Is it really there or just in our heads?
George
Washington University
Researchers
at the George Washington University have gained important insight into how the
human brain processes an object in the visual system and where in the brain
this processing takes place. 
Artist: Anna Freerksen
Their study, "Mugs and Plants: Object
Semantic Knowledge Alters Perceptual Processing with Behavioral
Ramifications," shows people perceive objects differently depending on
their prior knowledge and experience with that object.
The
findings could have important implications in applied settings such as medical
displays, cognitive assistants, and product and environmental design, according
to the researchers.
"Since the way we perceive objects determines how we interact with them, it is important to visually process them quickly and with high detail" Sarah Shomstein, a professor of cognitive neuroscience at GW said.
"However, the
way our eyes perceive and process an object can be different depending on what
we know about this object. Our study shows, for the first time, that if we
recognize an object as a tool, we perceive it faster but with less detail. If
we recognize an object as a non-tool, we perceive it slower but with higher
detail."
To determine how the human brain processes an object visually, Shomstein and Dick Dubbelde, a recent PhD graduate at GW and co-author on the study, showed participants several images of objects that can be easily manipulated by hand such as a coffee mug, snow shovel or screwdriver, and several images of objects that are infrequently manipulated by hand, such as a potted plant, a picture frame or a fire hydrant.
For half of the experiment, a small gap could be cut
out of the bottom of each object. For the other half of the experiment, the
objects could flicker on the screen. The team asked participants to report the
presence or absence of a gap or the flicker, which helped the researchers
figure out the speed and detail of object processing, and also which regions of
the brain were being used to process the object.
Researchers
found that objects usually manipulated by your hands are perceived faster than
non-manipulable objects, making it easier to see the flickering. Alternatively,
objects that we usually do not manipulate are perceived with greater detail
than manipulable objects, making it easier to see the small gaps.
"The
differences in perception between 'mugs' and 'plants' in both speed and detail
of perception means that these objects are sorted by the visual system for
processing in different brain regions," Dubbelde said. "In other
words, your knowledge of the object's purpose actually determines where in the
brain object processing will occur and how well you will perceive it."
The
study also showed that if you interfere with object recognition by making it
harder to recognize an object as either manipulable or not manipulable -- for
example, by turning it upside down -- then the differences in the speed and
detail perception of the objects disappear.
Shomstein
and Dubbelde note that this study could possibly explain individual differences
in object perception and underscores that what you know and what your personal
experience is with any particular object has direct consequences for
perception.
The
National Science Foundation (BCS-1921415 and BCS-2022572) supported this work.
Story
Source:
Materials provided by George Washington University. Note:
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