To introduce the concept of how sensation influences perception, the narrator of this psychology course, the fifth in a series of 13 videos, presents the case of Dr. Oliver Sacks, a physician that suffers from prosopagnosia. Also known as face blindness, prosopagnosia is a neurological disorder that impairs a person's ability to recognize faces. Signal Detection and Sensory Adaptation Theory, Weber's Law, and other scientific explanations for the neurology of vision are covered in the video.