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BCPE CPE practice questions

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Question 1Human Factors/Ergonomics (HF/E) professional knowledge

Which type of anthropometric data is most appropriate when designing a doorway height that must accommodate nearly all users?

  1. A high percentile of stature, such as the 95th Correct answer.
  2. The mean stature plus one standard deviation
  3. A low percentile of stature, such as the 5th
  4. The 50th percentile of stature

Explanation

For clearance dimensions where the body must fit through or under a space, designers use a large percentile (often the 95th) so that most of the population is accommodated. Using a small percentile would exclude taller users and cause interference.

Question 2Human Factors/Ergonomics (HF/E) professional knowledge

A workstation is being designed so that a small-statured operator can reach controls at the front of the work surface. Which percentile of arm reach should guide the placement?

  1. The 95th percentile of reach
  2. The 50th percentile of reach
  3. A low percentile of reach, such as the 5th Correct answer.
  4. The maximum recorded reach in the database

Explanation

Reach requirements are limiting dimensions: the design should suit the smallest users so that everyone can reach the controls. A low percentile such as the 5th is the conventional choice for reach envelopes.

Question 3Human Factors/Ergonomics (HF/E) professional knowledge

In NIOSH lifting equation terms, which factor primarily reflects how far the load is held from the body?

  1. The horizontal distance multiplier Correct answer.
  2. The coupling multiplier
  3. The frequency multiplier
  4. The asymmetry multiplier

Explanation

The horizontal multiplier accounts for the distance between the load and the body's midpoint, since holding a load farther away increases spinal compressive forces. Frequency, asymmetry, and coupling are separate multipliers addressing different stressors.

Question 4Human Factors/Ergonomics (HF/E) professional knowledge

Which principle best describes Fitts's law as applied to control and display design?

  1. Error rate rises linearly with the number of display elements
  2. Reaction time is independent of stimulus complexity
  3. Movement time depends only on the mass of the limb being moved
  4. Movement time increases as target distance increases and target size decreases Correct answer.

Explanation

Fitts's law states that the time to acquire a target is a function of the ratio of distance moved to target width. Larger, closer targets are acquired faster and with fewer errors than small, distant ones.

Question 5Human Factors/Ergonomics (HF/E) professional knowledge

A warning label is printed in very small type on a low-contrast background. According to signal detection and attention principles, what is the most likely consequence?

  1. The signal-to-noise ratio will be reduced and detection probability will fall Correct answer.
  2. The signal will be detected more quickly because less visual scanning is required
  3. The label will be perceived as more urgent
  4. Operators will compensate by increasing their vigilance indefinitely

Explanation

Legibility depends on the ratio of the signal (the text) to background noise. Small, low-contrast text lowers this ratio, reducing the probability that an observer detects and reads the warning.

Question 6Human Factors/Ergonomics (HF/E) professional knowledge

Which lighting condition is most likely to produce glare that impairs performance at a computer workstation?

  1. A bright unshielded window directly behind the monitor Correct answer.
  2. Diffuse overhead lighting with luminance below the recommended level
  3. Indirect lighting reflected off the ceiling
  4. Task lighting aimed at the document holder from the side

Explanation

A bright source in the field of view, such as an unshielded window behind the monitor, creates discomfort and disability glare that reduces contrast and visibility. Positioning light sources away from the line of sight and shielding them reduces glare.

Question 7Human Factors/Ergonomics (HF/E) professional knowledge

Which is the best example of a forcing function in interface design?

  1. A confirmation dialog that can be dismissed with a single keypress
  2. A physical interlock that prevents a machine from starting until a guard is closed Correct answer.
  3. A tooltip that explains a button's function
  4. A color-coded status indicator on a dashboard

Explanation

A forcing function constrains behavior so that a required step must be completed before the next action can occur. A physical interlock that blocks operation until a guard is closed is a classic forcing function.

Question 8Human Factors/Ergonomics (HF/E) professional knowledge

Which statement best characterizes the concept of affordance in human factors?

  1. An affordance is a measure of system reliability
  2. An affordance is a property of an object that suggests how it can be used Correct answer.
  3. An affordance is the cost of training a new operator
  4. An affordance is a written instruction for operating a device

Explanation

Affordances are perceived properties of objects that indicate possible actions, such as a handle suggesting pulling. They help users understand how to interact with a device without explicit instruction.

