The purpose of this study is to analyze the way students enhance their learning activities by interacting with each other in the process of collaborative discovery learning. Ten pairs of high school students participated in learning the computer microworld discovery materials designed for this study, and their verbal protocols were then analyzed.
In this paper, we propose the LUTE (Link-UniT-Element) model. The LUTE model is composed of three levels: the third level consists of dialogue elements (level III); the second of conceptual units (level II); and the first of links between the two units (level I). The conceptual units involve three types of data (D), three types of model (M), and knowledge (K).
Analysis based on the LUTE model shows that collaborative learning correlated with the following factors: 1) the extent to which an inactive learner participated in learning processes; 2) the number of times an active learner questioned and objected to an inactive learner during the dialogues; 3) the total number of links connecting the two units; 4) the appearance of links signifying hypothesis formation and verification; and 5) the proposals of strategical units.
The factors mentioned above are discussed from the viewpoint of the correlation of the three levels. Our analysis leads us to conclude that 1) learning processes were in progress in the correlation of the three levels; 2) an active learner developed his/her learning processes autonomically, while the activity of an inactive learner depended on an active learner; and 3) proposing strategical units activated the interaction between the two learners.

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This research proposes and tests a reactivation theory of spacing effects which assumes them to be caused by the reactivation of representations whose activation levels have decayed within spaces, and recall rates to increase as the amounts of the reactivation increase. According to this theory, therefore, recall rates are supposed to increase sharply when the spaces are small enough for the representations formed at the first presentation to remain in working memory because their activation would decay rapidly and, on the contrary, the amount of reactivation at the second presentation would increase rapidly. They also are supposed to be rather high and stable when the spaces are large enough for the representations to be transferred to and consolidate in long-term memory because their activation levels there would be relatively low and stable and the amount of reactivation would be relatively high and stable. Two experiments and two simulation were conducted to test this theory. In Experiment 1, recall rates at various spaces and presentation times were examined, using two-digit numbers for stimuli on which encoding variability should have little effect and the effects of spaces themselves should be clear, and the results were consistent with most of the suppositions above. In Simulation 1, a simulation model of the reactivation theory was made on the experimental data and a simulation was conducted to find the estimated recall rates approximated to the measured recall rates in Experiment 1. In Simulation 2, recall rates on various expanding space conditions in three-times presentation were predicted. Then in Experiment 2, recall rates on the same conditions with those in Simulation 2 were measured to find they are very close to the predictions in Simulation 2. Finally, this theory was applied to explain several previous inconsistent experimental results found under the other theories of spacing effects.

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We propose functions of Japanese Sentence Final Particles(JSFPs henceforth) YO, NE, NA, ZO and ZE that are based on a hierarchical memory model which consists of Long Term Memory, Episodic Memory and Discourse Memory. The proposed functions of JSFPs are basically monitoring functions of the mental processes being done in utterance. By this characterization of JSFPs, we account for the possible and impossible uses of conjoined JSFPs.

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In a “subject-oriented sentence” such as “Taroo-ga Hanako-ni Tokyo-e iku koto-o hakuzyoosita (Taroo confessed to Hanako to go to Tokyo)”, the person who will go to Tokyo is “Taroo”. On the other hand, in an “object-oriented sentence” such as “Taroo-ga Hanako-ni Tokyo-e iku koto-o meireisita (Taroo ordered to Hanako to go to Tokyo)”, “Hanako” will go to Tokyo. In the above examples, the main clause verb's location at the end of sentence causes a tentative ambiguity which is not resolved until this verb becomes available to the human sentence processing mechanism (i.e., a “parser”). How does the parser deal with this informationally ambiguous situation? More specifically, is the processing procedure “top-down” or “bottom-up”? We report the results of an experiment using a dichotic-listening method, examining the real-time processing of sentences. A sentence was presented to one ear of a subject, and after the offset of the sentence, a possible antecedent for the empty subject (i.e., either the subject or the object of the main clause) was given to the other ear. There were 6 test points with 300 msec intervals. The subject's task was to answer whether the given antecedent would really go to Tokyo or not, by pressing the yes- or no-key as quickly as possible. In the case of ‘yes’ responses, at 0 msec ISI, the mean RT in the subject-oriented sentences was significantly shorter than that in the object-oriented sentences. In the case of ‘no’ responses, only the effect of ISI was statistically significant, showing that the RTs became shorter, and overlapped with those of ‘yes’ responses beyond 900 msec ISI. These results suggest that the human parser assumes that the main clause subject is the default antecedent for the empty subject of a subordinate clause. This initial “top-down” assumption seems to be suppressed by a “bottom-up” process by 900 msec after the end of the sentence.

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