Reaction-time symptoms of deception

Professor Hugo Munsterberg began experiment upon what was planned to be a series of psycho-physiological problems in the field of legal testimony. The first psycho-legal problem to be approached was the investigation of the psycho-physiological symptoms of the deceptive consciousness. The systolic blood pressure symptoms of lying were reported upon by the present writer in the Journal of Experimental Psychology for April, 1917. Analysis of reaction time association experiments and tests reported in the literature shows that judgments have been based jointly upon the qualitative and quantitative aspects of the results. The qualitative aspect of these tests lies in the association reaction words, and the quantitative in the reaction times recorded. Our problem in the present experiment was to eliminate the words and isolate, if possible, the quantitative measurements. In all previously reported tests no unanimity of qualitative results has been reported but, on the other hand, so great a unanimity of quantitative results has generally been found that psychologists seem to have accepted as established the thesis that deceptive emotions tend to increase both association reaction times and mean variations. Ten different subjects were used in the principal experiment in which two distinct types of reaction time behavior have been found during deception. The positive type, which is characterized by increased length of reaction times during deception, with accompanying increase of mean variations, and the negative type, in which the reaction times during deception appeared to be consistently shortened with, however, no consistent accompanying effect upon mean variations. (PsycINFO Database Record (c) 2012 APA, all rights reserved)