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. Author manuscript; available in PMC: 2017 Nov 1.
Published in final edited form as: Dev Psychol. 2016 Oct 6;52(11):1858–1866. doi: 10.1037/dev0000167

IQ at age 12 following a history of institutional care: Findings from the Bucharest Early Intervention Project

Alisa N Almas 1, Kathryn A Degnan 2, Charles A Nelson 3,4,5, Charles H Zeanah 6, Nathan A Fox 2
PMCID: PMC5083169  NIHMSID: NIHMS820337  PMID: 27709994

Abstract

Young children removed from institutions and placed into foster care or adoptive homes have been shown to experience significant gains in IQ relative to children who remain in institutions. Less is known about the long-term impact of severe early deprivation on development in late childhood. Data are presented from a follow-up of children at 12 years of age in the Bucharest Early Intervention Project, a randomized clinical trial of foster care for institutionally reared children. One hundred and seven of the original 136 children in the study were tested with the WISC IV. Results revealed continued benefit from the intervention through age 12, with 12-year-old children placed in foster care scoring significantly higher on full scale IQ compared to their peers who received prolonged institutional care. Longitudinal IQ data revealed two IQ profiles from early to late childhood. Attachment security emerged as a significant predictor of a profile of stable, typical IQ scores over time. We demonstrate the continued importance of foster care intervention and the negative effects of severe, early psychosocial deprivation on IQ into late childhood.

Keywords: Institutionalization, foster care, intervention

The impact of severe psychosocial deprivation on children’s development has long been studied, with conclusions consistently pointing to negative effects across cognitive, social and emotional domains in childhood (e.g., Bowlby, 1951; Dennis & Najarian, 1957; Goldfarb, 1943). Less is known, however, about the consequences of early deprivation on long-term outcomes during middle and late childhood. Only a handful of studies have followed post-institutionalized children into late childhood and adolescence (e.g., Beckett, Castle, Rutter, & Sonuga-Barke, 2010; Vorria, Mtouna, & Rutter, 2015), and even fewer have examined the development of children who remain in institutional care for part or all of this time (e.g., Dennis, 1973; Humphrey et al., 2015; McLaughlin et al., 2015).

In some of the earliest work tracking the effects of institutional care over time, Dennis (1973) assessed the intelligence of Lebanese foundlings living in institutions into the late childhood and adolescent years. He found a mean IQ score of 54 for girls aged 12 to 16, while boys aged 10 to 14 with the same early institutional experience had a mean IQ score of 81. Dennis attributed the gender difference in adolescents’ IQ scores to the more enriched environments afforded adolescent boys. Dennis did not observe gender differences in his sample during childhood when boys and girls were exposed to similar environments. These results highlight the potential negative impact of low quality institutional care on IQ well into the adolescent period and are in line with research on interventions targeted at providing more enriched environments within institutions that result in cognitive improvements (Hakimi-Manesh, Majdchi, & Tashakkori, 1984; Hunt, Mohandessi, Ghodssi, & Akiyama, 1976).

Dennis (1973) was also able to compare his two study groups who had lived in institutions since birth to those who had come to live in the same institutions at later ages, as well as children who attended school with the study sample children. He found that adolescents who had come to live in the institutions at later ages had significantly higher IQ scores than those who had lived in institutional care since birth, and that both groups were lower than children who attended school with the sample children and came from more “typical” families. These results are important because they highlight the greater influence of deprivation occurring early in development on long-term outcomes.

Alternatives to institutional care, including foster care or adoption, have long been viewed as the best way to provide post-institutionalized children with an enriched environment with the goal of remediating the negative effects of severe psychosocial deprivation experienced early in life. The English Romanian Adoptee (ERA) project has examined the effects of adoption on cognitive development across childhood and adolescence. In their sample of children from Romanian institutions initially placed in institutional care but later adopted into the UK, they found that when children were 11 years of age, those who were adopted prior to six months of age fell within the normal range of cognitive functioning while children adopted after six months of age had cognitive deficits (Beckett et al., 2006). Similarly, at 15 years of age, adolescents who had lived in an institution for longer than six months before being adopted having significantly lower IQ scores than those adolescents who had been adopted earlier (Beckett, Castle, Rutter, & Sonuga-Barke, 2010). Hodges and Tizard (1989), in their follow up of children from the UK who were institutionalized and later placed in foster care, reunited with their biological families or adopted, found that, at age 16, adolescents who were adopted before age 4.5 years had significantly higher IQs than adolescents in all other groups.

