Man v. Machine

Man was still fighting hard against the machine last week. In Chicago, seasoned liars were still holding out against the lie detector.

The machine had won the first round. When the lie detector was introduced, its grim little pointer spotted surprised liars almost as soon as they opened their mouths. Hardened virtuosos who could fool a cop, a clergyman--or even a wife--were no match for the polygraph.

But the machines and their operators both had weaknesses. The liars, gaining experience, became so accomplished that Policeman John E. Reid, Chicago's lie-detector expert, has had to modernize his machines to cope with trickier lying.

The original lie detector measured the subject's respiration and blood pressure. These stayed at normal levels while the suspect was answering harmless preliminary questions. But when the questions struck nearer home, the emotional effort of lying made the heart pound harder, the breathing irregular. The machine marked such telltale reactions on a moving strip of paper.

But liars soon learned a better defense. They wriggled in their chairs, panted, peered wildly around the room. This made it hard to establish their normal respiration. Some tensed their muscles, trying to raise their blood pressure artificially even when telling the truth.

Mr. Reid now puts inflated rubber bladders under his subjects' arms and thighs. The new gadgets record all wiggles, jumps and muscle-tensing, so that self-induced reactions can be spotted.

The liars had not yet counterattacked, but no one believed they had really given up. So far, the struggle is a draw: the lie detector's findings are not accepted now (except by mutual agreement) in any court of law.

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