Conditional Discrimination Performance Research Articles

Matching and oddity conditional discrimination in the goldfish as avoidance responses: Evidence for conceptual avoidance learning

Goldfish, trained in the avoidance shuttlebox with a variant of the linear discrimination procedure, learned to conditionally discriminate between color signals, both for the matching (M) and oddity (O) criterion forms. Transfer to assess the possibility of concept learning was also tested. In original learning, oddity-trained groups learned faster and reached higher conditional discrimination performance levels than did matching-trained groups. In transfer, various groups were tested with the same criterion (MM or OO) or a shifted criterion (MO or OM), and half of each group retained the same color signals and the remaining half had its color signals changed in transfer. Groups with the same criterion in original learning and transfer (MM or OO), regardless of signal colors, showed comparable positive transfer. Groups with their criterion shifted between original learning and transfer (MO or OM) showed comparable negative transfer, regardless of signal colors. Since both positive- and negative-transfer effects were independent of signal colors, it is clear that what was learned for one set of signal colors transferred to at least one other signal-color set. These findings are consistent with the interpretation that goldfish learned the original conditional discrimination at a conceptual level, and learned about the general matching or oddity relationships between colors, rather than about a specific set of colors.

ニホンザルにおける高次条件性弁別の習得と転移

ニホンザルにおける高次条件性弁別の習得と転移

Control of conditional discrimination performance by CS-evoked event representations

The ability of visual CSs previously paired with flavored substances to substitute for those substances as conditional discriminative cues was examined in two Pavlovian appetitive conditioning experiments using rat subjects. In Experiment 1, a visual stimulus was first paired with the delivery of a sucrose solution. Then the rats were trained in conditional discrimination tasks in which sucrose delivery alone served as a conditional cue signaling whether or not a subsequent tone would be reinforced with food pellets. Subjects rapidly acquired discriminative performance to the tones, especially in a feature-negative condition in which sucrose delivery signaled when the tone would not be reinforced. In a subsequent test in which neither food nor sucrose was delivered, presentation of the visual CS also controlled discriminative performance to subsequently presented tones. Experiment 2 showed the ability of a visual CS to substitute for a flavored substance as a conditional cue to be highly stimulus specific. Experiment 2 also showed that a flavored substance was less effective as a conditional cue when it was made to be expected by preceding it with a previously associated visual signal than when it was made to be surprising by preceding it with a visual stimulus signaling another flavored liquid. These results indicate that CS-evoked representations of events can substitute for those events themselves in the control of previously established conditional discrimination performance.

Effects of phencyclidine, pentobarbital, and d-amphetamine on the acquisition and performance of conditional discriminations in monkeys.

In each of two components of a multiple schedule, monkeys were required to respond on a right or left lever depending upon the stimulus combination (a color and a geometric form) presented. Reinforcement of a response in the presence of one stimulus (the form) was therefore conditioned upon the other stimulus (the color). The completion of a two-member chain of discriminations produced a food pellet. Errors produced a brief timeout. One composition of the multiple schedule was a repeated-acquisition task where the discriminative stimuli for left- or right-lever responses changed each session (learning). In the other component, the discriminative stimuli for left- or right-lever responses were the same each session (performance). Phencyclidine, pentobarbital, and d-amphetamine each produced dose-related decreases in the overall rate of responding in both components of the multiple schedule. At high doses each drug increased the percent errors in each component. At lower doses, however, the three drugs produced selective effects on accuracy. Errors were increased in the learning component at lower doses than those required to disrupt the discrimination in the performance component. A signal detection analysis of the data revealed that none of the drugs tested increased errors by selectively affecting either discriminability or bias.

Effects of altering outcome expectancies on pigeons' delayed conditional discrimination performance

An outcome-expectancy mediation theory of learning was tested in a series of transfer experiments with pigeons. The principal technique employed was a delayed two-choice conditional discrimination in which the subject's correct choice yielded a food reward on one kind of trial and a feedback tone on the other. According to the theory, this task engenders two-link mediational chains in that each conditional cue controls a particular outcome expectancy (S-E link) and the expectancy, in turn, cues a specific choice response (E-R link). Relative to the hypothetical mediators established by preceding training, transfer problems required either the same mediational chains, the alteration of one link in each chain, or the alteration of both links in both chains for optimal performance. The results of four separate transfer experiments confirmed detailed theoretical predictions, including that of an unusual nonmonotonic transfer effect. The relation of the present theory to earlier mediation theories is discussed.