In a study following Greek children adopted from an infant care center, Vorria and colleagues (Vorria, Mtouna, & Rutter, 2015) examined academic performance and IQ during a 13-year follow up. They found that adolescents who had been adopted from institutional care demonstrated significant catch-up in cognitive performance, with a mean score of 106 across four subtests of the WISC-III, as well average school attainment scores. Nonetheless, this group scored significantly lower on both IQ and school attainment scores than their non-adopted peers from a prospectively followed comparison group of children who had attended daycare but lived with their families. However, the authors note that their comparison group of non-adopted peers was not representative of the larger population of Greece in that the adolescents in this group had atypically high educational attainment and scored, on average, one standard deviation above the mean for IQ. Therefore, the significant group differences should not necessarily be seen as indicative of a long-term negative impact of institutional rearing on cognitive development during adolescence and instead should be seen as highlighting the potential for the positive impact of adoptive care on cognitive catch-up.

Although the existing literature on cognitive development in post-institutionalized children provides some insight into the ongoing consequence of early deprivation in this domain across development, the conclusions that can be drawn from these studies are somewhat limited. For one, there may be a selection bias in which children are adopted early vs. later from institutions (also who gets adopted and who does not). Therefore, in the present study, we draw on data from the Bucharest Early Intervention Project (BEIP), a longitudinal study that affords a rare opportunity to examine the effects of severe psychosocial deprivation on cognitive development during late childhood as well as to examine the potential impact of foster care intervention using a randomized controlled trial (RCT) design.

The BEIP intervention began in 2001, when a sample of infants and young children between the ages of 6 and 31 months of age were recruited from institutions in Bucharest, Romania. These children, who had been abandoned to institutions very early in life (almost half were abandoned at birth) were randomly assigned to one of two groups: 1) Foster Care Group (FC), where children were placed into foster care homes; 2) Care As Usual Group (CAU), where children continued to receive institutional care. Children were subsequently followed and assessed at 30, 42, 54 months, at which point the trial concluded and the foster care network was turned over to local child protection authorities. Subsequently, we conducted follow-ups at 8 and 12 years of age and compared the children who had been randomized to a control group of typically developing Romanian children from families in the community (Never Institutionalized Group, NI). Throughout the course of the project, ethical concerns and considerations have been discussed in detail (Millum & Emanuel, 2007; Nelson et al., 2014; Zeanah et al., 2012).

At each assessment in the RCT, we consistently found negative effects of early psychosocial deprivation on IQ in the BEIP sample when comparing all children who received institutional care early in life to a comparison group of children living in the community (Fox et al., 2011; Nelson et al., 2007; Smyke et al., 2007). In addition, we also consistently found positive effects of foster care intervention on IQ, including in the follow-up at age 8 years (Fox et al., 2011). Children placed in foster case scored significantly higher than those randomized to care as usual. In some of the most recent work, we have identified factors that predicted distinct patterns or profiles of IQ across development up to 8 years of age, including language abilities in early childhood and, for children in the FC group, characteristics of the caregiver-child relationship (Fox et al., 2011). The latter findings further highlight the value of high quality care as a successful strategy for remediating the effects of early psychosocial deprivation on child development.

In the present study, we extend previous work from the BEIP by examining the impact of early psychosocial deprivation on cognitive performance at age 12 in the sample. We address some of the weaknesses of previous research on cognitive development of institutionalized children in three ways: 1) By comparing two groups of children: those who lived in institutional care during infancy and early childhood and those who received foster care intervention at an early age. These comparisons allow for an examination of the impact of severe deprivation and intervention on cognitive development. Furthermore, because our comparison is amongst groups of children living in Romania, there is no risk of confounding issues with new language and cultural contexts that may affect studies of children adopted into other countries; 2) Unlike some other studies, the BEIP includes a representative comparison group, the NI group; 3) The current paper extends our own previous work on children’s cognitive performance at 30, 42 and 54 months (Nelson et al., 2007) and 8 years of age (Fox et al., 2011), by examining IQ at 12 years of age. Thus, we explore the lasting impact of early psychosocial deprivation and foster care intervention into early adolescence. Furthermore, similar to our work with this sample at age 8, we include an examination of longitudinal profiles of IQ from 30 months of age to age 12, as well as the influence of characteristics of the child (e.g., gender, birth-weight, gestational age) and their caregiving environment (e.g., attachment security, caregiver-child relationship quality), all assessed early in childhood, on IQ profiles. Birth weight and gestational age were chosen to index the quality of the prenatal environment, while attachment security and caregiving qualty provide insight into the early interactions with a caregiver that set the stage for children’s socio-emotional development, both of which are thought to impact cognitive development over time (de Ruiter & van IJzendoorn, 1993). These analyses allow for an examination of the patterns of IQ across childhood for all children in our sample (FC, CAU, & NI groups) and the factors that may differentiate their IQ trajectories over time.

