05 Apr 2018
Houston, K. A., et al. (2013). The Emotional Eyewitness: The Effects of Emotion on Specific Aspects of Eyewitness Recall and Recognition Performance. Emotion, 13 (1), 118-128. doi: 10.1037/a0029220
In the world of criminal science, there are several factors that can interfere with the accuracy of eyewitness reports. This article, by Kate Houston and her team, delves into the effects of emotion on eyewitness encounters. The main argument that they are looking at focuses on negative emotion enhancing central memory while impairing the peripheral memory, where central memories are the main details that occurred, likely relating specifically to the action of the crime, and peripheral memories are the smaller details that were happening around the crime.
Houston notes that in spite of all of the writings on eyewitness memory, very few studies attempt to show a correlation between it and memory. She goes on to hypothesize that negative correlations will indeed enhance the central memory of the event, further exploring details like the crime itself. In her observations of other studies however, she does note that high stress scenarios tended to cause subjects to forget details about the perpetrator of the situation, at least in the case of a previous study on soldier’s interrogations. In order to test their hypotheses, Houston and her team set up two different experiments designed to test recall memory performance, as well as the participant’s ability to identify the perpetrator of the crime, both associated with negative emotional response.
In their first experiment, the team hypothesized that a negative emotional response would allow the participants to more easily describe details about the perpetrator. They gathered a participation group of 101 students from the University of Aberdeen (30 males; 71 females) to engage in the study. They divided the group into two subgroups. The group of 51 was shown a video that was meant to induce an emotional response, and the group of 50 was shown a video intended to illicit a neutral response from the participants. Both videos used the same actors and scenarios up to the point in which the story deviates to the emotional induction.
Once the participants had watched their respective videos, they were asked to answer a brief survey about how the video made them feel. They were given several different emotions, as well as a neutral “I feel nothing” option, and were asked to rank all of these emotions on a scale of 0-3 (0 being not at all, and 3 being very much). After they rated what they were feeling, the results were collected and the participants were given a 20 minute wait period in which they had to fill out a questionnaire on likes and dislikes, though this questionnaire was truly only present to provide a distraction for the next part of the experiment. The participants were then asked to write down as many details about the video that they could remember.
In the results of the experiment, Houston’s team discovered that the emotion-inducing video tended to cause much higher responses to negative emotions than the neutral video did. They also noticed that the group viewing the emotional video recalled the events of the emotional moment in much more clarity and complete detail than the neutral video control group, however, they could not recall details about the perpetrator as well. Their data also shows that there is not a significant correlation between the negative emotional responses and the amount of information given about the perpetrator and the critical moment. This data concludes that those experiencing negative emotions tended to focus their attention directly on the perpetrator, however, there was no significant difference in their ability to describe the perpetrator when compared to the results from the neutral video control group. While the idea that focus is altered in a critical moment coincided with the evidence, the data could not identify any significant difference in memory and recall.
The second experiment was designed to test whether or not negative emotions and stress impair the individual’s ability to identify a perpetrator when they are presented with a series of options (in this case, a photo line-up). Houston’s team used two separate photo line-ups for the experiment: one in which the perpetrator’s photo was present, and another where the perpetrator’s photo had been replaced by one that looked very similar to them. The team made sure to select alternates for the replacement photo based on resemblance to the perpetrator according to a method recommended by the Police and Criminal Evidence Act used to identify criminals in the United Kingdom.
They split up a group of 233 participants into relatively even subgroups at the beginning of the study. They began the study in the same way as the first experiment: two separate videos were shown, one emotional, one neutral, then the participants were asked about their emotional responses to the videos, and given time after the emotional response portion. Once the period after the emotional response survey had passed, the participants completed a recall survey about the videos, then they divided the groups again into two separate subgroups. One subgroup was shown the picture line-up containing the perpetrator’s image, while the other was shown the line-up with the face double’s image.
The results of the second experiment confirmed the team’s previous theories that the video was successful in eliciting an emotional response, and that emotional responses were similar to the previous experiment, based on their initial observations.
The second set of findings turned out to be in accordance with the initial hypothesis of the second experiment. Participants who watched the emotional video were much more likely than those who watched the neutral video to incorrectly identify an innocent target as the perpetrator. Around 25% of the time, participants in the group in which the perpetrator’s photo was included would claim that the perpetrator’s picture was not among those in the line-up. Those who saw the neutral video were much more likely to identify the real perpetrator (40.4% as opposed to 27.1% from the emotional video group). In the group in which the perpetrator’s photo was absent however, there appeared to be no significant correlation between emotional response and the answers given. The recall results for this experiment were very similar to the recall results for the first experiment.
In collecting their results from the second experiment, Houston’s team arrived at several conclusions based on the data that had been collected. Their data further supported the idea that people exposed to negative emotional experiences focused more on the perpetrator, but less on the rest of the situation, but they no longer had any sense of improved environmental detail. They both however showed the same level of accuracy in describing the target. The photo line-up tests show very different results however, showing that those exposed to negative emotional experiences would more likely identify the wrong target when the target’s picture appears along with others similar in appearance and features to them. When the target was not shown however, the emotional video groups tended to have similar results to those in the neutral video group.
In the team’s conclusion to their article, they discussed the probable reasoning behind the discrepancies in their experimental results. They note that the environmental results differ between the experiments, showing that it may be unreliable. The data as a whole shows that negative emotional responses may have different results on eyewitness testimony, depending on the situation.
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