ecological validity may be hard to support could be the difficulty in testing this effect on actual eyewitnesses and their memory of a crime. On the other hand, a study published in 2004 found the opposite when confronted with weapon focus. It found that the exposure to firearms was associated with significantly better eyewitness descriptions especially regarding basic features such as gender, height, build, age, and ethnicity. Causes of weapon focus A leading explanation for a cause of weapon focus is the unusualness of the situation, being a witness to a crime. Since the initial research conducted by Johnson and Scott (1976) and Loftus et al. (1987), others have demonstrated a similar effect using unusual objects rather than weapons. These findings are described as the "Unusual Item Hypothesis." This effect is seen when an object does not fit with the schema of the situation. Attention is then drawn to the out-of-place object and less attention is paid to other objects in the scene making recalling these other objects more difficult. This effect was observed in Toronto in 1997 when a robber entered a coffee shop and demanded money while threatening to strangle a goose he was holding if the he did not receive the money. Meanwhile, the customers were too focused on the strangeness of a goose in the coffee shop to observe any details about the perpetrator himself. This effect has also been observed in the lab. For example, Pickel (1998) demonstrated an effect comparable to weapon focus using a video in which a man approached a cashier and presented a whole raw chicken or miniature Pillsbury Dough Boy instead of an expected item such as a wallet. From her finding, Pickel (1998) argued that the weapon focus arose from the unusual nature of the object in the relation to the context in which it was presented. In their 2013 meta-analysis, Fawcett et al. (2013) presented the issues surrounding the arousal/threat hypothesis. This is one of the oldest explanations connected to the weapon focus phenomenon, and relies on the Yerkes-Dodson law that links arousal and performance; emotionally arousing states, such as stress, can enhance performance up to a point, but after this there are detrimental impacts on cognitive functions, like memory and learning. The amygdala, a brain region located near the center of the brain, is responsible for fear processing and emotional response to both negative and positive stimuli.