Question 9Human Factors/Ergonomics (HF/E) professional knowledge

A control panel uses a rotary knob for continuous adjustment and a push button for a discrete on/off action. Which design principle does this best illustrate?

  1. Stimulus-response compatibility Correct answer.
  2. Hick's law
  3. Redundancy gain
  4. Vigilance decrement

Explanation

Stimulus-response compatibility means the control's movement or type maps naturally onto the effect it produces. A continuous rotary control for continuous adjustment and a discrete press for an on/off action are natural mappings.

Question 10Human Factors/Ergonomics (HF/E) professional knowledge

Which factor most strongly increases the risk of a vigilance decrement during a monitoring task?

  1. Low signal probability over a long period Correct answer.
  2. High ambient illumination levels
  3. Frequent, salient changes in the monitored signal
  4. Short task duration with regular breaks

Explanation

Vigilance decrement is greatest when signals are rare and the monitoring period is long, because sustained attention is difficult to maintain under low event rates. Increasing signal salience or providing breaks tends to reduce the decrement.

Question 11Human Factors/Ergonomics (HF/E) professional knowledge

In a short-term memory task, an operator must recall a seven-digit code after a ten-second delay. Which factor is most likely to cause forgetting?

  1. Proactive interference from prior similar codes Correct answer.
  2. Reduction in sensory receptor sensitivity
  3. Increase in long-term memory capacity
  4. Decrease in the number of items presented

Explanation

Proactive interference occurs when previously learned material disrupts recall of new material, which is common when similar codes are presented repeatedly. Short-term retention is especially vulnerable to this interference.

Question 12Human Factors/Ergonomics (HF/E) professional knowledge

Which measure is a direct index of mental workload based on the assumption that a person has limited information-processing capacity?

  1. Heart rate variability at rest
  2. Number of years of operator experience
  3. Machine mean time between failures
  4. Subjective ratings from a validated workload scale Correct answer.

Explanation

Subjective workload scales such as the NASA-TLX ask operators to rate perceived effort and demand, directly indexing the load placed on limited processing resources. Physiological and performance measures can supplement these ratings.

Question 13Human Factors/Ergonomics (HF/E) professional knowledge

Which design change best reduces the likelihood of a postural stress injury in a repetitive assembly task?

  1. Requiring operators to wear heavier protective gloves
  2. Adjusting the work height and reach distance to keep joints in neutral postures Correct answer.
  3. Adding more visual displays near the workstation
  4. Increasing the required work pace to shorten exposure time

Explanation

Neutral joint postures reduce biomechanical stress on muscles, tendons, and joints during repetitive work. Adjusting work height and reach distance to match the operator is a core ergonomic intervention.

Question 14Human Factors/Ergonomics (HF/E) professional knowledge

A worker repeatedly performs a forceful pinch grip with the wrist deviated. Which musculoskeletal disorder is most specifically associated with this exposure pattern?

  1. Noise-induced hearing loss
  2. Contact dermatitis
  3. Carpal tunnel syndrome Correct answer.
  4. Lower back disc herniation

Explanation

Carpal tunnel syndrome is associated with repeated forceful gripping and awkward wrist postures that compress the median nerve at the wrist. Reducing force and maintaining a neutral wrist are key preventive measures.

Question 15Human Factors/Ergonomics (HF/E) professional knowledge

Which statement about the human information-processing stages is most accurate?

  1. Perception, decision making, and response selection occur simultaneously with no sequential dependency
  2. Sensory input is filtered and interpreted before a response is selected and executed Correct answer.
  3. Response execution always precedes stimulus identification
  4. Decision making occurs before sensory registration

Explanation

Information processing is commonly modeled as a sequence in which stimuli are sensed, perceived and interpreted, then a response is selected and executed. This staged view explains why perception and response selection can each become bottlenecks.

Question 16Human Factors/Ergonomics (HF/E) professional knowledge

Which technique is most appropriate for analyzing the cognitive demands of a complex control-room task before errors occur?

