Learn: the research behind the signals

By the RedFlag team

RedFlag measures body-language and voice signals in video. These explainers cover what the peer-reviewed research actually says about each signal — including the parts that cut against the hype. No technology can detect lies, and we say so on every page; what can be measured is where a speaker's signals diverge from their own baseline.

Can AI detect lies from video? What the evidence says

Short answer: no — and any tool that claims otherwise is overselling. What the research supports instead, and what is honestly measurable in a video.

Blink rate and deception: what the research shows

Do people blink more under pressure? The evidence on blink suppression, the post-load rebound, and why only person-relative baselines make sense.

Does your voice change under stress? Pitch, monotony and the evidence

What decades of paralinguistics research says about pitch under cognitive strain — and why commercial voice-stress analyzers scored at chance.

Cognitive load in speech: pauses, fillers and speaking rate

Thinking hard leaks into speech. The research on pauses, speech rate and fillers, and what a careful listener (or analyzer) can actually pick up.

Want the exact thresholds and test procedure behind the verdict? Read How RedFlag scores a video.