Several studies of the validity of the intensive time-series design have revealed a post-intervention increase in the level of achievement data (the "momentum effect"). Reports on the development and use of a technique to study the effect as it is observed in several data sets on the learning of plate tectonics. (Author/JN)

Reviews various evidences on the relationship between age and the reception of major innovations in science. Examines the possibility that age patterning of reception may vary over time. Reports the potential importance of age on the reception of ideas while rejecting the presumption that advanced age leads to increased resistance. (YP)