These fun and informative lectures provide a tour of human perception systems and processes. They start by addressing each sensor: vision, hearing, tasting and smelling, and touching. The author then provides self-contained lectures on some interesting phenomena and research work in the field to provide a deeper understanding of sensory systems and human neurology in general. The facts that impressed me most are:
• Our visions are coupled with head motion senses. If you push your eyeball with a finger to move it, you see the world move in the opposite direction, as expected. But if your eyeball moves under the eye muscle control or because of the head motion, the world would appear stationary. Namely, the apparent motion is compensated by the brain.
• Vision and actions are closely related. While we have optical illusions and misjudge an object’s size, our hands know the correct size when we reach out to grab the object. Also, when we get ready to grab the object, the optical illusion about size goes away. This means we have two sets of neurons for size measurements. The action-related set takes over when we intend to take action.
• Before the body takes action, our mind rehearses the move. So, a more complicated move takes longer to get started.
• Our neural systems are plastic. But practicing a particular cognition task, we group multiple steps into a unit and execute faster. I wonder if I can leverage this knowledge in piano practice.
• Infants are born with certain cognitive prepositions. They recognize the mother’s voice and even the poem if the mother reads to them during pregnancy. They also display preferences to face and certain other objects.
• The brain can fill in the details that a sensor fails to catch. Our field of vision with high resolution is very small. However, the brain forms a large picture with high resolution by stitching multiple sensed images due to eye movement. I also noticed a video seems to be of higher resolution than a frozen frame. Perhaps that is related.\
• The opposing systems in the sensory systems suppress each other. The “red” sense suppresses the “green” sense. The “left-tilting” sense suppresses the “right-tilting” sense. These mechanisms usually work very well in enabling our ability to perceive the world. However, they can also create interesting illusions.
I wish the author cover the following topics in more details
• How does the brain construct a narrative from senses, and what role does attention play in the process? The author talked about attention and narrative here and there. A more systematic coverage would be excellent.
• What can AI and robotics learn from human perception studies?
• How do people vary in their perception abilities? Are these differences due to generics, childhood experiences, or training?
• How would our views of the world be if our sensory capability is different? What if we have a much sharper vision? What if we can hear a higher pitch or a lower pitch sounds?
Overall, these are outstanding lectures. They are easy to follow without requiring physiology and neurology backgrounds. The author passes not only his knowledge but also his love for the field. The lectures are worth listening to again at a later time.