Participants who heard only audio identified lies with 61.7% accuracy, versus 35% for those who watched video with sound in Dora Giorgianni’s mock-suspect interview tests.
Giorgianni argues visual and verbal cues together can overload attention and memory, making people worse at judging deception than when they focus on voice alone.
The findings challenge the common belief that facial expressions and body language reliably expose liars; stress cues such as faster speech or a higher pitch can appear in truthful people too.
University of Portsmouth research during the pandemic similarly found face masks improved jurors’ ability to distinguish truth from lies, reinforcing the case for limiting visual input in investigative settings.
Even so, experts say no single vocal cue consistently reveals deception, and voice analysis remains probabilistic rather than definitive.
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