The purpose of this experiment was to test the SPENGE theory of discrimination learning. Eight monkeys were given 112 problems each, 13 trials in length. The 8 th to 13 th trials were reversals of the 1 st to 6 th trials after a single cue on the 7 th trial in one half of the problems. The performance of learning set under a shift from the positive to the negative cue was superior to the shift from the negative to the positive. These trends of the learning set curves in terms of Trial 8 differed from each other. These differences may be interpreted in terms of neither SPENCE theory, nor Uniprocess theory. It was suggested that BIRCH'S interpretation might be appropriate to learning set situation.

View full abstract

Effects of fear-conditioning and electric-shock on the self-selections of 3 % NaCl, 4 % NaH₂PO₄, 1 % K₂HPO₄, 2 % calcium-lactate, 1 % MgSO₄ and 2 % ferric-citrate water solutions were discussed.
Wistar strain albino rats were subjected to the selection of each inorganic salt which was presented by the individual drinking tube and the selections were measured every 24 hours.
Experiment was consisted of 30 days in 6 periods of 5 days.
In Group 1, buzzer (A. C. 4 V., for 5 sec.) and electric shock (A. C.. 5 mA., 100 V., for. 2 sec.) were presented with 5 sec. intervals for 10 times within 30 min. per day for 10 days during the period 3 and 4.
In Group 2, electric shock alone was presented under the same condition as Group 1.
Group 3 animals were put in a grid box without any stimulations under the same condition as Group 1.
Group 4 animals were subjected to the selection without any of these treatments.
Body weight increase in Group 1 and 2 was retarded during the period 3 and 4, and then increased markedly during the period 5.
Jumping on a barrier and then into the next small room occurred within 60 sec. for the first time during the period 3 and then 4, 5 and 6 in Group 1 and 2. Both jumping latencies decreased rapidly and then recovered gradually.
In Group 1 and 2, marked behavior changes were observed during and after the period 3 and 4 which were parallelly proceeded with fluctuations in calcium-lactate and K₂HPO₄ selections.
In both groups, calcium-lactate selection increased rapidly during the period 3 and 4 and then recovered rapidly during the period 5 and 6. It reached to less than the value during the period 1 and 2 in Group 1.
Potassium hydrogen phosphate selection decreased rapidly during the period 3 and 4 in both groups and then tended to recover gradually during the period 5 and 6.
Calcium-lactate selection increased and K₂HPO₄ selection decreased in all animals.
Calcium-lactate and K₂HPO₄ selections in Group 3 and 4 were almost constant throughout the experiment, and no significant fluctuations were observed.
Sodium chloride, NaH₂PO₄, MgSO₄ and ferric-citrate selections were very similar among 4 groups during any of the period.
It is suggested that calcium-lactate selection was increased because of calcium. For only source of calcium was calcium-lactate, and the same result was obtained in the case of CaCl₂ which was used instead of calcium-lactate.
It is also suggested that K₂HPO₄ selection was decreased because of potassium. For only K₂HPO₄ selection was decreased in spite of simultaneous presentation of NaH₂PO₄ and K₂HPO₄ as sources of phosphate.
Two types were noted among animals in both groups in the mode of fluctuation in calcium-lactate and K₂HPO₄ selections.
The average percentage of increase in calcium-lactate selection during the period 3 and 4 reached at 261 and 271 per cent of selection of the period 2 in Group 1, and 312 and 350 per cent in Group 2. And recovered to 125 per cent in Group 1, and 250 and 219 per cent in Group 2 during the period 5 and 6, and then decreased during the period 6 to 93 per cent in Group 1.
The average percentage of decrease in K₂HPO₄ selection during the period 3 and 4 reached at 34 and 35 per cent in Group 1, and 27 and 23 per cent in Group 2, and recovered to 57 and 58 per cent in Group 1, and 62 and 85 per cent in Group 2 during the period 5 and 6.
Fluctuations in calcium-lactate and K₂HPO₄ selections were very similar in Group 1 and 2 respectively.
Inverse correlational tendency was noted between fluctuations of calcium-lactate and K₂HPO₄ selections.

