Cross-Cultural Variation and fMRI Lie-Detection

Abstract

As decidedly underscored by a recent editorial in Nature Neuroscience (2010), many experiments in cognitive neuroscience have been carried out using samples that are not representative of the general human population, as the subjects are usually university students in psychology. The underlying assumption of this practice is that the workings of the brain do not vary much even when subjects come from different cultural groups. Recent research by Henrich et al. (2010) shows that this assumption is unwarranted. On several basic features of perception and cognition, Western university students turn out to be outliers relative to the general human population. Hence, data based on them should be interpreted with caution. In particular, this situation seems to provide an argument for questioning the conformity of functional Magnetic Resonance Imaging (fMRI) lie-detection to Federal Rule of Evidence 702 and the Daubert standard. Deception is a social phenomenon and is related to mental functions, such as theory of mind, for which cross-cultural variability at the neural level has been detected. Furthermore, culture is a multi-dimensional variable whose effects are diverse. Thus, the use of fMRI lie-detection in legal contexts may hinder the ascertainment of truth if experimental results are not shown to be conserved in different cultures. Cross-cultural variability in neural activation patterns is just a facet of a broader issue of external and ecological validity for neuroscientific experiments on deception. Nonetheless, fMRI lie-detection is unlikely to meet the Daubert standard if cross-cultural variation is not controlled by appropriate experiments.

Keywords: fMRI, lie-detection, culture, cross-culturality, Daubert standard