AN INTERESTING DEVICE

King Country Chronicle, Volume XXVI, Issue 3442, 12 March 1932, Page 2

AN INTERESTING DEVICE

TO BETRAY LIES. INDICATOR NOT YET PERFECT. An interesting device, with great possibilities; yet even its inventor regards it as not yet perfected, and does not advise its use in courts of law as the main or most important evidential feature—that is the verdict on the “lie indicator.” George JV. Hanley of the Institute for Juvenile Research of the State of Illinois writes in The Finger-Print Magazine (Chicago.) Late in the nineteenth century, Lombroso, working with criminal suspects, found a positive correlation between pulse rate and attempts to deceive on cross-examination. V. Benussi used the pneumograph to detect deception. He determined the inspiration-expiration ratio of each breath, and discovered significant changes in the breathing ratios fol- * lowing attempts at lying. H. E, Burtt used Benussi’s method, and also noted changes in the systolic blood-pressure, as had Marston before him. “Early in 1921 Dr. John A. Larson devised a method of taking bloodpressure and breathing changes continuously. He modified the Erlanger sphygmcmanometor (a blood pressure apparatus) so that the hearty activity could be recorded graphically on smoked drums, which in turn were driven continuously and at a constant speed. The method is simple and direct. No attempt is made to play upon the emotions of the suspect or in any way to startle him into making an erratic record. The examinee is seated in a comfortable chair, his left arm bared above the elbow. The 'blood-pressure cuff is adjusted about the left arm and the pneumograph

placed about the chest. “Pressure is pumped into the cuff. The examinee is cautioned not to move or speak until he is told to do so. For three minutes a normal record is taken. Following this he is asked three non-significant questions, e.g., ‘Have you had your breakfast?' ‘Do you live in Chicago?’ Do you live at 2310 56th Street?” The record made while these questions are being asked is used as a check against the record later made when significant questions are asked. “The last three questions are the significant questions. ‘Do you have any guilty knowledge of this theft (murder, etc.).’ ‘Did you take the cashbox?’ ‘Have these answers been truthful?’ “At the close of the examination the record is scanned, special attention being paid to changes between that portion where ‘crime’ questions were asked, and those sections known as ‘normal’ and non-significant. “The innocent are not especially disturbed by being questioned on the crime.

“There have been some 8000 records run on criminal suspects, and of the 8000 there have* been six checked failures. By failures is meant that the interpretation of the record is in error.

“Either the individual examined has given a “clear” record, and has subsequently been proven guilty, or, he has given a “disturbed” record, and has later been able to prove himself innoce'nt.

“Just now Dr. Larson’s laboratory is attempting to determine accurately just what the percentage of failure will prove to be. Suffice is to say, since it has failed in six or 8000 instances, it should never be considered as court evidence on an equal footing with finger-prints. “No suspect should ever be ‘booked’ fior should the ‘lie-detector record’ be used against him when such a record forms the main and most important body of the evidence. One is never able to predict when the next failure will come.

“As an indication of the extremely conservative attitude regarding court evidence, it might be of interest to know that Dr. Larson was asked in as a consultant for the defence in a murder case which recently has attracted very wide public interest. “Dr. Larsen refused to become a consultant in this case. His reasons were those Which he has maintained for ten years in trials in which he has been a witness.

“First of all he feels that the method is not perfect. Out of every hundred cases, perhaps as many as twenty show failures. This is due not only to the method but to the interpretation of the record itself. Of the eight or ten men in the country who are acquainted with the technique, and therefore reasonably qualified to interpret the record, there is likely to be disagreement as to what the record in any particular case really shows.”