The Experiments On The Cognitive Mechanism And Development Of Directed Forgetting

Directed forgetting emphasizes the intentionality and directedness of forgetting. The term of directed forgetting was first used by the American Psychologist, R.A.Bjork in 1972. In general, when the research participants were asked to remember certain displayed materials(to-be-remember, TBR) while forgetting the rest displayed materials(to-be-forget, TBF), the participants would recall more TBR items and fewer TBF items in later recall tasks.Over the past years, two experimental paradigms have been used in directed forgetting research: list method and item method. It was once believed that the two research paradigms involved different creating mechanisms that lead to directed forgetting: retrieval inhibition and selective rehearsal. However, in recent years, more and more research evidence suggests that although one creating mechanism may be more emphasized than the other in a research paradigm, both of the mechanisms are involved.Another popular topic of directed forgetting is on the factors that influence directed forgetting and the theories about why and how these factors function. Some identified factors include intensity of clue, affective characteristics of the materials, semantic characteristics of the materials, memory load etc. Theories such as Resource Limitation Theory, Source Monitoring Theory and Automatic Target Search Theory were proposed to explain how the factors function and influence directed forgetting. Among them, the opposition between the Source Monitoring Theory and the Automatic Target Theory became prominent.In education, directed forgetting can be considered as a type of memory ability or cognitive strategy. Because of the significance of directed forgetting on memory, it is important to examine the development of directed forgetting in students of various grades. To achieve this purpose, four experiments were conducted. In study 1, the materials were displayed in the form of block by combining the list method and the item method. Using multi-factorial experimental design, I sought to examine whether directed forgetting exists under this circumstance and whether the intensity of items and the item-prompt interval influence directed forgetting. The research finding would provide experimental evidence for later exploratory studies. In study 2, using the block display method, I attempted to examine the developmental trend of directed forgetting in students from 6 grades(from elementary grade 3 to middle school grade 2). Detailed analyses on the function and the development of the two production mechanisms were provided. In study 3, I focused on students from two natural middle school classes. I was interested in examining whether high-achievement students displayed more directed forgetting than low-achievement students. The impact of the intensity of items was also examined. In study 4, I examined whether directed forgetting was influenced by the correspondence of display methods between the learning session and the recognition session, and how this influence is changed with age. The results indicated that:1. Directed forgetting was observed while using block display method. Both retrieval inhibition and selective rehearsal were found simultaneously.2. the intensity of items, but not item-prompt interval, influenced directed forgetting. The results conflicted with the Resource Limitation Theory, meanwhile, were not very consistent with the Source Monitoring Theory and the Automatic target theory.3. Directed forgetting and retrieval inhibition were found to start development from grade 4. However, they can be fostered from grade 3. In contrast, selective rehearsal was found to start development from grade 5, which is one year after retrieval inhibition. There are two developmental spurts of directed forgetting, one in grade 6 and the other in middle school grade 2. In grade 6, both retrieval inhibition and selective rehearsal developed rapidly. In middle school grade 2, students became more flexible and effective in selective use of retrieval inhibition and selective rehearsal.4. High-achievement students displayed significantly higher level of directed forgetting than low-achievement students. Further analyses revealed that high-achievement students scored higher than low-achievement students on both retrieval inhibition and selective rehearsal.5. The inconsistency of the item display method during learning session and recognition session has no significant influence on directed forgetting. This finding did not support the Transfer-appropriate Processing Theory about memory.6. Compared with visual display, auditory display in learning session were more likely to induce directed forgetting. This could be related with the different characteristics of visual and auditory memory.