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Authors' reply

Published online by Cambridge University Press:  02 January 2018

Rachael S. Fullam
Affiliation:
Centre for Forensic Behavioural Science, School of Psychology, Psychiatry and Psychological Medicine, Monash University, Victorian Institute of Forensic Mental Health, Locked Bag 10, Fairfield VIC 3078, Australia. Email: [email protected]
Mairead C. Dolan
Affiliation:
Centre for Forensic Behavioural Science, Monash University, Australia
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Abstract

Type
Columns
Copyright
Copyright © Royal College of Psychiatrists, 2009 

Dr Ehjaz appears to have misinterpreted the purpose of our study and his comments suggest a lack of awareness of the extensive literature examining the utility of fMRI for the detection of deception. Reference Simpson1Reference Spence4

The primary goal of our study was to examine the influence of psychopathic personality traits on neural responses exhibited during deception. We used a direct replication of a previously published simple deception paradigm developed by Spence et al Reference Spence, Farrow, Herford, Wilkinson, Zheng and Woodruff5 and our definition of deception was lifted directly from Spence's work in this area. We have clearly acknowledged in the paper that the work presented needs to be replicated with more sophisticated paradigms, including those with an emotional component. The issues surrounding deception paradigm design are adequately covered in the existing literature.

Dr Ehjaz states that our main findings were the reported reaction time differences between the lie and truth conditions. This is not correct. The key findings lie in the modulation of deception-related blood oxygen level-dependent responses by personality traits. The response time data are reported as a direct replication of Spence et al's Reference Spence, Farrow, Herford, Wilkinson, Zheng and Woodruff5 finding and indicate increased cognitive load associated with the production of a lie at the same time as withholding a truthful response. In neural terms, a mean response time difference of a tenth of a second is really rather significant.

References

1 Simpson, JR. Functional MRI lie detection: too good to be true? J Am Acad Psychiatry Law 2008; 36: 491–8.Google ScholarPubMed
2 Bles, M, Haynes, JD. Detecting concealed information using brain-imaging technology. Neurocase 2008; 14: 8292.CrossRefGoogle ScholarPubMed
3 Sip, KE, Roepstorff, A, McGregor, W, Frith, CD. Detecting deception: the scope and limits. Trends Cogn Sci 2008; 12: 4853.Google Scholar
4 Spence, SA. Playing Devil's advocate: the case against fMRI lie detection. Legal and Criminological Psychology 2008; 13: 1125.CrossRefGoogle Scholar
5 Spence, SA, Farrow, TD, Herford, AE, Wilkinson, ID, Zheng, Y Woodruff, PWR. Behavioural and functional anatomical correlates of deception in humans. Neuroreport 2001; 12: 2849–53.Google Scholar
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