Mental Models, Metaphors, Errors Flashcards
1
Q
Mental Model
A
“If the organism carries a small-scale model of external reality and of its own possible actions within its head, it is able to try out various alternatives, conclude which is the best of them…[and] utilize the knowledge of the past events in dealing with present and the future
2
Q
Mental Models 2
A
- A mental model is an internal representation that we form in our mind of how something works
- A mental model explains how a system works
- We use mental models to make predictions of how a system will reach when we interact with it
- Our mental model of a system can be different from how the system actually works
- Mental models can be functional (know what to do, but not why) or structural (know what to do and why)
3
Q
Example: Heating
A
- It’s winter and you come home, and it is cold in your room, only 15 °C.
- You want a cozy room temperature of 20°C,
as quickly as possible. - What do you do?
- Strategy 1: set the thermostat to 20°C and wait
- Strategy 2: set the thermostat to max (=30°) and turn down to 20° once it is warm?
4
Q
Acquiring mental models
A
- Mental models can be learned from explanation
- Somebody can teach us how something work
- Tutorials, instructions
- Mental models can be formed from experience
- Interaction with the system and observing what happens
- Forming a model that is consistent with the observed behaviour
- Often based on physical analogies and metaphors
- Can be incomplete
- Can be incorrect
5
Q
Characteristics of Mental Models
A
- ” A mental model is what the user believes about the system at hand” (Jakob Nielsen)
- A mental model is based on belief, not facts
- It’s a model of what users know (or think they know) about a system
- Mental models are not perfect
- Incomplete – users will understand some parts better than others
- Inertia – once learned, users will stick to their model, and not easily adapt
- Unscientific – models reflect superstitious behaviour
6
Q
Designers’ and Users’ Models
A
“One of usability’s big dilemmas is the common gap between designers’ and users’ mental models” (Jakob Nielsen)
- Individual people each have their own mental model
- Designers form wonderful mental models of their own creations
- Leading them to believe that each feature is easy to understand
- Users’ mental models of the user interface are often more deficient
- Making it more likely for users to make mistakes
- Users often find the user interface much more difficult to use
7
Q
Mental Models - Key Points
A
- Users form mental models of how a system works, through their interactions with the system
- Users plan their actions based on what their mental models predicts about the appropriate course of action
- If the system behaves as predicted by the user’s mental model, then it will appear logical
- If it does not behave as predicted, it will appear confusing
- If their interaction leads users to form flawed models, users will likely make more errors
8
Q
Conceptual models
A
- A conceptual model is a high-level description of how a system is organized and how it operates
- Conceptual models are created by designers, to provide users with everything they need to know, to be able to use the system
- Abstracting from system detail the user does not need to know about
- Focusing on aspects of the system the user needs to understand for their interaction with
- User interfaces are designed to convey the conceptual model to the user
9
Q
Different Models of a System
A
- The UI communicates the CM to the user
- Hiding other system aspects (transparency)
- Through interaction, users form a MM
- Ideally the MM is consistent with the CM
10
Q
Conceptual models 2
A
- How can a user interface communicate a conceptual model?
- User interfaces describe the concepts and actions that users need to know to be able to interact with an application, device or system
- To make it easy for users to learn how to use a new system or interface, conceptual models are designed to draw on users’ previous knowledge
- Metaphors: using concepts that are familiar from other domains
- Mappings: showing the user how actions relate to effects, based on familiar analogies
11
Q
Metaphors
A
- Metaphors take concepts from one domain and apply them to another
- they help users form a mental model in new domain
- User can draw on their knowledge from another domain and apply it to reason about how a new system works
- Metaphors are used pervasively in computer systems, and become so familiar that we forget that they were adopted from other domains
- Files and folders
- Copy, cut, paste
- Cursor
12
Q
Desktop metaphor
A
“if a new user wants to understand about how the computer file system works, he need only think about how an office filing cabinet works and then carry over this same way of thinking to the computer file system”
13
Q
Mappings
A
- Mappings help users build a mental model of how actions relate to effects
- Mappings are an important design principle that we do not notice when it is well applied
-Good mappings are:
- Understood immediately (mental model is instantly clear)
- Consistent with knowledge the user already has
- No effort to remember
14
Q
Natural Mappings
A
- Many mappings feel natural because they are based on analogies
- Spatial analogies
- e.g., elevator controls ordered from top to bottom
- Metaphorical analogies
- e.g., rising levels (volume, temperature, etc) associated with going up (as in water levels rising)
- Cultural analogies and standards
- e.g., water taps in UK: left is for cold, right is warm
15
Q
Historical analogies and metaphors
A
16
Q
Natural Mappings 2
A
- Stimulus-Response compatibility
- Degree to which the physical arrangement of the stimuli matches the location of the expected responses
- Natural mappings
- Design in which the system’s controls represent or correspond to the desired outcome
- When controls map to the actions that will result, systems are faster to learn and easier to remember
- Bridging gulf of execution
19
Q
Types of Error
A
