Survey respondents were asked to provide knowledge responses to public events and names that occurred as long ago as the 1930s and as recently as the 1980s. Respondents made errors that reflect the use of semantic and lexical memory systems, and reconstructive processes based on a semantic theme. Errors, as well as correct responses, are affected by whether the events originally occurred during the transition phase (TP; early teens to mid-twenties). Responses indicate that events that occur during the TP are remembered better than events that occur during other life phases, but that events that occur during the TP can also promote error-prone reporting by interfering with other events or by promoting inaccurate reconstructions. Evidence suggests that the TP is not a monolithic entity, but that young adolescence differs from older TP ages by having a greater concentration on determining general properties of the world. Support is strongest for cognitive accounts of TP effects such as the 1st experience hypothesis, and results challenge physiological and evolutionary accounts that are tied to the TP promoting better memory. The more dramatic observed errors (such as inverting the S and object of an event) point to possible undocumented instances of autobiographical misremembering. (PsycINFO Database Record (c) 2007 APA, all rights reserved)