A possible relationship between diurnal variation in performance of step-through passive avoidance response (PAR) and that in adrenocortical response was investigated. In Wistar-Imamichi strain rats, retention latency of PAR and serum corticosterone (CORT) level immediately after retention test were measured as a function of time of day. Basal CORT level was found to be low during early phase of light period, and thereafter to elevate toward dark period (Exp. 1). Eighty animals were divided into eight groups, which consisted of a combination of two diurnal times of training/testing (light phase=14:00 and dark phase=2:00) and four shock intensities for training (0, 0.5, 0.75, 1.0 mA) (Exp. 2). The latency of PAR was found to be longer in the light than in the dark phase, and CORT markedly increased only in the light phase in the groups with 0.75 mA. In addition, PAR was conducted at four times of day (8:00, 14:00, 20:00, 2:00) with 0.75 mA shock (Exp. 3). It was confirmed that the diurnal variation of PAR latency was associated with that the CORT elevation, with the maximum at 14:00 and the minimum at 2:00. These results indicate that diurnal variation in performance of PAR has a close relationship with that in emotional or stress response to aversive situation.
The proportion of the words that were common to the study phase and the test phase was manipulated in two experiments. Subjects previously studied either 20% or 80% of the words appearing in the test. In Experiment 1, the subjects performed a word fragment completion test. In the 20% condition, reading words produced more priming than generating words. In the 80% condition, however, generating words produced priming as much as that of the 20% condition. Experiment 2 examined this proportion overlap effect on fragment cued recall test. The generation effect was observed in the 80% condition, but not in the 20% condition. These findings indicate that performance on memory tests is determined by the manipulations of both encoding and retrieval conditions.
From different aspects than the frequency response analysis of the visual system, we investigated characteristics of the nonlinear response of the visual system to flickering stimuli in low temporal frequency domain. We measured increment threshold curves (masking functions) for 2Hz flicker of rectangular and sawtooth waveforms, using six and three subjects, respectively. When the amplitude of the flicker was at a supraliminal level, the increment threshold curve had on-transients for the rapid onset larger than off-transients for the rapid offset of the flicker wave. However, around a liminal amplitude level off-transients were more prominent. This result suggests that at low temporal frequencies (2Hz) the temporal contrast sensitivity may be determined mainly by the ‘off-responses’ in the visual system. Moreover, we found the similar changes of increment threshold curves to the flicker stimuli for a single rectangular stimulus, which means that the results as above mentioned are not specific to the periodical stimuli.
This study examined the semantic interaction of the constituent words of a metaphor on comprehension. In Experiment 1, 40 undergraduates rated 48 nouns using 37 semantic differential scales, and rated the same nouns in 24 similes (TOPIC is like a VEHICLE). In comprehending the metaphor, greater semantic change occurred in the topic than in the vehicle, and the change was toward an increased similarity between them. The Abstract Performance Grammar (APGo) (Osgood, 1980) explained that the rated value of constituent words predicted that of the metaphor topic. In Experiment 2, 46 undergraduates rated three isolated topics and the same topics used in 15 similes paired with one of five different vehicles. The rated meanings of the same topic changed in different directions according to the vehicle's meaning. In Experiment 3, 237 undergraduates rated isolated topics and vehicles and the same topics used in similes. The rating distribution of the topic was constrained to that of the vehicle in the simile, with the result that skewness and kurtosis increased, thus, the meaning of the topic changed.
A highly structured set of stimuli was used in this study. Each stimulus had four binary attributes, whose values were determined so that any two stimuli could be transformed into each other by changing values of one or more attributes. In one experiment, 93 undergraduates rated similarity of paired stimuli. In another experiment, the same subjects learned three stimuli which were presented one after another for 10 seconds each. Later, in the recognition task, they made “old” or “new” judgment and rated the confidence of their judgment for each of the test stimuli. Two groups of subjects served the two experiments in different order. The results showed that (1) the rated similarity between the paired stimuli is a monotonically decreasing function of the number of transformations needed to get the pair equal, (2) the recognition confidence for new stimuli is significantly higher for stimuli generated by relevant transformations from the learned stimuli than for stimuli not so generated. The results support a model of memory-representation-generation (Suto, 1987, 1988), but not “prototype plus transformation model” nor “context model”.
The present study involved three motor learning experiments; Experiments 1 and 2 measured regulating grasping power and isometric elbow flexion power, respectively. Knowledge of Results (KR) was given after completion of a task of short duration. Experiment 3 was similar to Experiment 2, but procedurally, KR was given concurrently with the task. Accordingly, KR processing takes place within the intertrial interval and parallel to taking task in Experiments 2 and 3, respectively. In these experiments, influences of varying intertrial intervals on the learing process were examined. The results were as follows; 1) In Experiments 1 and 2, shortening of the intertrial interval caused a delay in learning, however this was not the case for Experiment 3. Insufficient KR processing time is considered to be partially responsible for the above delay, 2) In Experiment 3, lengthening of the intertrial interval caused the above delay. These results suggest motor information processing to involve a property of natural decay with the course of time.
Two expriments investigated the representation of letter position in visual word recognition process. In Experiment 1, subjects (12 undergraduates and graduates) were asked to detect a target word in a briefly-presented probe. Probes consisted of two kanji words. The letters which formed targets (critical letters) were always contained in probes. (e.g. target: _??__??_ probe: _??__??_ _??__??_) High false alarm rate was observed when critical letters occupied the same within-word relative position (left or right within the word) in the probe words as in the target word. In Experiment 2 (subject were ten undergraduates and graduates), spaces adjacent to probe words were replaced by randomly chosen hiragana letters (e.g. _??__??__??__??__??__??__??_), because spaces are not used to separate words in regular Japanese sentences. In addition to the effect of within-word relative position as in Experiment 1, the effect of between-word relative position (left or right across the probe words) was observed. These results suggest that information about within-word relative position of a letter is used in word recognition process. The effect of within-word relative position was explained by a connectionist model of word recognition.
The effects of overt self-verbalizations with different contents were examined developmentally with an experimental paradigm under which children were to resist temptation while waiting alone. Subjects, either four or six year old, were forbidden to touch attractive toys while the experimenter was out of the room, and were variously instructed to self-verbalize during the period. “Task-oriented” subjects were to verbalize what they were told not to do. “Positive temptation-oriented” subjects were instructed to talk about the attractiveness of the forbidden objects. “Distraction” subjects were to verbalize irrelevant things to the waiting task. “Negative temptation-oriented” subjects were instructed to talk about the toys' unattractive aspects. No self verbalization instruction was given to “No verbalization” subjects. Transgression latency was used as an index of waiting behavior. The results were as follows: (1) Positive temptation-oriented did not affect the four-year olds' waiting behavior, but made waiting more difficult for the six-year olds'. (2) Task-oriented verbalization helped waiting behavior for both groups. (3) Neither distraction nor negative temptation-oriented verbalization affected waiting behavior of either group.
Normative data on intelligence in adults with Down syndrome was collected on 93 males and 80 females, aged 16 years and above, who had been given the Suzuki-Binet Intelligence Scale. Both the male and female groups showed bimodal curves in the distributions of IQs. Only for the low IQ groups, the distributions were defined by binomial distributions. The mean ages of starting to walk for the low IQ groups were six months or more later than those for the high IQ groups. However, no significant differences were observed in birthweights, terms of pregnancy, and ages between the two groups. In addition, significant sex differences were found in mean IQs, females scored higher in both the two groups.