Each of some promising theories explains human performances on the indicative Wason selection task. For example, participants usually select the 5 case, in the selection task with the conditional “if an E, then a not-5”. This tendency of the selection was explained by the heuristic-analytic theory, which is one of the dual-processing theories, that people are likely to regard a matching case as relevant to the truth of the conditional in the heuristic process (Evans, 1998). However, because a positive concept constructs a smaller set than its negative one does (a rarity assumption), it is more effective to get information on the truth of the conditional in a positive set than in a negative set. Thus the optimal data selection theories can also explain the effect. Yama (2001) found that the so-called matching bias was an amalgam of two different cognitive components, namely, relevance judgment by matching and the optimal data selection process. It was examined if the dual-processing theories captured the optimal data selection process with some evidences and concluded that, although the heuristic-analytic theory should be revised, the implication of the evidences could be discussed within the framework of the dual-processing theories.

View full abstract

We investigated the role of visual information in prehension movements, especially in the manipulation (grasp) component. In Experiment 1, we examined the fundamental properties of reaching and grasping movements. Subjects performed target-directed grasping under natural conditions, with no constraints imposed on the duration of movement. In Experiment 2, we investigated the stage at which visual feedback was effective, as well as the difference between prehension movements to a real object and prehension based on an “internal image”. A metronome was used to control the subject's movement duration. Subjects reached and grasped a cylinder (diameter of 6cm), wearing liquid crystal shutter goggles under four conditions. (1) The goggles opened (normal condition); (2) the goggles closed 0ms, 150ms, 500ms, or 700ms after the beginning of an arm movement (restricted condition); (3) subjects pretended to reach and grasp the cylinder (pantomime condition) and (4) subjects reached and grasped the cylinder without visual information (blind condition). In condition (3) and (4), their vision was occluded 3 seconds before initiating a movement. Kinematics of the wrist trajectory (transport component) and the distance between the thumb and middle finger (manipulation component) were analyzed. The results showed that the manipulation component was influenced by the shutter speed. Fast speeds (0ms, 150ms) caused a significantly large overshoot. Results also indicated that wrist velocity profiles in the acceleration phase are remarkably similar to the no visual and pantomime conditions, although the kinematics of the manipulation component in these two conditions was significantly different. These findings suggest that visual feedback is important during the early stage of movements and that the movements in pantomime and no-visual conditions probably involved an image-driven process, which is different from online visuomotor performance.

View full abstract

In this study, we discuss the following two research themes on human discovery processes, using a traditional discovery task, the Wason's 2-4-6 task. One theme is the relation between nature of targets that subjects are required to find and an effective hypothesis testing strategy. The other theme is effects of collaboration in the process of discovery. The experimental results are summarized as follows. (1) There was interaction between targets' generality and an effective hypothesis testing strategy. That is, a positive test was effective in finding a specific target, while a negative test was effective in finding a general target. (2) The effect of two subjects collaboratively finding a target emerged only in a particular situation. That is, we confirmed, through our experiments, an evidnece of the effect of collaborative discovery when a pair of two subjects repeatedly conducted a positive test in their experiments for finding a general target.

View full abstract

Human prehensile movements consist of two motor components: a transport component and a grasp component. The purpose of this study was to determine how the transport component is related to the grasp component in terms of spatiotemporal aspects such as the time series of a hand transport trajectory.
Seven subjects were asked to point to a target (a circle of 2 cm in diameter) by using the right index finger or to grasp a disc (2, 4, 6, or 8 cm in diameter and 2 cm in length) between the thumb and index finger of the right hand. Both the target and disk were placed 30 cm directly in front of the starting position of the right hand.
The results showed that: (1) As the size of the disk increased, the inclination of the hand in its final shape became larger; (2) As the inclination of the hand when grasping the disk became larger, both the peak and final heights of the wrist position during the hand transport movement increased; and (3) the hand aperture was related spatiotemporally to the change in the hand transport trajectory. These results suggest that transport and grasp components are coordinated spatiotemporally during human prehension movements.

View full abstract

The first purpose of this study was to demonstrate the durability of spacing effects produced by the Modified Low-First Method. The Modified Low-First Method is an optimal spaced learning method which was derived from a reactivation theory of spacing effects and was designed to be effective by setting as advantageous spaces as possible for all items and for any learners with various working memory capacities. It consists of three principles; the first is to sort all items by their probabilities of recall in ascending order at the end of each learning session for the subsequent session, and the second is to omit items whose probabilities of recall have reached a certain level, and the third is to transit to a new learning session when the number of unrecalled items in a session have reached a certain number. The second purpose of this study was to extend a reactivation model to be able to predict probabilities of delayed recall by incorporating a forgetting function into the previous model. In Experiment, the probabilities of delayed recall in the control condition with simple repetition method and in the experimental condition with the Modified Low-First Method were compared. The result indicated that the Modified Low-First Method was constantly more effective than the former for as many as 14 days. In Simulation, a forgetting power function derived from the experimental data was incorporated into the existent model, and the experiment was simulated with it. The result showed that the estimated probabilities of delayed recall approximated closely to the experimental data, indicating the adequacy of the extended reactivation model.

View full abstract

In this paper, the effects of three lexical properties in processing Japanese are investigated using an eye-movement monitoring technique. The lexical properties investigated in this paper are: 1) familiarity of lexical items; 2) acceptability of orthography; and 3) transparency of sound-character correspondence in orthography. The stimuli sentences were all simple Japanese sentences with four to five phrases, in canonical word order as well as scrambled word order. In accord with previous studies that reported significant effects on reaction times, etc., of these lexical properties when tested in isolation, our results showed that all three lexical properties showed significant effects on eye movement. In particular, lexical familiarity showed a strong effect on all measured aspects of sentence processing. The effect of orthography was significant, not in terms of whether words were written in Kanji or in Kana, but on how appropriate the orthography was for the particular word. In addition, the degree of transparency between orthography and pronunciation had a limited but significant effect on the gaze duration. This implies that phonological processing may influence silent reading. The effect of scrambled word order was observed in the total gaze duration and it was mainly caused by increasing frequency of regressive eye-movement.

View full abstract

Eye movement analysis has been used to understand human higher cognitive processes for over a century. It permits observation of a person's activities in detail without disturbing his or her behavior. This tutorial first discusses eye movement analysis topics, including the definition of gaze, various eye movement detection methods, eye movement analysis methods. Next, it introduces cognitive research on the analysis of eye movement for observing cognitive activities. Finally, it describes gaze based interactive systems as the application of eye movement analysis.

View full abstract