  1. Vibration exposure measurement
  2. Cognitive task analysis Correct answer.
  3. Spirometry testing
  4. Time-and-motion study

Explanation

Cognitive task analysis elicits the knowledge, decision rules, and strategies experts use, revealing where cognitive demands and error-likely situations arise. It is suited to complex tasks where the work is largely mental rather than physical.

Question 17Human Factors/Ergonomics (HF/E) professional knowledge

Which is the primary purpose of a human error taxonomy such as skill-, rule-, and knowledge-based classification?

  1. To assign blame to individual operators
  2. To determine the legal liability of a manufacturer
  3. To identify the cognitive level at which an error occurred so controls can be targeted Correct answer.
  4. To calculate the financial cost of an accident

Explanation

Classifying errors by the cognitive level involved (skill, rule, or knowledge) helps analysts understand why an error happened and design controls suited to that level. For example, skill-based slips call for different interventions than knowledge-based mistakes.

Question 18Human Factors/Ergonomics (HF/E) professional knowledge

In a system where a single operator must monitor several automated subsystems, which phenomenon is most likely when automation fails silently?

  1. Increased manual control proficiency
  2. Reduced vigilance because automation is reliable
  3. Improved situation awareness from automation
  4. Complacency leading to delayed detection of the failure Correct answer.

Explanation

Highly reliable automation can foster complacency, so operators monitor less actively and may detect failures slowly, especially when failures are silent. This is a well-documented cost of automation that designers must counter with salient feedback.

Question 19Human Factors/Ergonomics (HF/E) professional knowledge

Which design approach best supports situation awareness in a dynamic supervisory task?

  1. Removing all alarms to reduce clutter
  2. Integrating key parameters and trends into a coherent overview display Correct answer.
  3. Displaying only the current sensor value for each subsystem
  4. Requiring operators to query each subsystem individually

Explanation

Situation awareness depends on perceiving, comprehending, and projecting system states. Integrated displays that show key parameters, trends, and relationships help operators build an accurate global picture.

Question 20Human Factors/Ergonomics (HF/E) professional knowledge

Which factor is the most important determinant of legibility of text on a visual display?

  1. The contrast between text and background Correct answer.
  2. The number of words on the screen
  3. The font family chosen for the text
  4. The color of the display bezel

Explanation

Contrast between characters and their background is the dominant factor in legibility, followed by character size and viewing conditions. Without adequate contrast, even well-chosen fonts are difficult to read.

Question 21Human Factors/Ergonomics (HF/E) professional knowledge

A control room uses a red indicator for both 'system running' and 'critical fault'. Which design principle is violated?

  1. Redundant coding
  2. Population stereotype consistency
  3. Color coding consistency Correct answer.
  4. Proximity compatibility

Explanation

Color coding should be used consistently so that each color has a single meaning. Using red for both normal running and a critical fault creates ambiguity and can lead to dangerous misinterpretation.

Question 22Human Factors/Ergonomics (HF/E) professional knowledge

Which statement best describes the relationship between illumination level and visual performance for most office tasks?

  1. Performance is unrelated to illumination level
  2. Performance is best in near-darkness to reduce glare
  3. Performance improves up to a point, after which glare and adaptation costs may offset gains Correct answer.
  4. Performance improves indefinitely as illumination increases

Explanation

Visual performance generally improves with illumination up to a moderate level, but excessive brightness can produce glare and discomfort that offset the benefit. Designers target recommended ranges rather than maximizing light.

Question 23Human Factors/Ergonomics (HF/E) professional knowledge

Which approach is most consistent with participatory ergonomics?

  1. Managers select interventions without consulting the workforce
  2. Ergonomic changes are implemented only after injuries occur
  3. Workers help identify problems and design and evaluate solutions Correct answer.
  4. External consultants make all decisions independently

Explanation

Participatory ergonomics involves the people doing the work in identifying hazards and shaping solutions, which improves fit and acceptance. It draws on workers' practical knowledge of the tasks.

Question 24Human Factors/Ergonomics (HF/E) professional knowledge

A task requires the operator to make a rapid choice among eight equally likely signals. According to Hick's law, how does reaction time change as the number of choices increases?

