Facilitation of source discrimination in the novelty effect

It has been demonstrated experimentally that recognition of novel items is more accurate than recognition of previously familiarized items. Tulving an d Kroll (1995) proposed that this effect is due to novelty detectors in the brain giving processing priority to novel information. Recently, Dobbins e t al. (1998) suggested that the effect is due to source discrimination prob lems. In the present two experiments attempts were made to facilitate sourc e discrimination by having different orienting tasks and materials in the f amiliarization and in the critical presentations. Degree of familiarization was manipulated by varying number of presentations one, two or three times . The results in Experiment I showed that the novelty effect increased line arly as a function of presentations in the familiarization phase. In the se cond experiment the difference between familiar and novel items was even mo re pronounced. Enactment at encoding was added as a manipulation during fam iliarization. The results of Experiment 2 showed that the novelty effect di d increase linearly for items with nonenacted encoding (in which the famili arization and the critical phase were more similar) but not for enacted enc oding. All subjects reported experiencing source discrimination difficultie s in both experiments despite the measures taken to diminish them. It seems safe to conclude that source discrimination difficulties are a part of the novelty effect.