Polygraphs Measure Stress, Not Lies

Polygraphs are machines that try to catch lies by measuring things like heart rate and sweating.

The idea is that lying causes stress, which shows up in these measurements.

But experts say this isn't always true.

Stress can come from lots of things, like anxiety or fear, not just lying.

Some people might lie and not show stress, while others might be truthful but show stress and seem like they're lying.

This makes polygraphs unreliable.

Courts in India don't even allow polygraph results as evidence.

There have been cases where polygraphs got it wrong, like a serial killer passing the test in the US.

So, while polygraphs might seem like a good way to catch lies, they're not foolproof and can be tricked by our bodies' natural responses.