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Effects upon conditioned response time of contingent photic stimulation in cats
Physiology and Behavior. e e l . 6, pp. 203-204, Pergamon Prem, 19"/1. Print~l in Great Britain
BRIEF COMMUNICATION Effects upon Conditioned Response Time of Contingent Photic Stimulation in Cats ISAO URAMOTO
Department of Neurophysiology, Institute of Higher Nervous Activity, Osaka University Medical School, Kita-ku, Osaka, Japan (Received 2 O c t o b e r 1970) URAMOTO,1. Effects uponconditionedresponsetime of contingentphotic stimulationin cats. PHYSIOL.BEHAV.6 (2) 203--204, 1971.--Six cats were conditioned to press a bar for a food reward using a trace conditioning procedure. When photic stimulation was introduced as a result of a correct response, the response time means and variances of all trials in the final five sessions both tended to be smaller than those under control procedure. Moreover, the distribution of the response times is almost unimodal under the procedure with photic contingency while it is either unimodal or multimodal under the control procedure. These findings were interpreted according to the stimulus-change hypothesis. Contingent photic stimulation
Conditioned response time
Stimulus-change hypothesis
animals approached the bar promptly on hearing the buzzer and sometimes held a paw above the bar until the delay period had elapsed. Previous workers have noted that bar pressing behavior or avoidance learning was accelerated when photic stimulation was introduced after correct responses. In the present experiment, however, no consistent difference was found in the rate of acquisition of the C R between Procedures A and B. This is shown in Table I representing the number of sessions needed for each animal to reach the criterion under each conditioning procedure. N o r was there any striking difference in the number of sessions needed for extinction; usually extinction was reached in 10--20 non-rewarded sessions. A remarkable finding in the present study was that the response time means and variances both tended to be smaller under Procedure B than under Procedure A. This is shown in Fig. 1 which includes the response time means and variances of all trials in the final five sessions of all conditioning periods regardless of their sequences in any one animal. The data from Procedure B fall within the lower section of the graph only while in the upper section there are only values obtained under Procedure A. A comparison between the two conditioning procedures in each subject reveals that the variances of the response times are consistently smaller under Procedure B than under Procedure A in all animals and, with one exception, the mean values show the same characteristic difference. A further difference was noted. The distribution of the response time in the last five sessions under Procedure B is almost unimodal. On the other hand, the distribution under Procedure A is either unimodal or multimodal. Figure 2 shows typical examples. Light-contingent bar pressing experiments [1,4, 6, 8,10] have
IN THE experiment to be reported here, cats were conditioned to press a bar for a food reward using a trac.¢ conditioning procedure. It was found that when photic stimulation followed a correct response, the response time means and variances both tended to be smaller than in control experiment. The experiment was carried out on six cats (three males and three females), weighing 2.3=-3.2 kg. The bar was locked for an initial delay period of 10 sec from the onset of a buzzer (CS) applied for 3 sec and the first bar pressing which occurred during the subsequent 20 sec was followed either by a pellet (UCS) (procedure A), or after 5 msec by four flashes at 6 Hz and a pellet (Procedure B). If the animals touched the bar during the delay period, the response was taken as negative and the trial was abandoned. Each day the cats received 2-4 training sessions, each consisting of 20 trials. A time of the first bar pressing from the onset of CS was measured by means of a pen recorder. Each animal was conditioned three times; in the order A ~ B ~ A (Cats 21,22 and 23) or in the order B - ~ A ~ B (Cats 11, 12 and 13). Cat 12 died after having received the first training under Procedure B and is not included in the following data. The conditioning procedure was changed whenever the C R score remained above 90 per cent in five successive sessions or above 80 per cent in ten successive sessions. The responses were extinguished between the different procedures until the animals showed a C R score of below 10 per cent in three successive sessions or below 20 per cent in five successive sessions. There was no striking difference in the observable behavior of the animals under t h e two conditioning procedures; all animals pressed the bar repeatedly at the earlier stages of the conditioning and these redundant bar pressing were later suppressed at similar rates in both cases. Thereafter the 203
1 JP.AM() I ()
204 TABLE I
!
