Inattentional Blindness is a psychological phenomenon where individuals fail to notice an unexpected stimulus in their visual field when they are focused on a different task. This occurs because the brain has limited processing capacity, leading to selective attention. As a result, important details can be overlooked, even if they are in plain sight. A classic example of Inattentional Blindness is the famous Gorilla Experiment, where participants watching a basketball game were asked to count the number of passes. Many failed to notice a person in a gorilla suit walking through the scene, demonstrating how focused attention can blind us to other significant events.