Kids combine sensory inputs after turning eight
Washington, May 2 : Kids develop the ability to combine stimuli coming from different senses after the age of eight, according to a pair of studies.
Appearing online in Current Biology, the research suggests that the perceptual systems of developing children may require constant recalibration, through the use of one sense to fine-tune another and vice versa.
The studies also reflect inherent limitations of the still-developing brain, say the researchers.
"Kids have to stay calibrated while they are growing all the time-their eyes get farther apart and their limbs longer. (Under these conditions) they may use one sense to calibrate the other," said David Burr of Universita Degli Studi di Firenze, who led one of the studies.
Marko Nardini of the Centre for Brain and Cognitive Development at Birkbeck College, University of London, said: "It could be adaptive for humans not to integrate sensory information while they are still developing."
The researcher who led the other of the two studies with colleagues at Oxford University's Visual Development Unit added: "But there might also be constraints on what children can do. It's possible that brain development needs to take place to make integration possible."
The researchers said that their studies built on previous findings that adults could integrate information obtained visually with that obtained through the sense of touch, optimally weighting each sense according to its reliability in a given situation.
During the present research, Burr's team assigned kids were asked to judge which of two blocks was taller, on the basis of touch or visual information or some combination of the two.
In another experiment, the subjects were asked to judge which of two bars was oriented more counterclockwise.
Based on the observations the researchers made throughout the studies, they came to the conclusion that the ability to combine sensory information does not develop in children until about the age of eight.
In another experiment, Nardini and his colleagues studied the navigating skills of children versus adults, which depends both on attending to visual landmarks and on keeping track of one's own movement (self-motion).
All study participants had to return an object to its original place in an arena, and they could use visual landmarks, non-visual self-motion information or both for that purpose.
The research team found Adults to be better than children below the age of eight at performing the task when both information sources were available.
"We already know that kids are more liable to get lost and disoriented, but this study suggests that a specific reason for that is poor ability to integrate different kinds of spatial information," Nardini said.
He further said that the study might help gain a better understanding of how adults manage to improve on all sorts of tasks over time.
"It demonstrates how adults build on their perceptual abilities not just by improving individual senses, but also by getting better at integration," he said.