It is important to note that children in both institutional care and foster care often experience a number of changes in their caregiving setting over the course of their lives (Kim, Pears, & Fisher, 2012; Nelson, Fox & Zeanah, 2014). These changes in caregivers and “homes” have been shown to negatively impact children’s and adolescents’ development in a number of domains, including the cognitive domain (Connell et al., 2006; Rutter, 2000). Therefore, we examined the impact of time spent in institutional care as a percentage score from birth to age 12, to account for later placements in institutional care. In addition, we considered the effects of placement stability on IQ by comparing children in the FC group who remained in their original foster care home to those who were disrupted from that placement and moved to a new care arrangement (e.g., placement with a new foster care home, placement with a biological family member).

In sum, the current study presents four sets of analyses: 1) Group comparisons using an “intent to treat” approach, where children’s IQ scores were compared based on their original group assignment (CAU, FC). These analyses allow for the most conservative estimate of the effects of the intervention; 2) Comparisons between IQ scores of the FC group and NI group. These analyses allow for an examination of the degree of catch-up seen in the FC group; 3) An examination of the relations between the percentage of time spent in institutional or foster care across 12 years, as well as foster care placement stability, on IQ at age 12; and 4) An examination of profiles of IQ among participants from all groups across development (30, 42, 54, months, 8, and 12 years of age), as well as predictors of membership in each profile.

Methods

Participants

Participants in the current study included 107 12-year-old children (M = 12.24, SD = .59) who had been recruited to participate in a longitudinal study of foster care intervention when they were less than 30 months of age and living in one of six institutions in Bucharest, Romania (Zeanah et al., 2003). Children’s mean age at institutionalization was 2.57 months (SD = 4.01; Range = 0–17.5 months), with 46% of the sample being placed into institutional care at birth. Further details on the sample and follow up through 54 months can be found in Nelson et al (2007).

After initial recruitment, 136 children receiving institutional care were randomly assigned to one of two groups: Care as Usual Group (CAU) or Foster Care Intervention Group (FC). Children in the FC group were removed from their institutional settings and placed in a project supported foster family, whereas children in care as usual had more extended institutional exposure. We maintained a policy of not interfering in any placement decisions beyond the initial randomization. As a consequence, many children changed living situations over the course of the study. Figure 1 presents a “consort” diagram in which the initial status of the children, as well as their status at age 12 years is displayed. At age 12, 52 CAU children and 53 FC children remained in the study, had IQ data available, and were the subjects of the present analyses. Four children from the FC group and 6 children from the CAU group did not participate in the WISC assessment at age 12 because they suffered significant developmental impairments that made it impossible to administer the WISC in a valid way. There were no significant differences in the IQ scores at age 12 of those children who remained in the study compared to those who dropped out after either the 54 month assessment, F (1, 107) = .59, ns, or the 8 year assessment, F(1,104) = .21, ns.

Figure 1.

Figure 1

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BEIP: Placement at 12 Years

An additional 72 children were recruited from the community at baseline to act as a comparison group (Never Institutionalized Group, NI group). Forty-nine children from this group had IQ data as well as predictor variable data available beginning at the 30-month assessment point and were included in the longidutinal data analysis. A further 60 children were recruited at age 8 to supplement the NI group following attrition. Of these, 23 children had IQ data at age 12 and were combined with 29 children recruited at baseline that also had IQ data at age 12 and were included in the analyses comparing IQ scores of the NI group and the FC group at age 12.

Informed consent was signed by the legal guardian for each child, as dictated by Romanian law. Further assent for each procedure was obtained from each caregiver who accompanied the child to the visit.

