2002 Conference Proceedings

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Gareth Evans and Paul Blenkhorn
Department of Computation, UMIST, PO Box 88, Manchester, M60 1QD, UK
email g.evans@co.umist.ac.uk


This paper presents some observations on the use of software used to develop switch skills in early years. Our observations are based on a number of years of experience in working with users interacting with software that the authors have developed. In this paper we will primarily consider the software packages Build Some More and Match 'Em, which are available from Sensory Software. We believe that the observations are not restricted to these software packages and have application in a variety of contexts.

In this paper we focus on three orthogonal issues:
* Using alternative input switches.
* Novel activation modes.
* Age and interest appropriate material.

Before we consider these aspects, we give introduce the terminology that we will use in this paper and give a brief overview of the characteristics of our software.


We are assuming that the user is using push-to-make switches. We will use the term 'switch depression' for the act of making the switch and 'switch release' for the act of breaking the switch. As noted below, the software may interpret either switch depression or switch release as a valid switching action. We use the term 'switch activation' when the software recognises that a valid switching action has taken place. Generally, the software responds to switch activation by updating the image presented on the screen, playing an animated picture and/or by playing or changing sounds and/or music. We refer to this response as the 'reward'. Finally, the software is supplied with a number of different resources that are designed to develop a number of different skills and to give the user some variety. Moreover, as note below, teachers/carers can create their own resources. We refer to the resources as 'activities'.

Characteristics of Build Some More and Match 'Em

Build Some More is a basic switch building program in which a series of rewards are given in response to a user pressing one (or more) single switches. In most activities the fundamental reward is the addition of some element to the picture presented on the screen. After a number of switch activations the picture will be complete and a more significant reward that typically involves animation and sounds is presented. A typical activity will have a set of pictures that can be built up that lead to a series of these more significant rewards. The material in the activities has been chosen so that they correspond to a wide range of ages.

Match 'em is designed to develop visual matching and discrimination skills. An activity will present a user with a set of images, the user's task is either to match one of these images against a reference image or to determine which of the set of the image is the odd one out. When the user has carried out the task correctly, he/she is presented with a reward. The activities vary in visual complexity from clear well-formed images on plain backgrounds to silhouettes presented on visually complex backgrounds such a checkerboards.

Use of Alternative Switches

A wide variety of switches can be purchased from special needs equipment suppliers and these work well. However, we have found that accepting input from other switches can in some cases be useful. The reasons for using alternative switches may be for economic or educational reasons. The former reason is particularly important when the software is used in the home environment or in areas where equipment budgets may be limited. We have found sound switches to be useful. Our software can be configured so that input from the microphone can be used for switch activation. This type of switch has economic benefits, it merely requires a sound card and a microphone - equipment that is found on virtually every PC that is capable of running the software. Perhaps more important, for some users, is that fact that it encourages and rewards vocalisation.

When a computer is used at home, it is quite common for a standard games joystick to be connected. Some users find that they are able to comfortably use the buttons provided on such joysticks as switches. Our software will, therefore, accept input form games joysticks as either switch input and/or, in the case of Match 'em, for mouse pointer control.

Mouse buttons can also be used as switches and this, again, provides a low cost switching option if the user is able to activate the switches on a standard mouse. In addition, there are other circumstances when mouse button input is useful. These situations include: when specialised mice are used; when a touch screen is used; or when mouse switch boxes are used. Touch screen activation works very well with Match 'em.

Novel Activation Modes

By default most software packages interpret switch depression as switch activation (i.e. switch activation occurs when the user first presses the switch). Some users find switch depression easier than switch release. In these cases, motivating the user to release the switch is important. Therefore, out software can be set so that switch activation is caused by switch release.

It is often desirable for a user to learn to use more than one switch. Our software provides two modes that encourage practice in this skill. In 'alternate switch' mode, the user is presented with two switches. Only one switch may be activated at any time. Some activities are designed so that they enforce strict rotation of switches (left-right-left-right) others vary the order and explicitly indicate which switch is to be used. This style of interaction can be a useful precursor to two-switch scanning. In 'co-operative switch' mode both switches must be depressed for switch activation to take place. This type of interaction can be used to develop co-ordination skills. Both of the two-switch modes can be used to encourage social development as well as switch skills. When developing these skills, one switch is given to the user and the other to the teacher, carer or peer. 'Alternate switch' mode encourages the concept of turn taking, whilst, 'co-operative switch' mode encourages social co-operation.

A number of early switch users repeatedly hit their switch - we refer to such users as 'switch bangers'. This may be because they find the feeling of the switch and the noise that it makes more satisfying than the rewards generated by the software. It may also be the case that switch bangers get a very high number of rewards. In order to encourage the latter user to be more controlled, our software can be configured to recognise switch activations only after a time delay. The length of this delay can be set by the teacher/carer. If the user activates the switch before the delay time has elapsed, the screen display does not change - no reward is presented. To receive the reward the user must pause between successive switch activations.

Finally, one of the motivations for developing skills is so that users can migrate to applications that require scanning (such as on-screen keyboards and communicators). Basic early scanning skills are addressed in Match 'em. There are basically two options: the system automatically scans the choices at a selectable rate and the user presses their switch to select; or steps from image to image with one switch and selects with the second.

Age and Interest Appropriate Material

Most software that is aimed at developing early switch skills presupposes that the user will be quite young. This can prove a problem when the same software is to be used by those who need to develop switch skills but who are much older. Several people report the problems of finding material appropriate for teenagers and in some cases adults use our software. Older users need activities that are appropriate to their age and interests. We have tried to provide activities that are appropriate to older as well as to younger users. However, to really match the interests of the user the software should be configurable in the sense that it should be possible to import material (primarily graphics but also sounds) into the software that reflects the age, interests and culture of the user. We have found the familiar images of family, friends and the environment taken with digital camera work particularly well. All of our software permits configuration and customisation for particular users. However, it should be noted that the teachers and carers who work with the users may not have significant levels of computer expertise and that configuration of tools requires a reasonable understanding of the use of a computer. Further work is probably needed on interfaces that allow computer novices to introduce appropriate material quickly and easily. However, it should be noted that, in the UK, we have found a small number of teachers who have constructed quite complex activities based on the interests of their students and which are related to ongoing classroom activities.

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