1.1b Psychological Factors

Topic 1

1.1a Anthropometrics

1.1c Physiological Factors

Planning Ergonomic Research

Essential idea

Designers consider three human factors to ensure products meet ergonomic needs.

Nature and Aims of Design

Nature of Design

Human beings vary psychologically in complex ways. Any attempt by designers to classify people into groups merely results in a statement of broad principles that may or may not be relevant to the individual. Design permeates every aspect of human experience and data pertaining to what cannot be seen such as touch, taste, and smell are often expressions of opinion rather than checkable fact. (Aims of Design: 1.5, 1.18, 1.20, 2.9)

Aims:

Aim 3: The analysis of the human information processing system requires a designer to critically analyse a range of causes and effects to identify where a potential breakdown could occur and the effect it may have.

Guidance

As a DP Design Technology Student, you will need to:

Manipulate data in relation to light, smell, sound, taste, temperature and texture as qualitative or quantitative (ordinal/interval)
Identify and apply methods of collecting psychological factor data
Represent the human information processing system using flow diagrams
Apply the human information processing system to a common task
Evaluate effects and reasons for a breakdown in the human information processing system
Identify user responses to environmental factors
Understand how environmental factors induce different levels of alertness
Understand the importance of optimizing environmental factors to maximize workplace performance
Assess the impact of perception in relation to the accuracy and reliability of psychological factor data

Discussion and analysis

Summmary

Human psychology is complex and difficult to classify into groups for designers
Designers must analyze the human information processing system to identify potential breakdowns and their effects
Designers use various methods to collect psychological data, and understanding the type of scale used and whether the data is qualitative or quantitative helps interpret its significance and application in the design context.

As you watch the video, consider the following questions:

What are the challenges designers face when trying to classify human beings into groups?
What are the different types of scales used to collect psychological data, and how do they differ from one another?
Why is it important for designers to understand how the human information processing system works and how it can break down?

Scales of measurement

The collecting of psychological data involves the study of human behavior and responses. Designers will use a variety of methods to gather psychological data.

Understanding each method, the type of scale it uses, and whether the data gathered is qualitative or quantitative can help designers interpret the significance of the data and how it can be applied to the design context.

Nominal Scale

Nominal scales are used for labelling a variable. Common examples are checkboxes for characteristics such as gender, city, favorite food, etc.. The items in the list have no real numerical value or relationship to one another.

Ordinal Scale

Ordinal scales list items in order of importance or significance. These types of scales usually measure a feeling or perception along a continuum (unhappy to happy; unsatisfied to satisfied). However there is no numerical difference between on value and the next. For example

In an ordinal scale, the values are ordered in sequence; there is no numerical relationship between them. Someone who chooses (5) above is not necessarily 5-times happier than someone who chose (1)

Interval Scale

Interval scales represent the order of values as well as showing the difference. A Celsius thermometer displays the difference between each unit as the same. i.e.

It is important to remember that Interval scales do not have an absolute zero. In the case of the Celsius thermometer the zero is arbitrarily set to the freezing point of water.

The difference between -5 degrees and -3 degrees is the same as the difference between 10 degrees and 12 degrees.

Ratio Scale

Ratio scales are the most comprehensive scales, and in some way are the perfect combination of other Scales: They show the exact difference between units (Interval scales); They show the order of units (Ordinal scales); and they have absolute zero.

Taken together, Ratio scales provide the most comprehensive form of quantitative data for analysis and research.

Speedometers have an absolute zero against which speed is measured.

Weight scales have an aboslute zero against which weight is measured

Why do designers need to know about the different scales?

As a designer, you need to understand how you are collecting data. Knowing what kind of scale you are using helps you evaluate the effectiveness of your data gathering methodology.

What kind of data are you gathering? Quantitative or Qualitative?
What type of scale are you using to gather this data? Ratio, ordinal, interval, or nominal?
What tools are you using to gather the data? Surveys, measuring tools like rules or scales, observation, stop watches, interviews?

This becomes especially important when developing surveys or interview questions. Your surveys should gather meaningful data.

See this guidance on how to construct meaningful surveys. What types of scales can you identify in the different examples?

Check out the Research for Design resources for more information

Collecting Psychological Data

Researchers, and designers, can use a wide variety of methods for collecting data about users, their behavior, and perceptions. Designers should consider what types of research strategies to use in order to gather meaningful, and accurate data.

Interviews involve asking people questions to learn more about their beliefs, experiences, needs, etc.

Surveys consist of a set of questions that are asked to each participant.

Observation involves watching the subject as they engage in a task, work in a space, or try to complete some activity. Observations can take place in the laboratory, place or work, or in a natural environment,.

Standardized tests are designed to measure a user's performance or ability and for the results to be compared to that of other users in the group.

Research Strategies:

For more information on Research Strategies in Design, check out the Research Strategies in User-Centered Design section.

Human Information Processing System (HIPS)

Humans are information processing systems, just as computers are. As designers, we must consider how the human mind processes and acts upon information.

Just as important as understanding how the mind processes information, it understanding how this system can break down. If there is too much stimulus (Input), or if there is no way to process the information, an error, mistake or accident can occur.

Take for example a driver of a car trying to answer a phone. The human brain can only process so much stimulus at a given time: reaching for the ringing phone, driving the car, paying attention to traffic signals, and noticing oncoming cars all place demands on the brain. There is simply too much information to processes quickly and accurately. The brain cannot cope, and something will get missed (not noticing a deer crossing the road?) and an accident will happen.

Resource:

Overview of information processing, with a focus on short term memory, working memory, and long term memory.

_______

Simply Psychology: Information Processing: introduction to cognitive psychology and how the brain processes information.

Many factors can affect how well we process information:

Age: the user may be too young and not have learnt the skills to accomplish the task; the use may be too old and have forgotten how to do the task. e.g. The fine-motor skills of young children may have not developed enough for them to turn a dial precisely
Strength: the user may be too weak to do the task. e.g. They may not be strong enough to press a switch or pull a lever.
Skills: the user may not have learnt the skills yet, or the skills may be to complex to learn without a lot of practice. e.g. Riding a bicycle on a flat surface requires practice before it can be done well. Riding a mountain bike downhill at speed requires even more practice.
Health: the user may not be physically or mentally healthy enough to carry out the task. e.g. They may be injured or have a condition which prevents them from doing the task easily.

Environmental Factors

Users respond to environmental factors and these can affect how they perform. Environmental factors include sound, temperature, lighting, air quality, and smell. Environmental factors can have effects on Comfort, Alertness, and Perception

Designers should understand that environmental factors can affect people in different ways. A room temperature that is comfortable to one person might be too hot or too cold for another. Likewise, a person who is mobile in a given space is going to be warmer than a person who sits at a desk (Think of teachers and students). Studies also show that women typically feel colder than men do, and thus prefer a warmer temperature.

Alertness

Alertness refers to the ability to be focused and awake. Environmental factors will affect our level of alertness in different ways:

Temperature: Too hot and we get sleepy and less alert; Too cold and we become very alert
Sound: Too loud and it can be distracting or even damaging to our hearing. Repetitive or high-pitched sounds can be annoying, distracting, or irritating.
Lighting: Too dark or too light can cause strain on the eyes, causing headaches. Types of indoor lighting can also affect people. Florescent lighting is cooler and can cause eyestrain and headaches, for example
Air quality: Dusty or stuffy air can make it difficult to breathe.
Smell: Bad smells can be distracting and repulsive.

Perception

As mentioned above, people will perceive environmental factors in different ways. While we may be able to measure an environmental factor using quantitative data (the room temperature, for example), the perception will vary from person to person.

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