Discrimination Reversal Learning Research Articles

Discrimination Reversal Learning in Yearling Horses

Discrimination Reversal Learning in Yearling Horses

Serial discrimination reversal learning as a repeated-acquisition method to test drug effects

A repeated-acquisition procedure utilizing serial discrimination reversal (SDR) was developed to test drug effects on acquisition. Rats were trained on SDR until successive acquisitions were uniform and repeatable. Scopolamine, DL-amphetamine, and tranylcypromine were tested for effects on acquisition with this method. DL-amphetamine and tranylcypromine facilitated acquisition; scopolamine disrupted discrimination.

The role of R-S ∗ expectancy in discrimination and discrimination reversal learning

Four experiments assessed the role of response-reinforcement (R-S ∗) expectancy as rats either learned a discrimination or a discrimination reversal. Experiment 1 showed that the higher the percentage of reinforcement during nondiscriminative pretraining the more quickly a subsequent discrimination is learned. Experiment 2 demonstrated that the overlearning reversal effect (ORE) can be obtained even though the overtraining phase consists of responses to a single neutral card. In Experiment 3 subjects were again overtrained on a single neutral stimulus under conditions of varying reinforcement. ORE was apparent under reinforcement of a high percentage of responses but was not apparent under reinforcement of a low percentage. Experiment 4 revealed that the fewer errors a subject makes prior to reversal the better its reversal performance is. Results of these studies were discussed in terms of generalized attention theories and the expectancy notions of Bolles ( Psychological Review, 1972, 79(5), 394–409 .

Some relations between stereotyped suckling in piglets and exploratory behaviour and discrimination reversal learning in adult swine

The relationship of stereotyped suckling positions in artificially fed and sow-fed infant swine to the behaviour of adult animals was investigated. Suckling behaviour was observed, and four animals from each feeding condition exhibiting low suckling stereotypy and four from each feeding condition exhibiting high suckling stereotypy were selected. Animals were tested at five months of age in exploratory situations and on a two-window position discrimination and reversals. Low suckling stereotypy and artificially reared animals made fewer errors on the first discrimination reversals than high stereotypy and sow-fed animals. They were also less emotional on the first reversals. Over nine reversals artificially reared animals made significantly fewer errors than sow-fed subjects and low stereotype sow-fed animals made fewer errors than high stereotypy sow-reared animals. Low stereotypy subjects explored more objects and over a longer period of time than high stereotypy subjects. It was concluded that stereotyped suckling in piglets is related to behaviour exhibited by the adult in problem-solving situations.

Serial discrimination reversal learning: Effects of scopolamine

A repeated acquisition procedure (baseline serial discrimination reversals, SDR) was used to test the effects of scopolamine hydrobromide in 12 male rats. The rats were trained in a tone/light SDR procedure until performance on successive reversals had stabilized. At that point, three drug doses were tested for effects upon learning, as measured by the repeated acquisition procedure. It was noted that, in general, scopolamine did not interfere with learning in this paradigm; instead, scopolamine interfered with the ability of the animals to discriminate between the various stimuli present in this situation. Thus, the conclusion was that the drug does disrupt performance in baseline SDR, but that the nature of the disruption is not related to the association process.

Human temporal behavior and discrimination-reversal learning.

The present study demonstrates that a relationship exists between individual differences in temporal behavior and individual differences in human discrimination-reversal learning behavior. When the results of performance on a time-estimation task employing the method of reproduction are compared with the results of acquisition performance on a complex form of discrimination-reversal learning task is can be demonstrated that underestimation of time is associated with faster learning and overestimation of time is associated with slower learning of the discrimination task. The experimental design was based on the historical fact that the Sechenov-Pavlov and Spence-Hull formulations assigned a primary role in learning to excitation and inhibition as intervening variables between the input of stimulation and output of response. The present study also used the tasks of time estimation and discrimination learning as dependent variables; and the concept that underestimation of time is associated with and underlying predominance of excitatory processes as a hypothetical construct. The conclusion was reached that one of the many theoretical processes which may be used to explain discrimination learning is the concept that acquisition of the correct response may be viewed as a function of the individual rates at which excitatory processes come to be conditioned to a predominance over existing inhibitory processes.

