Abstract
People often believe that they have a fairly accurate perception of the world and events that take place during normal waking life. We know this not to be true. When engaged in cognitively complex tasks, we do not attend to, perceive, and remember some aspects of a scene, even if glaringly conspicuous. A gorilla walking through a scene will often go unnoticed by observers concentrating on a counting task (Simons & Chabris, 1999). Failures in attention and perception have often been implicated in this inattentional blindness. In two experiments, the roles of attention and perception on detection of an unexpected event are further explored. To do this, the salience of the unexpected event, a gorilla walking through a scene, was manipulated. In the first experiment, the salience of the unexpected event was manipulated by changing the extent to which the gorilla blended into the background of the scene. In the second experiment, the salience of the unexpected event was manipulated by presenting an auditory cue at various times during the observed scene. In both experiments, increased salience of the unexpected event leads to increased detection of the unexpected event, however a very salient unexpected event can still go undetected. Increases in the salience of unexpected events may still not be enough to change the focus of attention away from a cognitively demanding task. Are we simply not good noticers or are we just good filterers?