NUMBER OF SESSIONS NEEDED TO REACH THE C R CRITERION 20
Order
Procedure
1
B
I1 I11
A B
Cat 11 13
Procedure
Cat 21 22 23
46 81 17 22 6 50
A B A
87 61 44 43 18 44 8 8 24
V IP.0CE E B Mean 12.2
~
Cot II
7
u~ ~ 2 see tu 6/,
PROCEDURE A
Mean 14.4
7
i, ~o
t5
k_£-I , ~o sec'
RESPONSE T I ME
FIG. 2. Two examples of the distribution of response times obtained in the final five sessions. :'36 =E 25 I-ILl ~16
n.-
i~O
15
20
see
RESPONSE TIME MEAN FIG. I. Correlation between response time means and variances. Solid circles, values under Procedure A. Open circles values under Procedure B. Points from the same animal are joined. attracted many investigators since the reports of Marx et aL and Kish [5, 7]. A similar experiment was undertaken in monkeys by Moon and LodaJal [9]. Berlyne et al. [1] reported that rats responded s i ~ t l y more often than control rats when the intensity of cage illumination was changed as a
result of bar pressing. Recently Bower et al. [3] showed, again in rats, that a change in intensity of an auditory conditioned stimulus following a correct response facilitated avoidance learning. On the basis of these results and their own observations, Bolles and Grossen [2] maintained that the rate of acquisition in avoidance learning and bar pressing behavior was a function of stimulation contingent upon the response. This view is now known as the stimulus-change hypothesis. The present experiment differs from those in which the rate of learning was accelerated by response-contingent photic stimulation both in the conditioning procedures used and the animal species. The number of animals was also small. However, the fact that the contingent photic stimulation brought about other positive behavioral changes might be interpreted according to the stimulus-change hypothesis. The author wishes to thank Dr. K. Iwama and other members of this laboratory for their discussion. Thanks are also due to Mr. T. J. Horder for his suggestion in preparing the manuscript.
REFERENCES
1. Berlyne, D. E., P. H. Salapatek, R. S. Gelman and S. I. Zener. Is light increment really rewarding to the rat? d. comp. physiol. Psychol. 58: 148-151, 1964. 2. Bolles, R. C. and N. E. Grossen. Effects of an informational stimulus on the acquisition of avoidance behavior in rats. J. eomp. physiol. Psychol. 68: 90--99, 1969. 3. Bower, G., R. Starr and L. Lazarovitz. Amount of responseproduced change in the CS and avoidance learning. J. comp. physiol. Psychol. 59: 13-17, 1965. 4. Forgays, D. G. and H. Levin. Discrimination and reversal learning as a function of change of sensory stimulation.J. comp. physiol. Psychol. 52: 191-194, 1959. 5. Kish, G. B. Learning when the onset of illuminationis used as reinforcing stimulus. J. comp. physiol. Psychol. 48: 261-264, 1955.
6. Kling, J. W., L. Horowitz and J. E. Dolhagen. Light as a positive reinforcer for rat responding. Psyehol. Rep. 2: 337-340, 1956. 7. Marx, M. H., R. L. Henderson and C. L. Roberts. Positive reinforcement of the bar-pressing response by a light stimulus following dark operant pretests with no aftereffect. J. eomp. physiol. Psychol, 48: 73-76, 1955. 8. McCall, R.B. Stimulus change in light-contingent bar pressing. 3". comp. physiol Psyehol. 59: 258-262, 1965. 9. Moon, L. E. and T. M. Lodahl. The reinforcing effect of changes in illumination on lever-pressing in the monkey. Am. J. Psyehol. 69: 288-290, 1956. 10. Robinson, J. S. The reinforcing effects of response-contingent light inc~ment and decrement in hooded rats. J. comp. physiol. PsychoL 54: 470-473, 1961.
