Design of Everyday Things Excerpt - Chapter 1 The Psychopathology of Everyday Things
Chapter 1: The Psychopathology of Everyday Things
Two of the most important characteristics of good design are discoverability and understanding
Relevant components must be visible
Discoverability and understanding, with complex devices, require aid of manuals or personal instruction
Major areas of design relevant to this books are industrial design, interaction design and experience design.
Experience design: the practice of designing products, processes, services, events, and environments with a focus placed on the quality and enjoyment of the total experience.
Most of the problems in man-machine interaction comes from the lack of understanding the design principles. Engineers think logically and design their machines this way.
Fundamental Principles of Interaction
Discoverability results from application of 6 fundamental psychological principles:
- Affordance
is a relationship (p.11 definition) between properties of an object and the capabilities of an agent that determine just how the object could possibly be used
- Signifiers
- Constraints (in Chapter 3 and 4)
- Mappings
- Feedback
- Conceptual Models - providing true understanding
Affordance
Quality of an object and ability of an agent determine the presence of affordance. Affordance must be able to be discovered or perceived. Perceived affordance help people figure out what actions are possible without the need for label or instructions. Designers have to design things to make them discoverable (understandable). (p. 13)
Signifiers
Design is to signify affordance. Affordance determine what actions are possible. Signifiers shows where the action should take place. People search for clues. Good design communicates the purposes, operations and structure of a device to the people who use it. Designers need to provide these clues. Signifiers can be mark, sound, or any indicator that communicate the appropriate behaviors to a person. Sometimes signifiers can also be accidentally or unintentionally made, e.g. trace of footprints on snow-covered ground.
Mapping
Mapping means the relationship between the elements of 2 sets of things. It is an important concept in design and layout of controls and displays. Natural mapping, taking advantage of spatial analogies, leads to immediate understanding. Some natural mapping are cultural, biological, as in the universal standard. Other natural mappings follow perception and allow for the natural grouping or patterning of controls and feedback.(p.22) Grouping and proximity principles from Gestalt psychology can be applied to map controls to functions: related controls should be grouped together. Control should be close to the item being controlled.(p.115) Good natural mapping, providing tangible clues requires no diagrams, no labels and no instructions.(p.116) Natural mapping can vary with culture.(p.118)
A device is easy to use when the set of possible actions is visible.
Feedback
Feedback communicates the result of an action. It must be immediate, and a delay will be disconcerting. It must be also informative. Poor feedback is worse than no feedback! Too much feedback cause people to ignore, and even disable it. Noise can interfere and prevent people from receiving timely and correct feedback. Therefore feedback has to be planned. Even important signals have to be prioritized.
Conceptual Models (=mental model)
is an explanation, usually highly simplified, of how something works. It doesn't have to complete or accurate (p.25) as long as it is useful. Conceptual models reside in mind of people who use the device, so they are also "mental model". Conceptual models can be inferred from the device itself, passed on from person to person, from manuals, from training, and through experience. Major clues in conceptual model of a device come from its perceived structure - in particular from signifiers, affordance, constraints, and mappings. A good conceptual model allows us to predict the effects of our actions.
Two of the most important characteristics of good design are discoverability and understanding
Relevant components must be visible
Discoverability and understanding, with complex devices, require aid of manuals or personal instruction
Major areas of design relevant to this books are industrial design, interaction design and experience design.
Experience design: the practice of designing products, processes, services, events, and environments with a focus placed on the quality and enjoyment of the total experience.
Most of the problems in man-machine interaction comes from the lack of understanding the design principles. Engineers think logically and design their machines this way.
Fundamental Principles of Interaction
Discoverability results from application of 6 fundamental psychological principles:
- Affordance
is a relationship (p.11 definition) between properties of an object and the capabilities of an agent that determine just how the object could possibly be used
- Signifiers
- Constraints (in Chapter 3 and 4)
- Mappings
- Feedback
- Conceptual Models - providing true understanding
Affordance
Quality of an object and ability of an agent determine the presence of affordance. Affordance must be able to be discovered or perceived. Perceived affordance help people figure out what actions are possible without the need for label or instructions. Designers have to design things to make them discoverable (understandable). (p. 13)
Signifiers
Design is to signify affordance. Affordance determine what actions are possible. Signifiers shows where the action should take place. People search for clues. Good design communicates the purposes, operations and structure of a device to the people who use it. Designers need to provide these clues. Signifiers can be mark, sound, or any indicator that communicate the appropriate behaviors to a person. Sometimes signifiers can also be accidentally or unintentionally made, e.g. trace of footprints on snow-covered ground.
Mapping
Mapping means the relationship between the elements of 2 sets of things. It is an important concept in design and layout of controls and displays. Natural mapping, taking advantage of spatial analogies, leads to immediate understanding. Some natural mapping are cultural, biological, as in the universal standard. Other natural mappings follow perception and allow for the natural grouping or patterning of controls and feedback.(p.22) Grouping and proximity principles from Gestalt psychology can be applied to map controls to functions: related controls should be grouped together. Control should be close to the item being controlled.(p.115) Good natural mapping, providing tangible clues requires no diagrams, no labels and no instructions.(p.116) Natural mapping can vary with culture.(p.118)
A device is easy to use when the set of possible actions is visible.
Feedback
Feedback communicates the result of an action. It must be immediate, and a delay will be disconcerting. It must be also informative. Poor feedback is worse than no feedback! Too much feedback cause people to ignore, and even disable it. Noise can interfere and prevent people from receiving timely and correct feedback. Therefore feedback has to be planned. Even important signals have to be prioritized.
Conceptual Models (=mental model)
is an explanation, usually highly simplified, of how something works. It doesn't have to complete or accurate (p.25) as long as it is useful. Conceptual models reside in mind of people who use the device, so they are also "mental model". Conceptual models can be inferred from the device itself, passed on from person to person, from manuals, from training, and through experience. Major clues in conceptual model of a device come from its perceived structure - in particular from signifiers, affordance, constraints, and mappings. A good conceptual model allows us to predict the effects of our actions.
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