Motor Behaviour Models

Question 1

What is a model?

Answer 1

A model is used to simplify the reality, for the purpose of understanding, designing and evaluating the system. It also helps developers and designers understand and work out how the interface will perform tasks and how efficient it is. Classified into 2 main types: Predictive and Descriptive.

Question 2

What is the difference between a predictive model and descriptive model?

Answer 2

Predictive: Use projectile model to predict and analyse.

Descriptive: Use the scaled model to describe and analyse.

Question 3

What are examples of Predictive models?

Answer 3

1. GOMS
   - Goals, Operators, Methods, Selection rules
   - Edit a document, I.e. move HCI before INF2002
2. Keystroke Level
   - Focuses on how long it takes users to use the HCI via hardware
3. Fitts’ Law
   - Pointing and targeting are common interactions
   - Predicts human performance in pointing tasks

Question 4

What are examples of descriptive models?

Answer 4

1. Key Action Model
   - looks at how users interact with keyboards, the kind of shortcuts they can use to carry out tasks
   - goal is to understand the operation of keys on a keyboard
2. Button’s Three State Model
   - simple expression of the operation of computer pointing devices in terms of state transitions
   - three states: Out of range, Tracking and Dragging

Question 5

What are predictive models?

Answer 5

They are a prediction of human performance without experimental measurement. Forecasts what happens without having to carry out research.

Question 6

What are descriptive models?

Answer 6

Describes a framework or context for thinking about a problem or situation. It provides a bases for understanding, reflecting and reasoning about certain facts and interactions.