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- P-ISSN1226-9654
- E-ISSN2733-466X
- KCI
ISSN : 1226-9654
Vol.6 No.1
Abstract
Zaidel(1983, 1986, 1991) proposed two models to explain the degree of hemispheric asymmetry in processing visual stimuli presented unilaterally. Direct-access model assumes that each hemisphere holds independent processing capacity without hemispheric specialization for a particular type of stimulus. Callosal-relay model presumes that if certain stimulus is presented to the nonspecialized hemisphere, it will be transmitted to the specialized hemisphere for the processing of the stimulus. Three experiments were administered to examine these two models. The subjects performed same-different matching task as verbal stimuli(Exp. 1: color words) and nonverbal stimuli(Exp. 2: color patchs, Exp. 3: pictograms) were presented to the left or right visual field. The results showed that interaction effects between the visual field and the response hand for both verbal and nonverbal stimuli, but not between the visual fields. Simple main effect analyses revealed that RTs were faster for the response hand in ipsilateral visual field for the stimulus presented. That is. regardless of the response hand, uncrossed pathway was always responded faster than crossed pathway. This means that left and right hemisphere can process input stimulus independently although the degree of hemispheric specialization is different. But when the stimulus was presented to the right visual field, right hand RTs were significantly faster than RTs for the left hand, but the reverse was not true. This is an infraction of an assumption of the direct-access model, which hypothesizes that motor command transmission time is the same between the two hemispheres. This aspect should be examined further for the refinement of the model.
Abstract
The purpose of the study was to examine the pattern and latency of the eye movement-related signals integrated into the cat visual cortical area 18. Animals' eye movements were recorded with magnetic search coil method and single or multile unit activities of these areas were recorded with conventional electrophysiological method in fully-awake cats. At eighty six percent of studied sites spontaneous neural discharges increased after the onset of saccadic eye movements in light condition, and at least 62% of these sites, the activity increased in the dark condition allowing no visual input. The pattern of eye movement-related activities also included inhibition around the onset of eye movements, and change in the level of activity depending on the eye position, although these classes constituted only 6%. When compared with previous results in the area 17, the proportion of cells showing increase in spontaneous activity was much higher in the area 18. The increase in the activity typically consisted of two temporally-distinguished components in the light condition. The first component modulation, reflecting visual reafference signal, occurred with shorter latency in the area 18 than in the area 17 by 20msec. These results indicate that the most area 18 cells increase excitabillity on the onset of eye movement and suggest that eye movement-related signals are differentially used across visual areas.
Abstract
The present study was conducted to determine whether the ventral medulla (VM) at the level of the inferior olive (IO) is involved in descending pain inhibition system including the anterior pretectal nucleus (APTN). Pain sensitivity was assessed using tail-flick test to radiant heat in the rat anaesthetized with pentobarbital. Electrolytic lesions of the VM or microinjections of lidocaine into the VM inhibited the analgesic effects of stimulating the APTN. Electrical stimulation of the VM or microinjections of glutamate into the VM produced analgesic effects similar to those of stimulating the APTN. These results suggest that the VM including the IO is involved in a descending antinociceptive pathway originating in the APTN.
Abstract
Varying the size and width of circles in Treisman and Paterson's (1984) experimental displays, three experiments were designed to test predictions derived from Treisman and her associates' feature integration theory of attention as against those from a visual routines hypothesis (Ullman, 1986) about illusory conjunctions. The former theory emphasizes the importance of spotlight of attention in the perception of objects, whereas the latter does non-attentinonal processes such as coloring and boundary tracing. Three experiments showed that the extraction of emergent features such as closure is heavily dependent on the size of spotlight of attention, thus rejecting the visual routines hypothesis in encoding of spatial relations. However, our results also indicate the need for further refinements in the feature rote-gration theory of attention, especially its explanations of illusory conjunctions.
Abstract
This study was conducted to determine whether the periaqueductal gray (PAG) is involved in descending pain inhibition system mediated by the anterior pretectal nucleus (APTN). Pain sensitivity was assessed using tail-flick test to radiant heat in the rat anaesthetized with pentobarbital. Microinjections of lidocaine into the PAG inhibited the analgesic effects of stimulating the APTN. After WGA-HRP was injected into the ventral medulla at the level of the inferior olivary nuclei, the labeled neurons were detected in the ventrolateral PAG and in the APTN. The results suggest that the PAG is at least partially involved in a descending antinociceptive pathway originating in the APTN.
