I'm a scientist (also a Great Professor contributor) who will be moving into a new position that involves the study of aging. My primary motivation was to understand how the senses change in advanced age. This isn't the primary motivation of this lecture - it seems that the aging aspect was added as a sideline at the end of topics to please the target audience. I did learn a lot that I didn't know about the senses and the professor is engaging and knowledgeable. Just don't expect an in-depth analysis of how our senses change in old age.