Introduction to Cognitive Ergonomics

Introduction to Cognitive Ergonomics: Comprehensive Notes

**1. Summary:**

This video provides an introduction to cognitive ergonomics, focusing on how the human mind interacts with the workplace. It explores cognitive limitations, human capabilities and limitations, the role of human senses, and various cognitive practices, with the goal of designing workplaces and systems that support human cognitive abilities and reduce errors, fatigue, and mental overload. The video emphasizes the application of these principles in production environments.

**2. Key Takeaways:**

* **Cognitive ergonomics** focuses on the mental aspects of work, aiming to create conditions that support correct interpretation of tasks and avoid cognitive overload.

* **Key Topics Covered:** Cognitive limitations in the workplace, human capabilities and limitations, human senses, and human cognitive practices.

* **Cognitive Limitations:** Humans are thinking, learning, and processing beings whose capacity changes, leading to inconsistencies in performance and susceptibility to errors. Fatigue significantly impacts cognitive abilities.

* **Human Senses:** The video highlights the importance of vision, hearing, and touch in the workplace and how they are used to interpret surroundings and respond appropriately.

* **Cognitive Processes:** The video discusses attention, memory, and perception and how they contribute to the overall cognitive process.

* **Expertise and Mistakes:** Discusses the SRK model (Skills, Rules, Knowledge) and the different types of mistakes

* **Mental Workload:** It acknowledges the difficulty in measuring mental workload objectively and uses the NASA-TLX questionnaire.

* **Design Principles**: Emphasizes design principles (minimize time and effort for information, proximity, engaging senses, legible displays etc.) that can improve cognition.

* **Cognitive Ergonomic Supports in Production:** Discusses tools and practices like design for assembly, fixtures, kitting, standardized work, poka-yoke (mistake-proofing), and andon systems.

**3. Detailed Notes:**

* **Introduction**

* Focus: Cognitive Ergonomics.

* Key Areas of Discussion:

1. Cognitive Limitations in the Workplace

2. Human Capabilities and Limitations

3. Human Senses

4. Human Cognitive Practices

* **Cognitive Limitations in the Workplace**

* Cognitive aspects of the workplace concern sensory signals that provide clues and cues.

* Engineers should create optimal conditions for workers to correctly interpret the task.

* Objectives: Reduce danger, errors, confusion, irritation, and mental overload.

* Design Focus Shift: From physical to mental.

* Cognitive Aspects Related To: Interpretation of sensory stimuli (vision, hearing, touch, smell, taste), pattern recognition, understanding instructions, and symbol association.

* Cognitive Processes are constant even during sleep.

* Impact of Fatigue: Adds limitations on attention, perception, memory, and mental models.

* Role of Production Engineers: Minimize mental workload, reduce errors, and improve efficiency.

* Roles that Benefit from Cognitive Ergonomics Knowledge: Systems performance improvers, purchasers, work environment or safety specialists.

* *Systems Performance Improvers:* Understand cognitive abilities and limitations, specify equipment, instructions, and interfaces.

* *Purchasers:* Understand the value of investing in human-machine systems.

* *Work Environment/Safety Specialists:* Identify safety hazards and risks due to misinterpreted signals.

* Cognitive Limitations of Human Workers

* Humans are preferred over robots in many assemblies due to their superior ability to respond to variations.

* Key Limitations:

* Humans are thinking, learning, and processing beings.

* Inconsistencies in performance.

* Misinterpretation of information and mistakes.

* Examples: Three Mile Island nuclear meltdown due to operator error and bad ergonomics.

* Operators can make shortcuts and lead to errors.

* Production-related cases.

* Multiple product variants causing confusion, errors, defects, and quality issues.

* Assembly line workers can make mistakes, resulting in defects.

* **Human Capabilities and Limitations**

* Focus: Abilities and limitations of the human mind and senses.

* Components:

* Mental capacity changes with age (improving and declining).

* Cognitive abilities are a combination of skills.

* Physical well-being has a significant impact.

* Figure 5.1 Presents how the brain interprets information from the environment.

* Key Limitations:

* Mental capacity changes with age.

* Cognitive abilities are a combination of various skills.

* Physical well-being.

* Consequences:

* When performing mentally intensive tasks while tired, overstimulated, stressed, etc., the brain may transfer from planning and reasoning to survival mode.

