Testing the Forensic Confirmation Bias: How Jailhouse Informants Violate Evidentiary Independence

The influence of jailhouse informant testimony on jury deliberation.

“…The jailhouse informant’s testimony is typically offered in exchange for an incentive (e.g., reduced sentence or dropped charges; Roth, 2016), and these witnesses usually testify in the most serious cases (e.g., murder, rape) when there is a lack of other evidence (see Neuschatz et al, 2020). Jailhouse informant testimony is very influential at trial, even though jurors recognize informants have an incentive to lie (DeLoach et al, 2020; Jenkins et al, 2021; Neuschatz, 2008). However, prior research has focused on the perceptions of individual jurors and has not addressed the role that informant testimony plays during jury deliberations.…”

“…These studies have led to several significant findings. First, there has been a robust effect of jailhouse informant testimony compared with when such testimony is not presented—that is, mock jurors give more guilty verdicts when a jailhouse informant testified compared with when there was no jailhouse informant testimony (Jenkins et al, 2021; Maeder & Pica, 2014; Maeder & Yamamoto, 2017; Neuschatz et al, 2008; Neuschatz et al, 2012; Wetmore et al, 2014). Moreover, Jenkins et al and Wetmore et al found that jailhouse informant testimony led to as many guilty verdicts as when defendants themselves had confessed to the police about a crime.…”

Sometimes the Snitch Recants

“…In 13% of the cases, informant testimony appeared to be the only major evidence supporting a conviction. In another 29% of cases, the defendant had the word of an informant and only one additional contributing factor (e.g., confession, eyewitness misidentification, unvalidated/improper forensic evidence), evidence that can be potentially influenced by the words of an informant (Jenkins et al, 2021;Mote et al, 2018), and/or has been demonstrated as prone to error (online: https://innocenceproject.org/#causes). We also see evidence of the influential nature of informants when you consider that there was a greater tendency for defendants incriminated by informants to be given the death penalty.…”

“…Many participants who had originally made a line-up choice and received feedback about the potential guilt of another individual changed their choice after hearing that another lineup member was implicated. Similarly, Jenkins et al (2021) found that an informant's testimony could change the perception of forensic evidence. Specifically, they found that information from a "reliable" jailhouse informant (as opposed to an "unreliable" one who did not provide details that mirrored the known details of the crime) affected how participants interpreted handwriting samples.…”

“…Neuschatz et al (2020) found that the third most often contributing factor in these cases was eyewitness misidentification. As discussed earlier, both forensic evidence (Jenkins et al, 2021) and eyewitness testimony (Mote et al, 2018) have been shown to be potentially influenced by the word of an informant, and both have been demonstrated to be prone to error (online: https://innocenceproject.org/#causes).…”