The Primary Investigators in the Abecedarian Project Identified Six Principles

The primary investigators in the Abecedarian Project identified six principles that underlie most successful interventions in early childhood. These principles include all of the following except

A) developmental timing - interventions that begin earlier and last longer tend to have larger effects than interventions that are briefer and begin later
B) focus -- superior results are achieved when intervention efforts are focused on parents rather than directly on children
C) individual differences - some children and families benefit more than others from the very same intervention
D) program intensity - interventions that include more hours of contact are most effective