The purpose of this study is to investigate the relationship between hunger drive level and the slope of colour light stimulus generalization gradients and to determine the optimal hunger deprivation level for the operant conditioning technique for chicks.
Throughout the entire experiment, subjects were classified into seven groups according to their feeding time : 30 min. (30M), 1 hour (1H), 2hours (2H), 4 hours (4H), free feeding (Free Feed) in Exp. I and 3 hours (3H), 4 hours (4H) in Exp. II. 28 White Leghorn chicks were each fed freely for 14 days after hatching in an isolated cage, and were then assigned to the above groups.
During the simple training, deprived chicks were trained to peck at a translucent diffused key illuminated by a wavelength 520 nm in Exp. I and 590 nm in Exp. II respectively. After subjects began to respond to the key, they were given continuously reinforced sessions and then intermittently reinforced ones to obtain enough responses. Subsequently, they were placed on a VI schedule with the mean interval of 30 sec. for about 11 min. per day for 10 days in Exp. I and the mean interval of 35 sec. for about 14 min. per day for 11 days in Exp. II.
On the following two days they were tested individually for generalization in extinction situation using five different colour light stimuli : 460, 500, 520, 540 and 580 nm in Exp. I and 500, 530, 560, 590 and 630 nm in Exp. II, respectively. The order of presentation was governed by 5 × 5 latin squares.
It was shown in the results that the hunger deprivation level affected the slope of generalization gradient and that the optimal feeding level was that of 4H group.

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The method of mother-infant reunion after separation is significant in investigating mother-infant relations in Japanese monkeys. This study aims to analyze behavioral changes of mother-infant relations before, during, and following separation for a total period of eight months in one-year-old Japanese monkeys. The infant's distress vocalization, filial clinging, infant's and mother's auto groomings, infant-mother grooming, maternal embracing, and mother-infant distance were used as indices for observing behavioral changes of mother and infant.
The difference in rearing conditions of mother and infant (Table 1) tended to give influence of the effect of separation, although individual differences were observed in the occurrences of behaviors of mother and infant (Fig. 1, 2, 3, 4, and 5). The mother-infant relations in the pre-separation period (Fig. 3, 4, and 5) had influence on behavioral changes of infant in the separation period (Fig.1 and 2) and on mother-infant interactions in the post-separation period (Fig. 3 and 4). The results suggest that the rearing conditions of mother and infant might be related with behavioral changes of infant in the separation period, and with mother-infant relations in the pre-and the post-separation periods.

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The purpose of this study was to investigate the dissociative effect of methamphetamine upon the 'reponse to environmental change' in albino rats according to the method described by DEMBER (1956).
Albino rats were put into an area of a T maze (consisting of a starting alley and a choice point separated from the arms with glass partitions on both sides) 15 min. per day for the consecutive 3 or 5 days and habituated to the apparatus. During the habituation sessions, one of the arms was colored black and the other white. On a test trial carried out the day after the habituation sessions, the glass partitions were removed and the arms of the maze were arranged either both black or both white (one of them changed, the other unchanged). We tested which arm the animal would choose, changed or unchanged.
Half of the animals were habituated while they were drugged (M ; methamphetamine hydrochloride injected subcutaneously 30 min. before putting the animals into the starting box of the maze) and the rest in a saline state (S). On the test trial each group of methamphetamine-injected (M) and saline-injected (S) animals was further divided into two and subjected to the same or shifted drug condition so as to produce the following four groups : M-M, S-S, M-S and S-M groups.
The results of Experiment I (3-day habituation sessions, 1.5 mg/kg methamphetamine hydrochloride) and Experiment II (5-day habituation sessions, 1.0 mg/kg methamphetamine hydrochloride) showed that the animals in M-M, S-S and S-M groups significantly chose the changed side of the arm, whereas the animals in M-S group randomly chose the arms. These results indicate that the transter of habituation was disturbed in M-S condition. However, in Experiment III (5-day habituation sessions, 0.5 mg/kg methamphetamine hydrochloride) the dissociation of habituation was found in S-M condition and not in M-S condition.
The results of the present study show that the effect of methamphetamine on the exploratory behavior are dose related, and may suggest that a higher dose might disturb the habituation process but facilitate the response to environmental change, while a lower dose might act in the opposite direction.

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This report was primarily concerned with the comparison of aggressivity in isolation-reared adult Japanese monkeys of various rearing conditions in the pairing experiment with strangers. Results for the males indicate that they were extremely aggressive to strange partners, and that their aggressivity was negatively correlated to the severity of their isolation (Table 1, Fig.1). According to the high frequencies of discreteness between the isolates and their partners (Fig. 2) and the remarkable tendency of the aggressees' withdrawal (Table 2), their aggression may be regarded as repulsive behavior directed to the strangers.
Because of the poverty of social experience, the strange partners were more novel for the isolates than for the controls, and so fear produced by the strangers' novelty may be thought as the cause of their aggression. However, the fact that the isolates rarely showed non-defensive aggression when they were subordinate to the partner (Fig. 1) indicates that excessive fear does not result in aggression. In other words, “moderate” level of fear causes aggression. On the other hand, occurrence of aggression also requires “primary” sociability which enables individuals to approach and contact with others, and this appears to be the main reason why the less severely isolated monkeys aggressed more. To summarize above, their aggressivity may be influenced by a level of fear and of “primary” sociability.
The isolates lack the more mature form of sociability, that is, “friendly” sociability which can act as an inhibitor of their aggression, and for that reason they showed their aggressivity in a less inhibited fashion.
In contrast to the males, the females rarely showed aggressive behavior except F-3 (Fig. 1). The severely isolated females were hyperfearful (Table 2), and the least severely isolated female was even friendly. This can be attributed to sex difference in which females tend to be more friendly, more fearful, and less aggressive than males.

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[in Japanese]

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