Observations That Leap Poem by gershon hepner

Observations sometimes leap
at you, some come while you’re asleep;
be ready for them always lest
you swallow, failing to digest.
Not only for the stimuli
that leap should you prepare your eye;
in what’s around you, live or written,
look carefully for what is hidden.
Observe beyond Gestalt the change
that may at first sight seem not strange;
for plains not peaks, where sight is level,
are details that delight the devil.


Natalie Angier (“Blind to Change, Even as It Stares Us in the Face, ” NYT, April 1,2008) , discusses change blindness, the frequent inability of our vision to detect changes:
When Jeremy Wolfe of Harvard Medical School, speaking last week at a symposium devoted to the crossover theme of Art and Neuroscience, wanted to illustrate how the brain sees the world and how often it fumbles the job, he naturally turned to a great work of art. He flashed a slide of Ellsworth Kelly’s “Study for Colors for a Large Wall” on the screen, and the audience couldn’t help but perk to attention. The checkerboard painting of 64 black, white and colored squares was so whimsically subtle, so poised and propulsive. We drank it in greedily, we scanned every part of it, we loved it, we owned it, and, whoops, time for a test. Dr. Wolfe flashed another slide of the image, this time with one of the squares highlighted. Was the highlighted square the same color as the original, he asked the audience, or had he altered it? Um, different. No, wait, the same, definitely the same. That square could not now be nor ever have been anything but swimming-pool blue... could it? The slides flashed by. How about this mustard square here, or that denim one there, or this pink, or that black? We in the audience were at sea and flailed for a strategy. By the end of the series only one thing was clear: We had gazed on Ellsworth Kelly’s masterpiece, but we hadn’t really seen it at all.Visual attentiveness is born of limited resources. “The basic problem is that far more information lands on your eyes than you can possibly analyze and still end up with a reasonable sized brain, ” Dr. Wolfe said. Hence, the brain has evolved mechanisms for combating data overload, allowing large rivers of data to pass along optical and cortical corridors almost entirely unassimilated, and peeling off selected data for a close, careful view. In deciding what to focus on, the brain essentially shines a spotlight from place to place, a rapid, sweeping search that takes in maybe 30 or 40 objects per second, the survey accompanied by a multitude of body movements of which we are barely aware: the darting of the eyes, the constant tiny twists of the torso and neck. We scan and sweep and perfunctorily police, until something sticks out and brings our bouncing cones to a halt. The mechanisms that succeed in seizing our sightline fall into two basic classes: bottom up and top down. Bottom-up attentiveness originates with the stimulus, with something in our visual field that is the optical equivalent of a shout: a wildly waving hand, a bright red object against a green field. Bottom-up stimuli seem to head straight for the brainstem and are almost impossible to ignore, said Nancy Kanwisher, a vision researcher at M.I.T., and thus they are popular in Internet ads. Top-down attentiveness, by comparison, is a volitional act, the decision by the viewer that an item, even in the absence of flapping parts or strobe lights, is nonetheless a sight to behold. When you are looking for a specific object — say, your black suitcase on a moving baggage carousel occupied largely by black suitcases — you apply a top-down approach, the bouncing searchlights configured to specific parameters, like a smallish, scuffed black suitcase with one broken wheel. Volitional attentiveness is much trickier to study than is a simple response to a stimulus, yet scientists have made progress through improved brain-scanning technology and the ability to measure the firing patterns of specific neurons or the synchronized firing of clusters of brain cells. Recent studies with both macaques and humans indicate that attentiveness crackles through the brain along vast, multifocal, transcortical loops, leaping to life in regions at the back of the brain, in the primary visual cortex that engages with the world, proceeding forward into frontal lobes where higher cognitive analysis occurs, and then doubling back to the primary visual centers. En route, the initial signal is amplified, italicized and annotated, and so persuasively that the boosted signal seems to emanate from the object itself. The enhancer effect explains why, if you’ve ever looked at a crowd photo and had somebody point out the face of, say, a young Franklin Roosevelt or George Clooney in the throng, the celebrity’s image will leap out at you thereafter as though lighted from behind.


4/1/08