MASTERBLIND - TESTING THE USABILITY OF AUDITORY FEEDBACK IN A COMPUTER GAME FOR BLIND PEOPLE Ana Rita Teixeira *1, *2 , Ana Carvalhal* 1 , Filipe Abrantes* 1 , Vladimiro Lourenço *1 , Anabela Gomes *3,*4 , João Orvalho * 1 *1 Master in Human Computer Interaction (HCI), Polytechnic of Coimbra, Rua Dom João III – Solum 3030-329 Coimbra, Portugal *2 Institute of Electronics and Informatics Engineering of Aveiro – University of Aveiro Campus Universitário de Santiago, 3810-193 Aveiro – Portugal *3 Engineering Institute of Polytechnic Institute of Coimbra Rua Pedro Nunes, Quinta da Nora, 3030-199 Coimbra, Portugal * 4 Centre for Informatics and Systems – University of Coimbra Pólo II - Pinhal de Marrocos, 3030-290 Coimbra ABSTRACT The present study presents an adaptation of the Mastermind board game for blind users - Masterblind. Given the focus on visual information in the original game, the game mechanics were simplified and auditory feedback introduced. The research object was to understand what kind of sounds would work better to help blind people play the game. Three versions were presented to the subjects - pentatonic notes, animal sounds and vowels - to help users recall previous steps in the game. The main hypothesis predicted that blind users would consciously benefit from the auditory feedback provided. The second hypothesis predicted that users would benefit less from the feedback that doesn’t provide semantic information. The results were congruent with the hypothesis, although revealing an important role for spatial awareness. Masterblind can be an usable, enjoyable and a challenging experience for blind users as long as it provides semantically significant feedback. KEYWORDS User Experience Design; User and Cognitive models; Interface Design Games/Play 1. INTRODUCTION A computer game adaptation of the board game Mastermind [1] was designed and prototyped to address the difficulties in visual interfaces blind users may have - Masterblind. There are several variations of the game, but the original concept is based on having a player generating/choosing a secret key of four coloured pieces out of a set of eight different colours - with or without repetitions of the same colour - while the other player, in several rounds, tries to guess the correct secret key previously generated. At each round the second player tests a combination of coloured pieces and according to the feedback given by the first player, he tries to deduce the key by presenting new combinations. The feedback provided by the first player consists in informing the second player of how many pieces are the correct colours in the correct position, and how many pieces are the correct colours but in the wrong position. The game ends when the key is discovered or the number of maximum attempts is reached. The main design problem was to understand how the original concept of Mastermind that relies so much on visual information could be adapted to a computer game for blind users, without any visual output. Three main aspects of the role of visual information were identified and hypothesized to have a significant role on the mechanics of the original game: 1) the distinctive capacity for the user to clearly identify each element of the secret key; 2) accurate but at the same time, vague feedback that provides just enough information for the player to derive the correct solution without losing the puzzling element that is essential for these kind of games; 3) accessibility of information about the previous