Unpacking the sandwich: Which mechanisms underlie the increase in sandwich priming during word recognition?

Lupker and Davis (2009) introduced a modification of Forster and Davis's (1984) masked priming technique that increased the size of priming effects. The modification involved briefly presenting the target as a preprime during the priming sequence (e.g., #####-JUDGE-judge-JUDGE; the "sandwich" method). At present, the precise mechanisms underlying this increase are not well understood, at least partially because most previous experiments comparing the two procedures involved between-subject comparisons. To examine these mechanisms more fully, we conducted three lexical decision experiments with sandwich and conventional priming methods using a within-subject design. We examined two types of form-related priming: letter transpositions (Experiment 1) and letter replacements (Experiments 2 and 3). Results showed an increase in masked priming effects with the sandwich method in all three experiments. Cross-method comparisons revealed the source of this increase: The sandwich technique sped up the responses to transposed-letter pairs and one-letter replacement letter pairs, produced no latency differences for double replacement-letter pairs, and slowed down responses to unrelated pairs. Experiment 3, using a control preprime (xxxxx), showed that the change in the nature of the priming effects was not simply due to the longer lag between the pattern mask and the target stimulus in the sandwich priming method. These findings pose problems for computational activation-based models that provide accounts of masked priming effects. (PsycInfo Database Record (c) 2025 APA, all rights reserved).