Behavioral pediatrics begins, as a discipline, with at least two important assumptions: (1) that all human experiences have psychosocial as well as biological or organic contexts; and (2) that the biological substrate with which the child is born is modifiable. Thus, behavioral pediatrics, by its own definitions and assumptions, initiates research questions at the biobehavioral interface.1 This paper attempts to delineate a number of research directions that may be used to investigate the complex relationships between behavioral and biological factors in behavioral pediatrics.
Research investigating biobehavioral processes can be approached on a number of different levels. The research can be organized in terms of the following specific causal assumptions relating behavioral and biological factors: (1) a parallel model; (2) a causal model in which behavioral factors influence biological factors; (3) a causal model in which biological factors determine behavior; and (4) a causal model in which there is bidirectional causality.
1. Parallels Between Behavior and Biology. This model assumes that there is no directional causality. Behavioral and biological factors represent parallel systems sharing a common underlying organization. Behavioral and physiological variables may be viewed as different levels of the same system, mediated by central nervous system processes. Various screening methods are based on this model. Research questions dealing with this model focus on indexing and predicting developmental outcome. Techniques such as the Neonatal Behavioral Assessment Scale2 or the identification of sleep patterns3 evaluate behavioral patterns and attempt to identify neurophysiological or neurological dysfunction. Similarly, physiological response patterns such as infant cry patterns4 or heart rate variability measures such as cardiac vagal tone5 have been used to predict developmental outcome when the behavioral repertoire is too limited to be useful in predicting subsequent behavior.