Manipulative design in user interfaces (conceptualized as dark patterns) has emerged as a significant impediment to the ethical design of technology and a threat to user agency and freedom of choice. While previous research focused on exploring these patterns in the context of graphical user interfaces, the impact of speech has largely been overlooked. We conducted a listening test (N = 50) to elicit participants' preferences regarding different synthetic voices that varied in terms of synthesis method (concatenative vs. neural) and prosodic qualities (speech pace and pitch variance), and then evaluated their impact in an online decision-making study (N = 101). Our results indicate a significant effect of voice qualities on the participant's choices, independently from the content of the available options. Our results also indicate that the voice's perceived engagement, ease of understanding, and domain fit directly translate to its impact on participants' behaviour in decision-making tasks.

翻译：用户界面中的操纵性设计（概念化为暗模式）已成为技术伦理设计的主要障碍，并对用户自主选择权构成威胁。尽管以往研究聚焦于图形用户界面中的此类模式，但语音的影响在很大程度上被忽视。我们通过一项听力测试（N=50）探究了参与者对不同合成语音的偏好，这些语音在合成方法（拼接式vs.神经式）和韵律特征（语速和音高变化）上存在差异，并在在线决策研究（N=101）中评估了其影响。结果表明，语音质量对参与者的选择具有显著影响，且该影响独立于可选内容本身。研究还发现，语音的感知参与度、易理解性和领域适配性直接影响其在决策任务中对参与者行为的调节作用。