Her work, published in the January/February 2005 issue of Child Development, comes as an increasing number of mothers entering the workforce find employment with nonstandard hours. Single, low-income mothers and/or welfare mothers are more likely to work such nonstandard hours, Dr. Han notes, and earlier studies suggest they often have difficulties balancing work and family responsibilities on such schedules.
Now, it appears, those difficulties are affecting their children's cognitive development.
Dr. Han used information from the National Institute of Child Health Development's (NICHD) Study of Early Child Care, which tracked 1,364 children from 10 sites around the country from birth in 1991 through 36 months. Her study focused on 900 children whose mothers had worked in the first three years of their child's life. About half the working mothers worked at nonstandard hours during this time.
Even after controlling for the quality of the home environment and child care, maternal depression, and the mother's sensitivity towards her children, researchers found that the children of mothers who worked nonstandard work schedules during their first three years of life performed much worse on cognitive tests. Those tests evaluated such things as language development, memory, learning, problem solving, and children's knowledge of colors, letters, numbers, and shapes.
One reason for the effect, Dr. Han suggests, may be the type of care children receive when their mothers work such hours. Earlier studies find that mothers working nonstandard hours were less likely to put their children in center-based child care than mothers who worked more traditional hours. Such child care has been linked with better child cognitive outcomes.
"The children of mothers working at nonstandard hours may miss out on this opportunity to get what could be a form of school preparation that many other children receive," notes Dr. Han.
Summarized from Child Development, Vol. 6, Issue 1, Maternal Nonstandard Work Schedules and Child Cognitive Outcomes by Han, WJ (Columbia University). Copyright 2005 The Society for Research in Child Development, Inc. All rights reserved.