Some of the Great Courses that I listen to or watch while I exercise inspire me to do write-ups. I recently finished listening to the audio version of Understanding the Secrets of Human Perception by Peter M. Vishton and watching the video version of The Big Bang and Beyond: Exploring the Early Universe by Gary Felder. The first, with a 2011 copyright, was in my shelves quite a while before I got to it. The second, with a 2022 copyright, is about as up-to-date as I get.
Some of the material on perception was familiar from long ago classes and more from years of keeping moderately current on new scientific research, but I learned a lot of details, especially about how much processing happens before we consciously perceive anything. Our brains do a lot of filling in before we consciously perceive, much of which depends on learning after birth. There is heavy processing of the sensory signals, integrated with a lot of knowledge about and modeling of the world we live in. There are dedicated brain regions for each of the senses and communication between these regions to coordinate data.
The invalidity of naive realism is something that has come up many times in years of LA-CCRS classes, and this course really reinforces that point. The amount of processing between sensory signals and conscious perceptions is a recurring theme through the whole course. There are also several points about non-conscious perceptions, such as the reflexes that close our eyes before we consciously see something approaching our faces. This course describes some pretty amazing capabilities built on limited sense organs, and also describes some quirks and problems.
One of my favorite lectures is about illusions. Since I was listening to an audio version rather than watching a video, I did some illusion searches on the web after hearing the lecture. These search terms all get very interesting pages to look at: “Kanizsa triangle”, “cafe wall illusion”, “motion-induced blindness”, and “paper dragon illusion”.
The lecture titles are “Your Amazing, Intelligent Senses”, “The Physiological Hardware of Your Senses”, “Neuroimaging—The Sensory Brain at Work”, “Brain Modules—Subcomponents of the Senses”, “Perceiving a World in Motion”, “Seeing Distance and Depth”, “Seeing Color and Light”, “Your World of Taste and Olfaction”, “Hearing the World around you”, “Speech and Language Perception”, “Touch—Temperature, Vibration, and Pressure”, “Pain—How It Works for You”, “Perception in Action”, “Attention and Perception”, “Kinesthetic Perception”, “Seeing, Remembering, Inferring Infants”, “How Infants Sense and Act On Their World”, “Illusions and Magic”, “Perceiving Emotion in Others and Ourselves”, “Sensing the Thoughts of Others—ESP”, “Opponent Process for Perception and Life”, “Synesthesia—Tasting Color and Seeing Sound”, “How Your Sensory Systems Learn”, and “Fixing, Replacing, and Enhancing the Senses”. I won’t try to summarize the whole course here. I recommend listening to the course or finding and reading a recently written book about human perception.
The Big Bang course stirred the sense of wonder that many science fiction readers and writers talk about. Much of the material covered ideas that have developed in my lifetime and that I have read about in newspapers and magazines, but watching the course really showed how much depth I missed that way.
One important distinction that is often ignored is that the “observable universe” is just a subset of the whole universe, but unless we find a way around light-speed limitations it is a firm limit on what we can ever perceive or measure despite how little of total reality it is.
The concept that impressed me the most is inflation—a VERY rapid expansion very early after the Big Bang. As described in the course, distances expanded by 10 to the million (a 1 followed by 1 million zeroes) in a billionth of a billionth of a billionth of a billionth of a second. I don’t think I ever read or heard the numbers before, just the label. Inflation is a refinement added to the basic Big Bang concept that explains several observed features of the universe that the basic concept left as puzzles (uniformity, flatness, lack of magnetic monopoles, and more). The basic version of inflation is solidly confirmed by observations. A not yet confirmed extension of the idea called “eternal inflation” takes it to mind-blowing levels, where our whole observable universe is barely a speck in a much vaster reality with new bits expanding into universes on an ongoing basis.
The lecture titles are “The Big Bang Changes Everything”, “The First Few Minutes of the Universe”, “First Galaxies, First Stars, and Dark Matter”, “How Big Was the Big Bang?”, “Mysteries That Reshaped the Big Bang Model”, “Inflation! The First Fraction of a Second”, “What Caused Inflation: The Scalar Field”, “More than One Big Bang in a Multiverse?”, “Other Universes across Other Dimensions?”, “The Origins of the Constants of Nature”, “From the Big Bang to the Universe’s Fate”, and “The Future of Early Universe Cosmology”. I recommend watching the course or finding and reading a recently written book about Big Bang cosmology.