Auditory verbal hallucinations (AVHs)—or hearing voices—occur in clinical and non-clinical populations, but their mechanisms remain unclear. Predictive processing models of psychosis have proposed that hallucinations arise from an over-weighting of prior expectations in perception. It is unknown, however, whether this reflects (i) a sensitivity to explicit modulation of prior knowledge or (ii) a pre-existing tendency to spontaneously use such knowledge in ambiguous contexts. Four experiments were conducted to examine this question in healthy participants listening to ambiguous speech stimuli. In experiments 1a (n = 60) and 1b (n = 60), participants discriminated intelligible and unintelligible sine-wave speech before and after exposure to the original language templates (i.e. a modulation of expectation). No relationship was observed between top-down modulation and two common measures of hallucination-proneness. Experiment 2 (n = 99) confirmed this pattern with a different stimulus—sine-vocoded speech (SVS)—that was designed to minimize ceiling effects in discrimination and more closely model previous top-down effects reported in psychosis. In Experiment 3 (n = 134), participants were exposed to SVS without prior knowledge that it contained speech (i.e. naïve listening). AVH-proneness significantly predicted both pre-exposure identification of speech and successful recall for words hidden in SVS, indicating that participants could actually decode the hidden signal spontaneously. Altogether, these findings support a pre-existing tendency to spontaneously draw upon prior knowledge in healthy people prone to AVH, rather than a sensitivity to temporary modulations of expectation. We propose a model of clinical and non-clinical hallucinations, across auditory and visual modalities, with testable predictions for future research.

中文翻译：

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对幻听的易感性与自上而下对言语期望的自发而非定向调制有关

听觉幻觉 (AVH) - 或听到声音 - 发生在临床和非临床人群中，但其机制仍不清楚。精神病的预测处理模型提出，幻觉源于对感知中先前期望的过度加权。然而，尚不清楚这是否反映了（i）对先验知识的显式调制的敏感性或（ii）在模棱两可的上下文中自发使用此类知识的预先存在的趋势。进行了四项实验来检查健康参与者听模糊语音刺激的这个问题。在实验 1a (n = 60) 和 1b (n = 60) 中，参与者在暴露于原始语言模板之前和之后区分可理解和不可理解的正弦波语音（即期望的调制）。自上而下的调制与两种常见的幻觉倾向测量之间没有观察到任何关系。实验 2 (n = 99) 用不同的刺激——正弦语音编码 (SVS)——证实了这种模式，该刺激旨在最大限度地减少歧视中的天花板效应，并更接近地模拟以前在精神病中报告的自上而下效应。在实验 3 (n = 134) 中，参与者在事先不知道它包含语音的情况下暴露于 SVS（即天真的聆听）。AVH 倾向性显着预测了语音的曝光前识别和 SVS 中隐藏的单词的成功回忆，表明参与者实际上可以自发地解码隐藏的信号。总而言之，这些发现支持了一种预先存在的倾向，即自发利用易患 AVH 的健康人的先验知识，而不是对预期的临时调整敏感。我们提出了一个跨听觉和视觉模式的临床和非临床幻觉模型，并为未来的研究提供可测试的预测。