Are effects of perceptual (dis)fluency on social judgments specific to visual processing?

Visual perception is often effortless, but not always: reading, for example, is faster and easier with some fonts compared to others. Such differences in visual *fluency* (the ease, or lack thereof, of information processing) can have profound effects on higher-level cognition and decision-making. When a written passage is held constant, for example, its author may nevertheless be judged as less intelligent (or the message may be judged as less truthful) when the passage is written in a disfluent (but still legible) font. Such effects are often normatively inappropriate, insofar as the ‘vehicle’ of a message (e.g. its font) has no necessary bearing on its actual content (e.g. its truth). Are such effects specific to visual processing, per se, or do they reflect more general perceptual principles? To find out, we explored analogous perceptual (dis)fluency in the auditory domain. In the modern era, the sounds of voices are often determined not only by intrinsic qualities (such as vocal anatomy), but also by extrinsic properties (such as videoconferencing microphone quality). We show that such superficial auditory properties also have surprisingly deep consequences for higher-level social judgments. Listeners heard short narrated passages (e.g. from job application essays), and then made various judgments about the speakers. Critically, the recordings were modified to simulate different microphone qualities, while carefully equating listeners’ comprehension of the words themselves. Common disfluent auditory signals (as in ‘tinny’ speech) led to lower judgments of intelligence, hireability, credibility, and romantic desirability. These effects were robust across speaker gender and accent, and occurred for both human and clearly artificial (computer-synthesized) speech. (And such effects may become more impactful as daily communication via videoconferencing becomes increasingly prevalent.) These results demonstrate that such fluency effects reflect a more abstract form of information processing that transcends visual perception.