  1. It increases exponentially with the number of choices
  2. It increases logarithmically with the number of choices Correct answer.
  3. It decreases linearly with the number of choices
  4. It remains constant regardless of the number of choices

Explanation

Hick's law states that choice reaction time increases as a logarithmic function of the number of equally likely alternatives. Doubling the choices adds a roughly constant increment rather than doubling the time.

Question 25Human Factors/Ergonomics (HF/E) professional knowledge

Which is the most appropriate first step when applying a hierarchical task analysis to an existing procedure?

  1. Define the overall goal and decompose it into subordinate subgoals and operations Correct answer.
  2. Immediately record every keystroke made by the operator
  3. Purchase new equipment to simplify the task
  4. Calculate the cost of each task step

Explanation

Hierarchical task analysis begins with the top-level goal and breaks it into subgoals, operations, and plans that describe how the steps are sequenced. This structure provides the basis for identifying problems and redesign options.

Question 26Human Factors/Ergonomics (HF/E) professional knowledge

Which anthropometric approach is most appropriate for sizing a seat pan that must accommodate a broad range of operators?

  1. Use the 5th percentile female dimension as the upper limit Correct answer.
  2. Use the 50th percentile of the combined population
  3. Use the 95th percentile male dimension as the upper limit
  4. Use the maximum recorded value from the sample

Explanation

For a clearance dimension that constrains the body, designers use a small percentile so most users still fit; for a reach dimension they use a large percentile. A seat pan depth that is too long for smaller users causes pressure behind the knee, so the 5th percentile female value sets the limit. Percentile choice follows whether the dimension is a clearance or a reach constraint.

Question 27Human Factors/Ergonomics (HF/E) professional knowledge

A workstation requires sustained overhead work. Which change most directly reduces the shoulder load imposed by this posture?

  1. Increase the reach distance to the work surface
  2. Increase the pace of the task to shorten exposure
  3. Add wrist supports to the tool handle
  4. Lower the work surface or bring the task within shoulder height Correct answer.

Explanation

Shoulder elevation during overhead work raises the gravitational moment arm at the glenohumeral joint and compresses subacromial structures. Bringing the work closer to shoulder height or below reduces that moment and the static load on the shoulder elevators. Wrist supports and pacing changes address other factors and do not remove the elevated-arm posture.

Question 28Human Factors/Ergonomics (HF/E) professional knowledge

Which metric is the standard basis for computing the NIOSH lifting equation's recommended weight limit?

  1. The load constant multiplied by six task-specific multipliers Correct answer.
  2. The worker's self-reported rating of perceived exertion
  3. Peak spinal compression measured by a force plate
  4. The total mass lifted summed over the whole shift

Explanation

The revised NIOSH lifting equation starts from a load constant of 23 kg and applies multipliers for horizontal distance, vertical location, travel distance, asymmetry, coupling, and frequency. The result is a recommended weight limit for a defined two-handed manual lift. It is a multiplicative model, not a direct measurement of spinal compression or a subjective rating.

Question 29Human Factors/Ergonomics (HF/E) professional knowledge

Which statement best describes the purpose of a thermal comfort standard such as ISO 7730?

  1. It sets the required air exchange rate for occupied buildings
  2. It defines the maximum noise level permitted in offices
  3. It specifies the maximum permissible core body temperature for work
  4. It predicts the thermal sensation and predicted percentage dissatisfied from environmental and personal variables Correct answer.

Explanation

ISO 7730 uses the predicted mean vote and predicted percentage dissatisfied models to relate air temperature, radiant temperature, humidity, air velocity, clothing, and metabolic rate to occupant thermal sensation. It is a comfort model, not a heat-stress exposure limit. Heat-stress limits and ventilation rates are addressed by other standards.

Question 30Human Factors/Ergonomics (HF/E) professional knowledge

An operator must detect a rare signal among frequent background events over a two-hour session. Which intervention is most likely to sustain detection performance?

  1. Increasing the background event rate while keeping the signal unchanged
  2. Making the signal more distinctive and providing feedback on detections Correct answer.
  3. Extending the session without breaks to build tolerance
  4. Removing all automation from the monitoring station

Explanation

Vigilance performance deteriorates with time on task, especially when signals are rare and hard to discriminate. Increasing signal salience and giving knowledge of results are well-supported countermeasures because they support both perceptual discrimination and sustained attention. Simply extending exposure or increasing event load generally worsens the decrement.

