-
Gulf of Execution
- Where people try to figure out how it operates
- How do I work this? What can I do?
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Gulf of Evaluation
- Where people try to figure out what happened
- What happened? Is this what I wanted?
Bridging the Gulfs
We bridge the Gulf of Execution through the use of signifiers, constraints, mappings, and a conceptual model. We bridge the Gulf of Evaluation through the use of feedback and a conceptual model.
- Bridge of Execution
- Plan
- Specify
- Perform
- Bridge of Evaluation
- Perceive
- Interpret
- Compare
The bridges are between Goal and world.
Those elements are the seven stages of action
| Stage | Desc. |
|---|---|
| Goal | form the goal |
| Plan | the action |
| Specify | an action sequence |
| Perform | the action sequence |
| Perceive | the state of the world |
| Interpret | the perception |
| Compare | the outcome with the goal |
The sequence starts with the world, causing evaluation of the state and the formulation of a goal
e.g., The person is reading a recipe book for cooking dinner. The light is getting dimmer and dimmer.
Reading is not the high-level goal. Ask "Why is that the goal" for each goal.
The hierarchy of goals is: satisfy hunger; eat; cook; read cookbook; get more light.
Because we are only aware of the reflective level of conscious processing, we tend to believe that all human thought is conscious.
Have you thought how to walk? But you can walk (subconsciousness)
Conscious though it slow and labored.
| Subconscious | Conscious |
|---|---|
| Fast | Slow |
| Automatic | Controlled |
| Multiple resources | Limited resources |
| Controls skilled behavior | Invoked for novel situations: when learning, when in danger, when things go wrong |
Three levels of processing within the brain (applicable to both cognitive and emotional processing)
- The visceral level
- subconscious
- immediate perception
- Engineers are proud of the inherent quality of their work and dismayed when inferior products sell better "just because they look better."
- The behavioral level
- subconscious
- When we play a sport, we are prepared for action required by practices
- The reflective level
- conscious
- occurs after an event happened, by evaluating the circumstances
- cognitive, deep and slow
Design must take place at all levels
| Three levels of processing | Seven stages of action |
|---|---|
| Reflective | Plan, Compare |
| Behavioral | Specify, Interpret |
| Visceral | Perform, Perceive |
Do people really diagnose the error correctly?
Everyone forms stories (= conceptual models) to explain what they've observed. The stories can be wrong.
e.g., People use their thermostats inappropriately, causing themselves unnecessary effort, and often resulting in large temperature swings, thus wasting energy.
People tend to blame themselves, especially others can use it. This creates a conspiracy of silence.
That failures can't be captured because nobody tells.
In general, each stage of seven actions requires its own design strategies. These questions will help:
- What do I want to accomplish?
- What are the alternative action sequences?
- What action can I do now?
- How do I do it?
- What happened?
- What does it mean?
- Is this okay? Have I accomplished my goal?
| Seven stages of action | seven fundamental principles of design |
|---|---|
| Discoverability | It is possible to determine what actions are possible and the current state of the device |
| Feedback | There is full and continuous information about the results of actions and current state of the product or service. After an action has been executed, it is easy to determine the new state |
| Conceptual model | The design projects all the information needed to create a good conceptual model of the system, leading to understanding and a feeling of control. The conceptual model enhances both discoverability and evaluation of results |
| Affordances | The proper affordances exist to make the desired actions possible |
| Signifiers | Effective use of signifiers ensures discoverability and that the feedback is well communicated and intelligible |
| Mappings | The relationship between controls and their actions follows the principles of good mapping, enhanced a s much as possible through spatial layout and temporal contiguity |
| Constraints | Providing physical, logical, semantic, and cultural constraints guides actions and eases interpretation |
Don't criticize unless you can do better
Try to understand how the faulty design might have occurred
Try to determine how it could have been done