In the context of encoding, describe how stress affects memory of an event. Discuss the results of the Morgan et al. (2004) study that examined the effects of stress on soldiers' ability to identify their interrogators.

Question

What will be an ideal response?

Answer 1

Answers may vary.Cognitive psychologists subdivide the building of a memory into three processes: encoding, storage, and retrieval. We describe the memory of eyewitnesses in each of these three stages. Encoding refers to the acquisition of information. Many aspects of a stimulus can affect how it is encoded; stimuli that are only briefly seen or heard cannot be encoded fully, of course. The complexity of a stimulus also affects its encoding. As the complexity of an event increases (consider an earthquake, explosion, or hurricane), some aspects of the event probably will be misremembered, whereas others will be accurately recalled.Contrary to what many people believe about a stressful event being "etched into memory forever," heightened arousal does not enhance the encoding of events. The stress of being victimized causes a defensive "fight or flight" reaction that interferes with the encoding of precise details. So although mild stress or arousal may indeed increase alertness and interest in a task, extreme stress usually causes the person to encode the information incompletely. Performance on many tasks is best when the level of arousal is sufficient to ensure adequate attention but not so high as to disrupt accuracy.A study of the accuracy of eyewitness memory in highly stressful military survival school interrogations provides good evidence of the effects of stress on memory (Morgan et al., 2004). Survival school interrogations are one of the greatest training challenges experienced by active duty military personnel. (These interrogations are intended to test one's ability to withstand exploitation by the enemy, and to train people to hold up under the physical and mental stresses of capture.) Participants in this study were 500 soldiers, sailors, and pilots who were placed in mock prisoner of war (POW) camps and deprived of food and sleep for approximately 48 hours prior to interrogation. During 40 minutes of intense questioning, half of them were physically threatened and all participants were tricked into giving away information. One day later, they were asked to identify their interrogators from an eight-picture photographic lineup (chance accuracy is therefore 1/8, or 12.5%). The results were startling. Among those who experienced moderate stress without the threat of physical injury, 76% were correct in identifying the target. But only 34% of participants who experienced the high stress of a physically threatening situation were correct.Characteristics of the witness also affect encoding in a variety of ways. The effects of stress are felt more acutely by those higher in anxiety and neuroticism. We all differ in visual acuity and hearing ability. When we have prior experience perceiving a stimulus we usually notice its details better than when we perceive something new. This is why experienced judges notice flaws in a gymnast's performance that the rest of us can detect only in a slow-motion replay. Different expectancies about upcoming events also influence how they are encoded; in general, we have a tendency to see what we expect to see.