Measures and Procedures

Physical characteristics

Data on specific child characteristics (gestational age and birth-weight) were collected at baseline assessment by either reviewing records (e.g., institutional, medical) or by interviewing the primary caregiver..

Placement stability

The BEIP programming and staffing support (e.g., frequent meetings with the foster parents, provision of consultation with issues with the child, etc.) of the foster families ended when children were 54 months old. As can be seen in the consort diagram (Figure 1) a number of children placed into foster homes that were supported by the BEIP left their placements over the course of the subsequent 8 years. In our previous examination of IQ when children were 8 years old we reported that those currently in our foster homes had higher IQs than those who had left. To re-examine this issue at age 12 years, we used a more conservative approach, one that assessed not only current placement but also movement of the child in and out of the foster care home. Hence, a grouping variable indicating the stability of their original foster care placement was created, by assigning a “1” to those FC children who were disrupted from their foster home and a “2” to those FC children who had remained in their original foster home continuously up to age 12 (see Humphreys et al, 2015, for more discussion).

IQ

IQ was assessed when children were 12 years of age in the BEIP laboratory using the Wechsler Intelligence Scale for Children (WISC-IV; Wechsler, 2003). The WISC-IV uses 10 subtests to assess intellectual functioning in four domains: verbal comprehension, perceptual reasoning, working memory, and processing speed. In addition, a full-scale IQ composite score is calculated based on the 10 subtest scores, scaled for age. Each of the four subscale scores as well as full-scale IQ scores was examined in the present analyses. IQ had been assessed at 30 and 42 months of age using the Bayley Scales of Infant Development, at 54 months of age using the WPPSI (see Nelson et al, 2007, for details), and at 8 years of age using the WISC-IV (see Fox, et al, 2011, for details). All of the IQ assessments were conducted by trained and reliable Romanian psychologists and supervised by U.S. clinicians.

Attachment security

Attachment security was assessed in the laboratory using the preschool version of the Strange Situation Procedure (Cassidy & Marvin, 1992) when children were 42 months of age. A complete presentation of these data may be found in Smyke et al (2010). A continuous rating of attachment security was used in the present study. In order to create this score, coders assigned a security score to each child using a scale from 1–9, with 1 = no security evident, to 9 = most secure (Cassidy & Marvin, 1992). As reported previously (Smyke et al., 2010), reliability for this coding was excellent (r = .87)

Relationship with primary caregiver

An adapted version of the Observational Record of the Caregiving Environment (ORCE; NICHD Early Child Care Research Network, 1996) was administered when children were 42 months of age in order to assess each child’s relationship with his or her primary caregiver. Caregivers included mothers of NI children, foster mothers of FC children, and “favorite caregivers” of CAU children (as identified by the staff). A Quality of Caregiving score was determined by calculating the mean of the scores for sensitivity, stimulation of development, positive regard for child, flat affect (reversed), and detachment (reversed). Scores on each behavior ranged from 1 to 4. Scale reliability was acceptable (Cronbach’s alpha = .82). A complete presentation of these data may be found in Smyke et al (2010).

Data Analytic Plan

Data were analyzed for the present study in four ways: 1) analyses are presented that use an intent-to-treat approach, whereby the CAU group and FC group were compared at 12 years of age on WISC full-scale IQ as well as the four WISC-IV subscales (verbal, perceptual reasoning, working memory, processing speed); 2) comparisons were made between the FC group and NI group on WISC full-scale IQ as well as the four WISC-IV subscales (verbal, perceptual reasoning, working memory, processing speed); 3) correlations between percentage of time spent in institutional care and IQ scores were examined and, for the FC group, group comparisons were conducted between those with stable and those with disrupted foster care; 4) latent profiles of IQ were estimated for all children in the sample (CAU, FC, and NI groups) using latent profile analysis (LPA). This method allowed for the examination of longitudinal patterns of IQ from 30 months to 12 years of age. Predictors and correlates of profile membership were also examined.

