Levels of processing and selective attention effects on encoding in memory.

The purpose of the present study was to investigate the effects of selective attention and levels of processing (LOPs) at study on long-term repetition priming vis-a-vis their effects on explicit recognition. In a series of three experiments we found parallel effects of LOP and attention on long-term repetition priming and recognition performance when the manipulation of these factors at encoding was blocked. When a mixed study condition was used, both factors affected explicit recognition, while their effect on repetition priming was determined by the nature of the test. Shallow processing at test did not benefit from long-term repetition, regardless of whether the words had been studied deeply or shallowly. Selective attention affected long-term repetition priming in a semantic, but not in a lexical decision (LD), test. Regardless of study condition, retention lag affected long-term repetition priming only in the semantic test. These results suggest that if the experimental conditions allow scrupulous selection of attended and unattended information or narrow tuning to a shallow, pre-lexical LOP, implicit access to unattended or shallowly studied items is significantly reduced, as is explicit recognition. We suggest a conceptual framework for understanding the effects of LOP, attention, and retention interval on performance of explicit and implicit tests of memory.