 or more hours) cause more errors
or
More sleep:
– Napping (>15min),
* But sleep inertia 8-10 minutes after waking, so wake
watch keepers 10 minutes before duty.
– Sleep credits
* Extra sleep before mission
– Sleep management
* Combination of above, supported by organization
– Caffeine
* not effective in the long run
* Not able to sleep when there is time to sleep
Menu’s
Users are faster in selecting items from a menu that has a small number of options, than from one with a larger number
What are the design steps for interaction:
- Eliminate interfaces where possible
- Make interfaces as natural as possible
- Adapt to people (don’t expect people to adapt)
What is affect, emotion and mood?
Affect is the general term for the judgmental system.
Emotion is the conscious experience of affect, often attributable to a specific source
Mood or a longer lasting emotional state, less specific and less intense.
What is cognitive appraisal?
It is the interpretation of the personal meaning of
current circumstances that results in emotion
Affective design
Affective responses are mainly determined by
Feeling (Affect)
*Implicit evaluations
*Explicit evaluations
Usability (Behavior)
*Effectiveness
*Efficiency
*Satisfaction
Expectations (Cognition)
*Goals
*Utility
What is Antropomorphism
Anthropomorphism is the attribution of
uniquely human characteristics to non-human
creatures and beings, natural and supernatural
phenomena, material states and objects or
abstract concepts.
Pareidolia
a psychological phenomenon involving a vague
and random stimulus (often an image or
sound) being perceived as significant.
