Final answer:
Eye movement is critical to overt attention, which is the conscious focusing on specific aspects of our environment. This can be seen in visual processing tasks as well as in phenomena like inattentional blindness.
Step-by-step explanation:
The presence of eye movement is critical to overt attention. Overt attention involves consciously focusing on some aspect of our environment, often something we are looking at. The act of redirecting our gaze, and thus our visual focus, is a strong indicator of where our attention is directed. This can be observed in tasks that require visual processing, such as when a subject has to recognize faces on a screen in an experiment. Additionally, the concept of inattentional blindness, where a person fails to see an unexpected object (like the famous invisible gorilla) because their attention is engaged on something else, underscores the importance of attention in perception.