Feature detection is the identification of particular features in a visual stimulus to allow the brain to quickly extract the most relevant information so it can respond appropriately. Research on this topic dates to the 1950s, and it is not entirely accepted in the neurology community. Some people argue against the claim that there are neurons capable of identifying specific traits in stimuli, suggesting that this phenomenon is actually the result of highly connected groups of neurons working together to enhance perception.
According to theorists who promote feature detection, it is made possible by neurons that fire very selectively, in response to particular stimuli like edges, angles, or movement. The neurons act to quickly inform the brain about key aspects of a stimulus, allowing it to sort through irrelevant background information and make a decision about how to proceed. Since many organisms need very fast reflexes, perceptual speed can be critical.
In a simple example, prey animals like horses and sheep need to be able to quickly identify movement, even when it occurs in their peripheral vision. Their feature detection is fine-tuned for any signs of movement so they can identify predators and respond to them. Conversely, predators may have neurons to help them quickly distinguish prospective prey in the environment by looking specifically for particular angles, edges, and shapes.
Early neurological development starts in utero, as the brain and nervous system develop, and babies are born with some reflexes, including basic feature detection abilities. Their vision will improve after birth as their brains start to develop more networks and connection. Neural development happens very rapidly in youth, as babies explore their environment and pick up copious information about the world around them. Some of this information allows the brain to develop better feature detection to help the baby navigate the world more successfully.
Theories about feature detection underlie scholarship about human perception all over the world. Some scholars perform research to learn more about alternative modes of perception, with the goal of determining whether theories about feature detection are right. Others are more interested in developing a better understanding of how the brain's feature detection works, with the goal of gathering supportive information to promote their ideas about human perception. Studies can involve working with patients, looking at neurons to learn more about their structure and function, and studying the development of the brain and nervous system in growing organisms.