Under some conditions, only a small part of a person's available attentional resources is directed to the task at hand. In these situations, people perform their task fairly well, on a more or less automated level, while keeping resources available for other tasks or thoughts. Typical situations include monitoring an ongoing process, such as in a radar air traffic control center or driving an automobile. This article reports on two studies that investigated the effects of eye fixations and responses to expected and unexpected information in a laboratory setting. Participants were shown either a predictable sequence of targets and distractors on a monitor, or shown a random sequence of targets and distractors on a monitor. The results showed that responses to targets were faster in the predictable condition than in the random condition. Irregularities were either missed or responses were slow. The author notes that incorrect expectations may have negative consequences, particularly in situations such as driving. In addition, the results showed a difference in the way people fixated stimuli according to whether they have expectations about which stimulus will be a target and which will be a distractor. The author concludes that actual or potential applications of this research include introducing operator support for tasks in which the risk of missing unexpected information or slow responses may be dramatic.
Abstract