EFFECTS OF INTELLIGENCE AND MEMORY ON NEUROPSYCHOLOGICAL RESPONSES IN POLYGRAPH TESTING

G. Li, Z. Hu

Abstract: The polygraph is widely used to detect concealed information or deception; however, whether examinees’ intelligence and memory quotients would influence the psychophysiological responses, and thus the effectiveness of the polygraph, has rarely been studied systematically. The present study investigated this issue by using a polygraph on 82 participants with intelligence or memory impairments in a Concealed Information Test (CIT). The Wechsler Adult Intelligence Scale and the Wechsler Memory Scale were used to measure participants’ intelligence and memory quotients. Analysis showed that participants’ total IQ score and their scores on subtests, including information, comprehension, similarities, arithmetic, digit-symbol coding, and block design, were positively correlated with skin conductance response and the detect accuracy of the polygraph test. Participants who were tested inaccurately had significantly lower IQ scores than those who were tested accurately. In contrast, no significant correlation was found between MQ and polygraph test accuracy; however, further research is needed to investigate this issue, considering the floor effect of the Wechsler Memory Scale. The present study is not only beneficial for utilizing polygraph more scientifically, but also for expanding its application on people with cognitive impairments.
Keywords: Polygraph, neuropsychological responses, electrodermal activity, intelligence, memory.