To develop normally, children require a wide variety of inputs from the environment. The simplest demonstration of this principle can be seen in sensory systems; normal visual development requires patterned light input from the environment during a sensitive period in the first six months of life. Similar sensitive periods exist for the development of more complex behaviors and competencies, including language and the formation of an attachment relationship to a primary caregiver. Early in life, most forms of learning occur in the context of interactions with caregivers. The sensory, motoric, linguistic, and social experiences provided by caregivers determine the complexity of the child’s environment and the degree of cognitive stimulation they receive. Caregivers regulate exposure to environmental inputs of numerous kinds, including language and auditory stimulation in the form of caregiver speech, social interaction through play, and sensory and motor stimulation through physical contact and the provision of objects for the child to manipulate. When caregivers are absent or unavailable children experience reduced sensory, cognitive, and social stimulation. This kind of deprivation is common among children who are raised in the absence of a stable caregiver (e.g., in an orphanage), experience neglect, and can also occur when caregivers are unable to provide consistent interaction. Our work has shown that this kind of deprivation in social and cognitive stimulation not only influences children’s social and emotional development, but also has profound implications for cognitive development, leading to difficulties or delays in the development of language and executive functions including working memory, inhibitory control, and cognitive flexibility. In addition, early deprivation can lead to changes in the structure and function of brain networks (e.g., the fronto-parietal network) that support these cognitive abilities. These changes in cognitive and brain development following deprivation appear to place children at risk for attention-deficit hyperactivity disorder (ADHD) as well as externalizing problems. Our ongoing work seeks to identify modifiable aspects of the early environment that are most important for scaffolding cognitive development that could be the target of early interventions for children who experience deprivation.
Our work examining the processes through which early deprivation influences children’s development and mental health has been funded by the National Institute of Mental Health and the National Institute of Child Health and Human Development and has been featured by the BBC, NPR, and Crosscut Magazine.