BRIEF COMMUNICATION Effects upon Conditioned Response Time of Contingent Photic Stimulation in Cats ISAO URAMOTO
Department of Neurophysiology, Institute of Higher Nervous Activity, Osaka University Medical School, Kita-ku, Osaka, Japan (Received 2 O c t o b e r 1970) URAMOTO,1. Effects uponconditionedresponsetime of contingentphotic stimulationin cats. PHYSIOL.BEHAV.6 (2) 203--204, 1971.--Six cats were conditioned to press a bar for a food reward using a trace conditioning procedure. When photic stimulation was introduced as a result of a correct response, the response time means and variances of all trials in the final five sessions both tended to be smaller than those under control procedure. Moreover, the distribution of the response times is almost unimodal under the procedure with photic contingency while it is either unimodal or multimodal under the control procedure. These findings were interpreted according to the stimulus-change hypothesis. Contingent photic stimulation
Conditioned response time
Stimulus-change hypothesis
animals approached the bar promptly on hearing the buzzer and sometimes held a paw above the bar until the delay period had elapsed. Previous workers have noted that bar pressing behavior or avoidance learning was accelerated when photic stimulation was introduced after correct responses. In the present experiment, however, no consistent difference was found in the rate of acquisition of the C R between Procedures A and B. This is shown in Table I representing the number of sessions needed for each animal to reach the criterion under each conditioning procedure. N o r was there any striking difference in the number of sessions needed for extinction; usually extinction was reached in 10--20 non-rewarded sessions. A remarkable finding in the present study was that the response time means and variances both tended to be smaller under Procedure B than under Procedure A. This is shown in Fig. 1 which includes the response time means and variances of all trials in the final five sessions of all conditioning periods regardless of their sequences in any one animal. The data from Procedure B fall within the lower section of the graph only while in the upper section there are only values obtained under Procedure A. A comparison between the two conditioning procedures in each subject reveals that the variances of the response times are consistently smaller under Procedure B than under Procedure A in all animals and, with one exception, the mean values show the same characteristic difference. A further difference was noted. The distribution of the response time in the last five sessions under Procedure B is almost unimodal. On the other hand, the distribution under Procedure A is either unimodal or multimodal. Figure 2 shows typical examples. Light-contingent bar pressing experiments [1,4, 6, 8,10] have
IN THE experiment to be reported here, cats were conditioned to press a bar for a food reward using a trac.¢ conditioning procedure. It was found that when photic stimulation followed a correct response, the response time means and variances both tended to be smaller than in control experiment. The experiment was carried out on six cats (three males and three females), weighing 2.3=-3.2 kg. The bar was locked for an initial delay period of 10 sec from the onset of a buzzer (CS) applied for 3 sec and the first bar pressing which occurred during the subsequent 20 sec was followed either by a pellet (UCS) (procedure A), or after 5 msec by four flashes at 6 Hz and a pellet (Procedure B). If the animals touched the bar during the delay period, the response was taken as negative and the trial was abandoned. Each day the cats received 2-4 training sessions, each consisting of 20 trials. A time of the first bar pressing from the onset of CS was measured by means of a pen recorder. Each animal was conditioned three times; in the order A ~ B ~ A (Cats 21,22 and 23) or in the order B - ~ A ~ B (Cats 11, 12 and 13). Cat 12 died after having received the first training under Procedure B and is not included in the following data. The conditioning procedure was changed whenever the C R score remained above 90 per cent in five successive sessions or above 80 per cent in ten successive sessions. The responses were extinguished between the different procedures until the animals showed a C R score of below 10 per cent in three successive sessions or below 20 per cent in five successive sessions. There was no striking difference in the observable behavior of the animals under t h e two conditioning procedures; all animals pressed the bar repeatedly at the earlier stages of the conditioning and these redundant bar pressing were later suppressed at similar rates in both cases. Thereafter the 203
1 JP.AM() I ()
204 TABLE I
!
