Spring Break
Attention regulates recognition of objects
Issue date: 12/6/07
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One of the most well-disguised of all optical illusions is the trick the human brain plays when an object is visually perceived.
An important component of object recognition, and visual processing in general, is the separation of what neuroscientists call "figure" and "ground."
A figure is an object of interest in your visual field. It could be your professor's head in front of the chalkboard, the tree you're about to bicycle into or the words on your computer screen. The ground, on the other hand, is the background of an image.
It might not seem obvious, but separating figure and ground is actually an incredibly complicated (and necessary) process in visual perception.
There is good evidence that the separation of figure and ground in the brain is associated with your attentional state as well. This makes sense: It is important for the soon-to-be-unfortunate bicyclist to recognize the tree, but more importantly, he needs to be paying enough attention to register that the tree is not just some other object in his visual field but rather something to avoid.
To determine whether the visual recognition mechanism of figure-ground organization is related to selective attention, researchers from the Krieger Mind and Brain Institute on Homewood campus studied the responses of neurons in a part of the visual cortex in monkeys performing a shape discrimination task.
They found that attention affected the perception of shapes when several objects were in the visual field. Border ownership signals were stronger with figures on top (or in the front of the visual field) versus figures that were partially occluded or cut off, indicating that they were further back in the visual field.
Responses were decreased when the monkey was trained to focus on the back of the visual field - in other words, when it focused on the ground rather than objects. These findings demonstrate that attention can be used to skew the perception of images and scenes.
An important component of object recognition, and visual processing in general, is the separation of what neuroscientists call "figure" and "ground."
A figure is an object of interest in your visual field. It could be your professor's head in front of the chalkboard, the tree you're about to bicycle into or the words on your computer screen. The ground, on the other hand, is the background of an image.
It might not seem obvious, but separating figure and ground is actually an incredibly complicated (and necessary) process in visual perception.
There is good evidence that the separation of figure and ground in the brain is associated with your attentional state as well. This makes sense: It is important for the soon-to-be-unfortunate bicyclist to recognize the tree, but more importantly, he needs to be paying enough attention to register that the tree is not just some other object in his visual field but rather something to avoid.
To determine whether the visual recognition mechanism of figure-ground organization is related to selective attention, researchers from the Krieger Mind and Brain Institute on Homewood campus studied the responses of neurons in a part of the visual cortex in monkeys performing a shape discrimination task.
They found that attention affected the perception of shapes when several objects were in the visual field. Border ownership signals were stronger with figures on top (or in the front of the visual field) versus figures that were partially occluded or cut off, indicating that they were further back in the visual field.
Responses were decreased when the monkey was trained to focus on the back of the visual field - in other words, when it focused on the ground rather than objects. These findings demonstrate that attention can be used to skew the perception of images and scenes.
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