Reconsidering the Voice Principle with Non-native Language Speakers

Researchers have suggested that use of pedagogical agents speaking with a human voice increases social perception and enables deeper learning when compared against computer-generated voice. However, recent research (Craig & Schroeder, 2017) found modern computer voice was as effective as human voice in certain social measures, and can outperformed human voice in particular learning outcomes. This research aimed to study whether two human voice conditions (strong-prosodic and weak-prosodic) produced consistent measures when compared against modern computer voice and each other in social perception and retention measures with non-native speakers. The human weak-prosodic voice was rated significantly higher on four of seven scale items compared to modern computer voice. However, no significant differences were found in the retention of information. These results show that non-native speakers prefer human voice with less prosodic elements, and factors behind voice are more complicated than just categorizing it as either human or computer.