NUMBER OF SESSIONS NEEDED TO REACH THE C R CRITERION 20
Order
Procedure
1
B
I1 I11
A B
Cat 11 13
Procedure
Cat 21 22 23
46 81 17 22 6 50
A B A
87 61 44 43 18 44 8 8 24
V IP.0CE E B Mean 12.2
~
Cot II
7
u~ ~ 2 see tu 6/,
PROCEDURE A
Mean 14.4
7
i, ~o
t5
k_£-I , ~o sec'
RESPONSE T I ME
FIG. 2. Two examples of the distribution of response times obtained in the final five sessions. :'36 =E 25 I-ILl ~16
n.-
i~O
15
20
see
RESPONSE TIME MEAN FIG. I. Correlation between response time means and variances. Solid circles, values under Procedure A. Open circles values under Procedure B. Points from the same animal are joined. attracted many investigators since the reports of Marx et aL and Kish [5, 7]. A similar experiment was undertaken in monkeys by Moon and LodaJal [9]. Berlyne et al. [1] reported that rats responded s i ~ t l y more often than control rats when the intensity of cage illumination was changed as a
result of bar pressing. Recently Bower et al. [3] showed, again in rats, that a change in intensity of an auditory conditioned stimulus following a correct response facilitated avoidance learning. On the basis of these results and their own observations, Bolles and Grossen [2] maintained that the rate of acquisition in avoidance learning and bar pressing behavior was a function of stimulation contingent upon the response. This view is now known as the stimulus-change hypothesis. The present experiment differs from those in which the rate of learning was accelerated by response-contingent photic stimulation both in the conditioning procedures used and the animal species. The number of animals was also small. However, the fact that the contingent photic stimulation brought about other positive behavioral changes might be interpreted according to the stimulus-change hypothesis. The author wishes to thank Dr. K. Iwama and other members of this laboratory for their discussion. Thanks are also due to Mr. T. J. Horder for his suggestion in preparing the manuscript.
REFERENCES
1. Berlyne, D. E., P. H. Salapatek, R. S. Gelman and S. I. Zener. Is light increment really rewarding to the rat? d. comp. physiol. Psychol. 58: 148-151, 1964. 2. Bolles, R. C. and N. E. Grossen. Effects of an informational stimulus on the acquisition of avoidance behavior in rats. J. eomp. physiol. Psychol. 68: 90--99, 1969. 3. Bower, G., R. Starr and L. Lazarovitz. Amount of responseproduced change in the CS and avoidance learning. J. comp. physiol. Psychol. 59: 13-17, 1965. 4. Forgays, D. G. and H. Levin. Discrimination and reversal learning as a function of change of sensory stimulation.J. comp. physiol. Psychol. 52: 191-194, 1959. 5. Kish, G. B. Learning when the onset of illuminationis used as reinforcing stimulus. J. comp. physiol. Psychol. 48: 261-264, 1955.
6. Kling, J. W., L. Horowitz and J. E. Dolhagen. Light as a positive reinforcer for rat responding. Psyehol. Rep. 2: 337-340, 1956. 7. Marx, M. H., R. L. Henderson and C. L. Roberts. Positive reinforcement of the bar-pressing response by a light stimulus following dark operant pretests with no aftereffect. J. eomp. physiol. Psychol, 48: 73-76, 1955. 8. McCall, R.B. Stimulus change in light-contingent bar pressing. 3". comp. physiol Psyehol. 59: 258-262, 1965. 9. Moon, L. E. and T. M. Lodahl. The reinforcing effect of changes in illumination on lever-pressing in the monkey. Am. J. Psyehol. 69: 288-290, 1956. 10. Robinson, J. S. The reinforcing effects of response-contingent light inc~ment and decrement in hooded rats. J. comp. physiol. PsychoL 54: 470-473, 1961.