Although hypothetical learning trajectories (HLTs) are often viewed as a valuable instructional tool, little research has directly evaluated their value. A basic assumption of HLTs is that ordering instructional activities by developmental difficulty enhances learning. A randomized control trial (RCT) served to evaluate this assumption with a…

The effects of instructing kindergarten students (five-year-old in their first year of public school) on patterning were tested. Up to nine students in each class were randomly assigned to three groups in each of six classes, i.e., as many as three from a class in each group. One group received instruction on complex patterns similar to those…