Motor Behaviour Models Flashcards
What is a predictive model?
A predictive model is an equation or calculation that is used to forecast an event.
Examples of events can be:
The time it takes to move the mouse or press a button.
The Reaction time of the interface OR the reaction time of the user
What is a descriptive model?
A descriptive model is a model that describes a system or other entity and its relationship to its environment. It is generally used to help specify and/or understand what the system is, what it does, and how it does it.
What is the difference between a predictive and a descriptive model?
Most simply, predictive models are used to forecast future events based on patterns, equations, calculations and data, while descriptive models describe and explain the relationships within a system, focusing on understanding current or historical states.
Predictive models do not require any research conduct and has no need for a working system.
What is GOMS?
GOMS is a modelling technique used in HCI. It is used to break down tasks into fundamental concepts.
What does G stand for in GOMS?
G in GOMS stands for goals. It represents the objectives or the end goals that a user wants to achieve. For example, my end goal for studying this is to get an A for HCI.
What does O stand for in GOMS?
O in GOMS stands for operators. They are the basic units of actions that an individual performs to achieve their goals. This includes both cognitive processes like decision making and remembering, and physical actions like clicking a button, moving the mouse, etc.
For instance, an operator in a web search would be to decide which search engine would be best to use.
What does M stand for in GOMS?
M in GOMS stands for methods. Methods are sequences and procedures formed by combining operators, to accomplish a specific goal.
For example, when i want to do a web search, one method may be
1. I open the google chrome web application
2. I click on the search bar
3. I type my search and enter
What does S stand for in GOMS?
S in GOMS stands for selection rules. These rules govern the selection of a method when multiple methods are available to accomplish a task.
Is GOMS a predictive or descriptive model?
It is a predictive model. With GOMS, an analyst can easily estimate a particular interaction and calculate it quickly and easily.
What is a Key-stroke model?
The key-stroke level model is a predictive model used to estimate the time it takes for a skilled user to complete a task, based on the number of keystrokes or mouse clicks involved. (hardware actions)
What type of data is collected in a Key-stroke level model? What is done with the data being collected?
Measurements of experts performing ‘low-level actions’ are collected. These measurements are used to predict the time required to complete a task.
Each operator is assigned a time in order to calculate how the system will respond.
Refer to example in lecture to know how it works
What is the difference between GOMS and the Key-Stroke model?is
For GOMS and the Key-Stroke model, they vary in scope. Operations in the GOMS model consist of both cognitive processes as well as physical interactions, whereas Operations in the Key-Stroke model focuses common
What is Fitt’s Law
Fitt’s Law is a predictive model that predicts the time required to rapidly move to a target area. It models the act of pointing, either by physically touching an object with a hand or a finger, or virtually, by pointing an object on a computer monitor with a pointing device.
Fitt’s Law is based on the idea that the time required to move to a target depends on the function of distance to the target and the width of the target
What is the formula for Fitt’s Law?
MT = a + b log 2 (D/W + 1)
where MT is movement time,
a and b are empirically determined constants, that are device dependent,
D is the distance from starting point to center of the target
W is the width of the target
How is Fitt’s Law helpful in designing interfaces?
Fitt’s Law is useful to create efficient and user-friendly computer interfaces by letting designers predict the amount of time it takes to move cursor and complete an action. From then on the designer will know whether to adjust the size of the target, grouping of elements and more.