Latent Profile Analysis, a form of Structural Equation Mixture Modeling, was used because it allows for the estimation of qualitatively different groups (i.e., latent profiles) from continuous data points when group membership cannot be determined a priori (Bauer & Curran, 2004). Data in the current study were analyzed using Version 7.31 of Mplus (Muthen & Muthen, 2015). Model fit was determined using the Bayesian information criterion (BIC; D’Unger, Land, McCall, & Nagin, 1998), as well as the Lo-Mendell-Rubin Likelihood Ratio Test (LMR-LRT; Lo, Mendell, & Rubin, 2001). This type of mixture model capitalizes on the fact that these analyses offer two main advantages over traditional cluster techniques. First, use of SEM’s maximum-likelihood estimation (MLE) method assumes the data are missing at random, which allows the model parameters to be informed by all cases that contribute a portion of the data, and is recommended as an appropriate way to accommodate missing data (Little & Rubin, 1987; Schafer & Graham, 2002). Second, unlike traditional cluster analysis algorithms, which group cases near each other by some definition of distance (e.g., Euclidean distance for k-means cluster analysis), the LPA approach relies on a formal statistical model based on probabilities to classify cases. Case classification is based on Bayes’ theorem and computes a posterior probability (based on a function of the model’s parameters) of membership for each individual for each latent class (Dayton, 1998; McCutcheon, 1987; Muthén, 2004). In addition, class membership (based on highest posterior probability) can be simultaneously regressed onto predictors or correlates of interest.

Results

IQ Scores at 12 Years of Age

Table 1 presents descriptive statistics for each of the four WISC subscales and for full scale IQ at age 12 for the CAU, FC and NI groups.

Table 1.

Descriptive Statistics for WISC Scores at 12 Years of Age

FCG (n=53) CAUG (n=52) NIG (n=52)
Variable M (SD) M (SD) M (SD)
Full Scale IQ 75.80 (18.98)a 68.76 (14.66) 98.61 (14.04)1
Verbal Comprehension 80.22 (18.03)a 71.40 (14.04) 99.73 (14.13)1
Perceptual Reasoning 77.26 (17.77) 74.53 (14.67) 97.58 (15.90)1
Working Memory 82.33 (20.04) 77.72 (16.57) 100.44 (17.28)1
Processing Speed 80.11 (16.63) 76.09 (11.97) 96.08 (13.97)1
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Note.

a

Significant group differences between the FC and CAU groups.

1

Significant group differences between the NI and FC groups.

Preliminary analyses across all groups revealed no gender differences on IQ scores at age 12, except for the subscale of Processing Speed, t (157) = 2.13, p = .04, with females scoring higher than males.

Intent-to-Treat Analyses: Comparison of Intervention Groups

In order to examine the impact of foster care intervention at age 12 for children who had received institutional care, we compared the FC group to CAU group on their full scale IQ and the four subscales of the WISC. A univariate analysis of variance (ANOVA) was conducted, with gender included as a covariate, in order to compare the full scale IQ scores of the two groups. The result revealed a significant effect of group, F (1,105) = 4.55, p = .035, η2 = .04, indicating that children in the FC group had significantly higher full scale IQ scores than children in the CAU group. A 2 (CAUG, FCG) X 4 (verbal, perceptual, working memory, processing speed) multivariate analysis of variance (MANOVA) was conducted with a Bonferroni correction for multiple comparisons in order to compare the IQ subscale scores of the two groups. Gender was included as a covariate. The multivariate test of differences between groups using the Wilks Lambda criteria was marginally significant, F (4, 99) = 2.32; p = .06, η2 = .09. Follow-up multivariate comparisons revealed a significant effect of group for the verbal subscale, F (1, 105) = 7.82, p = .006, η2 = .07, indicating that children in the FC group scored higher on verbal comprehension than those children in the CAU group. Scores on the perceptual, F (1,105) = .88, ns, working memory, F (1,105) = 1.46, ns, and processing speed, F (1,105) = 2.10, ns, subscales were not significantly different for the two groups. There were no significant direct effects of gender in either analysis.

Foster Care Children and the (Never Institutionalized) Comparison Group

We then compared the FC group to the NI group, in order to determine the degree of recovery experienced by the children in the intervention arm of the study. A univariate analysis of variance (ANOVA) was conducted, with gender included as a covariate in order to compare full scale IQ scores of the two groups. The result revealed a significant effect of group, F (1,105) = 42.73, p < .001, η2 = .26, indicating that children in the NI group had significantly higher full scale IQ scores than children in the FC group. A 2 (FCG, NIG) X 4 (verbal, perceptual, working memory, processing speed) MANOVA was conducted with a Bonferroni correction for multiple comparisons in order to compare the IQ subscale scores of the two groups. Gender was included as a covariate. The multivariate test of differences between groups using the Wilks Lambda criteria was statistically significant, F (4, 99) = 11.04, p < .001, η2 = .31. Follow-up multivariate comparisons revealed a significant effect of group for the verbal, F (1,105) = 36.38, p < .001, η2 = .26, perceptual, F (1,105) = 36.54, p < .001, η2 = .26, working memory, F (1,105) = 23.79, p < .001, η2 = .19, and processing speed, F (1,105) = 26.86, p < .001, η2 = .21, subscales, indicating that children in the NI group scored significantly higher than the FC group on all subscales. There were significant direct effects of gender in all analyses, indicating that girls scored significantly higher than boys on full scale IQ as well as each of the subscale (all ps < .05).

