知识整合的时间进程:ERP研究

The Time Course of Knowledge Integration:An ERP Study

本研究借助ERP技术,采用分离句子范式,考察了被试通过整合主干事实生成新知识的时间进程。结果发现:(1)知识整合事实相对于传递性推理事实和新颖事实诱发了更小的N400,与众所周知事实没有显著差异,表明通过整合生成的新信息纳入了知识库;(2)对比两次呈现,延迟性整合事实在第二次呈现时与众所周知事实没有显著差异,表明知识经验影响了整合的时间进程,与两个新信息间的即时整合相比,新旧信息间的延迟整合需要更多的时间。

Building a knowledge base is one of the most important tasks in development.New content can be entered into semantic memory not only through direct experience(e.g.,explicit instruction,observation),but also through self-generation resulting from a number of logical processes,including deduction,induction,and analogy.Another means of extension of semantic memory is self-generation of new knowledge through integration of information acquired in two(or more)separate but related learning episodes.Previous studies mainly investigated knowledge extended through integration that remains accessible after delay,little is known about the time course over which newly self-derived information through integration and the effects of prior knowledge on undergraduate students’self-generation of new knowledge through integration.The present study aimed to examine the time course of self-generated knowledge through integration of separate but related facts pair by using the event-related potentials(ERPs)technique of high temporal resolution.Considering the role of prior knowledge experience,this study distinguished knowledge integration into instant integration and delayed integration.In addition,also have added transitive reasoning facts to further exolore the similatities and differences of cognitive processing between reasoning and knowledge integration.At the encoding phase,subjects read each of the 180 sentences presented on a computer,and then judged when the facts in the sentences should be learned:primary school,middle school,or college.After a break of 5 minutes,participants were tested with the new information by integrating the stem facts learned during encoding phase.ERPs were collected as subjects read each of the 100 sentences.To permit observation of anticipated changes over time in the neural status of the self-derived information,each sentence was presented twice.Behavioral results showed a significant main effect of the number of presentations.The average reaction time to all fact types on the second presentation was significantly faster than the first presentation.Reaction times to the fact type were also found faster in response to well-known facts than to immediate integration,delayed integration and novel facts.Besides,the results of ERP showed that the N400 responses to integration facts differed from responses to transitive reasoning facts and novel facts,and did not differ from responses to well-known facts,suggesting that the selfderived new information through integration occurred quickly and the integrated fact had been incorporated into the semantic knowledge base.In addition,according to the analysis of time course,we also found that the amplitude of the delayed integration facts decreased and moved closer to well-known facts in 350ms during the second presentation,indicating that the delayed integration had been occurred by combining the stem facts and the new factual knowledge quickly transited to known.Comparing the two presentations revealed that knowledge experience affected the time course of integration.Delayed integration occurred later than immediate integration,as it needed to activate relevant information in long-term memory.Combing the behavioral and the ERP findings,these results show that the time course of self-generated new knowledge through integration of separate but related facts pair and the prior knowledge experience does affect the time course of integration.These findings help explain the richness of semantic memory and further our understanding of the basic cognitive processes involved in extension of knowledge.