Sixty children, enrolled in second, fourth, and sixth grade, responded
to a series of tasks designed to measure six persuasive message pract
ices: creating consensus about a problem, advocating a proposal, creat
ing an impressive message, motivating the other to act, seeking credib
ility, and building the other's self-concept. Except for message impre
ssiveness and seeking credibility, there were systematic age changes i
n each persuasive message practice. The findings are interpreted with
a conception of rhetorical competence, and implications for instructio
nal practice are discussed.