Inhibitory control and working memory in post-institutionalized children.

Inhibitory control and working memory were examined in post-institutionalized (PI) children adopted into United States families from Russian institutions. The PI sample originated from institutions that were less severely depriving than those represented in previous studies and approximated the level of psychosocial deprivation, which is characterized by adequate physical resources but a lack of consistent and responsive caregiving. PI children (N = 75; 29 male) ranged in age from 8-17 years (M = 12.97; SD = 3.03) and were grouped according to whether they were adopted after 14 months or before 9 months. A non-adopted comparison group (N = 133; 65 male) ranged in age from 8-17 years (M = 12.26; SD = 2.75). PI children adopted after 14 months of age displayed poorer performance on the stop-signal and spatial span tasks relative to PI children adopted before 9 months of age after controlling for age at assessment. The two PI groups did not differ in their performance on a spatial self-ordered search task. Older-adopted PI children also showed poorer spatial span task performance compared to non-adopted children, but younger-adopted PI children did not. Task performance was significantly associated with parent-rated hyperactive-impulsive behavior in everyday contexts. These findings suggest that exposure to prolonged early institutional deprivation may be linked with inhibitory control and working memory difficulties years after adoption.