A foolproof lie detector sounds like a marvellous breakthrough. But a world of pure honesty would be unbearable
“There’s no art to find the mind’s construction in the face,” wrote Shakespeare. But there is, increasingly, a science that does exactly that.
The search for a reliable lie detector has been going on for centuries, with limited success. In the 17th century Daniel Defoe argued that a lying criminal could be spotted by a raised pulse rate. The psychologist William Moulton Marston invented a systolic blood pressure test to assess honesty — a slightly more scientific version of his other enduring creation, the comic-book heroine Wonder Woman with her lasso that forces evildoers to tell the truth.
The polygraph, recording