The twin study method is deemed to be the most reliable one in order to study the hereditary and environmental influences upon the development of intelligence. Among the various conditions the problem of early physical conditions was this time taken up, using individual intelligence test scores obtained from 269 pairs of monozygotic (MZ) twins and 64 pairs of same-sexed dizygotic (DZ) twins, all twelve years of age. Among the results obtained, the statistically significant ones were as follows: I. The analysis of the physical conditions compared between MZ and DZ twins indicated that MZ twins showed much more similar birth weights, a shorter time interval in birth, and less difference in the initiation of walking than DZ twins. As to MZ twins with a great difference in the start of walking, it was found that the first-born, or the heavier twin began to walk earlier than the other twin, while this relationship could not be seen in DZ twins. II. The view of many previous researchers that MZ twins as a whole show higher degree of conformity in the development of intelligence than DZ twins was not supported by all cases of our MZ twins, and in some MZ twins a great difference of intelligence was found. This difference was considered having been caused by the environmental factors. III. Those MZ twins who showed a great intra-pair difference in their biological conditions at birth were selected. The comparative analysis of the data indicated that 1) as to pairs with a great intra-pair difference in birth weight, the heavier twin showed the higher intelligence score, 2) as to pairs with a long intra-pair interval in birth, the first born showed the higher score, 3) when a twin was born with asphyxia neonatorum, he showed a lower score, and 4) those twins who showed a great difference in intelligence scores also showed a difference in their initiation of walking and/or talking. Although there was a tendency that MZ twins were born with much more similar physical conditions than DZ twin, there was a great intra-pair difference observed in the development of intelligence at the age of twelve if MZ twins passed through different physical conditions at birth. A definite relationship between the early physical conditions and the intelligence development was thus illustrated, that is, the MZ twin born with superior conditions generally showed superiority in the development of intelligence.
Yokose, Kawamura, and Ichikawa have found that when a very small point was placed in the neighborhood of various kinds of figure, the point was influenced by the figure and was perceived to be displaced (or changed in location) in various directions. Whereas they demonstrated the displacement effect of figure on the same plane as the figure, I assume that such effect exists also in the surrounding visual space in front of the figure. To test this assumption experiments were performed with following procedures. 1. Two kinds of figure, that is, a circular figure and an angular figure were used as stimulus objects. 2. A small test point was presented at various positions in front of the figure as shown in Fig. 3, 8, and the amount of displacement (or the change of location) of the test point was measured by observing the apparent distance between the test point and the surface of the figure. Main findings were as follows: 1. A circular figure (Exp. I, II) A point placed closely in front of the figure was displaced toward the figure. When it was placed farther away, the displacement increased to the maximum as shown in Fig. 4, 5, and as it was put still farther away, the displacement decreased gradually and reached to Zero. When put farthest away, it was displaced away from the figure. 2. An angular figure (Exp. III) When a point was placed in front of the inside of an angle, the amount of displacement toward the figure was the largest near the corner of the angle (cf. Fig. 9, 10). When it was put in front of the outside of an angle, the displacement rapidly decreased to Zero as the actual distance between the surface of the figure and the point increased, as shown in Fig. 9, 11. Such relation between the actual distance and the amount of displacement was on the whole similar to that of the circular figure. From these results it was concluded that firstly, the displacement effect in the third dimension demonstrates the similar tendency to that in the frontal plane secondly, the results of an angular figure reveal the dependency of the displacement effect in the third dimension on the strength of the visual perception field in the frontal plane; thirdly, the marked difference of the effect in the third dimension from that of the frontal plane is the occurrence of the displacement away from the figure, or negative displacement, at a large distance from the figure.
This paper consists of two parts. In part I (Exp. I and II), two factors on the discrimination of avoidance conditioning (AC) were analysed. (Exp. I) The purpose was to analyse the effect of stimulus similarity. Method Ss: 26 male albino rats. Apparatus: The modified Mowrer-Miller shuttle box. Procedure: After the establishment of AC to CS (2,000cps pure tone), Ss were divided into three groups and given discrimination training. Reinforced stimulus (S+) for each group was 2,000cps tone and each non-reinforced stimulus (S-) for Group I, II and III was, 500cps, 1,000cps, and 1,500cps, respectively. The Ss of each group were given twenty daily trainings for 15 days. Results 1) The discrimination learning curves for three groups are shown in Fig. 1, 2 and 3. A comparison of the number of responses of S+ to that of S- indicated significant differences for Group I and II, but not for Group III. 2) The progresses of discrimination ratio (S+-S-/S+) for three groups are presented in Fig. 4. An analysis of variance on the ratio revealed significant difference among three groups (See Table 2). (Exp. II) The purpose was to analyse the effect of strength of UCS to S+. Method Ss: 30 male albino rats. Apparatus: The same apparatus as in Exp. I. Procedure: Ss were divided into three groups and conditioned avoidance response to CS (2,000cps tone) using UCS strength of 0.4mA shock for Group W, 0.5mA for Group M and 0.6mA for Group S. After the establishment of AC, discrimination training between 2,000cps (S+) and 1,000cps tone (S-) was given for 15 days. The UCS strength of each group to S+ was the same as in conditioning period. Resuits 1) The progresses of discrimination ratio for three groups are presented in Fig. 5. An analysis of variance on the ratio indicated no significant difference among three groups. (See Table 4). 2) These results of Exp. I and II suggested that the discrimination of AC was affected by the similarity of S+ to S- and not by the UCS strength to S+. In part II (Exp, III), the procedures of discrimination in AC were considered. Although the fundamental conditions of discrimination learning are to give S+ reinforcement and S- non-reinforcement, the conditions are not satisfied in case of discrimination of AC especially when stimuliare very similar. Therefore, it is inferred that special procedures are necessary to the discrimination of AC. (Exp. III) The purpose was to compare following two procedures; 1) S+ and S- were both stopped as soon as Ss finished response. 2) While S+ was stopped simultaneously with finish of response, the termination of S- was not syncronized with response, but delayed. In case of the discrimination of AC, the latter procedure was theoretically considered necessary to statisfy the basic conditions for discrimination. Method Ss: 39 male albino rats. Apparatus: The same apparatus as in Exp. 1. Procedure: Group IT and ID made discrimination between 2,000cps (S+) and 1,500cps tone (S-), and Group IIT and IID did between 2,000cps and 1,000cps. The discrimination procedure was the first one for Group IT and IIT, and the second for Group ID and IID. The training was continued for 20 days. Results 1) The curves of discrimination learning are presented in Fig. 6 and 7.2) Table 5 shows the mean discrimination ratio in the last 2 days of training for each group.
