“How Do We See?” A Discussion on Visual Perception

On May 17, 2017, Jonathan Fanton introduced a discussion on visual perception, entitled “How Do We See?Ken Nakayama moderated the discussion between Charles Gilbert and Dale Purves.

The discussion served as the 2054th Stated Meeting of the American Academy of Arts and Sciences.

Good evening.  I am Jonathan Fanton, President of the American Academy. It is my pleasure to welcome you and to call to order the 2054th Stated Meeting of the American Academy of Arts and Sciences.

Our topic this evening is “How do we see?” As you can imagine, questions about how vision works have been ever-present throughout the life of the Academy. In fact, an issue of the Academy’s Memoirs from 1809 contains a communication from Peres Fobes, a Massachusetts clergyman elected to the Academy in 1780, entitled “A Curious Phenomenon of Vision.” His letter describes the case of a 46-year-old man named Pierce who had “a kind of ulcer collected in his head,” which confined him to his home with weak eyesight and extreme sensitivity to light.

One night the ulcer broke, and Mr. Pierce awoke free of pain, feeling well and composed. He arose and went to look out a window, and, as Reverend Fobes described,

“to his great surprise [Pierce] saw, at a place called Reed’s ware-house, near the ferry, at the distance of near two miles, a cart and yoke of oxen. He could plainly discern the color of the oxen, the rounds in the cart, the stones on the beach, and even the courses and joints in the shingles on the ware-house. This extraordinary degree of acute, telescopic vision continued for about one hour; after which his sight returned to its usual state.”

The letter goes on to vouch for Mr. Pierce’s character and judgment.

Reverend Fobes concludes by lamenting that he lacked the time to attempt to explain the phenomenon using knowledge of the structure of the eye and the principles of optics, noting it could be the topic of a future dissertation.

Over the years, the Academy continued to elect members concerned with the mechanisms of vision. Some examples include:

  • Englishman Thomas Young, a Foreign Honorary Member elected in 1822, who has been called the father of physiological optics and is identified as the first to describe astigmatism.
  • Foreign Honorary Member John Dalton, elected in 1834, was color-blind and one of the first scientists to take interest in the subject of color blindness, sometimes called Daltonism.
  • Americans Halden Keffer Hartlin, (Fellow elected 1957) and George Wald (Fellow elected 1948), won the Nobel Prize in 1967 along with Ragnar Arthur Granit for discoveries concerning the primary physiological and chemical visual processes in the eye.
  • And two years ago, the Academy elected Margaret Livingstone, a neurobiologist at Harvard, who wrote “Vision and Art: The Biology of Seeing,” a book that explores how the visual effects observed in works of art are created through physical and biological processes.

Recently, the Winter 2015 issue of the Academy’s journal Daedalus called “What is the Brain Good For?” featured an article by neuroscientist Robert H. Wurtz on “Brain Mechanisms for Active Vision,” alongside essays about perceiving, hearing, memory, sleep, and more. Wurtz’s contribution describes how active vision works though rapid eye movements, known as saccades, guided by shifts of visual attention. He concludes that

“We currently have only a glimpse of the neuronal basis of active vision in the brain. However, even with the limited methods we have now, an understanding of the system’s organization seems reachable. The hope is that active vision becomes an example of how a complex problem is solved by the brain in simple and clever – but not necessarily intuitive – ways.”

Despite the attention paid to the subject over 237 years, and years earlier, as we will learn from our panelists tonight, scientists still have not reached consensus about how we see. The Academy is proud to be a place where scholars can come together to discuss unresolved issues and engage in thoughtful, civilized debate.

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