Polygraphs — do they really work

• Published date: 01 October 2022
• Publication title: Hawkes Bay Today

By Amit Katwala, HarperCollins, $37.99

This is the story of how truth telling could be scientifically measured, and used to convict or free someone suspected of a crime. And whether it’s actually trustworthy.

The polygraph measures heart rate, breathing and is supposed to be infallible as the body betrays its owner. Except that’s not actually true. There are hundreds who failed polygraphs for whatever reason who were later exonerated.

Katwala looks into the early invention by a rookie detective and a teenage magician. The detective had a PhD and researched fingerprint...