Examines the construct of emotionality, developmental relations between cognition and emotion, and neural plasticity and frontal cortical functioning. Proposes a developmental neurobiological model of self-regulation skills development, noting implications for children's school readiness. Suggests direct links among emotionality, use-dependent synaptic stabilization related to the prefrontal cortex, development of executive function abilities, and academic and social competence. (Contains references.) (SM)