Effect of prenatal heat stress on brain growth and serial discrimination reversal learning in the guinea pig

Exposure of pregnant guinea pigs to an environmental temperature of 42°C for 1 hr daily on Days 20–24 of gestation resulted in a significant reduction in the birthweight and brainweight of newborn offspring. These deficits persisted to early maturity and were still evident at 250 days of age following behavioral testing. Although some degree of postnatal neurogenesis and brain growth had occurred, this was not sufficient to compensate for the retarding influence of prenatal hyperthermia. Heat stress was also observed to seriously impair learning performance on the original discrimination task and this tendency persisted over the subsequent 4 reversals for both initial and perseverative errors. Impaired learning performance was related to reduction in brainweight. Animals with lower brainweights made significantly more initial, perseverative and total number of errors over the 5 problems. In addition, 12 of the 14 behaviorally tested stressed progeny had brainweights that were at least 2 standard deviations below the mean of the controls and as a result were classified as micrencephalic. Although heat stressed animals showed a significant reduction in the number of amacrine synapses in the inner plexiform layer of the retina, performance differences were not attributed to changes in synaptic organisation of the retinal circuitry or to visual or other ophthalmic defects, but brain function. Animals with higher mean maternal poststressing core temperatures gave birth to progeny which had smaller whole and part wet-brainweights. Examination of the effect of poststressing core temperature on brainweight revealed that brain growth, independent of bodyweight, was retarded when this temperature elevated above 41.5°C. This represented a rise of approximately 2.1°C above normal and for each 1°C rise above this temperature, brainweight was reduced by 0.4227 g of the control value. Analysis of the atmospheric content of the incubator during stressing sessions ruled out the possibility that changes in level of oxygen and carbon dioxide may have contributed to the retarding influence on fetal development and learning ability in the guinea pig.

Variability and discrimination reversal learning in the open field following septal lesions in rats

Response variability on a 10 position horizontal response task and a position-habit discrimination followed by 2 reversals was examined in groups of rats with septal damage and operated control rats in the open field. As revealed by the number of positions with responses and the one position with the most responses, the rats with septal damage were reliably less variable in responding than the controls. In addition, the rats with septal damage made a reliably greater number of responses during extinction of the response. In the second experiment, groups of animals were tested for discrimination learning in a 2 part experiment using both a free-ranging and restricted open field. In both parts of the experiment, the rats with septal lesions learned the discrimination and both reversals faster than the controls. Animals tested in the restricted field learned the discrimination slightly faster than those tested in the free-ranging field. The superior discrimination learning for the rats with septal lesions was discussed as a lesion-induced increase in the incentive value of positive reward, producing shorter observed response latencies, resulting in a shorter delay of reinforcement.

Retention of functional tolerance to ethanol in rhesus monkeys ( Macaca mulatta)

Tolerance to ethanol (3 g/kg 90 min prior to testing) was assessed in a group of 4 rhesus monkeys in which tolerance development had been observed using the same behavioral task one year prior to the present study. Although some decrements in performance on a two-choice discrimination-reversal learning task were observed, these changes were transient and statistically insignificant. Results indicate that functional tolerance persisted throughout a one year abstinence period.

Effects of diagnostic ultrasound irradiated during foetal stage on emotional and cognitive behaviour in rats.

Our previous work demonstrated that the prenatally irradiated ultrasound of even a low-intensity might affect the functional development of the brain of offspring in rats. In the present study, in order to investigate the emotional and cognitive behaviour of offspring of rats that received the irradiation of a diagnostic ultrasound on the 9th day of gestation, the following three experiments were carried out: 1) The emotional reactivity of the offspring was measured by the open-field technique. 2) The same reactivity was further evaluated in terms of the excape response from electroshock. 3) The cognitive function of the offspring was assessed through the discrimination learning and the discrimination reversal learning. The offspring of irradiated rats showed significantly more distinct vocalization response to handling in the open-field test and significantly more distinct escape response from the electroshock, when compared with the two control rats (untreated control and sham-irradiated control). From these findings it may be suggested that the emotional behaviour in rats can be influenced by a low-intensity ultrasound irradiated during foetal stage. On the other hand, as for the cognitive behaviour, the results of the present study suggest no adverse effect on it.

Reward vs extinction in discrimination reversal learning

Pigeons trained on a series of color-discrimination reversals were presented either reward or extinction single-stimulus pretraining at various points during reversal learning improvement. Extinction of the previous S+ facilitated reversal learning more than reward of the previous S-, with this relation remaining unchanged throughout training.

