Designing multi-level affordance to improve usability of interactive products; Case study: ATM

The conformity of products affordances and their signifiers with the level of physical and cognitive abilities of users, is a key factor determining the usability of different products, especially interactive products. The multi-functionality of interactive products has created the process of working with them through sequential and nested affordances, Therefore, working with them is more complex and difficult than many products. In some interactive products (such as Mobile phone and some applications), there is the possibility to customize interfaces and some affordances, so users can match them with their needs, level of ability and skill; but in generic interactive products (such as ATM, ticket vending machines) which users have different physical and cognitive abilities, it's not possible to customize and match the products affordances and signifiers with different users, so the interaction involves many problems.
The purpose of this research, is to provide a good solution for improving the design of generic interactive products and enhancing their usability; so it is assumed that designing multi-level affordances can provide the appropriate use of generic interactive products for a wide variety of users. Accordingly, the background of the affordance theory in the field of product design has been briefly outlined. Then, the start point of this research and the reasons for choosing ATM as the case study are mentioned, and the full process of an applied research is described. Applied data in this research is gathered through the field study, using the questionnaires. Independent variables such as age, gender, level of education, user experience and skills, and familiarity with intelligent systems, were selected as the most important variables affecting the understanding of the affordances and the way of using the ATM.
In the first stage of research, the users problems and needs in dealing with the ATM, different users preferences in the design of affordances and the most important variables affecting the desirable affordances, were determined using the questionnaire. In the second stage, significance of the relationship between independent variables with understanding the simplicity or difficulty of the process of interaction with ATM, became clear using the second questionnaire and Chi-square test and the severity of the relationship was determined using Cramer's test. In the third stage, in order to prepare multi-level affordance test, the affordances of three services of ATM were designed in three levels based on the results of the first and second questionnaires. In the fourth stage, the affordances and user interaction steps were programmed and simulated by application, then presented to the statistical sample and tested with the third questionnaire. In the fifth stage, the statistical data were analyzed using SPSS software in descriptive and inferential manners.
The result of this study shows that if be possible to select a level of affordance which is appropriate to the physical and cognitive abilities of the users, the process of doing the work will be less difficult and less complicated and the work will be satisfactory for the user. At the end of the article, some suggestions on how to apply multi-level affordances in generic interactive products are provided.