In order to understand long-term learning and the acquisition of expertise, human-computer interaction needs to take a developmental turn. Adopting a developmental approach means using longitudinal research methods, building developmental sequence models of the acquisition of expertise, and analyzing tasks as scenarios specific to developmental levels. The psychology of programming seems particularly amenable to a developmental approach because of the length of time that it takes to become an expert. We propose a model of seven developmental levels for Smalltalk/V programming, and provide sample scenarios for each level. We conclude that developmentally ordered scenarios convey valuable design information that would be lost in the standard "average user" approach to scenarios.