Anxiety can have positive or negative effects on eye witness testimonies. The positive effect that anxiety can have on eye witness testimony is when the fight or flight response is triggered, which causes an increase in arousal. This increase in arousal increases alertness and allows people to attend to more cues in the situation, e.g. pupil dilation means that more cues can be attended to in the environment. Therefore, we pay attention to more cues in a situation it means that more information can be retrieved rather than forgotten, improving the accuracy of eye witness testimony.

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An evaluation of how anxiety can be positive on eye witness testimonies is from Yuille and Cutshall (1986) a real-life shooting in a gun shop in Vancouver. The shop owner shot a thief dead, there was 21 witnesses, and 13 took part in the study. Interviews were carried out for the study 4-5 months after the shooting, and were compared with the interviews carried out by police at the time of the incident. The accuracy of the testimonies were measured by the number of details reported in each account. Participants also had to rate how stressful they felt at the time and asked if they had any emotional problems since the event. Witnesses were very accurate in their accounts, there was little change in the accuracy after 5 months. Those who rated the highest levels of stress were most accurate in their recall 88% compared to 77% less stressed.

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However, anxiety can also have a negative effect when someone becomes over aroused. Over arousal can happen when the event is serious, e.g. lots of blood or there is a weapon involved. When we become over aroused this then negatively affects our attention as it reduces our ability to attend to cues in a situation. With a weapon or blood you can suffer from “tunnel vision” where you only attend to the stimulus not the cues in the whole environment. This then results in retrieval failure and causes EWT to be less accurate because the cues from the situation were not attended to.

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This difference in anxiety can be explained by the Yerkes Dodson law of stress. There is an optimum level of anxiety that results in maximum memory accuracy, but any stress after this optimum level negatively affects recall.

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An evaluation of how anxiety an be negative on eye witness testimonies is from Johnson and Scott (1976) participants believed they were taking part in a lab experiment. Whilst sitting in the waiting room the participants heard an argument between two people in the next room. There was a low anxiety condition where a man walked through the waiting room after the argument with a pen and grease on his hands. And there was a high anxiety condition – heard same argument + broken glass – a man then walked through the waiting room with a knife covered in blood. They found that participants had to identify the man who had walked through waiting room. Those who had low anxiety were 49% accurate and those who had high anxiety were 33% accurate. In conclusion tunnel theory of memory shows that a witness’s attention narrows down to the weapon due to it being a source of anxiety.