* Results in mistakes and accidents.

* Particularly limited in a state of fatigue.

* Fatigue contributes to mistakes, especially in tasks requiring sustained vigilance.

* Cognitively Well-Designed Work Systems:

* Lessen the impact of fatigue by minimizing incorrect actions.

* The more demanding a task, the more important carefully designed cues.

* **Human Senses**

* Focus: Senses that convey information about surroundings and the internal state of bodies.

* Senses Discussed: Vision, Hearing, Touch (Tactile).

* The video doesn't provide depth about smell and taste.

* These three senses (vision, hearing, touch) make the majority of the signals for humans in a workplace setting.

* Humans are said to have a sense of balance and muscle sense which can be used to interpret surroundings.

* For the senses, it is all about the stimuli and receptors sending the information to the brain to process.

* Vision:

* Dominant sense.

* Field of vision is about 170 degrees.

* Peripheral vision detects movement.

* Cones: Sensitive to shape and color but need good lighting.

* Rods: See in dim light but cannot distinguish color.

* Perception: Looking for patterns and structures.

* Table 5.1: Parameters affecting sensory processing of light: contrast, color, dark-adapted vision, depth perception, movement detection, and glare.

* Contrast sensitivity (light vs. dark) and the ability to see lines, text, shapes, and contours.

* Visual abilities tend to deteriorate after 40.

* Important: readable information should have enough differentiation.

* Color: Brain's interpretation and distinction of light wavelengths.

* Different color abilities depending on the person's age, education, culture, genetics, etc.

* Table 5.2: Design principles for visual information (intensity, choice of color, strength of lighting, angle of vision)

* Hearing:

* Tightly coupled to cognitive pattern recognition skills.

* Allows distinguishing many nuances of sound.

* Can identify direction, volume, and pitch.

* Can filter sounds that carry no meaning (selective hearing).

* Table 5.3: Parameters that influence sound and hearing (loudness, pitch, location/direction).

* The brain allows the sound to travel in waves to interpret (loudness).

* Loudness: Sounds travel in waves with amplitudes.

* High pitch frequencies the human ear can hear.

* To determine sound from a source, by interpreting the differences between the two ears (location/direction).

* Audible sounds perceived via vibration and have sensitivity to a wide range.

* Human hearing and ability is to hear or understand in noise environments.

* Touch (Tactile):

* Allows us to perceive differences in pressure, temperature, and frequency.

* Received through nerve receptors in the skin.

* Sensitive to stimulation from hairs and pain.

* Hands are sensitive to small sensations.

* **Human Cognitive Practices**

* Focus: Overall process of handling information.

* Components: Sensory stimulation, focus, perception, working memory, long-term memory, and interpretation.

* Leads to decision-making and response.

* Categories of Mental Processing:

* *Bottom-Up:* Response to sensory stimuli; unconscious or automated. (e.g., "What am I seeing?")

* *Top-Down:* Conscious, based on desires, previous experience, or expectations. (e.g., "Is that something I've seen before?")

* **Attention:** Devoting mental resources to a task or event.

* Undivided Attention: Focuses all cognitive processing capability on one stimulus.

* Divided Attention: Performance decreases when attention is divided.

* Attention functions best: with events at regular, relatively frequent intervals.

* Attention Levels Fall: if the activity frequency is too low.

* Alertness or Vigilance: the ability to keep focus on a process for a duration of time.

* Need to support attention: Using enough sensory stimulation (right amount of pressure and frequency).

* Monotonous Task or Environment: This lacks support (leads to boredom and decreased motivation).

* Boredom: deactivates certain nervous centers and results in awareness lethargy.

* Leads to mistakes.

* *Memory:*

* Allows learning through storage of information, experiences, and rules.

* *Long-Term Memory:*

* Stores information temporarily.

* Makes sense of patterns and relationships between data points.

* Short-Term Memory:

* Capacity is limited.

* Works to recall recent events.

* Rule of Seven: seven plus minus two is the maximum amount of unrelated items.

* Practice tasks and movements until they are stored in the long-term memory.

* Training to decrease sensitivity to stress.

* Table 5.4: Categories of memory (declarative and non-declarative).

