Abstract
The cumulative deficit hypothesis proposes that under conditions of marked social and environmental deprivation growth and development deficits in children will augment as children grow older. This study assessed between group (cultures) differences in intra-group (age) changes in performance of 3 to 6-year-old children in a battery of tests (Discrimination Learning, Short-Term Memory and Oddity Learning) derived from a theoretical model relating attention, learning and memory processes. Subjects were selected from Cambridge, Massachusetts, and from two lowland villages in Guatemala. The two groups of children were exposed to markedly different environments and presented significant differences in health and nutrition status. The focus of the study is on whether the developmental trends observed within groups are different between groups. Age trends within samples were analyzed by breaking the age into three groups: 31 to 42, 43 to 54, and 55 to 66 months. In Cambridge changes in test performance as a function of age were present in all Discrimination Learning and Oddity Learning tasks; whereas in Guatemala there was no systematic evidence of an age improvement in learning. In both samples there were generally no age effects in the Memory tests. The evidence presented is in line with the notion of progressively increased risk, at least during the preschool period, among severely impoverished populations where the psychosocial and biophysical needs of children are not adequately met.
