Deficits in attention regulation are associated with a wide range of poor outcomes including decreased academic achievement, school dropout, and increased risk for disruptive disorders. Research on the biological processes associated with attention regulation has shown differences between children with and without deficits in attention regulation. These differences include decreased brain volume and blood flow to areas associated with attention. Current research has also shown differences in the cardiovascular functioning (e.g., heart rate) of school-aged children and adults with ADHD. The current study investigated the relations between cardiovascular functioning and behavior (e.g., aggression) and attention problems in preschool children.

Participants in the present research were part of a larger study which examined physiologic and emotional responding in four and five year-old disruptive and non-disruptive preschoolers. Children were drawn from four Head Start centers in Baltimore City and Howard County, Maryland. The current sample included 35 children and their primary caregivers who were selected based on the Devereux Early Childhood Assessment. Participants were invited to the Social Development Lab at UMBC to complete questionnaires and games.

During their lab visit, children played a continuous performance task (CPT) called the Penny Game in which the objective was to “catch” pennies and place them in a holder. The task required children to identify “real” and “fake” pennies. Children’s heart rate was measured using an electrocardiogram (ECG) during resting periods and the CPT. Heart rate was broken down into two frequency components, fast and slow, to determine if either one was associated with disruptive behaviors. Caregivers, teachers, and independent observers completed the Behavior Assessment System for Children to provide measures of behavior and attention problems.
Overall, we found that children’s heart rate (both slow and fast frequencies) decreased during times when attention regulation was required, such as during the Penny Game. When we examined specific frequencies of heart rate and their relation to disruptive behavior, results indicated that the fastest heart rate frequency was related to both aggression and attention problems. The slowest heart rate frequency, however, was not related to either of these components of disruptive behavior.Our results may suggest that the relation between cardiovascular functioning and attention problems and aggression comes from a similar underlying biological mechanism. However, measureable differences in cardiovascular functioning between aggression and attention problems may not occur until later in development. Considering that these differences have been found in school-aged children and adults, continuous exposure to negative events (i.e., poor parenting practices) may make these behaviors more stable over time and result in differences in cardiovascular functioning.

The results of this study add to the current literature on the association of heart rate and disruptive behaviors. Our study demonstrates that changes in heart rate are associated with attention regulation during periods when cognitive effort is required. This may suggest that heart rate can be used as a biological index for attention. Our finding that heart rate related similarly to attention and behavior problems in preschoolers has implications for intervention. During preschool years, the relation between behaviors and biological functioning is not yet stable. As such, we may be in a position to intervene to help improve the lives of children before unwanted behaviors such as aggression become problematic.