Effects of Age at Placement into Foster Care

To determine whether the age at which FC group children were placed into foster care had an impact on their IQ scores at 12 years of age, dichotomous grouping variables were created for entry cutoffs at 20, 22, 24, and 26 months of age. Children in each group were compared on their verbal, perceptual, working memory, and processing speed using a series of MANOVAs, and full scale IQ using a series of ANOVAs. Results revealed no significant effects of age at placement into foster care. Partial correlations were calculated for age at placement into foster care as a continuous variable and full scale IQ as well as each of the subscale scores, controlling for gender. There were no significant results.

Percent Time in Institutional Care

Because of the variability in placement status over time, with many children moving out of and back into institutions over the course of the study, we examined partial correlations between the percentages of time spent in institutional care from birth to age 12 and IQ scores, for CAU and FC children, controlling for gender. Results revealed that the percentage of time spent in institutional care was significantly and negatively correlated with full scale IQ, r (102) = −.26, p = .008 as well as two of the four subscales (verbal, r (102) = −.29, p = .003; working memory, r (102) = −.23, p = .02), suggesting that children who spent more time in institutional care up to age 12 had significantly lower full scale IQ, verbal and working memory scores.

Effects of Caregiving Stability on IQ at 12 Years of Age

In previous work (Fox et al., 2011) we showed that current placement at age 8 (whether the child was in the original foster family placement or not) played an important moderating role in various developmental outcomes (IQ, EEG). Here, we examined the impact of stability in caregiving experiences on IQ at 12 years of age using a Placement Stability variable. Comparisons were made between two groups of children in the FC group: 1) Those who remained in their original MacArthur foster care placement through age 12 (FCG-Stable; n = 23), and 2) Those who were disrupted from their original placement and were moved to a new care arrangement (FCG-Disrupted; n = 29). A univariate ANOVA, controlling for gender, revealed no significant effect of stability on full scale IQ, F (1, 49) = 2.78, ns. A multivariate ANOVA, controlling for gender, revealed no significant effect of stability on IQ scores, F (4, 46) = 1.97, ns. Gender was not directly related to IQ, nor was there any interaction effect of gender and stability.

Longitudinal Profiles of IQ from 30 Months of Age to 12 Years of Age

In order to examine IQ across childhood in our sample, as well as to determine whether subgroups of children with particular patterns of IQ scores existed across the three groups (CAU, FC and NI), longitudinal patterns of IQ across 30, 42, 54 months, 8 and 12 years were examined. This was accomplished by fitting models of latent profiles with one through four profiles to the IQ data from each of the five assessment points. Predictors of child characteristics (gender, birthweight, and gestational age), as well as caregiving quality and degree of attachment security, were simultaneously included as predictors of membership in the profiles.

Across the profile models, the BIC was 9705.34 for the one profile model, 5389.01 for the two profile model, 5314.43 for the three profile model, and 5332.91 for the four profile model. In terms of the Lo-Mendell-Rubin Likelihood Ratio Test (LMR-LRT; Lo, Mendell, & Rubin, 2001) of model fit, the two-profile model fit significantly better than the one-profile model, χ2(16)=394.78, p = .01, the three-profile model fit did not fit significantly better than the two-profile model, χ2(16)=152.29, p = .22), and the four-profile model did not fit significantly better than the 3-profile model, χ2(16)=60.39, p = .06. Given the low BIC and significantly better model fit indices, the two-profile model was selected.

