Interactive Sonification of Geographical Maps: a Behavioural Study with Blind Subjects

Sonification is a promising solution for facilitating the access to geographical maps by blind people. This study aims at evaluating the representations of geographical maps acquired by means of a sonificated exploration. Three groups of subjects (10 early-blind, 10 congenitally-blind and 10 blindfolded sighted subjects) explored four sonificated maps of progressive difficulty by means of two interfaces (Keyboard-TouchTablet). For each one of the heard maps, subjects chose the correspondent tactile map among four alternatives (one target and three distractors). Then, subjects answered a questionnaire about the features of the acoustic geographical information. Main results indicate that all the groups of subjects achieved a good representation of the maps. Both keyboard and touch tablet are useful devices for navigating acoustical maps. Interestingly, we did not find any performance difference between the three groups. These results may imply that an early exposition to visual information is not a necessary condition for spatial mental mapping.