RESUMEN
Consecutive training on two movement sequences often leads to retroactive interference-obstructing memory for the initially trained sequence but not for the second. However, in the context of hippocampal-system dependent memories, a poor learning experience, memory for which would soon decay, can be enhanced if temporally paired with a "strong," memory triggering experience. The synaptic tagging and capture hypothesis explains this paradoxical enhancement by suggesting that only strong experiences generate cellular resources necessary for synaptic remodeling. However, synapses engaged in a "weak" learning experience can capture and utilize plasticity-related resources generated for a subsequent strong learning experience. Here, we tested whether such "paradoxical" outcome would result in the context of motor (procedural) memory, if two movement sequences are unequally trained, consecutively. We show, in young adults (n = 100), that limited practice on a novel sequence of finger-to-thumb opposition movements led to different long-term outcomes, depending on whether and when (5 min, 5 hr) it was followed by extensive training on a different sequence. Five-minute pairing, only, resulted in overnight gains for the limited-trained sequence that were well-retained a week later; the overnight gains for the extensively trained sequence were compromised. Thus, consecutive training on different motor tasks can result in mnemonic interactions other than interference. We propose that the newly discovered mnemonic interaction provides the first-tier behavioral evidence in support of the possible applicability of notions stemming from the synaptic tagging and capture hypothesis in relation to human motor memory generation, specifically in relation to the practice-dependent consolidation of novel explicitly instructed movement sequences.
RESUMEN
In two experiments, we examined the role of differential levels of knowledge between the genders in different domains, which we term gender expertise, in accounting for differences in episodic memory performance. In Experiment 1, we validated the assumption of differential gender expertise among men and women and selected the categories for the subsequent experiments. In Experiment 2, participants from both genders studied exemplars from these female-oriented, male-oriented, and gender-neutral categories and were tested after 24 hours on studied items, critical lures, and unrelated lures. A gender-congruity effect was found in terms of the recognition rates of both studied items and critical lures: Participants from each gender recognized more studied items and more critical lures from gender-congruent categories than from gender-incongruent categories. A parallel pattern of results was found for subjective confidence, supporting the notion that gender congruity enhanced the phenomenological experience that an item was studied. Our findings highlight the unique role of gender expertise in accounting for gender-congruity effects in episodic memory performance, using a well-defined operationalization of gender expertise. These findings show that in addition to benefits in terms of enhancing true memory, gender expertise also has a "dark side" of increasing false memories.