Stimuli fixation and manual response as a function of expectancies

Two experiments investigated effects of expectations on eye fixations and responses to expected and unexpected information in a laboratory setting. Stimulus fixation and manual responses to predefined targets among distractors were measured in a dynamic environment shown on a monitor. Participants were part of either a predictable condition (predictable sequence of targets and distractors) or a random condition. In the predictable condition, participants fixated expected distractors less than targets, with similar fixation times in the random condition. Responses to targets were faster in the predictable condition than in the random condition. Irregularities were either missed or responses were slow. This indicates that incorrect expectations may have negative consequences, with practical implications for skill-based tasks such as operator monitoring and driving. Actual or potential applications of this research include introducing operator support for tasks in which the risk of missing unexpected information or of slow responses may be dramatic.