Comment »Posted on Friday 14 August 2009 at 1:40 pm by Jacob Aron
In Biology

Picture a dog playing with a ball. The dog is alive, and the ball is inanimate. Obvious stuff, but how do we know? You might think our brains use visual cues to sort the living from the non-living, but research published in the journal Neuron this week proves it’s a little more complicated.

A team of scientists lead by Alfonso Caramazza of Harvard University found that even people who have been blind since birth use different areas of the brain when thinking about dogs or balls.

The part of the brain used to identify objects is known as the ventral stream. Previous research has shown that looking at inanimate objects like a spanner or a house activates a different part of the ventral stream to viewing animals or faces.

In an experiment with both sighted and blind individuals, participants were asked to listen to recordings of various words, including animals and tools. They then had to judge which category the word belonged to (living or non-living) and the relative sizes of the objects described.

“Using functional magnetic resonance imaging, we found that the same regions of the ventral stream that show category preferences for non-living stimuli and animals in sighted adults, show the same category preferences in adults who are blind since birth,” explains Caramazza.

The researcher caution this does not necessarily mean sighted individuals don’t use visual information to categories objects. It does however suggest that blind individuals access the same areas of the brain by using a different stimuli such as hearing or touch.

Mahon, B., Anzellotti, S., Schwarzbach, J., Zampini, M., & Caramazza, A. (2009). Category-Specific Organization in the Human Brain Does Not Require Visual Experience Neuron, 63 (3), 397-405 DOI: 10.1016/j.neuron.2009.07.012

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