APA Dictionary of Psychology

any of various hypothetical or actual mechanisms within the human information-processing system that respond selectively to specific distinguishing features. For example, the visual system has feature detectors for lines and angles of different orientations as well as for more complex stimuli, such as faces. Feature detectors are also thought to play an important role in speech perception, where their function would be to detect those binary features that distinguish one phoneme from another. Also called feature analyzer.