Retention of fixed-interval performance in rats.

Three groups of 12 pigeons each were trained to discriminate between lights of 550 m,u (SD), correlated with 1-min variable-interval reinforcement and 570 m,u (SA), correlated with extinction. Group A was tested for wavelength generalization in extinction 1 min after meeting the discrimination criterion; Group B was tested 24 hr later; Group C was tested 24 hr later after a 3-min (reinforced) warm-up with the SD. The post-discrimination gradient of Group B was significantly flatter and showed significantly greater area shift than that of Groups A and C. The gradient of Group C was similar to that of Group A, indicating that the warm-up eliminated the effect of the delay period.The present study was designed to reconcile the discrepancy between the results of several earlier experiments on the effects of a delay period between training and testing for generalization.In 1958 Perkins and Weyant reported a study in which (response speed) generalization gradients obtained from rats one week after training on a runway were shown to be reliably flatter than those obtained immediately after training. Four groups were used, one tested immediately on the training stimulus, one tested immediately on the novel stimulus (alley and goal box of different color), one group tested after a one-week delay on the original alley, and one group tested after a one-week delay on the novel alley.Subsequently Thomas, Ost, and Thomas (1960) weeks after reaching a criterion, subjects were tested for generalization carried out in extinction in a manner introduced by Guttman and Kalish (1956). A wide range of spectral stimuli was successively presented with subjects' rate of responding to each providing the measure of generalization. There was no evidence that the three delay groups produced post-discrimination gradients which differed in any way whatever.There are many possible reasons for the discrepancy in the findings of these two studies. Different species were used, a different type of task, a different stimulus dimension, etc. Unlike Perkins and Weyant (1958), Thomas et al. (1960) tested for generalization after administering discrimination training. It is possible that one effect of this training was to increase the "stability" of the generalization gradient over a time period. In addition, Thomas et al. (1960)

Section: Resultsmentioning

confidence: 99%

STIMULUS GENERALIZATION AS A FUNCTION OF THE DELAY BETWEEN TRAINING AND TESTING PROCEDURES: A REEVALUATION¹

Thomas

Burr

1969

“…The measures derived from accumulated daily counts are derived in the same way as those from an individual interval, and are distinguished from the individual measures by the subscript D, which signifies the Average Daily Value of the measure. and Bernheim, 1963), was also calculated for each session. This measure is the proportion of responses during the first half of the interval.…”

Section: Methodsmentioning

confidence: 99%

THE RELATIONS' AMONG MEASURES OF PERFORMANCE ON FIXED‐INTERVAL SCHEDULES¹

Gollub

1964

142

Quantitative measures of the performances of seven rats and two pigeons under Fl schedules of reinforcement were obtained. For the rats (under Fl 2 and Fl 100 sec) the mean response rate and two measures of the temporal distribution of responses within the interval (quarterlife and an Index of Curvature) were computed for individual intervals. The measures of curvature were highly correlated with each other, whereas the response rate was only moderately correlated with either of them. Similar results were found for comparisons of the same measures on a session-by-session basis. The performances of the pigeons (under Fl 10) were analyzed to yield response rate, quarter-life and elapsed time to the first, fifth and tenth response. Response rate was only moderately correlated with quarter-life, whereas quarter-life and time to the fifth or tenth response were highly correlated. Measures of temporal distribution based on an average of the intervals of a daily session were highly similar to the means of those measures calculated from the individual intervals.How can performance under a fixed-interval schedule be characterized simply but accurately? With only a minimal amount of training, rats (as well as other organisms) respond uniformly throughout each interval, and the rate of responding summarizes the performance (Skinner, 1938). With prolonged training, however, the rate changes characteristically through the interval (Ferster and Skinner, 1957). This latter performance cannot be specified by rate alone.

“…On the other hand, a number of reports describe sizable retention decrements of foodreinforced instrumental behavior (Gleitman and Bernheim, 1963;Steinman, 1963, 1964;Cleitman, Steinman, and Bernheim, 1965;Kehoe, 1963). It is difficult to abstract any one common dimension from these studies that might be responsible for the retention decrements.…”

Section: Temple Universitymentioning

confidence: 99%

“…It is difficult to abstract any one common dimension from these studies that might be responsible for the retention decrements. However, two of these studies (Gleitman and Bernheim, 1963 (FI) performance after a retention interval. The scalloped responding characteristic of this schedule of reinforcement was attenuated by an increase in the number of responses during the first half of the fixed interval.…”

Section: Temple Universitymentioning

confidence: 99%

“…It is difficult to abstract any one common dimension from these studies that might be responsible for the retention decrements. However, two of these studies (Gleitman and Bernheim, 1963;Gleit- analogous type of temporal discrimination has been reported with the conditioned suppression procedure (Millensen and Hendry, 1967;Zelinski, 1966). After prolonged conditioning with a long-duration conditioned stimulus (CS), greater suppression was observed toward the end of the CS period than at the beginning; the suppressed operant showed an inverted scallop during the CS period.…”

Section: Temple Universitymentioning

confidence: 99%

See 1 more Smart Citation

FORGETTING AND CONDITIONED SUPPRESSION: ROLE OF A TEMPORAL DISCRIMINATION¹

Hammond

Maser

1970

Several experiments have found complete retention of conditioned suppression when overall suppression to the signal for shock was measured. The present experiment examined retention of conditioned suppression but did so with a paradigm that produced temporal discrimination of shock occurrence. Nine rats were exposed to a flashing light signal of 5-min duration that always terminated with a shock. After several months, a temporal discrimination was well established, as shown by maximum suppression toward the end of the signal period. After remaining in the home cage for 25 days, the rats were again subjected to the conditioning procedure. The overall level of suppression remained the same but the temporal discrimination was not observed.