Who Can Best Catch a Liar? A Meta-Analysis of Individual Differences in Detecting Deception

1. Who Can Best Catch a Liar?A Meta-Analysis of Individual Differences in Detecting Deception Michael G. Aamodt & Heather Mitchell Radford University Radford, Virginia

2. Criminal investigations Suspects Accusers Witnesses Psych evaluations Pre-employment Fitness for duty Insanity pleas Competence to stand trial Threat assessment Employment Interviews Reference checking Internal affairs Courtroom testimony Hostage negotiation Conflict management Political survival Detecting Deception in Police Psychology

3. Old Ways of Detecting Deception • India- Trial by Sacred Ass • Arabs - Hot iron to tongue • Chinese - Swallow rice flour • Hindus - Chew rice and spit • Inquisition - Chew and swallow a slice of bread and cheese • Judicial torture in Europe • King Solomon Source: Jack Annon

4. Electronic Methods Polygraph Voice stress analyzer Neurological Methods Brain fingerprinting Brain mapping Extreme Methods Chemicals Torture Communication Actual words used Paralanguage Body language New Ways of Detecting Deception

5. General Research Findings • People usually detect deception at slightly above chance levels • Subjects have a “truth bias” when responding • Training can help, but… • Having a baseline is essential • Listeners are better than interrogators • Use of patterns rather than single cues is essential

6. Behavioral Indicators Will Only Be Successful If • You have a baseline of behavior • There is a consequence for getting caught • The response is spontaneous • The person does not believe the lie (e.g., Clinton, O.J.) • The lie involves a high degree of cognitive complexity Source: Jack Annon

7. Scientific Inquiry • Deceiving • Cues used • Individual differences • Detecting Deception • Overall accuracy • Conditions affecting accuracy • Effect of training • Cues used • Individual differences in accuracy

8. Study of Deception is International in Nature • Sweden • Pär Anders Granhag (Göteborg University) • Leif Strömwall (Göteborg University) • Maria Hartwig (Göteborg University) • United Kingdom • Aldert Vrij (University of Portsmouth) • Siegfried Sporer (University of Aberdeen) • United States • Bella DePaulo (University of Virginia) • Paul Ekman (University of California, San Francisco) • Charles Bond (Texas Christian University) • Canada • Stephen Porter (Dalhousie University)

9. Australia Canada China England Germany Israel Jordan Netherlands Scotland Sweden United States Countries with Studies in Our Meta-Analysis

10. Our Study • Conduct a meta-analysis on individual differences in the ability to detect deception • Meta-analysis is a statistical review of the literature • Individual difference variables • Experience • Confidence • Sex • Personality

11. The Literature Review • Goal: Find all relevant studies from 1970-2003 • Others dates included when found • Study had to report correlations or a statistical test or raw data that could be converted into a correlation • Method • Computer searches • Bibliography leads • Hand searches of key journals

12. Volume 76 studies 9,453 subjects Study Date 1960s (2) 1970s (8) 1980s (22) 1990s (26) 2000s (18) Source Journal articles (67) Dissertations (7) Master’s theses (1) Book chapters (1) Literature Review Results

13. Each Meta-Analysis Contains • Number of studies (k) • Number of officers in the analysis (n) • Mean validity coefficient (r) • 95% confidence interval • % of observed variance explained by sampling error • If < 75% a search for moderators was conducted

14. Are Professionals Better than Students?

15. Problems in Comparing StudiesThe Stimuli are Different • Task • Realism • Consequence of getting caught • Stimulus • Length • Number of attempts • View (full body, head, voice only)

16. Is Confidence Related to Accuracy? Is confidence related to accuracy? Yes Size of the relationship? Small Can we generalize the findings? Yes Cops (k=11) Students (k=17) Other (K=2)

17. Is Experience Related to Accuracy? Is experience related to accuracy? No Size of the relationship? Can we generalize the findings? Yes Cops (k=7) Students (k=1) Other (K=0)

18. Is Age Related to Accuracy? Is age related to accuracy? No Size of the relationship? Can we generalize the findings? Yes Cops (k=5) Students (k=2) Other (K=1)

19. Is Sex Related to Accuracy? Note: A positive “d” indicates men were more accurate than women Is sex related to accuracy? No Size of the relationship? Can we generalize the findings? No Cops (k=3) Students (k=10) Other (K=2)

20. Is Personality Related to Accuracy? • Too few studies to determine • Openness (k=1) • Conscientiousness (k=1) • Extraversion (k=4 related, 2 on extraversion) • Agreeableness (k=2) • Neuroticism (k=2) • Other (k=7)

21. Analyses Still to be Conducted • Track down a few missing studies • Investigate moderators for Accuracy Rates • Medium (audio, visual, written) • Visual cue (face, body, legs) • Presence of a baseline • Number of segments viewed • Enhance database for sex differences • Contact recent authors for more info • Explore truth vs. lie accuracy • Actual difference • Role of truth bias and/or context

22. Questions? Michael G. Aamodt, Ph.D. Department of Psychology Radford University Radford, VA 24142-6946 (540) 831-5513 maamodt@radford.edu www.radford.edu/~maamodt

23. Citation Information for this Presentation Aamodt, M. G., & Mitchell, H.. (2004, October). Who can best catch a liar? A meta-analysis of individual differences in detecting deception. Paper presented at the annual Meeting of the Society for Police and Criminal Psychology, Rome, Italy.