An examination of the two-profile model revealed that it had an acceptable number of members in each profile (n’s of 89 and 56), and the average posterior probabilities of membership were all greater than 0.97. The first IQ profile, labeled “Low,” displayed very low IQ scores on average across time (30 months, M = 77.43, SD = 9.83; 42 months, M = 78.45, SD = 12.42; 54 months, M = 74.80, SD = 15.89; 8 years M = 78.18, SD = 13.35; 12 years, M = 71.65, SD = 15.48). The Low profile included 45 children from the CAU group, 37 children from the FC group, and 5 children from the NI group. The second IQ profile, labeled “Typical,” displayed more typical IQ scores on average across time (30 months, M = 102.07, SD = 11.35; 42 months, M = 105.09, SD = 7.88; 54 months, M = 108.77, SD = 17.17; 8 years, M = 104.81, SD = 14.15; 12 years, M = 100.63, SD = 11.87). The Typical profile included 0 children from the CAU group, 12 children from the FC group, and 44 children from the NI group.

A univariate analysis of variance (ANOVA) was conducted, with gender included as a covariate, in order to examine the effect of group on profile membership. The continuous score of membership in the Typical profile was included as the dependent variable. The result revealed a significant effect of group (F (2,143) = 116.83, p < .001, η2 = .63). Post-hoc pairwise comparisons with a Bonferroni correction revealed that children in the NI group had a significantly higher probability of membership in the Typical profile than did children in the CAU or FC groups, while children in the FC group had a significantly higher probability of membership in the Typical profile than did children in the CAU group (all ps < .001).

Child characteristics (gender, birthweight, and gestational age at birth), as well as caregiving quality and level of attachment security at 42 months, were included as predictors of profile membership in the two-profile model. Correlations between predictor variables are presented in Table 2. All predictors were entered simultaneously to examine their relations with the IQ profiles above and beyond the other predictive measures of interest. The two IQ profiles were significantly differentiated by levels of birth weight and 42-month attachment security, such that greater birth weight, b = .002, t = 3.66, p < .001, d = .63, and attachment security, b = .948, t = 5.21, p < .001, d = .89, were associated with a greater likelihood of following the “Typical” IQ profile.

Table 2.

Zero-order Correlations Between Predictor Variables

1. 2. 3. 4. 5. 6.
1. Gender -- .06 (130) .13 (126) −.05 (130) −.22* (132) .08 (114)
2. Birth weight -- .55** (182) −.06 (155) .02 (153) .16 (122)
3. Gestational Age -- −.04 (149) .00 (148) .17 (115)
4. Relationship with Caregiver -- .22** (163) −.21* (116)
5. Attachment Security -- −.45** (116)
6. Percent Time Institution --
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Note. Scores are indicated for the total sample, including children from CAU, FC and NI groups for variables 1–5, CAU and FC groups only for variable 6.

Sample size for each correlation is in parentheses.

*

p < .05,

**

p < .01.

Institutional and Foster Care Experience Predicting Longitudinal Profiles of IQ from 30 Months of Age to 12 Years of Age in CAU and FC Groups

Linear regression analyses were also performed to examine the relations between percent time in institutional care and probability of profile membership for those children who had experienced institutionalization (CAU and FC groups only). Percent time in institutional care significantly predicted membership in the ”Low” IQ profile, b = −.01, t = −3.41, p = .001, with greater time spent in an institution predicting a lower probability of membership in the “Typical” profile.

Age at placement into foster care, as a continuous variable, was also examined in relation to profile membership (FC group only), and emerged as a significant predictor, with older age at placement predicting a lower probability of membership in the “Typical” profile, b = −.03, t = −3.48, p = .001.

Discussion

The present study extends our understanding of the impact of early and severe psychosocial deprivation on cognitive development in several ways. First, our results show significantly higher scores for children who received foster care intervention (FC) on both full scale IQ and the verbal comprehension subscale when compared to children who remained in institutional care (CAU). These results highlight the positive impact of high quality, foster care experienced early in life on remediating some of the negative effects of severe psychosocial deprivation on cognitive development even 8 years after the RCT concluded. In addition, our results show that the negative impact of early institutional experience on IQ continues into late childhood, in that children who were institutionalized in infancy and early childhood (both the CAU and FC groups) showed significantly lower IQ scores than children from the community (NI) who had never experienced institutional care. These results are consistent with previous work showing the lasting effects of early experience on cognitive performance in adolescence (Beckett, Castle, Rutter, & Sonuga-Barke, 2010; Vorria, Mtouna, & Rutter, 2015).

