Christof Koch Visual Demonstrations

These four demonstrations are excerpts from Christof Koch’s 2005 J. Robert Oppenheimer Memorial Lecture titled The Quest for Consciousness: A Neurobiological Approach. (Also the name of his 2004 book available on Amazon.com.) The J. Robert Oppenheimer Memorial Lecture series is sponsored by the J. Robert Oppenheimer Memorial Committee.

Note that I have made edits and inserted comments in these excerpts to aid the online viewer’s experience. Used with permission of Christof Koch and with thanks to the J. Robert Oppenheimer Memorial Committee.

These clips illustrate, in Koch’s words:

Conscious perception is, in a sense, a con job of the brain. It [our sense of perception] suggests there’s a stable world out there, and there’s a very simple relationship between what’s out there in the world and what’s inside our head. But in fact it’s a very complicated relationship. It’s actively constructed by our brain. We’re now beginning to understand that what I see in my head is actually constructed by my head, by my neurons.

Koch Demonstrates the Afterimage Effect

“This is called an afterimage, a negative afterimage … It belies the simple notion there’s a one-to-one relationship between the outside world and my inner mental experiences. In this case … the colors fade. So it depends not only on what’s out there, it depends on what’s the history? So clearly this naive, realistic view that there’s a world, there’s my head and this simple mapping, it can’t be true.”

Koch Demonstrates Change Blindness

Koch Demonstrates an example of Visual Consciousness

Koch Shows the Limits of Attentiveness


Compare Koch’s 2005 demonstrations with Alfred Korzybski’s 1948 demonstration of abstracting with his fan-disk.