How Does the Brain Make
Sense of An Object?

Imagine you’re in a gift shop on Black Friday. Though it may be stressful, the average shopper’s brain is computing the surrounding array of shapes, colors, motions, smells and sounds with seeming ease. Princeton neuroscientist Anne Treisman researches how the human brain manages complex visual information in a process called “binding.” Her research suggests that a central factor in solving or failing to solve these visual riddles is a person’s spatial attention.

Studies suggest that our brains code one object at a time. By momentarily focusing on one object, we can bind the features of the object clearly. After the features have been bound into correct groupings, we then give real-world interpretations to the information collected. For example, our ability to visually decipher a box of pens among boxes of cards is based on data concerning pens, boxes, and cards we’ve collected over time.

However, when we are visually overloaded, the binding of features can fail. For example, when research participants are given less than a second to attend to an array of images that include the letter "S" as well as straight lines nearby it, they often report seeing dollar signs, where no dollar signs were present.

To explain these observations, Treisman proposes that sensory stimuli are initially registered both in separate feature maps and in a location map. We recombine the features by focusing on one object at a time and form a temporary representation, or object token, of the features currently in the attended location. We can then compare the object token to a store of knowledge built up over time and identify the object as, for example, a cat, or a pencil, or a telephone. The object token tells us what it looks like at this moment of time and updates its position and appearance if it moves and changes. It also allows us to represent novel objects that we have never seen before and therefore cannot identify. We seem to be limited to holding three or four object tokens at a time in temporary memory, and we lose the bindings even for those if attention is attracted elsewhere.

Treisman studied a patient with Balint’s syndrome, a disease characterized by lesions to the parietal cortex, which destroy the ability to localize objects in space. Treisman and her collegues predicted that this would also lead to failures of object binding and confirmed that the patient did indeed see illusory combinations of features, even with presentations of just two colored letters for up to ten seconds. (Treisman’s paper on this subject was published by the Royal Society in 1998, Vol. 353).
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