It is important to note that the group comparison results were found using a conservative “intent-to-treat” approach, meaning the data were analyzed based on original groups to which children were assigned to at the outset of the study. As mentioned previously here, and in other papers (see Fox et al., 2011), the BEIP maintained a non-interference policy throughout the course of the study, meaning children changed placements based on decisions made by child protection authorities regardless of group assignment. Indeed, many children in both the CAU and FC groups changed placements over the course of 12 years (see Consort Diagram, Figure 1). Therefore, we examined children’s IQ scores in the context of two additional variables: the percentage of time spent in institutional care up to age 12, and, for the FCG, their foster care placement stability. We found that, as expected, cumulative time spent in institutional care significantly and negatively predicted IQ scores at age 12. However, we found an effect of placement stability for the FC group only on working memory. It seems that, at least in the case of IQ at age 12 in our sample, having the experience of high quality care early in life may be more important than stability of that care into late childhood in maintaining enhanced cognitive performance. These results are inconsistent with those examining psychopathology outcomes in our sample at age 12 (Humphreys et al., 2015), where those children who remained in their initial foster care home showed fewer psychiatric symptoms. However, it is possible that having a consistent caregiver is more important for outcomes in the social and emotional domains, compared to the cognitive domain, as children approached adolescence. Indeed, Roy, Rutter and Pickles (2000), when examining a sample of children specifically selected for their continuity of placement, found similar results. Foster children in their sample, who had lived continuously in the same foster home, demonstrated significantly lower rates of problem behaviors compared to institutional-reared children, while the foster children, however, did not differ from the institutional children on IQ.

Although in previous work we have found the timing of placement into foster care was important in early childhood, with earlier placement predicting higher IQ scores (Nelson et al., 2007), we did not find similar results at age 12. This is not surprising given that this is more than 8 years after the RCT concluded. In fact, we found weak timing effects in our sample at age 8 as well, where processing speed was the only subscale for which there were a significant effect (Fox et al., 2011). There are two possible explanations for the lack of timing effects: 1) In the BEIP, children received foster care intervention at, on average, 22 months of age. It is possible that more robust timing effects would be seen in late childhood if the intervention had taken place during early infancy. 2) The timing of the intervention has a lesser impact on IQ over time, with effects being minimal by mid childhood and undetectable by late childhood. It is possible that variability in caregivers, formal schooling, environmental characteristics, and opportunities for learning over the course of 12 years have an equal or even greater impact on cognitive performance by late childhood.

Using the longitudinal data from the BEIP we examined distinct profiles of IQ in all three groups across development. We found that children’s scores revealed two profiles: low and typical. We examined constructs specific to the child, including their physical characteristics at birth (e.g., birth weight), as well as constructs specific to their early caregiving experience, including the degree of attachment security, as predictors of IQ profile membership. Greater birth weight and attachment security were associated with a greater likelihood of membership in the typical IQ profile. Furthermore, less time spent in institutional care and younger age of placement into foster care also predicted a greater probability of membership in the typical IQ profile. These finding lend further support to the notion that high quality care early in life has an impact on cognitive success through to late childhood.

It is important to acknowledge some of the limitations of this sample, and the impact on the interpretation of the results. Our sample size may have restricted our ability to detect a greater number of longitudinal profiles, thus masking some of the variability in IQ over time. As well, in both groups of children with a history of institutionalization there were a significant number who had extremely low IQ scores. Prior to randomization, while infants were living in the institution, we screened each child for obvious physical handicaps or genetic anomalies. However, it is possible that subtle signs of developmental disorders went unnoticed. On the other hand, almost twice as many children in the CAU group (n=30) had IQ scores at age 12 below 70 compared to those in the FC (n=18). Given the random assignment to groups we must conclude that the foster care intervention rescued a number of children from very low IQ scores. The high number of very low IQ scores in both groups is worrisome, nonetheless, and testifies to the significant and negative impact of early deprivation on cognitive development. It is also important to note the comparison group of never institutionalized children were not matched to the CAU or FC children on socioeconomic status, and therefore direct comparisons between the groups should be interpreted with caution.

In summary, the present study provides some evidence of the lasting positive impact of high quality foster care as a form of intervention during early childhood on cognitive abilities late in childhood for children who have experienced severe psychosocial deprivation in the context of institutional rearing.

Figure 2.

Figure 2

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Profiles of IQ Scores at 30, 42, 54 Months, 8 and 12 Years of Age for Children in the CAU, FC and NI Groups

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