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One of the students, Annie Olinick, noticed that the monkeys looked at items by focusing on details — they tended to scrutinize by looking closer and rotated their heads often. She thought that they may be seeing a conflict between local details and global shapes and groupings, as do people with autism. We decided to test this empirically by making the monkeys (along with children and adult humans) make a choice between two stimuli, like the pair at the top of this image:

The subjects learned to select the circle made of circles rather than the square made of squares to get rewarded. Once they made that selection, test items like the two shapes at the bottom of the visual picture were presented in rare test trials. One of the test items is a circle but it is made of squares, and the other is a square, but it is made of circles. Which is right?

If you are driven toward a global bias, the circle is the one you will choose, regardless of the elements by which it is made. But if you prefer local details, the square, made of circles, matches the local detail of the original. Monkeys and children under 5 will pick the local features as often as the global shape if the shape is less clear (as in a sparse display, see the graph below). If the shape is made very clear in a dense display, they will favor the global shape over whatever local elements are used to construct it. This demonstrates a bias in children and adult fully developed tamarin monkeys not known before, and suggests an equivalence of local and global details in their processing.

Read the published article on global-local processing (2006).

CITATION: Neiworth, J. J., Gleichman, A. J., Olinick, A. S., & Lamp, K. E. (2006). Global and local processing in adult humans (Homo sapiens), 5-year-old children (Homo sapiens), and adult cotton-top tamarins (Saguinus oedipus). Journal of comparative psychology (Washington, D.C. : 1983), 120(4), 323–330.

View the poster on global-local processing presented at the Minnesota Undergraduate Psychology Conference (MUPC) (2004).
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