Verbal Reinforcement Combinations, Task Complexity, and Overtraining on Discrimination Reversal Learning in Children

Summary In a simultaneous brightness discrimination reversal task, 96 third- and fourth-grade children were either verbally reinforced for correct responses (Rn), verbally punished for incorrect responses (Wn), or verbally reinforced for correct and punished for incorrect responses (RW) at either of two levels of task complexity (1 vs. 3 irrelevant dimensions) subsequent to either criterion or overtraining on the original problem. Regardless of task complexity, performance on the original problem was nearly equivalent for the RW and Wn combinations, and both were superior to the Rn combination. At all levels of task complexity and training, the RW and Wn S s reversed at similar rates, and both groups reversed faster than the Rn Ss.

Reversal Learning Set in Successive Discrimination Reversal Learning and Transfer with Rats Using Visual and Olfactory Cues

Hooded male rats trained on simple discriminations between odor or brightness cues learned successively to reverse between the odor or brightness cues. They were then transferred to a successive discrimination reversal (SDR) of the other modality. The transfer data indicated that SDR training with one set of cues facilitated the learning of a subsequent discrimination in the other modality.

Verbal discrimination reversal in a whole/part re-pairing transfer paradigm

Whole/part transfer and re-pairing of rights and wrongs were employed in a study of verbal discrimination reversal learning. The whole/part and re-pairing procedures were used to create reversal conditions (0%, 50%, or 100% reversal) that were similar at the outset of reversal learning in that all correct alternatives on the reversal list were higher in situational frequency than their respective incorrect alternatives. Similarly, reversal lists were constructed that were similar in that all incorrect alternatives on the reversal list were higher in situational frequency than their respective correct alternatives. The results were consistent with the existing literature on verbal discrimination reversal, as performance was impaired when items reversed functions (50% and 100% reversal). There was little evidence that uniform frequency relations between rights and wrongs affected ease of reversal learning.

Spatial and non-spatial discrimination reversal (SDR) learning in the guinea pig

Spatial and non-spatial serial discrimination reversal performance was investigated in guinea pigs over eleven reversals. Difference in learning ability between albino and pigmented strains was not evident on spatial or non-spatial SDR tasks. The guinea pigs' ability to learn rapidly successive spatial and non-spatial reversals with increasing proficiency corresponds well with previous published findings using other mammalian species. These studies also demonstrated behavioural research with the guinea pig to require extended periods of intensive experimental management.

Methamphetamine’s effect on SDR: Replication and extension

Methamphetamine’ s effect on serial discrimination reversal learning (SDR) was studied in rats; selected doses reduced errors during acquisition of SDR with successive reversals spaced by either 24 or 48 h.

Decision making in the rat: Response-choice and response-time measures of discrimination reversal learning.

Decision making in the rat: Response-choice and response-time measures of discrimination reversal learning.

The relationship between patterns of incorrect responses and enhanced discrimination-reversal learning in rhesus monkeys ( Macaca mulatta)

Discrimination-reversal learning was assessed in nine rhesus monkeys ( Macaca mulatta) using an automated learning-set apparatus which permitted the measurement of learning-set skills and analysis of the patterns of incorrect responding. The three animals who attained the highest reversal scores (High) were compared with the three animals which had the lowest reversal scores (Low) with respect to the relative frequencies of errors involving either a single wrong response or more than one wrong response (2–9 consecutive errors). The groups did not differ from each other in acquisition, whereas in reversal the High Group made more errors involving a single incorrect response and fewer strings of consecutive errors. For the Low Group the relationship was reversed. These results suggest that the patterning of incorrect responses is an index of discrimination-reversal performance which may be useful in comparative studies of primate learning.

Long-term memory following serial discrimination reversal learning

Twelve rats were tested through a series of 33 daily reversals of a light/tone successive discrimination; training was halted for 1 month and then resumed for six sessions. For the test session, the first one when training resumed, six rats relearned the last discrimination (the same correct stimulus on Sessions 33 and 34), but the other six rats learned the reversed discrimination (different correct stimuli on Sessions 33 and 34). The rats in the nonreversed group learned the test discrimination faster than the discrimination on Session 33, so they must have remembered the correct stimulus from Session 33, demonstrating a well established memory for the last correct stimulus in a series of discrimination reversals.

Pretraining and discrimination reversal learning by rhesus monkeys

Groups of five to seven macaques were trained on repeated reversals of a visual (or spatial) discrimination habit after no pretraining, extended discrimination training, or repeated reversal training on spatial (or visual) cues. Neither sort of pretraining had a significant effect on reversal learning on the second cue. These results indicate that monkeys’ capacity to develop generalized “win-stay, lose-shift” hypotheses may have been exaggerated in previous experiments.