Publications

Abstract

Memory representations of words are thought to undergo changes with consolidation: Episodic memories of novel words are transformed into lexical representations that interact with other words in the mental dictionary. Behavioral studies have shown that this lexical integration process is enhanced when there is more time for consolidation. Neuroimaging studies have further revealed that novel word representations are initially represented in a hippocampally-centered system, whereas left posterior middle temporal cortex activation increases with lexicalization. In this study, we measured behavioral and brain responses to newly-learned words in children. Two groups of Dutch children, aged between 8-10 and 14-16 years, were trained on 30 novel Japanese words depicting novel concepts. Children were tested on word-forms, word-meanings, and the novel words’ influence on existing word processing immediately after training, and again after a week. In line with the adult findings, hippocampal involvement decreased with time. Lexical integration, however, was not observed immediately or after a week, neither behaviorally nor neurally. It appears that time alone is not always sufficient for lexical integration to occur. We suggest that other factors (e.g., the novelty of the concepts and familiarity with the language the words are derived from) might also influence the integration process.

Abstract

The aim of the present study was to examine whether repetition of radicals during training of Chinese characters leads to better word acquisition performance in beginning learners of Chinese as a foreign language. Thirty Dutch university students were trained on 36 Chinese one-character words for their pronunciations and meanings. They were also exposed to the specifics of the radicals, that is, for phonetic radicals, the associated pronunciation was explained, and for semantic radicals the associated categorical meanings were explained. Results showed that repeated exposure to phonetic and semantic radicals through character pronunciation and meaning trainings indeed induced better understanding of those radicals that were shared among different characters. Furthermore, characters in the training set that shared phonetic radicals were pronounced better than those that did not. Repetition of semantic radicals across different characters, however, hindered the learning of exact meanings. Students generally confused the meanings of other characters that shared the semantic radical. The study shows that in the initial stage of learning, overlapping information of the shared radicals are effectively learned. Acquisition of the specifics of individual characters, however, requires more training.

Abstract

This study explores the effect of feedback with hints on students’ recall of words. In three classroom experiments, high school students individually practiced vocabulary words through computerized retrieval practice with either standard show-answer feedback (display of answer) or hints feedback after incorrect responses. Hints feedback gave students a second chance to find the correct response using orthographic (Experiment 1), mnemonic (Experiment 2), or cross-language hints (Experiment 3). During practice, hints led to a shift of practice time from further repetitions to longer feedback processing but did not reduce (repeated) errors. There was no effect of feedback on later recall except when the hints from practice were also available on the test, indicating limited transfer of practice with hints to later recall without hints (in Experiments 1 and 2). Overall, hints feedback was not preferable over show-answer feedback. The common notion that hints are beneficial may not hold when the total practice time is limited.

Abstract

Research into strategies that can combat episodic memory decline in healthy older adults has gained widespread attention over the years. Evidence suggests that a short period of rest immediately after learning can enhance memory consolidation, as compared to engaging in cognitive tasks. However, a recent study in younger adults has shown that post-encoding engagement in a working memory task leads to the same degree of memory consolidation as from post-encoding rest. Here, we tested whether this finding can be extended to older adults. Using a delayed recognition test, we compared the memory consolidation of word–picture pairs learned prior to 9 min of rest or a 2-Back working memory task, and examined its relationship with executive functioning and mindwandering propensity. Our results show that (1) similar to younger adults, memory for the word–picture associations did not differ when encoding was followed by post-encoding rest or 2-Back task and (2) older adults with higher mindwandering propensity retained more word–picture associations encoded prior to rest relative to those encoded prior to the 2-Back task, whereas participants with lower mindwandering propensity had better memory performance for the pairs encoded prior to the 2-Back task. Overall, our results indicate that the degree of episodic memory consolidation during both active and passive post-encoding periods depends on individual mindwandering tendency.