Memory connections between thematically similar episodes.

Recent theories about the representation of thematic information in memory propose that two episodes that share a theme are connected together through a thematic structure. We investigated the use of such cross-episode connections in comprehension and memory in six experiments. Experiments 1 and 2 used a priming technique; it was found that verification time for a test sentence from one story was speeded by an immediately preceding test sentence from a thematically similar story but only when subjects were given instructions to rate the similarities of the stories. In the remaining experiments, a single test sentence was presented immediately after a story was read, with timing controlled by presenting the story one word at a time. Response time for a test sentence from a previously read story was facilitated if the immediately preceding story was thematically similar, but only if the previously read story was extensively prestudied. We conclude that, during reading of an episode, thematic information may be encoded so as to lead to activation of similar episodes and formation of connections in memory between episodes, but such encoding is not automatic and depends on subjects' strategies and task difficulty.