List-length and list-strength effects in recognition memory

Abstract

The study of interference effects is important to constrain models of memory. List-length manipulations test how adding new information to memory affects memory for the other stored information (list-length effect; LLE). List-strength manipulations test how strengthening some information in memory affects memory for the other non-strengthened information (list-strength effect; LSE). Whereas LLE and LSE are generally found in recall tasks, their empirical status in recognition tasks is less well established. In this thesis, we investigated some boundary conditions for both list-length and list-strength effects. The results provided evidence for the following claims: i) LLE and LSE are real effects in recognition (the effects were obtained after controlling for several confounds); ii) LLE and LSE are modulated by the relative contribution of recall-like processes operating at test (more recollection at test yielded larger effects); iii) LLE and LSE can be modulated by the number of study-test blocks in an experimental session (fewer study-test blocks resulted in larger effects); iv) LLE and LSE can be modulated by the time interval between study and test (shorter intervals produced larger effects) and iv) LLE and LSE may not be strongly modulated by the magnitude of length and strength manipulations (stronger manipulations did not result in larger effects). Taken together, the results support memory models that attribute forgetting in recognition to competition between memory traces during either encoding or retrieval. The results provide little support for models that attribute forgetting solely to interference between the contexts in which a memory was originally stored