Visual Perception
Last weekend we (Magdalena, Helenka and I) went to a lecture by Dr. Sabine Kastner, professor of neuroscience at Princeton University, about how the brain sees.
Professor Kastner opened with an experiment that clearly demonstrated that the brain determines what we see, not the eyes alone.
In this experiment we were shown a convex (pushed in from a flat surface) mask of the face of Albert Einstein. After looking at it for a few seconds it appeared to become concave, like a normal face.
The illusion demonstrates that our brains take visual information that comes into our retinas, and adjusts it to make sense.
It also demonstrates that the physics of sight are complicated.
We don't necessarily see what is right in front of our eyes!
Kastner explained that if these illusions, error corrections and selective inattentions didn’t occur, our brains would become extremely overworked. And that the cause of this is deeply embedded, the product evolutionary benefits a longtime in the making.
Several other experiments and demonstrations expanded Professor Kastner’s description of visual perception:
visual memories can be formed extremely quickly (in milliseconds)
binocular vision involves input switching from one eye to the other (but the dominant eye gets more time)
pre-existing information determines what we see (the name/title of an artwork literally influences our eye movement)
our brains classify and consolidate visual information into categories of memories (humans, faces, individuals)
Professor Kastner’s work carries forward that of her influential predecessor Charlie (Charles Gordon) Gross. His research involved listening for the pulses that happen in the brain after exposure to different types of images. For example, there are recognizably different pulses in our brains when we distinguish an image as “a person” or “a face” or "Albert Einstein”.
The lecture was part of a series called “Science on Saturday" geared toward high school science students (like my daughter) at the Princeton Plasma Physics Lab. You can see it and others, here:
https://www.pppl.gov/events/science-saturday-visual-perception-%E2%80%94-art-brain
