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The impact of the apparently unreliable co-witness

Friday, January 31, 2014
posted by Rita Handrich

intoxicated witness 2We’ve written before about the intoxicated witness. While our mock jurors tend to dismiss them as unreliable, recent research presents a mixed picture as to their accuracy. New work out of New Zealand adds to the murkiness by having apparently intoxicated confederates witness an incident along with the research participant and then contribute misinformation during a discussion of what they had seen. The researchers were interested in whether apparent intoxication would influence the participant’s acceptance of the (intoxicated) co-witnesses’ misinformation. 

The researchers hypothesized that when the misinformation presented by the intoxicated witness was something the participant had not seen for themselves, it might “fill in the gaps” in participant memory and therefore be accepted as fact.

In those circumstances where the participant had their own memory and the intoxicated witness report varied from their own recollection–the participant would not accept the intoxicated person’s information as fact.

To test their hypotheses, the researchers had participants (and their paired confederate) watch a video clip of two simulated thefts committed in the university library by a male and female working together.

In half of the cases, both people drank lemonade (e.g., the sober co-witness condition). In the other half of the cases, the participant drank lemonade and watched their companion/confederate drink what appeared to be three alcoholic beverages (the intoxicated co-witness condition). The confederate behaved exactly the same way in both conditions (i.e., whether “sober” or “intoxicated”) so that the only difference was the research participant seeing them drinking a mixture of what appeared to be vodka and lemonade and then having the researcher “test” blood alcohol (which was always “over the legal limit”).

If you are wondering what the participant thought of being given lemonade while the confederate drank what appeared to be alcohol, the recruitment advertisement had warned the participants that they “may be required to consume enough alcohol to place them over the legal driving limit”. Plus, researchers are ever alert to suspicion, so, prior to each video viewing, the “bench surfaces in the testing room were wiped down with an alcohol solution” so that a distinct smell of alcohol was present.

After watching the videos, the two observers (i.e., the actual participant and the either intoxicated or sober co-witness confederate) discussed what they had seen (while the experimenter allegedly went to print some forms) and the confederate introduced misinformation (e.g., the accomplice’s eyes were blue not brown, a male student was visible behind the thieves and not a female student, the male thief wore black rather than blue jeans, and the thieves stole an MP3 player rather than a phone).

The experimenter then returned and separated the two so they could “complete subsequent tasks separately”. The actual research participant then completed a “filler task” on a computer and was then asked a series of questions about what they had seen on the video. They were asked to do another “filler task” for a few minutes and then were shown a series of 6 photographs with the actual thief in the video not present among them. They were told the actual accomplice might not be present in the photos and asked to identify the accomplice if possible.

The researchers went to great lengths to present a convincing “intoxicated co-witness” and had apparently done a pretty effective job, based on the impressions of research participants following the experiments. However, the research participants were just as likely to accept misinformation from the intoxicated co-witness as from the sober co-witness.

Follow-up analysis showed them that when there was a clear discrepancy between what the participant observed and what the co-witness told them (i.e., the misinformation), the participant was more likely to accept the accuracy of the sober witness than the intoxicated witness.

However, when the participant did not know the answer to the question shared by the misinforming co-witness, there was no real difference between their tendency to accept the information from a sober witness or an intoxicated witness.

It should be noted that this is research from an undergraduate population, a group that is surely very accustomed to interacting with intoxicated people towards whom they have positive feelings. Indeed, they might be regular ‘over the legal limit’ drinkers themselves. These factors are surely relevant to findings. Almost certainly, people who don’t ever drink, who are members of anti-drinking groups or who are critical of drinking seem likely to respond is a different way.

While our mock jurors resoundingly say you cannot rely on an intoxicated witness, these findings (and other research) muddies the water. Intoxicated witnesses may actually be credited with unimpaired recall, and, despite the voluminous research on issues with eye witness identification, participants in today’s research are more likely to rely on their own recollections than the discrepant feedback from even a sober co-witness.

Depending on your goals, there are two ways to go based on this (and prior) research:

Educate the jurors about problems with eye witness identification.

Educate jurors about the actual research showing intoxicated witnesses may have unimpaired recall.

Bolster the cognitive capacities of the intoxicated person, if possible, by pointing out that they did various things well (spoke clearly, was considered sober by non-drinkers present with them, et cetera) that indicate capacity.

Reasonable doubt, anyone?

Zajac, R., Dickson, J., Munn, R., & O’Neill, S. (2013). Trussht me, I know what I sshaw: The acceptance of misinformation from an apparently unreliable co-witness. Legal and Criminological Psychology. DOI: 10.1111/lcrp.12032


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