Feature detection is a process in which the brain detects specific elements of visuals, such as lines, edges or movement. Nerve cells respond to the specific details and hone in on selective shapes and lights, thus blurring out the larger image.
As an element of the model of form perception, feature detection occurs gradually as a person's eyes are attracted to an image, object or person while nerve cells attract to a narrowed form of the overall visual and focus on smaller stimuli. For example, when looking at a large photo of a woman's face, most people first focus on the overall image. With feature detection, as neurons in the brain focus in on the photo, smaller details within the photo become more clear and focused, such as a small scar on the face, a close up of the skin's pigment or even one strand of hair versus the entire head of hair. People also hone in on lights or small flashes of light during feature detection. Instead of seeing a room full of blinking lights, when feature detection occurs, only certain colors or flashes are visible as the neurons in the brain become more narrowed and selective, thus communicating information to a person's eyes.