An Examination of the Impact of Synthetic Speech on Unattended Recall in a Dichotic Listening Task

Abstract

Synthetic speech, which is generated by a computer, is widely used in both everyday situations (e.g. GPS devices; weather alerts) and the military (e.g. aviation). Synthetic speech is not identical to spoken speech, as it has a different pacing and varying pronunciations. Participants engaged in a Dichotic Listening Task in which they actively repeated information that was being presented in one ear, while ignoring their other (unattended) ear. The task was adapted and used both synthetic and spoken speech in the attended and unattended ears. It was found that when the unattended information was Spoken participants were more likely to hear an alert word ("fire") and familiar character names when engaging in a difficult task. When unattended information was in the form of Synthetic Speech less of these low-threshold words were reported by the participants. This research has important implications for the development and use of synthetic speech in high workload situations, and in alerts.

Differences in the Performance of Older and Younger Adults in a Natural vs. Synthetic Speech Dichotic Listening Task

“…The Sinatra, et al (2011) study was used as a guide for coding the reported unattended data. Two independent coders examined the reported information from the current study, and the original data, and coded it in three categories, each of which had a maximum possible score of 2.…”

“…However, more recent studies have indicated that some participants could report information about the content of their unattended ear (Sinatra, Sims, Najle, & Chin, 2011;Wood & Cowan, 1995). One possible reason for this difference is that the earlier dichotic listening studies tended to be less consistent with their unattended stimuli, which often were without context (e.g., numbers, unrelated words, newspaper articles).…”

“…The current study set out to replicate the Sinatra et al (2011) study by using the same methodology and stimuli used in the original task, but with an older adult sample. The results of the new older adult sample were then compared to that of the original younger adult sample.…”

“…Specifically, the amount reported was significantly higher when Natural speech was present in their unattended ears, as opposed to Synthetic speech (Sinatra, et al, 2011). See tables 3 and 4 for the means and standard deviations for the semantic and low-threshold information.…”

“…In Sinatra, et al (2011) the impact of shadowing natural versus synthetic speech, and blocking out natural versus synthetic speech were examined.…”