The Event-Related Potentials Studies Of Item Memory And Source Memory For Pictures And Chinese Characters

Item memory and source memory are two important aspects of episodic memory, which are also one of the hot issues in memory research. Item memory refers to the memory of event's content, and source memory refers to the memory of event's context. The neural mechanisms of these two kinds of memory are different. And there are many factors influencing source memory, such as material, encoding mode, test style, and so on. There are three hypotheses for the relationship between item memory and source memory: dual-process model, source monitoring framework and diagnostic context model. And the frontal two hypotheses consider that the differences between these two kinds of memory are qualitative, but the last one indicates that the differences between these two kinds of memory are quantitative.Voice and location are two important sources. Presently, the neural mechanism studies of voice source are mainly on words, and there is not any research on other materials. In addition, the conclusions on voice source are not completely consistent. There are some FMRI researches on location source, but the ERP researches are so rare, and the comparison between materials is also a deficit for location source research.Thereby, in order to inspect the differences between item memory and source memory and also the relationship between these two kinds of memory, four ERP researches were conducted with pictures and Chinese characters as stimuli and with voice and location as different sources, and with undergraduates as subjects. These researches were (1) The ERP study of item memory and voice source retrieval on pictures; (2) The ERP study of item memory and voice source retrieval on Chinese characters; (3) The ERP study of item memory and location source retrieval on Chinese characters; (4) The ERP study of item memory and location source retrieval on pictures. Meanwhile, the roles of material and source were also been investigated.For the first research, the old/new effects of item memory and voice source retrieval on pictures were significant. And the old/new effect of item memory appeared at 200ms, and the spatial distribution of this effect was also different from that of previous researches. And the possibilities for these differences were the channel of stimuli presentation, the complexity of encoding task, and the item number in each block. The old/new effect of voice source retrieval for pictures also appeared at 200ms, but the temporal distribution of this effect was longer than that of the item test effect, and the spatial distribution of the former effect was also wider than the latter,which demonstrated that the retrieval of voice source was more difficult than the retrieval of items, and more cognitive resources were demanded to fulfill the former task. As for the non-target pictures, the old/new effect was also significant, but the spatial and temporal distributions of this effect were not the same as those of the target pictures. And the waveforms of the learned pictures in the two tests were also different and there was a possibility that the test task was an important factor for the differences. In addition, the waveforms between new pictures in the two tasks were not significant, which demonstrated that test task was not a factor influencing the judgment of new items.From the second research we could see that Chinese characters also had significant item memory and source memory old/new effects, and the temporal distribution of the latter effect was longer than that of the former, and the spatial distribution of the latter effect was wider than that of the former. Compared with the first research, the temporal and spatial distributions of the two kinds of effects were different between Chinese characters and pictures, which indicated that material was an important factor affecting old/new effect.From the third research we could see that the old/new effect of location source retrieval for Chinese characters was also significant, but the temporal and spatial distributions of this effect were different from those of voice sourc...