His research has focused on
characterizing cognition, understanding how cognition develops early in life, how it
changes with advanced
age and whether it can be modified
with the use of drugs, nutritional supplements, or behavior interventions.
Most notably were
changes in the presentation of co-occurring internalizing and externalizing problems over time: a profile
with co-occurring internalizing and externalizing problems was found at all
ages but was
characterized by more severe problems at 6 years than at 1.5 and 3 years.