G063 - Mental Models

The Psychology of HCI design

Learning Objectives:

By the end of this topic you should be able to:

• define the term ‘Mental Model’

• describe how ‘Mental Models’ can be applied to the design of a user interface;

• discuss the importance of designing a system model which matches the user's mental model;

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Mental Models :• we view the world as a series of causes and effects:

– “if I do this, then that will happen”

• we have preconceived ideas in our mind – of how things should work

• preconceived ideas = mental model

• mental models relate causes to effects– we can predict the results of an action based on prior experience:

– “I’ve seen this before, so I think that will also happen this time”

• mental models form the basis of any further interaction with a system

Mental Models and designing an HCI:

• users will bring their own mental models to a system

• mental models form the basis of interactions with a system– users will predict the behaviour of a system

based on past experiences

• many users learn to use a system by trial and error– using their mental models

Mental Models and designing an HCI:

• HCI designers must consider user’s mental models,

• if interface matches mental model then = intuitive use

• need to design systems to match mental models– convergence between mental model & system model

Effect of Mental Model on user :Users: • find a new system easy to learn and remember• be more confident using the system • know what is likely to happen next as a result of the

current action– beep = error,

– trashcan is used to delete files

– red for bad, green for good

– icons on toolbars give a preconception of use

• require less training• won’t ‘get lost’ while using the system