Question 31Human Factors/Ergonomics (HF/E) professional knowledge

Which measure is most commonly used as a physiological index of mental effort during cognitive task performance?

  1. Grip strength
  2. Skin temperature of the forearm
  3. Body mass index
  4. Pupil diameter change Correct answer.

Explanation

Task-evoked pupillary responses track cognitive effort and are widely used as a physiological workload index because pupil dilation increases with processing demand. Grip strength, forearm skin temperature, and body mass index are not established indices of momentary mental effort. Physiological workload measures must be sensitive to changes over seconds to minutes.

Question 32Human Factors/Ergonomics (HF/E) professional knowledge

Which statement best captures the core premise of the ecological approach to interface design?

  1. Interfaces should display the invariant properties of the work domain that support skilled perception and action Correct answer.
  2. Interfaces should replace operator judgment with automated decision rules
  3. Interfaces should minimize the number of controls the operator can see
  4. Interfaces should present information in the smallest possible screen area

Explanation

The ecological approach holds that skilled performance depends on perceiving affordances and invariants in the environment, so displays should make those higher-order properties directly perceptible. The aim is to support perception-action coupling rather than to reduce visible controls or automate judgment. Interface design therefore focuses on what information is made available and how it maps to the domain.

Question 33Human Factors/Ergonomics (HF/E) professional knowledge

A display shows a trend line whose slope indicates whether a process is drifting toward a limit. Which display principle does this best illustrate?

  1. Redundant coding
  2. Color saturation coding
  3. Display inertia
  4. Predictive aiding through emergent features Correct answer.

Explanation

When a display is designed so that the relation between variables produces a directly perceivable feature such as slope, the operator can see the future state without mental extrapolation. This is an emergent feature that supports prediction. Redundant coding and color coding improve discriminability but do not by themselves convey future state.

Question 34Human Factors/Ergonomics (HF/E) professional knowledge

Which condition is most likely to cause an operator to miss a change in an automated system's mode?

  1. The mode change requires an explicit operator confirmation
  2. The mode change is announced by a distinct auditory alert
  3. The mode is displayed continuously in the primary visual field
  4. The mode indicator is small and located away from the operator's area of attention Correct answer.

Explanation

Mode errors arise when the operator's mental model of the system state diverges from the actual state, and inconspicuous, peripheral indicators make that divergence likely. Placing mode status in the primary visual field, alerting changes, and requiring confirmation all reduce the chance of mismatch. The vulnerability is greatest when feedback is weak or displaced.

Question 35Human Factors/Ergonomics (HF/E) professional knowledge

Which statement best describes the function of a population stereotype in control design?

  1. It is a statistical outlier in anthropometric data
  2. It is a legal requirement for control labeling
  3. It is a consistent expectation about how a control or display should behave, such as turning clockwise to increase Correct answer.
  4. It is a bias introduced by sampling error in usability testing

Explanation

Population stereotypes are widely shared expectations linking control movement to system response, such as clockwise rotation increasing a value. Designing to match them reduces errors and learning time. They are empirical regularities about expectations, not statistical artifacts or regulatory mandates.

Question 36Human Factors/Ergonomics (HF/E) professional knowledge

A control that must be operated quickly and accurately without looking, such as an emergency stop, is best distinguished by which design feature?

  1. A color identical to adjacent controls
  2. A shape that is tactually distinct from surrounding controls Correct answer.
  3. A label printed in small type
  4. A position inside a recessed panel

Explanation

When a control must be found and operated without vision, tactile shape coding lets the hand identify it by feel. Shape coding is therefore preferred for critical or blind-reach controls. Small labels and recessed placement hinder rapid location, and identical color removes a distinguishing cue.

Question 37Human Factors/Ergonomics (HF/E) professional knowledge

Which factor most strongly determines the effectiveness of a warning signal in a noisy industrial environment?

  1. The number of signals installed in the facility
  2. The signal's duration in milliseconds alone
  3. The signal's frequency content relative to the background noise spectrum Correct answer.
  4. The color of the housing around the signal device

Explanation

Audibility of a warning depends on the signal-to-noise ratio in the relevant frequency bands, so the signal must stand out from the background spectrum. A signal that shares the dominant noise frequencies will be masked regardless of duration. Housing color and device count do not determine whether the signal can be heard.