Abstract
Two experiments were carried out to examine the nature of distance effects in a task that requires subjects to shift their attention from one location to another. A continuous model of attention movement predicts that RT increases as the interletter distance increases, whereas a discrete model of attention shift predicts no distance effects on RT. Experiment 1 presented stimulus display with long exposure to examine the nature of attention movement in the natural condition that permits subjects' eye movements. Subjects' task was to determine whether one of the two letters cued by green circles contained a target letter in the stimulus display. As a result, reaction time to the target letter increased as the distance between cued letters increased, supporting the continuous model. In experiment 2, eye movements were controlled by presenting the stimulus display briefly. In contrast to the result of experiment 1, experiment 2 did not show any effect of distance. The data suggest that when eye movements are restricted, attention moves in a discrete manner.
Abstract
Using a curve-tracing task that requires subjects to determine whether two Xs lie on the same curve or not, we carried out two experiments to test whether visual curve-tracing is qualitatively different from mental curve-tracing. We presented curves and an X before another target X was presented, and required subjects to determine if the X in the target display lies on the curve that contained the other X in the preview display. In experiment 1, the ISI between the preview display and the target display was 1 sec, whereas the ISI in experiment 2 was varied from 100ms to 2 sec. Since it was assumed that at the ISI level of 1 or 2 sec subjects must perform curve tracing operation based on mental imagery, it can be called 'mental curve-tracing', whereas the curve-tracing in the previous studies and the one using 100ms ISI level in experiment 2 can be called 'visual curve-tracing', As results, the response time for determining whether two Xs lie on the same curve increased with X-X distance regardless of ISI, suggesting that a serial curve-tracing processing was needed in both mental and visual curve-tracing tasks. It is also suggested that both the visual curve-tracing and the mental curve-tracing may share the same elemental operations and routines.
Abstract
The purpose of this study was to examine the effects of the aggression and social dominance on stress ulcer in isolated mice. Subjects were ICR strain of mice that were separated from their own litters on the 21st day of life and reared in isolation and in group for 150 days. All animals divided into four groups, "no-aggressiveness", "low-aggressiveness", "middle-aggressiveness" or "high-aggressiveness" on the basis of the frequency of aggressive behaviors to the stimulating animals. Twenty-four hours after aggression rating, animals were exposed to cold-restraint stress for an hour, and then stomach ulcer was estimated under operational microscope. The results were as follows: First, Ulcer scores of "low-aggressiveness" and "high-aggressiveness" group were lower than group rearing animals. Second, "no-aggressiveness" and "middle-aggressiveness" group were not different from group animals in ulcer score. Third, Ulcer scores in "middle-aggressiveness" group were higher than another three isolation groups. The results of this study hold similar views that if the reaction of emotion is suppressed, physical diseases tend to happen or if unpleasure feeling such as anger does not vent, various psychosomatic diseases such as stomach ulcer or hypertension can be induced.
Abstract
Two experiments were performed to measure the effect of bizarre imagery with paired - associate learning task. In experiment 1 for cued recall, common imagery increased recall when imagery type was manipulated in pure-lists design but not when imagery type was manipulated in mixed-lists design. In experiment 2 for free recall, bizarre imagery faciliated recall in mixed-lists design but not in pure-lists design. In conclusion bizarre imagery produced better recall only with a mixed-list design in free recall.
Abstract
This study examined effects on acquisition and retention of conditioned fear of nucleus accumbens(n.Acc) lesion and central amygdaloid nucleus(ACe) lesion. The suppression ratio in bar-pressing of ACe-lesioned group was compared with that of Sham-Conditioning group and Sham-Control group. In n.Acc groups same comparisions were made respectively. If was found that ACe-lesioned animals and n.Acc-lesioned animals showed the deficit in acquisition of conditioned fear. It was suggested that ACe seemed to be essential in the formation of associations between motivationally significant stimuli and that mesolimbic dopamine system was involved in the activation of behavior by motivationally significant stimuli.
Abstract
This study was designed to investigate the nature of representational images on mental rotation. Shepard and Metzler (1988) estimated rates of mental rotations which were much slower in the two-stimuli task than in the one-stimulus task. Differences in estimated rate of mental rotation between two tasks could be resulted from the following two components. The first one is the nature of experimental task which may induce some individuals to rotate the image of stimulus externally presented one piece at a time in the two-stimuli task, and which may induce some individuals to rotate the image of stimulus already learned as a whole in the one-stimulus task. Therefore, not the one-stimulus task but the two-stimuli task would entail still longer time to complete a mental rotation. The second one is the nature of interstimulus intervals (ISIS) which were allowed to represent standard stimulus in the one-stimulus task better than in the two-stimuli task. Because a stimulus was to be compared with an image of stimulus that was previously learned, the images would be rotate much faster in the one-stimuli task than in the two-stimulus task. In this study, the type of stimulus task was varied into the fixed-standard stimulus task and the variable-standard stimulus task. The ISIS in the study were varied into 100 msec, 500 msec, and 1000 msec. The results sheowed that there was no difference in the estimated rate of rotation between the two tasks. However, the longer ISIS were, the faster estimated mental rotation rate was. It suggested that mental rotation accomplished faster as time for representation of standard stimulus increased.
