Center for Neuroscience, University of California, Davis, Davis, United States; Department of Psychology and Child Development, California Polytechnic State University, San Luis Obispo, United States
America Romero
Department of Psychology and Child Development, California Polytechnic State University, San Luis Obispo, United States
Anthony H Vierra
Department of Psychology and Child Development, California Polytechnic State University, San Luis Obispo, United States
Rebecca S Luenser
Department of Psychology and Child Development, California Polytechnic State University, San Luis Obispo, United States
Robert D Hawkins
Princeton Neuroscience Institute, Princeton University, Princeton, United States
Kelly A Bennion
Department of Psychology and Child Development, California Polytechnic State University, San Luis Obispo, United States
Two fundamental issues in memory research concern when later experiences strengthen or weaken initial memories and when the two memories become linked or remain independent. A promising candidate for explaining these issues is semantic relatedness. Here, across five paired-associate learning experiments (N=1000), we systematically varied the semantic relatedness between initial and later cues, initial and later targets, or both. We found that learning retroactively benefited long-term memory performance for semantically related words (vs. unshown control words), and these benefits increased as a function of relatedness. Critically, memory dependence between initial and later pairs also increased with relatedness, suggesting that pre-existing semantic relationships promote interdependence for memories formed across episodes. We also found that modest retroactive benefits, but not interdependencies, emerged when subjects learned via studying rather than practice testing. These findings demonstrate that semantic relatedness during new learning retroactively strengthens old associations while scaffolding new ones into well-fortified memory traces.