Enhancement of pigeons’ conditional discrimination performance by expectancies of reinforcement and nonreinforcement

Prior work has shown that when the separate correct responses of a conditional discrimination are followed by different reinforcing outcomes, performance is enhanced relative to that obtained under the conventional, single-reinforcer procedure. Four experiments with pigeons yielded the analogous finding when the different outcomes were reinforcement and explicit nonreinforcement. Controls indicated that the results could not be attributed to the effects of intermittent reinforcement, to possible differences in cue duration, or to a variety of potential sources of conditioned reinforcement. An interpretation in terms of expectancy learning is proposed.

Expectancies as mediators in the differential-reward conditional discrimination performance of pigeons

In a series of within-subject experiments employing a two-choice delayed conditional discrimination task, pigeons chose correctly more often when kind of correct choice and kind of reinforcer were perfectly correlated than when uncorrelated. Correct choice behavior fell to chance levels when the correlation was reversed or when it was removed by using only one kind of reinforcer. Implications for mediation theories are discussed, with the conclusion being that, although the possibility that instrumental mediators are present in this situation cannot be dismissed, the overall pattern of results indicates that classical mediators are of principal importance in this type of task.

CONDITIONAL DISCRIMINATION PERFORMANCE BY PIGEONS ON A RESPONSE‐INDEPENDENT PROCEDURE1

Pigeons were trained on a differential autoshaping procedure in which both components of two-stimulus sequences predicted delivery or nondelivery of food. All birds acquired the conditional discrimination. When the subjects were exposed to an extinction procedure, the stimuli maintained conditional control as long as the birds continued to peck the key. When a delay interval was imposed between the two components of a stimulus sequence using a titration procedure, the stimuli maintained conditional control up to delay values of 7 to 10 sec. These data are consistent with the view that the controlling stimuli in conditional discrimination situations are compounds of stimulus elements.

EFFECTS OF RESPONSE‐PRODUCED STIMULI UPON CONDITIONAL DISCRIMINATION PERFORMANCE1

In zero-delay matching procedures the performance of three groups of pigeons was examined when exteroceptive stimuli, response-produced stimuli associated with the completion of either of two fixed ratios, or a compound of exteroceptive and response-produced stimuli were available as samples. Exteroceptive samples were found to control a higher level of matching accuracy than response-produced samples, while compound samples controlled a higher level of accuracy than did exteroceptive samples alone. When all subjects were placed on a transfer procedure, during which the previously used red and green samples were replaced by horizontal and vertical lines, the availability of sample-specific fixed-ratios facilitated acquisition of the task.

Generalization and response mediation of a conditional discrimination.

Fifteen pigeons were given conditional discrimination training in which a colored sample stimulus determined which of two line comparison stimuli (vertical and horizontal) was correct. As part of the conditional discrimination procedure, birds were required to make an "observing response" to the sample stimulus presented on a wide key. The location on this key of the required observing response for the two sample stimuli differed by 0, 3, or 6 in. (0, 7.6, or 15.2 cm) for three groups of birds. Accuracy of conditional discrimination performance was directly related to the amount of separation. In subsequent generalization tests with novel sample stimuli, both observing-response location and comparison responding changed within the same region of the wavelength continuum from that appropriate for one of the training samples to that appropriate for the other. A maintained generalization test (continued reinforcement for training stimuli) revealed this relation more strongly. A test in which observing-response location was the only sample stimulus of a conditional discrimination revealed stimulus control by this observing response, supporting a response mediation interpretation of the data.

Some effects of fixed-ratio size and reinforcement frequency on the accuracy of a conditional discrimination performance

The effects of two values of fixed-ratio size, FR 1 and FR 5, and two frequencies of reinforcement, one pellet and five pellets, on the accuracy of a conditional discrimination were studied in the baboon. In general, no differences in accuracy were observed when either FR 1, one pellet or FR 5, five pellets were used. High levels of accuracy were produced by the FR 5, one pellet reinforcement contingency.