Mental Models by Phoebe Barnett

Introduction

phoebe_mb — 2015-10-06 11:43:15 UTC

Users of computer systems can be divided into two groups: those who have some understanding of the operation of a computer and those who have little or no understanding.

Users in the first group are generally able to carry out and complete tasks more quickly and more effectively than those in the second group.

Users who have little understanding of the operation of a computer will generally read and follow a set of instructions with no clear comprehension of how the tasks are being processed by the computer. This may lead to an uncertainty, and possibly some panic, about how to deal with any messages that appear on the screen and which are not defined in the instructions being followed by the user.

When a 'new' user saves a file, it is often the case that they will be unable to locate the file again at a later date. This is because they user has a limited understanding of how the filing system of a computer works.

Mental Models

phoebe_mb — 2015-10-06 11:48:06 UTC

If a user has a mental model of the computer and has some knowledge of how it works, then they should be able to use the computer more effectively. The mental model a user has when working with a computer is based on the way people process tasks. The processing that is carried out will be based on various types of input. These inputs will be based on, for example, sound and visuals as well as experience.

The mental model of the user will not only cover such operational functions as the use of RAM, menus, sub-menus and file management, but should also cover the generic features of the software package being used. For example, if a user is creating a work-processed document, then the generic concepts of automatic word-wrapping at the end of a line of text and text formatting, will enable the user to produce an effective and appropriate document.

A user's mental model should let them envisage the results of an action. They will then use this experience again in the future to predict actions that may be needed in another situation. This means that the mental model forms the basis of any further interactions with the computer and should enable the user to predict the performance of the computer based on past experiences. The action of the computer will then, hopefully, match the action that they intend to take or have taken. A user's mental model lets them base their actions to save a file in the spreadsheet package on those experiences in the word-processing package, for example.

Development

phoebe_mb — 2015-10-06 11:54:23 UTC

The development of an effective user interface will have to take into account the fact that different users will have different mental models. In general, this is related to the user's experience of using the interface. The designer must design the interface to ensure that the intention of the user is translated by the interface into the appropriate activity or action. Conversely, the action of the computer should match that anticipated by the user.

The actions of the computer can then be matched by using audio-visual indicators. For example, word-processing packages can produce print dialogue boxes. The options that can be selected by the user can be highlights (a visual indication) by stepping through the box areas by pressing the tab key.

The design of a user interface must take into account the perception of the majority of users. This means that a designer of the interface will have to maintain a natural method of completing an action by the user. When this action has been completed the interface display must reflect the current, and accurate, state of the system. This accuracy will then enable a user to carry out further actions.

Design

phoebe_mb — 2015-10-06 12:02:01 UTC

A designer must consider the mental model when designing a system model. This ensures that the final product matches the mental model as closely as possible. One of the most important reasons for this match is to ensure that the user does not 'get lost' while using the system. The system must, as far as possible, build on the experience of the user to ensure that previous experience can be used when the user is faced with any problems that might occur. This might mean the use of the same audio cue when an error occurs, or the display of a useful error message.

Users will bring their own preconceptions to any system. These will be based on their own mental model of a system. The designer must try to provide a convergence between the user mental model and the system model being created. For example, a user will expect the command 'open' to open a document or file. By ensuring that these expectations are met when the system is designed then the confidence of the users will increase as they use the system model.

Another reason for the system matching the mental model is that the speed with which the user will learn to confidently use the system will be increased.