An investigation of the effects of language dominance on polygraph results
Polygraphy is a practice plagued by controversy within psychophysiological science. Debated issues range from whether or not a relationship between lying and physiology exists, to the accuracy of the test itself. This experiment was directed towards bilinguals: are bilinguals at any type of disadvantage when subjected to a polygraph? It was hypothesized bilinguals who were asked questions in their non-dominant language would show different physiological responses compared to when they are asked questions in their dominant language during a CQT. Questions addressed in the non-dominant language were expected to elicit novelty responses, or emotional arousal, and it was expected that responses to these questions would be larger compared to the responses to questions asked in the examinee's dominant language. A total of 60 (37 female) bilingual participants were part of the study. Participants filled out 2 instruments to measure English/Spanish language use, read a scenario, and were subjected to a polygraph test regarding the scenario. The polygraph test was conducted in both English and Spanish. Physiological responses questions were recorded using a physiograph, and were used in the analysis as the dependent variable. Two within subjects MANOVAs were conducted to look for language effects. Language in which the question was asked did not have any effect on response size. The analyses revealed that no significant interactions were present. Possible factors that could have caused a null result include a large amount of individual variability within the data, no relationship between language and physiological response, or the lack of realistic consequences that would be present during a real polygraph test. Future studies on this topic should attempt to use better equipment to record the data, concentrate on participants who are highly dominant in one language and less fluent in their second language, or focus on reaction times rather than skin resistance responses.
Pizana, Andrea Aimee, "An investigation of the effects of language dominance on polygraph results" (2004). ETD Collection for University of Texas, El Paso. AAI1423714.