April 2001

From University of North Carolina at Chapel Hill

Study: Children with more hours of child care act more aggressively

CHAPEL HILL - At age 4-and-a-half, children in better quality child care score higher on tests of thinking and language skills than others who stay home or who receive lower-quality care, a major national study concludes. Those findings mirror results reported two years ago for the same children at age 3.

The study also found, however, that youngsters spending more time in child care in general and center-based care in particular were somewhat more aggressive than other children who spent less time there or who remained at home. Whether that heightened aggression is a problem that will continue -- or might even be an advantage -- remains to be seen, say researchers at the University of North Carolina at Chapel Hill and nine other U.S. research sites who did the work.

Drs. Martha Cox and Margaret Burchinal led UNC's participation in the continuing multi-year project, which has followed more than 1,300 children since birth and is sponsored by the National Institute of Child Health and Human Development.

"This is an important study because this is the age during which children make the transition into school, and there are a number expectations that we haven't imposed on them in quite the same way before," Cox said. "They go to school and are expected to have or attain skills related to reading and also cooperate in routines that are much more formal than what they were used to."

Cox is a principal investigator for the study, senior scientist and research professor of psychology at the university's Frank Porter Graham Child Development Center. Burchinal directs the center's design and statistical unit and serves as methodologist for the entire study, which is the largest long-term investigation of its kind ever undertaken.

They and other scientists presented the findings at the Minneapolis Convention Center Thursday (April 19) at a meeting of the Society for Research in Child Development.

Researchers and trained observers, in cooperation with caregivers, assessed children using age-appropriate tests, questionnaires and direct observation and controlled for varying characteristics such as family backgrounds.

On the positive side, both high-quality care, regardless of type, and center care, independent of quality, appeared to boost intellectual growth, memory and language skills. Differences were small but statistically significant.

Those in lower quality care, for example, fell into the 42nd percentile, on average, in pre-academic skills, while those in higher quality care averaged the 57th percentile, Burchinal said. Children with fewer than 10 hours a week of center care averaged the 44th percentile in language skills, while those with 30 or more hours a week fell into the 57 percentile, on average.

"This work documents more strongly than ever before that better educated and trained teachers are providing more language stimulation so that that the children they take care of do better on tests regardless of family background," Cox said. "Quality indeed makes a difference."

Researchers also found, however, that children who spent more time in care outside the home somewhat more aggressive toward other children and disobedient or defiant toward adults at 54 months and later when they were in kindergarten. They also were more likely to bully, fight with or act mean to others. "We saw that three times as many kids with extensive child care -- 30 or more hours per week on average between birth and 54 months -- had behavioral problems when compared with compared with children with little child care -- less than 10 hours per week on average," Burchinal said. "That was 16 percent of subjects in the former group vs. 5 percent in the latter.

"At the same time, though, we want to emphasize that these were not extreme behaviors, were well within the normal range and might or might not disappear entirely later on," she said. "By the time the children were in kindergarten, differences had narrowed to 17 percent vs. 9 percent."

Higher quality care corresponded with fewer problem behaviors, the study showed. Center care during infancy was not linked to either positive or negative trends among participating children. Children who watched more television scored lower on tests of mathematical reasoning and vocabulary and displayed more behavior problems.

Most subjects, who are from racially and socially diverse families, now are in the third and fourth grades and will be followed at least through the sixth. Analyses have now been completed and reported for ages 6, 15, 24, 36 and 54 months.

Investigators consider their sample reasonably but not perfectly representative of U.S. children, Cox said. Strengths of the study include its large sample size, the repeated direct assessments and the diversity of subjects, a quarter of whom are minorities.

Besides UNC, which follows 130 children, other data collection centers are located at the universities of Arkansas at Little Rock, California at Irvine, Kansas, New Hampshire, Pittsburgh, Virginia, Washington at Seattle and Wisconsin and Temple University. Research Triangle Institute staff in Research Triangle Park, N.C., also participates in the project.

Note: During the meeting, Cox and Burchinal will stay at the Hilton (612-376-1000) and Marriott (612- 349-4000) hotels, respectively, and have agreed to check their messages regularly. Beginning 4/23, they can be reached at (919) 966-3509 and 966-5059, respectively.

UNC News Services

This article comes from Science Blog. Copyright 2004

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