View full abstract

The purpose of the present study was to investigate the effects of the fluctuation of US-duration during conditioning training upon the acquired properties of the backward CS paired with electric shock as US. CS was a 5-sec illumination and US was an electric shock to four paws of white rat, delivered through a grid floor. According to the 2×3 factorial design animals were assigned to six groups. One of the classification of the design was done by the type of conditioning, i. e.. backward, forward, and control treatments, while the other was made by the duration of US, i. e., fixed vs. fluctuated US durations. During conditioning training, animals received USs 15 times in irregular intervals averaging 60 sec. In the backward conditioning group, the onset of CS was always coincided with the termination of US, while in the forward conditioning group the termination of CS coincided with the onset of US. In the control group, CSs were interspersed semi-randomly among USs : i. e., Ss in this group were treated in the same manner as those in the other two groups except that they did not receive any temporally correlated presentation of US and CS. In the “fixed-US” groups the duration of shock was always 10 seconds, whereas in the “fluctuated-US” groups it was varied semi-randomly between two levels, 15 sec and 5 sec. After the conditioning training, a metal bar was inserted in the experimental box, and the presentation of the light was made contingent upon S's bar-press response, and the bar-press frequency was recorded.
Principal findings were :
1. Constant and fluctuated US-duration during conditioning training produced no differential effects upon the number of bar-press responses.
2. As to the mean level of bar-press frequency, the backward group gave the highest level, the forward group the lowest, and the control group the middle in both of the US conditions, but forward conditioning group did not differ significantly from the control group. This casts some doubt upon the neutrality of the control CS.
3. With respect to trends displayed in the curves of responding by the two backward groups, decreasing trends were observed, which were in conflict with the increasing trends observed in the previous study.
In conclusion, although the present study presented findings which seemed to be in accordance with the hypothesis of secondary reinforcing properties of the backward CS paired with electric shock, provided the effect of the control CS was taken as the base, no definite statement can be made as yet about the validity of the proposition that “acquired properties of forward and backward CSs are opposite (BARLOW, 1956), ” until more knowledge is obtained.

View full abstract

In discussing various types of training procedure in learning experiments, stress is usually placed on the acquisition and extinction of the responses which are directly relevant to reinforcement, with little regard to the change of general activity level under different experimental situations. Recently, however, it has been suggested, with some experimental evidence, that the response vigor in “frustrative” situation has a tendency to increase (1, 2, 10, 12). Present study was designed to investigate the alleged facilitating effect of the general activity level on the relevant responses (bar-pressing, in this case) during the testing or extinction process in secondary and partial reinforcement trainings.
In Exp. I, procedure used was essentially similar to Bersh's experiment on secondary reinforcer (3), except that an activity wheel, which has a response bar, a flickering light source, and a feeding device, was used to record the general activity level together with the learning course. Ss were 28 male albino rats. Prior to the training, adaptation session was given in which each bar-pressing by the animal produced 3-sec. light, and the operant level of bar-pressing was recorded for each animal for 30 min. In training, the bar was withdrawn, and Ss were divided into two groups, F (forward conditioning) group and B (backward conditioning) group. F group was given 30 presentations of 3-sec. light followed by two pellets (100 mg) of food for each day and for six consecutive days. B group was given the same pairing of light and food, but in reversed order. Then in testing the bar was re-inserted, and each group was subdivided into two groups, Lc (light contingent) group and NLc (not light contingent) group. The procedure for Lc group was the same as in the adaptation session, whereas in NLc group lights were presented by E, independently of S's bar-pressing, with the restriction that the number of light presentations as well as the distribution of their intervals were for F-NLc group the same as in F-Lc group, and for B-NLc group the same as in B-Lc group.
Training procedure of Exp. II was shown in table II. Apparatus used was the same as Exp. I except for the omission of the light source. Ss were 21 male albino rats. The criterion for extinction was the nonoccurrence of bar-pressing for 10min. Records were taken, however, at least for 60 min. after extinction had begun.
Main findings were as follows.
1. In Exp. I, the effect of secondary reinforcement on bar press responses was insignificant, while the light contingent effect was significant at the 5 % level.
2. Amount of activity recorded by the activity wheel was significantly larger in F-groups than in B-groups.
3. In Exp. II, resistance to extinction was not significantly different between C-64 and P-64 groups.
4. Difference in bar press responses for 60min. among three groups in Exp. II was not significant, but difference in activity level was highly significant.
From these results, it was suggested that bar press responses might be facilitated by the enhanced activity level in a situation which is “frustrative” but has no “outlet” of enhanced activity such as the activity wheel in this experiment.

View full abstract

First social responses of White Leghorn chicks which had been isolated in small cardboard boxes from 3 to 24 hours after hatching were observed at their first encounter.
Four types of pre-contact stage of socialization, which were seen then, were as follows : Type a) Immediately after the start of meeting, chicks readily approached one another until they physically came into contact with each other without hesitation. Type b) Chicks did not readily approached one another until after performing such exploratory behaviors as attention, looking around, distress notes and rigid immobile attitude. The first physical contact occured immediately after approaching thus. Type c) At the first attempt of approaching, chicks did not come into contact with each other and exhibited attention, looking around, distress notes, floor-pecking, immobile attitude and repetition of approaching before contact. Type d) In addition to those responses cited in type c), such preliminary contactual behaviors were seen as pecking, bill-to-bill posture and head-movement facilitated by the partner's head-movement between the first approach and physical contact.
Following response was rarely observed in the pre-contact stage. These response were elicited by fleeing or retreating of the pecked partner. The first approach seemed to be released by partner's approaching, looking around, floor-pecking, bill-to-bill posture and preening, but many approaches toward immobile state were seen. Responses to the partner's approach were, in the order of frequency, no response, approach, getting up, bill-to-bill posture, pecking, attention and retreat. The first contact taked place in many cases immediately after mutual approaching, and also bill-to-bill posture and mutual bill pecking seemed to facilitate contact. The responses to the first contact were pushing, pecking, bill-to-bill posture, retreating and surprise-response, but one third of observed cases resulted no overt response.

View full abstract

[in Japanese]

View full abstract