Abstract
The relation between recognition and categorization was investigated in two experiments which used independently determined features but different category structures. In Experiment 1, verbal letter strings were categorized better than visual bar charts and analytic strategies were preferred by subjects. Bar charts were categorized better than letter strings in Experiment 2 which enhanced holistic strategies. But in both experiments recognition was not affected by stimulus types. Block effects suggested that recognition memories decreased across blocks of practice, whereas categorization increased across blocks. Thus stimulus types and blocks of practice had separable effects on categorization and recognition, implying that categorization was based on abstract rules. The two experiments were different in the effects of specific exemplar memories on categorization: Exemplar memories had no effect in Experiment 1, but they had significant effects in Experiment 2. The results suggest that recognition is based on memories for specific exemplars, while categorization depends on abstract rules but is also influenced by exemplar memories in some conditions.
Abstract
This study was planned to investigate representational aspects of categorical information by analyzing time courses of categorization. In experiment 1, category size and overlap were manipulated to test whether subject acquires summary information through category learning. It was found that categorization judgements of stimulus similar to prototype were more accurate than those similar to learned exemplars as category size increased. And it took more time to categorize stimulus similar to learned exemplars in small category size condition as category overlap increased. But category overlap didn't affect categorization time in large category size condition. In experiment 2, priming effects of prototypes or learned exemplars on categorization of novel stimulus were analyzed to find out differences of categorical informations accessed. As a result, in prototype priming condition, priming effects of stimulus similar to prototypes were larger than those similar to learned exemplars in large category size condition. But, in exemplar priming condition, the reverse was true in small category size condition. In conclusion, these results implicate that subject categorizes instances by retrieving similar learned exemplars from his memory in small category size condition, but by similarities between prototype and them in large category size condition.
Abstract
This study was to examine the overhearer's effect in referential communication. In the first experiment, we examined whether director's performance was affected by overhear's presence itself. We examined triples of people in which one person told another person in conversation how to arrange 12 complex figures while an overhearer tries to arrange them too. All three began as strangers with the same background information. As predicted, addressees were more accurate at arranging the figures than overhearers although the two shared the same information. The result showed that addressees in the nonexistence condition spend more time and made longer sentences than the existence condition. The second experiment was about the familiarity effect. Two alternative hypothesis was tested. The first hypothesis. "familiarity maintenance hypothesis" assumes that if the overhearer is familiar with the director, the director will use more words to help the overhearer. The alternative hypothesis, "common ground sharing hypothesis", assumes that the director will show no difference in both condition. The result indicated that the performance showed no difference between the two conditions, so the common ground sharing hypothesis was supported. The effect of overhearer's existence and the commonground sharing hypothesis showed that even the same information was provided. active participant(addressees) perfomance was better than passive participant(overhearer). It implies that to be successful communication, active collaboration was needed in addition to the appropriate information.
Abstract
This study performed three experiments to investigate transfer conditions of the analogical problem solving. Experiment 1 and 2 employed the inter-domain transfer problems; however, the number of analogous base stories was either one or two respectively, Experiment 3 used word arithmetic problems. The primary purposes of the study were to empirically demonstrate the analogical transfer of problem solving and to examine the effect of conceptual understanding on the analogical transfer. The results obtained could be summarized as follows. (i) The baseline level of spontaneous transfer, which implied spontaneous noticing, was about 8%, either with or without exposure to the base problem. (ii) the relevancy of response structure of the base to the target problem determined the direction of analogical transfer in problem solving. (iii) the ensuring of the original learning was prerequisite for transfer to occur. That is, unless certain sufficient level of the original learning of the base problem achieved, the potential transfer could not be obtained. (iv) Giving hint either at the initial attempt to solve the transfer problem or after completing the initial effort did not differ in transfer effect. And (v), finally, the verbal direction to summarize the base task facilitated the positive transfer compared to the simple recall processing. However, the diagram showing the solution structure or the elaborateness of model solution of the base problem was not necessarily useful in helping the analogical transfer.
Abstract
In two experiments, representation of causal information in reading was investigated. In Experiment 1, the order of presentation and that of testing of causal information were manipulated. Regardless of the order of presentation, the cause events were recognized faster than the consequent events, which suggested that the causal information was represented in natural order. In the single cause condition of Experiment 2, recognition was marginally faster when a target event was a cause than when the event was an enabling condition. In the two cause condition of Experiment 2, recognition time was not affected by the order of the two causes, which suggested that causality of possible causal events were differentially judged and processed based on the nature of the causal events.