Final answer:
According to feature-integration theory, attention is required to bind together the individual features of a stimulus.
Step-by-step explanation:
According to feature-integration theory, attention is required to bind together the individual features of a stimulus. Feature-integration theory is a psychological theory proposed by Treisman that explains how we perceive and process visual stimuli. According to this theory, when we encounter a visual stimulus, we initially perceive its individual features (such as color, shape, and orientation) separately. However, to perceive the stimulus as a whole, attention is required to integrate these features into a unified perception. This process is known as feature integration, and it occurs in the brain's visual processing areas.