Figure - available from: International Journal of Social Robotics
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Each trial in Experiment 2 consists of a fixation screen, a visual cue (Human or Android), and an auditory target (human or robotic voice) after which subjects need to respond with a keypress
Source publication
Recent work in cognitive science suggests that our expectations affect visual perception. With the rise of artificial agents in human life in the last few decades, one important question is whether our expectations about non-human agents such as humanoid robots affect how we perceive them. In the present study, we addressed this question in an audi...
Citations
... Ultimately, naturalness research should also systematically consider interactions between vocal and visual aspects of naturalness in combination. Indeed, accumulating evidence suggests a complex interplay of visual appearance, vocal features, behavior, and the interactional context for the acceptance of virtual agents [28,[31][32][33][106][107][108][109][110][111][112][113]. ...
... Moreover, Sarigul and Urgen [46] showed that participants had shorter reaction times and more accurate responses when interacting with a robot that had a synthetic voice matching its mechanical appearance rather than a human voice. This congruence effect is evidence that matching a robot's voice and appearance improve participants' behavioral responses. ...
... Two different hypotheses can be derived from the literature. On the one hand, it has already been shown that an anthropomorphic appearance should match its communication [45,46] and the emotionality it contains [44]. As a consequence, affective speech, which is a human-like trait, should align better a human-like robot according to the congruence effect. ...
... The instructions of study II stated that the appearance of the robots should not be considered when evaluating the audios, and at least for the perceived attribution of a mind, the appearance of the robot had neither a positive nor a negative influence. Nevertheless, with this first approach, it was possible to investigate whether the matching hypothesis applies [46,52], which in our case showed that a human-like voice is even more beneficial for a technical appearance at least for social presence ratings. ...
The attribution of mind to others, either humans or artificial agents, can be conceptualized along two dimensions: experience and agency. These dimensions are crucial in interactions with robots, influencing how they are perceived and treated by humans. Specifically, a higher attribution of agency to robots is associated with greater perceived responsibility, while a higher attribution of experience enhances sympathy towards them. One potential strategy to increase the attribution of experience to robots is the application of affective communication induced via prosody and verbal content such as emotional words and speech style. In two online studies (NI = 30, NII = 60), participants listened to audio recordings in which robots introduced themselves. In study II, robot pictures were additionally presented to investigate potential matching effects between appearance and speech. Our results showed that both the use of emotional words and speaking expressively significantly increased the attributed experience of robots, whereas the attribution of agency remained unaffected. Findings further indicate that speaking expressively and using emotional words enhanced the perception of human-like qualities in artificial communication partners, with a more pronounced effect observed for technical robots compared to human-like robots. These insights can be used to improve the affective impact of synthesized robot speech and thus potentially increase the acceptance of robots to ensure long-term use.
... Humanoid robots have a strong representation in the media, which might shape the public's perception and assumed capabilities. For different robot appearances, the expected voice and resulting effects might differ [97]. ...
With the increasing performance of text-to-speech systems and their generated voices indistinguishable from natural human speech, the use of these systems for robots raises ethical and safety concerns. A robot with a natural voice could increase trust, which might result in over-reliance despite evidence for robot unreliability. To estimate the influence of a robot's voice on trust and compliance, we design a study that consists of two experiments. In a pre-study ( ) the most suitable natural and mechanical voice for the main study are estimated and selected for the main study. Afterward, in the main study ( ), the influence of a robot's voice on trust and compliance is evaluated in a cooperative game of Battleship with a robot as an assistant. During the experiment, the acceptance of the robot's advice and response time are measured, which indicate trust and compliance respectively. The results show that participants expect robots to sound human-like and that a robot with a natural voice is perceived as safer. Additionally, a natural voice can affect compliance. Despite repeated incorrect advice, the participants are more likely to rely on the robot with the natural voice. The results do not show a direct effect on trust. Natural voices provide increased intelligibility, and while they can increase compliance with the robot, the results indicate that natural voices might not lead to over-reliance. The results highlight the importance of incorporating voices into the design of social robots to improve communication, avoid adverse effects, and increase acceptance and adoption in society.
