LIE DETECTION

Evening Post, Volume CXXV, Issue 151, 29 June 1938, Page 14

LIE DETECTION

SCIENTIFIC METHODS

ADDRESS BY PROFESSOR SHELLEY

The scientific detection of lies was the subject of an address given by Professor James Shelley, Director of Broadcasting, at the monthly luncheon of the Wellington Returned Soldiers' Association today. During the past generation, said Professor Shelley, there had been many successful attempts to get, as it were, beneath the surface of things. The detection of frauds had been very successfully applied to old One under suspicion would be first subjected to an X-ray examination and that would probably be quite sufficient to show whether it was a genuine old master or not. If that failed an analysis of the colours of the picture by ultraviolet rays would reveal the age of the picture, for seventeenth century colours were very different in chemical constitution from more modern colours which gave the same visual appearance. Ultra-violet rays were also used upon old manuscripts. Palimpsests, or pieces of parchment which because of the scarcity of parchment had had their original writing erased and had been used again, were subjected to ultra-violet rays which revealed the first writing. By that means, in the United States in particular, old plays and poems had been found written on manuscripts that on the surface bore only a man's personal accounts, or the like. , . Modern methods of lie detection in human beings, continued ProfessorShelley, were based upon the fact that when a man told a lie, or even smiled or coughed or made any facial movement, not only the muscles of the face but his whole being was affected. His whole make-up was changed. The needle of a psycho-galvanometer, the electrodes of which were in contact with the body, would flicker with a cough because of the change in the action of the sweat glands of the skin. A smile, or the emotion of fear, would similarly affect the sweat glands and the change would be registered by the Sa Anoth« et way of detecting lies was by the measurement of the changes in the heart-rate and the breathing. It was an instrument for doing this that was commonly called the "lie detector " said the professor. The action of the heart could not consciously be controlled, but it and blood pressure changed according to one's mental state and could be recorded on a graph. Sometimes the heart-beats and blood pressure and the sweat glands were tested simultaneously, the results being shown on two or three curves. "By an examination of these curves, said Professor Shelley, "you can tell when the person is lying. You can also tell when he is innocent. It is obvious that you can never rely on things like that in order to condemn a man, but you can in order to acquit him." Suspicions aroused by the results of the tests, said Professor Shelley, would give a lead as to investigations that would lead to conviction.

A person questioned about a crime, sai3 Professor Shelley, would be in a state of high nervous tension whether he were innocent or guilty, but the "lie detector" could not be deceived. .A man, though telling the truth, might blush and show other signs on his face, but they would not be recorded on the heart-pressure graph. A person might

tell a lie not connected with the crime, but with a little experience it vas easy for the investigator to eliminate things like that. The ancient practice of ordeal and torture was based on a similar principle to that of the scientific lie-detect-ing instruments, said the professor. All were directed to the breaking down of the nervous controls, but whereas torture and ordeal were directed against the conscious controls, the scientific methods were directed against the unconscious parts of the system that could not be controlled.