Criminal investigation TV programs and forensic science/forensic psychology
I liked detective TV programs when I was a child, and I watched a lot of them.
On the trail of a suspect, the detective would show a person living near the scene of the crime a photograph and ask, “Have you seen this man?” If the local resident gave a big nod and said, “Yes, I have!” the person in the photograph was sure to be the criminal. And when fingerprints lifted at the scene were mechanically analyzed, they were compared against the huge number kept in the police database very quickly like the spinning wheels of a slot machine. If a fingerprint that matched perfectly was found when the wheels stopped, the person with the fingerprint was invariably the culprit.
But such scenes do not reflect reality.
Photographic identification by witnesses
In order to prevent false accusations, the process of having a witness pick out the photograph of a suspect should be handled by an investigator who does not know who the suspect is, and photographs of multiple people who resemble the suspect should be shown one at a time (consecutive display) rather than all at once (simultaneous display).
Zimmerman et al. (2017) have shown that investigators who know which photograph is of the suspect exert more pressure on witnesses when they are choosing than those who do not. This pressure includes both verbal signals (such as asking, “Are you sure?” if the witness points to a picture that is not of the suspect) and non-verbal signals (such as pointing at a particular picture). They also showed that pressure is applied more frequently when pictures are shown simultaneously than when they are shown consecutively, and that the rate of witnesses misidentifying an innocent person one week later is higher in cases in which the investigator handling the identification process knows who the suspect is. It is also important that investigators instruct witnesses in advance that the criminal may or may not appear in the photographs they are shown. Giving these instructions reduces the misidentification of innocent people as criminals (Steblay, 2013).
Fingerprint analysis by experts
Fingerprint analysis is conducted by comparing the characteristics (ridge ending, short ridge, bifurcation, etc.) of fingerprints obtained at the scene of the crime with the characteristics of the suspect’s fingerprints, and the determination of whether the fingerprints belong to the same person is made based on the similarity of these characteristics (Hiraoka, 2018). Ultimately, however, this is a judgement made by a person looking at the fingerprints, and several biases that can affect the results of fingerprint analysis have been identified.
Dror et al. (2011) have shown that the results of fingerprint comparisons differ among experts. According to their research, when ten experts with no knowledge of the suspect compared the same fingerprints, consistency in the measurement of characteristics was not seen, and their standards for detecting characteristics differed. Even the results of the comparison of the same fingerprints by a single expert were not always consistent. In addition to these findings, Hiraoka (2018) cites the fact that the fingerprints left at the scene are often insufficient (too few in number or incomplete) for analysis and bias affecting fingerprint analysis caused by other information obtained by the analyst (such as the results of DNA testing) in warning against blind faith in the evidence presented by fingerprint experts.
Criminal investigation TV programs and forensic science/forensic psychology
The possibility of bias emerging in the process of identifying criminals has also been pointed out in regard to other identification processes in addition to photographic identification and fingerprint analysis. If the knowledge concerning various biases obtained through research in forensic science/forensic psychology were incorporated into criminal investigation TV programs, this would perhaps help raise awareness of the reliability of evidence. I’m sure that forensic scientists and forensic psychologists would be happy to collaborate in the production of such programs.
References
- Dror, I.E., Champod. C., Langenburg, G., Charlton, D., Hunt, H., & Rosenthal, R.（2011） Cognitive issues in fingerprint analysis: Inter-and intra-expert consistency and the effect of a ‘target’ comparison. Forensic Science International, 208, 10-17.
- Hiraoka, Y.(2018) Forensic Science and Bias. Konan Hogaku : Konan Law Review, 58, 3・4, 93-111..
- Steblay, N, M.（1997）Social Influence in Eyewitness Recall: A Meta-Analytic Review of Lineup Instruction Effects. Law and Human Behavior, 21（3）, 283–297.
- Zimmerman, D. M., Chorn, J. A., Rhead, L. M., Evelo, A. J., & Kovera, M. B. (2017) Memory strength and lineup presentation moderate effects of administrator influence on mistaken identifications. Journal of Experimental Psychology: Applied, 23, 460–473.
