If you've ever been captivated by an M.C. Escher drawing of stairways that
lead to nowhere or a waterfall that starts and ends at the same place, then
you are familiar with what Psychologists describe as "impossible" objects
and scenes. These are pictures or illusions of three-dimensional images that
do not make any visual sense. Inevitably, we end up gawking at the image for
several moments, attempting to make sense of the impossible.
These images are, of course, mere deceptions that result from our ability to
create three-dimensional objects from two-dimensional images. An artist will
use techniques such as shading, shadow, texture and the like to give his or
her image a three-dimensional quality and sometimes, as in Escher's case, to
confuse our ability to perceive them.
So when do we develop this ability to perceive coherence in
three-dimensional objects? New York University perception researcher Sarah
Shuwairi and her colleagues are now attempting to use this natural
propensity to gaze at images of impossible objects to pinpoint when human
infants develop the ability to perceive three-dimensional shape information
from two-dimensional images.
Possible Object
Sarah Shuwairi at New York University
Impossible Object
Sarah Shuwairi at New York University
To do this, Shuwairi enlisted 30 4-month-old infants to take part in a
series of related experiments. With the help of their parents, the infant
subjects sat in front of a computer screen that displayed alternating
"possible" and "impossible" three-dimensional images. In the process, the
researchers recorded how long the infants looked at each of the objects. As
the reasoning goes, if the infants are sensitive to the visual features that
give images a three-dimensional quality, they will inevitably gaze at the
images that make no sense just as adults do; that is, they will stare at
impossible objects longer.
The result was that infants looked significantly longer at impossible
figures, suggesting that that as young as 4-months-old, humans have the
ability to detect at least some three-dimensional features that give rise to
the perception of object coherence.
Shuwairi explains that these findings, the first to document such abilities
so early in development, "provide important insights into the development of
mechanisms for processing pictorial depth cues that allow adults to extract
3D structure from pictures of objects." Ultimately, the implications of the
research extend beyond the ability to be perplexed by visual impossibilities
as researchers now have an additional tool to explain how infants develop an
understanding of the physical world around them.
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Psychological Science is ranked among the
top 10 general psychology journals for impact by the Institute for
Scientific Information. For a copy of the article "Discrimination of
Possible and Impossible Objects in Infancy" and access to other
Psychological Science research findings, please contact Catherine West at
the
Association for
Psychological Science.