Question 38Human Factors/Ergonomics (HF/E) professional knowledge

Which statement best describes the relationship between noise exposure level and permissible exposure duration in occupational noise standards?

  1. Permissible duration is set only by the peak sound pressure
  2. Permissible duration halves for each 5 dB increase in level under the common exchange rate Correct answer.
  3. Permissible duration is independent of level once 85 dBA is exceeded
  4. Permissible duration doubles for each 3 dB increase in level

Explanation

Equal-energy principles underlie noise standards, and many use a 5 dB exchange rate under which allowable exposure time halves as level rises by 5 dB. Some jurisdictions use a 3 dB rate, which is a different rule. Peak limits apply in addition to, not instead of, the duration-level relationship.

Question 39Human Factors/Ergonomics (HF/E) professional knowledge

A worker must perform a precise visual inspection of small parts. Which lighting variable most directly affects the ability to resolve fine detail?

  1. The number of fixtures in the room
  2. The reflectance of the ceiling
  3. Illuminance on the task surface Correct answer.
  4. Correlated color temperature of the lamps

Explanation

Resolving fine detail depends on the amount of light reaching the task and on contrast, so task illuminance is the most direct controllable variable. Color temperature and fixture count influence appearance and distribution but not the light level at the task itself. Ceiling reflectance affects indirect light but is a secondary factor.

Question 40Human Factors/Ergonomics (HF/E) professional knowledge

Which approach best characterizes macroergonomics?

  1. Measuring muscle activity in a single repetitive task
  2. Optimizing a single workstation for one operator
  3. Analyzing and redesigning the sociotechnical system, including organizational and work-process factors Correct answer.
  4. Selecting employees based on physical strength

Explanation

Macroergonomics addresses the design of work systems as a whole, including organizational structure, work processes, technology, and the people within them. It is distinguished from microergonomics, which focuses on individual tasks and workstations. Sociotechnical system analysis is its characteristic method.

Question 41Human Factors/Ergonomics (HF/E) professional knowledge

Which indicator is most useful for detecting the early onset of a work-related musculoskeletal disorder in a surveillance program?

  1. Reports of symptoms and discomfort collected systematically from workers Correct answer.
  2. Number of grievances filed about scheduling
  3. Annual turnover rate of the department
  4. Average years of service in the plant

Explanation

Early detection relies on systematic symptom surveillance, since discomfort and early symptoms precede diagnosable injury. Turnover, grievances, and tenure are organizational indicators that do not track physical symptoms. Combining symptom reports with job exposure data strengthens the program.

Question 42Human Factors/Ergonomics (HF/E) professional knowledge

Which statement best describes the role of a job safety analysis in an ergonomics program?

  1. It replaces the need for injury records
  2. It measures only the physical dimensions of the workplace
  3. It breaks a job into steps and identifies hazards and controls for each step Correct answer.
  4. It is used solely to assign disciplinary responsibility for incidents

Explanation

A job safety analysis decomposes a task into sequential steps, identifies the hazards associated with each step, and specifies controls. It complements injury records and exposure measurements rather than replacing them. Its focus is hazard identification and control, not blame assignment.

Question 43Human Factors/Ergonomics (HF/E) professional knowledge

A firm wants to reduce the risk of falls on a loading dock. Which control follows the hierarchy of controls most appropriately?

  1. Require slip-resistant footwear
  2. Provide training on careful walking
  3. Post a warning sign at the edge
  4. Install a physical barrier at the dock edge Correct answer.

Explanation

The hierarchy of controls ranks elimination and engineering controls above administrative controls and personal protective equipment. A physical barrier removes or isolates the fall hazard at its source and is therefore the strongest option listed. Training, signage, and footwear depend on human behavior and are lower-order controls.

Question 44Human Factors/Ergonomics (HF/E) professional knowledge

Which statement about the human visual field is most accurate for display placement?

