Mental models, Metaphors, Errors

What is a Mental Model?

internal representation that we form in our mind of how something works

used to make predictions of how a system will react when we interact with it

can be functional (how to use) or structural (facts)

Can a Mental Model be different from how the System actually works?

yes

How do we acquire Mental Models?

can be learned from explanation or formed from experience

What is the difference between Designers and Users Models?

designers form wonderful methods of their own creations leading them to believe that each feature is easy to understand

users are often more deficient - more likely to make mistakes

What is a Conceptual Model?

high-level description of how a system is organised and how it operates

created by designers for users

How is the Conceptual Model communicated to the user?

through the user interface - using metaphors and mappings

How is a Mental Model formed?

through interaction with the system

What is a Metaphor?

take concepts that are familiar from one domain and apply them to another

What is Mapping?

the relationship between a control and its effect in the world

help users build amental model of how actions relate to effects

What are Errors?

any situation in which an action sequence doesn’t lead to the intended result

What are the 2 reasons why an Error would Occur?

error in planning that results in the wrong choice of action

error in execution that results in an unintended action sequence

What are the Types of Errors?

lapse - usually missing a step in execution

slip - accidental mistakes in execution

mistakes - mental model was wrong

How do we prevent Errors?

mistakes - provide clear conceptual model, familiar concepts/metaphors, good mappings

slips - improve ergonomics of the interface, forgiving formatting, make larger click targets

lapses - design interactions so there is nothing users need to do after they reached their primary goal