Search

A fundamental issue in cognitive neuroscience is how the brain encodes others' actions and intentions. In recent years, a potential advance in our knowledge on this issue is the discovery of mirror neurons in the motor cortex of the nonhuman primate. These neurons fire to both execution and observation of specific types of actions. Researchers use this evidence to fuel investigations of a human mirror system, suggesting a common neural code for perceptual and motor processes. Among the methods used for inferring mirror system activity in humans are changes in a particular frequency band in the electroencephalogram (EEG) called the mu rhythm. Mu frequency appears to decrease in amplitude (reflecting cortical activity) during both action execution and action observation. The current meta-analysis reviewed 85 studies (1,707 participants) of mu that infer human mirror system activity. Results demonstrated significant effect sizes for mu during execution (Cohen's d = 0.46, N = 701) as well as observation of action (Cohen's d = 0.31, N = 1,508), confirming a mirroring property in the EEG. A number of moderators were examined to determine the specificity of these effects. We frame these meta-analytic findings within the current discussion about the development and functions of a human mirror system, and conclude that changes in EEG mu activity provide a valid means for the study of human neural mirroring. Suggestions for improving the experimental and methodological approaches in using mu to study the human mirror system are offered.

To study the effects of perinatal HIV-1 infection and early institutional rearing on the physical and cognitive development of children, 64 Ukrainian uninfected and HIV-infected institutionalized and family-reared children were examined (mean age = 50.9 months). Both HIV infection and institutional care were related to delays in physical and cognitive development, with a larger effect of the rearing environment. Family care, even of compromised quality, was found to be more favorable for children's physical and cognitive development than institutional care. The impact of the quality of child care on physical and cognitive development is discussed in light of future interventions. (Contains 4 tables and 2 figures.)

This study addresses the extent to which insecure and disorganized attachments increase risk for externalizing problems using meta-analysis. From 69 samples (N = 5,947), the association between insecurity and externalizing problems was significant, d = 0.31 (95% CI: 0.23, 0.40). Larger effects were found for boys (d = 0.35), clinical samples (d = 0.49), and from observation-based outcome assessments (d = 0.58). Larger effects were found for attachment assessments other than the Strange Situation. Overall, disorganized children appeared at elevated risk (d = 0.34, 95% CI: 0.18, 0.50), with weaker effects for avoidance (d = 0.12, 95% CI: 0.03, 0.21) and resistance (d = 0.11, 95% CI: -0.04, 0.26). The results are discussed in terms of the potential significance of attachment for mental health.

In this meta-analysis of 75 studies on more than 3,888 children in 19 different countries, the intellectual development of children living in children's homes (orphanages) was compared with that of children living with their (foster) families. Children growing up in children's homes showed lower IQ's than did children growing up in a family (trimmed d = 0.74). The age at placement in the children's home, the age of the child at the time of assessment, and the developmental level of the country of residence were associated with the size of the delays. Children growing up in children's homes show a substantial lower level of IQ (average IQ of 84) than their peers reared in (foster) families (average IQ of 104), and the difference amounted to 20 IQ points. More research is needed to detect the causes of the large IQ delays and to test ways of improving the intellectual development of millions of children in orphanages around the world. (Contains 3 tables.)

The current study examined whether adolescents' attachment representations were associated with differences in emotion regulation during the Adult Attachment Interview (AAI; C. George, N. Kaplan, & M. Main, 1996) and during a mother-adolescent conflict interaction task (Family Interaction Task [FIT]; J. P. Allen et al., 2003). Participants were one hundred and fifty-six 14-year-old adolescents. Dismissing adolescents showed less interbeat interval (IBI) reactivity (indicating less stress) during the AAI than secure adolescents. However, during the FIT, dismissing adolescents showed more IBI reactivity. No differences in physiological reactivity were found between individuals with resolved or unresolved loss or trauma during the AAI or FIT. The results indicate that dismissing adolescents may effectively use a defensive strategy during the AAI but less so in direct conflict interaction with their attachment figure.

This study on sensitivity and attachment included 55 toddlers and their parents. Samples included children with autism spectrum disorder (ASD), mental retardation, language delay, and typical development. Children were diagnosed at 4 years of age. Two years before diagnosis, attachment was assessed with the Strange Situation procedure, and parental sensitivity and child involvement during free play were assessed with the Emotional Availability Scale. Parents of children with ASD were equally sensitive as parents of children without ASD, but their children showed more attachment disorganization and less child involvement. More sensitive parents had more secure children, but only in the group without ASD. Less severe autistic symptoms in the social domain predicted more attachment security. Autism challenges the validity of attachment theory.

Are preventive early childhood interventions effective in improving home environments, as assessed with the HOME inventory (Caldwell & Bradley, 1984)? The authors traced 48 published articles, presenting 56 intervention effects (N = 7,350). The combined effect size on the HOME total score was d = 0.20 (p less than 0.001). Randomized intervention studies were effective, but the combined effect size was limited (d = 0.13). Nonrandomized studies showed inflated effects (d = 0.58). Interventions with middle-class, non-adolescent parents showed higher effect sizes than interventions with low-SES or adolescent samples. Effective interventions used a moderate number of sessions in a limited period and were home-based. Learning Materials, Involvement, and Responsivity showed significant intervention effects. Families in better living conditions profited more from parent education (the Matthew effect). (Contains 4 tables and 1 figure.)