Young children rely on one sense or another, not a combination, studies find

Unlike adults, children younger than eight can’t integrate different forms of sensory input to improve the accuracy with which they perceive the world around them, according to a pair of studies reported online in Current Biology on May 1st.

The findings suggest that the perceptual systems of developing children might require constant recalibration—through the use of one sense to fine-tune another and vice versa, according to the researchers. They might also reflect inherent limitations of the still-developing brain.

“Kids have to stay calibrated while they are growing all the time—their eyes get farther apart and their limbs longer,” said David Burr of Università Degli Studi di Firenze, who led one of the studies. Under these conditions, “they may use one sense to calibrate the other.”

“It could be adaptive for humans not to integrate sensory information while they are still developing,” agreed Marko Nardini of the Centre for Brain and Cognitive Development at Birkbeck College, University of London. “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.” Nardini led the other of the two studies with colleagues at Oxford University’s Visual Development Unit.

The studies followed earlier findings that showed that adults can integrate information obtained visually with that obtained through the sense of touch, optimally weighting each sense according to its reliability in a given situation.

In the new study, Burr’s team first had children complete a task in which they 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 set of experiments, the children were asked to judge which of two bars was oriented more counterclockwise.

Their studies revealed that the ability to combine sensory information doesn’t develop in children until about the age of eight. Prior to that, integration of visual and touch-derived spatial information (also known as haptic information) is far from optimal, they reported, with either vision or touch dominating totally even in conditions where the dominant sense is far less precise than the other. However, they found no evidence that either vision or touch acts as a “gold standard,” always dominating the other.

In the task involving size discrimination, their results fit with the old notion that ’touch educates vision,“ Burr noted. “At first it looked like that was what was happening,” he said, “but in the case of orientation tasks, the opposite occurred. It’s doesn’t just go in one direction.”

At eight to ten years of age, children’s integrating skills become optimal, as in adults, they showed.

Nardini’s group made a similar discovery while studying the navigating skills of children versus adults. Navigation depends both on attending to visual landmarks and on keeping track of one’s own movement (self-motion), they explained.

In their study, children and adults attempted to return an object to its original place in an arena, using visual landmarks only, non-visual self-motion information only, or both.

Adults—but not four- to five-year-olds or seven- to eight-year-olds—got better at the task when both information sources were available, they found.

Further observations supported the notion that adult behavior was best explained by sensory integration, while children’s behavior suggested they were alternating between using the two types of information. The findings led them to conclude that people can integrate spatial cues nearly optimally to navigate, but that this ability depends on an extended developmental process.
“ We already know that kids are more liable to get lost and disoriented,” Nardini said, “but this study suggests that a specific reason for that is poor ability to integrate different kinds of spatial information.”

It might also explain how adults manage to improve on all sorts of tasks over time, he added. “It demonstrates how adults build on their perceptual abilities not just by improving individual senses, but also by getting better at integration.”

Source: Cell Press

Related stories:

Researchers find important clue to learning deficit in children with autism
A study by researchers at the UC Davis M.I.N.D. Institute has discovered an important clue to why children with autism spectrum disorders have trouble imitating others: They spend less time looking at the faces of people who are modeling new skills.
The beat goes on: Artificial heart technology holds promise for alternatives
Patients on the waiting list for a heart transplant soon may have more options thanks to a new device being developed by the Texas Heart Institute in collaboration with two University of Houston professors.
Researchers Teach Computers to Search for Photos Based on Their Contents
A pair of Penn State researchers has developed a statistical approach, called Automatic Linguistic Indexing of Pictures in Real-Time (ALIPR), that one day could make it easier to search the Internet for photographs. The public can participate in improving ALIPR's accuracy by visiting a designated Web site (http://www.alipr.com), uploading photographs, and evaluating whether the keywords that ALIPR uses to describe the photographs are appropriate.
Jump seen in staph-linked flu deaths in kids
(AP) -- More children have died from flu because they also had staph infections, according to a new government report that urges parents to have their kids get the flu shot.
Survey confirms parents' fears, confusion over autism
The first national survey of attitudes toward autism reveals that a small but significant percentage of people still believe the disease is caused by childhood vaccines. The survey of 1000 randomly selected adults was conducted for the Florida Institute of Technology.
Time travel: Plantation harvest is done the old-fashioned way
The old one-row corn picker may not be much to look at compared to the giant agri-industrial combines of today. But when the first practical models began to appear in the fields during the 1930s, this small, simple harvester proved to be a labor-saving wonder.
Immigrant children from poor countries academically outperform those from developed countries
Immigrants who seek a better life in Western countries may not be able to escape the influence of their home country when it comes to their children's academic performance, according to findings from the October issue of the American Sociological Review.
Endoscopy may not be necessary in asymptomatic children after caustic ingestion
A new study from researchers in Italy reports that endoscopy may not be necessary in children who show no symptoms after a caustic ingestion. The results demonstrated that the incidence of severe abnormalities of the esophagus in children without any early symptoms is very low and an endoscopy could be avoided. The study appears in the September issue of GIE: Gastrointestinal Endoscopy, the monthly peer-reviewed scientific journal of the American Society for Gastrointestinal Endoscopy (ASGE).

News discussion:

Medicine & Health news