Vocabulary development of children placed in foster care and children who remained with birth parents after involvement with child protective services

In order to assess the role of foster care on children’s language abilities, researchers compared the Peabody Picture Vocabulary Test-Third Edition (PPVT) scores of children whose caregivers had participated in the Attachment and Biobehavioral Catch-up (ABC) studies, including children who had participated in the ABC-T trial (presented in Lee Raby et al., 2018). These children either lived with foster parents (n = 176) or remained in the care of their biological parents following child welfare involvement (n = 144). They were followed until at least 48 months of age. Both groups (i.e. foster care versus birth parents) included children who had participated in the treatment intervention (Attachment and Biobehavioral Catch-up; ABC) and the remainder had participated in a control intervention (Developmental Education for Families; DEF). There were no differences between children living in foster care and those who stayed with their birth parents in terms of intervention status. In other words, there were approximately equal proportions of children who had participated in the treatment intervention (ABC) who then remained in foster care as there were children who participated in ABC who returned to their birth families. Similarly, there were approximately equal proportions of children who had participated in the control intervention (DEF) living in foster care and living with their birth families. There were no other notable differences in child characteristics between those living in foster care and those who returned to their birth families.

The authors hypothesized that the children living in foster care would live in more resource-rich environments than the children living with their birth families, and that these environmental differences would impact the children’s vocabulary skills. To assess this, the data were analyzed using a series of correlations, independent samples T-tests, and regressional analyses. Preliminary analyses showed that caregiver education was positively correlated with children’s PPVT scores at both 36 and 48 months of age, as was caregiver income at both ages. T-tests showed that children living with caregivers who were married also had higher PPVT scores. When looking at differences between children living in foster care and those living with birth families, T-tests showed that the receptive vocabulary abilities of children living in foster care were higher than children who remained with their birth parents at both 36 and 48 months of age.  

Within the regressional analysis, the authors purposely did not initially control for caregivers’ demographic variables (e.g. income, education, marital status), as they expected systematic differences in these variables between foster and birth families; controlling for these variables would likely remove any meaningful variance between groups. As expected, children who were living with caregivers with higher income, higher educational achievement, and who were married had better language abilities than children whose caregivers had lower education, lower income, and/or were unmarried. The overall model predicted children’s PPVT scores at both 36 and 48 months of age. However, none of the caregiver factors (i.e. education, income, marital status) individually predicted the children’s PPVT scores. Based on these findings, the authors recommended that economic resources be provided to biological parents who are involved with child welfare services in addition to foster parents in order to mitigate some of the disadvantages that families of lower income and/or education level experience.