  1. Central vision provides high acuity while peripheral vision is sensitive to motion and change Correct answer.
  2. Acuity increases steadily toward the outer edges of the field
  3. Peripheral vision is best suited to fine acuity tasks
  4. The visual field is uniform in acuity across its entire extent

Explanation

Acuity is highest in the fovea and declines sharply with eccentricity, while peripheral vision is comparatively sensitive to motion and sudden change. Display design therefore places fine detail centrally and uses peripheral cues for alerts. Treating the field as uniform misrepresents both capabilities.

Question 45Human Factors/Ergonomics (HF/E) professional knowledge

An operator's performance improves when a second task is added, provided the two tasks use different processing resources. Which model does this observation support?

  1. The Yerkes-Dodson law
  2. A single-capacity resource model
  3. Signal detection theory
  4. Multiple-resource theory Correct answer.

Explanation

Multiple-resource theory proposes separate resource pools, for example by modality or processing stage, so tasks drawing on different pools interfere less than tasks sharing one. Improved dual-task performance with dissimilar resource demands is consistent with that prediction. Single-capacity models predict interference whenever total demand rises.

Question 46Human Factors/Ergonomics (HF/E) professional knowledge

Which statement best describes the purpose of a cognitive walkthrough?

  1. It measures the physical forces exerted on a worker during a task
  2. It estimates the metabolic cost of a job
  3. It records the frequency of incidents over a year
  4. It evaluates a design by stepping through task scenarios to find where users would fail to make progress Correct answer.

Explanation

A cognitive walkthrough is an inspection method in which analysts walk through representative tasks and ask, at each step, whether the user would know what to do and recognize progress. It targets learnability and discoverability of an interface. It is a qualitative analytic method, not a biomechanical or epidemiological measurement.

Question 47Human Factors/Ergonomics (HF/E) professional knowledge

Which statement best characterizes the concept of mental model in human-machine interaction?

  1. It is the automatic control algorithm embedded in the system
  2. It is the manufacturer's written operating manual
  3. It is the physical layout of controls on a panel
  4. It is the operator's internal representation of how a system works, used to predict its behavior Correct answer.

Explanation

A mental model is the operator's internal, often simplified, representation of system structure and behavior that supports prediction and diagnosis. Designers aim to make the system image consistent with plausible operator models. The manual and the control algorithm are external artifacts, not the operator's internal representation.

Question 48Human Factors/Ergonomics (HF/E) professional knowledge

In a fault-diagnosis task, an operator who has extensive experience with normal operation performs poorly when an unfamiliar fault occurs. Which explanation is most consistent with human factors research?

  1. The operator's experience supports routine pattern recognition but not reasoning about novel causal states Correct answer.
  2. The operator is experiencing a vigilance decrement
  3. The operator has lost all procedural knowledge
  4. The operator lacks the motor skills required for diagnosis

Explanation

Expertise built on frequent normal operation yields strong pattern-based skill but can leave operators without adequate knowledge-based reasoning for unfamiliar situations. This is a common finding in automated and complex systems. The problem is a mismatch between the demands of the novel fault and the operator's available knowledge, not a loss of all procedural skill or a motor deficit.

Question 49Human Factors/Ergonomics (HF/E) professional knowledge

Which design feature best supports recovery from an operator error in a control system?

  1. Hiding system state to reduce display clutter
  2. Increasing the number of similar-looking controls
  3. Removing all confirmation steps to speed operation
  4. Providing an undo or reversible action for consequential commands Correct answer.

Explanation

Reversibility allows an operator to detect and correct an erroneous action before it produces harm, which is a central principle of error-tolerant design. Confirmation steps and clear state information also support recovery. Removing safeguards or obscuring state makes errors harder to detect and correct.

Question 50Human Factors/Ergonomics (HF/E) professional knowledge

Which statement best describes the purpose of the NASA Task Load Index?

  1. It computes the metabolic energy expenditure of a job
  2. It yields a multidimensional subjective rating of workload across six factors Correct answer.
  3. It measures physical strength through a maximal exertion test
  4. It records eye movements during a tracking task

Explanation

The NASA Task Load Index collects subjective ratings on mental demand, physical demand, temporal demand, performance, effort, and frustration, then combines them using importance weights. It is a multidimensional subjective workload instrument. It is not a strength test, an eye-tracking method, or a metabolic calculation.