Research explores common visual error of 'boundary extension'

By Andrea Muddiman
Subjects were presented with a photograph and then had to draw the photograph from memory. Boundary extension is illustrated in these examples, because the participants’ memory of the scene is a more expanded view than what was shown in the actual photograph.

(Medical Xpress) -- Helene Intraub, professor of psychology at the University of Delaware, and then-undergraduate researcher Mike Richardson first published their paper on the phenomenon of "boundary extension" in 1989, describing a phenomenon that surprised many observers.

They found that boundary extension is an error people make after viewing a photograph. Instead of remembering the view in the photograph correctly, they report having seen more of the world than was actually shown in the picture.

Since that initial research finding, Intraub and colleagues have learned more about boundary extension. She and her then-postdoctoral researcher Chris Dickinson discovered that the phenomenon occurs in as little as one-twentieth of a second (one-eighth the duration of an eye blink), and, through research conducted in collaboration with fellow UD psychology Prof. Paul Quinn in his infant lab, they found that babies as young as 3 months make this error.

Now, Intraub has found that boundary extension is not restricted solely to vision. People make this same error through their after manually exploring a scene, she says.

Her latest discoveries, published earlier this year in the journal , were part of an with Eleanor Maguire in the United Kingdom, where boundary extension was examined to see if it occurred in patients with a type of that had led to a severe form of amnesia.

Interestingly enough, Intraub said, these patients with severe actually made little or no boundary extension errors. Because their imaginations were impaired, they were unable to imagine and anticipate what their unseen surroundings would look like. As a result, they remembered the boundary limits of a view more accurately than those people without damage.

Boundary extension may be applicable to the medical field as well, Intraub said, explaining that her research may help scientists understand brain damage and provide further insight into it. It also may be helpful in describing to patients with visual deficits what their condition entails and what is occurring in their brain to cause it.

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Temple
not rated yet Mar 09, 2012
Prepare yourself for commenters that have read far more into this article than is present.
gwrede
not rated yet Mar 09, 2012
More or not, this is something we should expect most animals do. You don't live long simply assuming there is no world behind a tree or a boulder.

Most of us will never see the day assuming the stairs don't exist under the toy panda. Therefore this assumption should be made on the cellular level, so it does not strain cognition, which is needed to catch food and flee predators.

What is childish and attention seeking, is to call boundary extension an error. They also seem quite unaware of the fact that a photograph is an incomplete representation of reality.

The one really amazing thing is that we seem to understand photographs and drawings virtually as fast as actual scenes! Now there's something to study!
gwrede
not rated yet Mar 09, 2012
Put a plate of food on a tiled floor and take a picture of it from above. Find a tiled sidewalk with a manhole (with the cover in place) and take a similar picture.

These scientists are in for some serious aha insights on seeing these pictures.