* *Declarative:* Requires active recall (semantic, episodic).

* Semantic: Meanings, concepts, and understandings.

* Episodic: Past personal experiences.

* *Non-Declarative:* Does not require active recall (procedural, perceptual).

* Procedural: Motor learning (riding a bike).

* Perceptual: Recognition of sensory stimuli (faces, voices, smells).

* *Perception:*

* Capacity to take in information from the environment, associate meaning, and mentally organize it.

* Based on previous recognition, knowledge, and experiences.

* Creates mental models or expectations.

* *Illusions:* Interpretation of sensory signals mismatched with reality (optical and the like).

* Automatic filters out information that it has learned to sort as meaningless.

* *Mental Models:*

* Provide a language for speaking about expectations.

* Based on previous knowledge and experiences, and preconceptions.

* Can lead a worker to look for specific cues.

* *Examples:*

* The word "tree" represents a concept.

* Mental model of a factory may differ.

* *Role of Expertise, the SRK Model, and Types of Mistakes:*

* As skills are developed over time they increase and are divided into three different modes.

* Progression: Novice to Expert.

* *Rasmussen's SRK Model:*

* Skills: action performed without consciousness.

* Rules: Actions governed by procedures.

* Knowledge: Actions require explicit thinking and problem-solving.

* *Novice:* Relies on knowledge-based mode.

* *Intermediate:* Uses more rule-based actions.

* *Expert:* Operates more instinctively in the skill-based mode.

* *Reasons's 1990 Theory:*

* Characterizes different types of errors related to cognitive processing.

* *Slips:* Correct plan, incorrect action.

* *Lapses:* Correct plan, but incorrect action.

* *Mistakes:* Incorrect plan.

* *Mental Workload:*

* Measuring mental workload is complex (assess all components of cognition).

* Difficult to measure objectively.

* A measurement of the individual's perception of it.

* Nasa TLX.

* Figure 5.4: The nasa tlx form.

* Individual rates the workload or task regarding to different components of physical and cognitive loading.

* **Cognitive Ergonomic Supports Used**

* Focus: Tools and methods that aid in production from a cognitive perspective.

* Methods: Design for assembly, the use of fixtures, kitting, standardized work, mistake proofing, pick-by barcodes, and the andon system.

* The best solution is dependent on the nature of the business at the time.

* Consider: Cost, quality, delivery time, reliability, production system, etc.

* Emphasis should be to make sure that is hard to do wrong and the operator should have cues and clues.

* *Design for Assembly:*

* A method to encourage designers to think about the assembly implications.

* Often, the product is designed without consideration of the fact it has to be put together.

* Minimizing the number of required components.

* Results: Time and cost during manufacturing stages.

* General guidelines and general DFa guidelines

* Should consider to have parts used geometrical or symmetrically features.

* *The Use of Fixtures:*

* A device that holds or supports the workpiece during the manufacturing operation.

* The purpose is to ease the mental workload.

* Fixtures can also hold tools

* In addition to that a jig provides support in the processing operations.

* Examples of a fixture can provide nothing but a table.

* Figure 5.4: Example of a fixture.

* To remedy problems the operator needs help

* Consider:

* Alignment of fixtures on the workstation.

* Should also align to the supply of material.

* *Kitting and Grouping*

* Kitting is a method to deliver all the required components to the operator's workstation.

* Table 5.5: Example of kitting bins.

* *Standardized Work:*

* Providing a specific set method to carry out tasks.

* Ensure a standardized method that all workers should take.

* *Work Instructions:*

* Provides guidelines to the operator.

* Instructions can be provided in paper form or computers and screens

* *Poka Yoke (Mistake Proofing):*

* Is a term that originated in japan and prevents errors from becoming defects.

* Figure. Example of Poka Yoke for clarity.

* Examples of Polka Yoke are shown in the sample images.

* Picking by Barcodes:

* Use bar codes and an optical barcode scanner.

* Provides information to the operator.

* Either handheld secured or shock mounted.

* Pick by Light:

* Use lights positioned on shelves.

* Pick by Voice:

* Users are wearing a headset.

* Andon System

* Visual display shows what the status of the plant floor.

* Examples of Andon System.

* Provides alerts to the management or other workers.

* **Key takeaways on Cognitive Ergonomics**.