The role of prior-event retrieval in encoding changed event features

When people experience everyday activities, their comprehension can be shaped by expectations that derive from similar recent experiences, which can affect the encoding of a new experience into memory. When a new experience includes changes-such as a driving route being blocked by construction-this can lead to interference in subsequent memory. One potential mechanism of effective encoding of event changes is the retrieval of related features from previous events. Another such mechanism is the generation of a prediction error when a predicted feature is contradicted. In two experiments, we tested for effects of these two mechanisms on memory for changed features in movies of everyday activities. Participants viewed movies of an actor performing everyday activities across two fictitious days. Some event features changed across the days, and some features violated viewers' predictions. Retrieval of previous event features while viewing the second movie was associated with better subsequent memory, providing evidence for the retrieval mechanism. Contrary to our hypotheses, there was no support for the error mechanism: Prediction error was not associated with better memory when it was observed correlationally (Experiment 1) or directly manipulated (Experiment 2). These results support a key role for episodic retrieval in the encoding of new events. They also indicate boundary conditions on the role of prediction errors in driving new learning. Both findings have clear implications for theories of event memory.