The present study was designed to examine the relationship between localization of function. in the brain and representation of the basic factors of intelligence. The quantitative findings reported in this investigation were based upon the test results from a battery of twenty-six intelligence-psychological indicators applied individually to thirty-nine subjects, including patients with various types of brain lesions, and to eighty normal control individuals. The experimental subjects were divided into a frontal lobe lesions group and a temporal lobe lesions group. The centroid method of factor analysis and orthogonal rotation of axes were applied to the correlation matrix based on those twenty-six variables, and three factors were extracted. The nature of these factors may be summarized as follows: (1) Factor I was interpreted as a basic capacity of reasoning. It shows the coalescence of knowledge and adaptive intelligence. (2) The variables positively loaded with Factor II were related to the abilities of reproducing knowledges in practical situation. (3) Factor III represented the abilities of application of a principle or knowledges to practice. When applied to patients with frontal lobe lesions and temporal lobe injuries, the following results were obtained: (1) Patients with damage in left-hemisphere of frontal lobe made poor records in variables positively loaded with Factor I and Factor III, and (2) those with main lesions in left-hemisphere of temporal lobe made poor scores in tests loaded with Factor II and Factor III. From these facts the following inferences were drawn: (1) Left-hemisphere of frontal lobe is relevant to the abilities of reasoning, and (2) the abilities of application of a principle to practice are dependent on left-hemisppere of temporal lobe. These findings and inferences are similar to those of W. C. Halstead.
The problem, of the number of objects one could judge instantaneously and correctly, had been discussed as the so-called “range of attention”. It had long been accepted that the “range” was six (Wundt, 1911). However, various doubts had been brought up against it, and the problem seemed not yet to have come to a satisfactory theoretical solution, although an attempt was except for few recent attempts which are based on information theoretical approach. (Miller, 1956). Our studies here reported aimed to reexamine the above problem using more systematic, experimental data obtained from subjects of various age groups. Stimulus objects: Thirty kinds of cards were used. Each card (20×20cm2) contained various numbers of outline circles (from one to ten), 1cm in diameter. On most cards they were arranged in a horizontal row, at equal intervals, and on others in an irregular pattern. As was necessary, the objects were divided into sub-groups, e.g. some of the circles on a card were blackened or else arranged in some regular, geometrical form. (see examples in Fig. 1) Subjects and conditons: 1) Thirty kindergarten children (3-6 years old) judged the number of circles on the stimulus cards were used for the still presentation of the stimulus objects, in which case under the condition where no time limit was set (Exp. I). After five months nine of them were again subjected to the same procedure (Exp. II). 2) One hundred and twenty-three primary school pupils (from the first to the fourth grades, i.e. 6-9 years old) were subjected to the “short time” presentation (about two seconds) (Exp. III). 3) Four adults were subjected to the tachistoscopic presentation, measuring the time values of the number cognition threshold (Exp. IV). Results: I. Pre-school children; the range of the number of objects judged instantaneously and correctly increased gradually up to five in number as the age increased. When the number of objects was beyond that range, 1) various kinds of actions accompanied the one by one counting of the objects, e.g. i) such motions as; a) touching or b) pointing with their fingers, c) turning their heads, d) moving their eyes, and ii) utterings such as calling numerals. 2) These accompanying action patterns seemed to change systematically as the age increased, that is, they shifted gradually from conspicuous to fractional in motions, and from louder to lower in utterings finally coming to non-verbal. As the action patterns became thus minimized they were also executed more rapidly. In rare cases the subjects gave correct ansveers, though not instantaneously, without such accompanying overt actions. And, as far as we confirmed later, they spontaneously divided the objects into sub-groups and utilized some arithmetical operations (Exp. I & II). II. School pupils; up to three objects, the percentages of correct answers were beyond 90. But over four, they decreasedd rapidly as the number increased. In the oldest group, however, they decreased more slowly than in the younger. See Fig. 2 (Exp. III). III. Adults; when the number of objects was three or less, the time values of the number cognition threshold were low and the same. From four to six, they increased almost linearly. But at seven, the time value showed a sudden increase. See Fig, 3 (Exp. IV). IV. When the objects were arranged to be divided into some sub-groups, the Ss of all age groups judged more easily and with confidence than on the ones arranged homogeneously. The tendency was most pronounced with school pupils. On the basis of the above mentioned results, we discussed the old problem of the constant “six”, from a genetic aspect, according to which aspect the “range” can be expanded as the learning of basic arithmetical operations (one by one counting or spontaneous sub division of the objects into sub-groups together with additive or multiplicative