“Blind” interviewing: Is ignorance bliss?

ABSTRACT

Current investigative interviewing guidelines [e.g., Technical Working Group: Eyewitness evidence. (1999). Eyewitness evidence: A guide for law enforcement. U.S. Department of Justice, Office of Justice Programs, National Institute of Justice. Retrieved from https://www.ncjrs.gov/pdffiles1/nij/178240.pdf] suggest that interviewers review available case information prior to conducting a witness interview. The present study investigated the effect of interviewers’ pre-interview awareness of crime details on eyewitnesses’ memory and interviewer behaviour shortly after a mock crime or a week later. Results indicate that blind interviewers with no knowledge about the crime elicited more correct information than those who were correctly informed about the crime. Differences in interviewer behaviour emerged only in the very first question of the interview: Blind interviewers were more likely to begin the interview with a non-suggestive question than the informed interviewers. Blind interviewers also recalled more details than the informed interviewers when asked to generate a report after the witness interview documenting the witness’ account.

KEYWORDS:

• Blind interviewing
• eyewitness memory
• investigator bias
• expectancy effects

Acknowledgments

We thank the following research assistants for their help with data collection and transcribing: Edin Mejia, Carmen Rodriguez, Nely Linares, Brock Brothers, ShirlyDorilas, Gabriel Mir, Amanda Lee, Irina Rodriguez, and Michelle Agudo.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Jillian R. Rivard http://orcid.org/0000-0002-7012-0396

Notes

¹Participants were asked to indicate the extent to which they knew the other participant prior to participating in the study. Three pairs (1.7 %) indicated a close, personal relationship (1 pair was dating, 2 pairs indicated they were family). Omitting these pairs did not significantly alter the pattern of results. Therefore all participant pairs were included in subsequent analyses.

²Combining correct and incorrect details into a measure of total quantity recalled also revealed a significant effect of interviewer type, F(2, 167) = 4.24, p = .016, and a marginal main effect of time delay on the number of details recalled, F(1, 167) = 3.63, p = .058, . The pattern of results was the same as for correct details recalled.

Additional information

Funding

This work was funded in part by the American Psychology-Law Society Grants-In-Aid Award.