Scanning for Digital Content: How Blind and Sighted People Perceive Concurrent Speech

摘要

The widespread availability of digital media has changed the way that people consume information and has impacted the consumption of auditory information. Despite this recent popularity among sighted people, the use of auditory feedback to access digital information is not new for visually impaired users. However, its sequential nature undermines both blind and sighted people's ability to efficiently find relevant information in the midst of several potentially useful items. We propose taking advantage of the Cocktail Party Effect, which states that people are able to focus on a single speech source among several conversations, but still identify relevant content in the background. Therefore, in contrast to one sequential speech channel, we hypothesize that people can leverage concurrent speech channels to quickly get the gist of digital information. In this article, we present an experiment with 46 (23 blind, 23 sighted) participants, which aims to understand people's ability to search for relevant content listening to two, three, or four concurrent speech channels. Our results suggest that both blind and sighted people are able to process concurrent speech in scanning scenarios. In particular, the use of two concurrent sources may be used both to identify and understand the content of the relevant sentence. Moreover, three sources may be used for most people depending on the task intelligibility demands and user characteristics. Contrasting with related work, the use of different voices did not affect the perception of concurrent speech but was highly preferred by participants. To complement the analysis, we propose a set of scenarios that may benefit from the use of concurrent speech sources, for both blind and sighted people, toward a Design for All paradigm.