Contextual Reference And Emotion Affect The Cognitive Neural Mechanism Of Vocabulary Learning

Language learning is an important way for individuals to master scientific and cultural knowledge which could also improve their quality or capacity for work and promote communications with other people.Our communication will have no contents without vocabulary,so in a way word learning is the core of language acquisition.Hence,it is necessary to explore the rules of word learning and find efficient ways to learn new words.Previous studies have found that self-reference exerted positive impact on learning performance,and that emotion could also affect word learning.However,how self and emotion affect word learning and the underlying neural mechanism have not been systematically studied.In the current work,behavioral and event-related fNIRS measures were used to examine the effects of contextual reference(self-reference,others-reference)and emotion(positive,negative and neutral)on word learning.Two experiments were included in the present study.In experiment 1,participants were asked to learn the form-meaning mapping between the novel word and its corresponding meaning in different referential and emotional contexts,and then were required to complete the semantic consistency judgment task and source judgment task.For semantic consistency judgment task,participants were asked to decide whether the meaning of the novel word and its corresponding real word was consistant.Through such explicit semantic retrieval,we could indirectly revealed the influence of different contexts on form-meaning mapping during encoding.For source judgment task,participants were asked to decide which referential context they learned the novel words,from which we could observe the memory traces of different referential learning contexts and infer the process of referential context.The accuracy on the semantic consistency judgment task showed that negative contexts hindered word learning,suggesting that negative emotions might affect participants'attention to the novel words,thus hindering word learning.The response time on semantic consistency judgment task showed self-reference context led to faster responses compared with other-reference condition,which indicated that information associated with self was easier to extract.The accuracy on source judgment task indicated interactions between reference and emotion,and a trend for self-positivity bias occured.To further investigate the neural meachanism of the effect of contextual reference and enotion on word learning,experiment 2 employed fNIRS and implemented the same procedure.Neuroimaging results showed that compared with other-reference,words learned in self-reference condition induced stronger activation in the brain regions related to language processing(left dorsolateral prefrontal cortex).To be noted,emotional effects were modulated by contextual reference:emotional effects only occurred in self-reference condition,which involved right dorsal lateral prefrontal cortex and right inferior frontal gyrus.We also found brain activity in left inferior frontal gyrus and the left dorsolateral prefrontal cortex showed a trend for self-positivity bias in source judgment task.The results indicate that novel words learned in self-reference context might be better processed and more deeply learned,and self-reference and emotion are not independent of each other.The dorsolateral prefrontal cortex seems to play a general role in language processing.The results of Experiment 1 and Experiment 2 indicate that self-reference could promote lexical processing,and its influence on lexical encoding persists in the retrieval phase.The contextual information associated with self has stronger memory traces.Self-referencing is an efficient encoding strategy in word learning.Negative context might affect attention and processing of the target word,thus stably imparing word learning.Emotional effects on word learning were modulated by contextual reference,suggesting that self-reference and emotion are not independent of each other.The modulating effect is related to brain activation in dorsolateral prefrontal cortex and inferior frontal gyrus.The dorsolateral prefrontal cortex seems to play a general role in language processing.