Baboons offer glimpses of left-brain brawn.Look at the letter "S" in the SCIENCE NEWS 1ogo on the cover and manipulate the image in your mind's eye mind's eye n. 1. The inherent mental ability to imagine or remember scenes. 2. The imagination. mind's eye Noun in one's mind's eye in one's imagination . Rotate it to various angles and you still recognize the letter, without confusing con·fuse v. con·fused, con·fus·ing, con·fus·es v.tr. 1. a. To cause to be unable to think with clarity or act with intelligence or understanding; throw off. b. "S" with its mirror image. Researchers have generally considered this a uniquely human ability that depends on the specialized functions of the brains left and right sides. But a new study finds that baboons can mentally rotate images and still recognize them, the first such demonstration in a nonhuman species. And thanks to an experimental procedure that delivers visual information to one side of the brain or the other, the researchers also conclude that the baboon's left hemisphere orchestrares this accomplishment. "Our data clearly challenge the theory that only humans have brain hemispheres that evolved to serve different functions," contends psychologist William D. Hopkins of Emory University Emory University (ĕm`ərē), near Atlanta, Ga.; coeducational; United Methodist; chartered as Emory College 1836, opened 1837 at Oxford. It became Emory Univ. in 1915 and in 1919 moved to Atlanta. in Atlanta. He and his collaborators French psychologists Jacques Vauclair and Joel Fagot, both of the National Scientific Research Center in Marseilles-will present their results in the March PSYCHOLOGICAL SCIENCE. Their paper comes on the heels of growing evidence that monkeys and other nonhuman primates nonhuman primate see primate. favor one hand over the other for particular tasks, an indirect sign that their brain hemispheres perform specialized functions (SN: 1/7/89, p.10). Right-brain superiority in identifying faces has emerged among "split-brain" monkeys, but it remains unclear whether surgically cutting off communication between hemispheres alters other aspects of brain function. Hopkins and his co-workers employed a technique developed in the late 1980s and first used in human studies. Its extension to nonhuman primates represents "a breakthrough for animal cognition Animal cognition, is the title given to a modern approach to the mental capacities of animals. It has developed out of comparative psychology, but has also been strongly influenced by the approach of ethology, behavioral ecology, and evolutionary psychology. researchers:' asserts psychologist Jeannette P Ward of Memphis (Tenn.) State University. Six baboons and three humans learned to control a cursor (1) The symbol used to point to some element on screen. On Windows, Mac and other graphics-based screens, it is also called a "pointer," and it changes shape as it is moved with the mouse into different areas of the application. on a computer screen with a joystick (hardware, games) joystick - A device consisting of a hand held stick that pivots about one end and transmits its angle in two dimensions to a computer. Joysticks are often used to control games, and usually have one or more push-buttons whose state can also be read by the computer. and to align it with a fixation point fixation point n. See point of fixation. in the center of the screen. They then saw either the "sample" letter "F" or "P" flash to the left or right of the square for about one-tenth of a second. For both humans and monkeys, if a letter or other stimulus appears to the left of a fixation point for a period faster than the one-fifth of a second needed for the eyes to focus on the stimulus, it enters only the left visual field and gets processed only by the right hemisphere. Speedy presentation to the right of the fixation point delivers a stimulus to the left hemisphere via the right visual field. Next, two "comparison" letters flashed for one-tenth of a second just above and below the center square; one was the original letter, the other its reversed image. Baboons moved the cursor to the position of the comparison letter that they thought matched the sample. letter and received food pellets for correct answers. On a series of trials, comparison letters were tilted tilt 1 v. tilt·ed, tilt·ing, tilts v.tr. 1. To cause to slope, as by raising one end; incline: tilt a soup bowl; tilt a chair backward. 2. at progressively sharper angles, thus requiring mental rotation for a correct response. Baboons proved highly accurate at the task only after left-brain exposures to letters. Human volunteers did well with both hemispheres, but prior studies with larger samples have found a left-brain advantage for mental rotation o! meaningful symbols such as letters, Hopkins notes. Both humans and baboons took longer to respond as comparison letters departed more sharply from the sample position. Overall, baboons performed mental rotations more than twice as fast as humans. Baboons treated the letters as meaningless shapes, whereas humans may have engaged in more laborious la·bo·ri·ous adj. 1. Marked by or requiring long, hard work: spent many laborious hours on the project. 2. Hard-working; industrious. processing of both meaning and shape, Hopkins suggests. His group plans to study hemispheric function among chimpanzees and other monkey species by facing them with the same mental rotation tasks. |
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