Concurrency in auditory displays for connected television

Many television experiences depend on users being both willing and able to visually attend to screen-based information. Auditory displays offer an alternative method for presenting this information and could benefit all users. This thesis explores how this may be achieved through the design and evaluation of auditory displays involving varying degrees of concurrency for two television use cases: menu navigation and presenting related content alongside a television show. The first study, on the navigation of auditory menus, looked at onset asynchrony and word length in the presentation of spoken menus. The effects of these on task duration, accuracy and workload were considered. Onset asynchrony and word length both caused significant effects on task duration and accuracy, while workload was only affected by onset asynchrony. An optimum asynchrony was identified, which was the same for both long and short words, but better performance was obtained with the shorter words that no longer overlapped. The second experiment investigated how disruption, workload, and preference are affected when presenting additional content accompanying a television programme. The content took the form of sound from different spatial locations or as text on a smartphone and the programme's soundtrack was either modified or left unaltered. Leaving the soundtrack unaltered or muting it negatively impacted user experience. Removing the speech from the television programme and presenting the secondary content as sound from a smartphone was the best auditory approach. This was found to compare well with the textual presentation, resulting in less visual disruption and imposing a similar workload. Additionally, the thesis reviews the state-of-the-art in television experiences and auditory displays. The human auditory system is introduced and important factors in the concurrent presentation of speech are highlighted. Conclusions about the utility of concurrency within auditory displays for television are made and areas for further work are identified.