Subsequent Discrimination Learning Research Articles

"Classifying-together" phenomenon in fish (Xenotoca eiseni): Simultaneous exposure to visual stimuli impairs subsequent discrimination learning.

When animals are previously exposed to two different visual stimuli simultaneously, their learning performance at discriminating those stimuli delays: such a phenomenon is known as "classifying-together" or "Bateson effect". However, the consistency of this phenomenon has not been wholly endorsed, especially considering the evidence collected in several vertebrates. The current study addressed whether a teleost fish, Xenotoca eiseni, was liable to the Bateson effect. Three experiments were designed, by handling the visual stimuli (i.e., a full red disk, an amputated red disk, a red cross) and the presence of an exposure phase, before performing a discriminative learning task (Exp. 1: full red disk vs. amputated red disk; Exp. 2: full red disk vs. red cross). In the exposure phase, three conditions per pairs of training stimuli were arranged: "congruence", where fish were exposed and trained to choose the same stimulus; "wide-incongruence", where fish were exposed to one stimulus and trained to choose the other one; "narrow-incongruence", where fish were exposed to both the stimuli and trained to choose one of them. In the absence of exposure (Exp. 3), the discrimination learning task was carried out to establish a baseline performance as regards the full red disk vs. amputated red disk, and the full red disk vs. red cross. Results showed that fish ran into retardation effects at learning when trained to choose a novel stimulus with respect to the one experienced during the exposure-phase (wide-incongruence condition), as well as after being simultaneously exposed to both stimuli (narrow-incongruence condition). Furthermore, there were no facilitation effects due to the congruence compared with the baseline: in such a case, familiar stimuli did not ease the performance at learning. The study provides the first evidence about the consistency of the classifying-together effect in a fish species, further highlighting the impact of visual similarities on discrimination processes.

Effects of similarity and experience on discrimination learning: A nonassociative connectionist model of perceptual learning.

This article describes a novel connectionist model of perceptual learning (PL) that provides a mechanism for nonassociative differentiation (J. J. Gibson & E. J. Gibson, 1955). The model begins with the assumption that 2 processes--1 that decreases associability and 1 that increases discriminability--operate during preexposure (S. Channell & G. Hall, 1981). In contrast to other models (e.g., I. P. L. McLaren, H. Kaye, & N. J. Mackintosh, 1989), in the current model the mechanisms for these processes are compatible with a configural model of associative learning. A set of simulations demonstrates that the present model can account for critical PL phenomena such as exposure learning and effects of similarity on discrimination. It is also shown that the model can explain the paradoxical result that preexposure to stimuli can either facilitate or impair subsequent discrimination learning. Predictions made by the model are discussed in relation to extant theories of PL.

The role of stimulus comparison in perceptual learning: an investigation with the domestic chick.

In two experiments an imprinting procedure was used to familiarize chicks with two stimuli, A and B, that subsequently served as the discriminanda in a simultaneous discrimination. On the first day of each experiment, subjects either received presentations of A and B that were intermixed within a session (mixed exposure) or presentations of A in one session and of B in another (separate exposure). For half of the subjects in each of the exposure conditions, A and B differed in both colour and form; for the remainder A and B differed in form alone. On the second day of the experiments, the chicks were placed into a cool test apparatus and given training in which approaching A was rewarded by the delivery of a stream of warm air, but approaching B was not. Acquisition of this discrimination was more rapid when A and B differed in two respects than when they differed in form alone. When A and B differed in both colour and form, the heat-reinforced discrimination was acquired more rapidly after separate exposure than after mixed exposure; but when A and B differed in form alone, discrimination learning was more rapid following mixed exposure than separate exposure. The latter finding, that the opportunity to compare stimuli differing in only one dimension facilitates subsequent discrimination learning, is consistent with earlier suggestions (Gibson, 1969) regarding the conditions that promote perceptual learning.

Role of context in perceptual learning in maze discriminations.

Three experiments with rats in a maze examined the effects of pre-exposure to the relevant discriminative stimuli (rubber- and sandpaper-covered maze arms) or the extra-maze context (the maze was surrounded either by black curtains or by variety of extra-maze landmarks) on the learning of a discrimination between rubber and sandpaper arms. In Experiment 1, pre-exposure to the extra-maze context facilitated subsequent discrimination learning. Experiments 2 and 3 showed that pre-exposure to rubber and sandpaper arms facilitated subsequent discrimination learning only when these cues were presented in the same context during pre-exposure and discriminative training. Taken together, the results are consistent with the hypothesis that a major cause of perceptual learning is the latent inhibition of stimuli or features common to the two discriminative stimuli, and that such latent inhibition may be disrupted by a radical change of context.

Perceptual Learning in Maze Discriminations

In Experiment 1, rats were trained on a discrimination between rubber- and sandpaper-covered arms of a maze after one group had been pre-exposed to these intra-maze cues. Pre-exposure facilitated subsequent discrimination learning, unless the discrimination was made easier by adding further discriminative stimuli, when it now significantly retarded learning. In Experiment 2, rats were trained on an extra-maze spatial discrimination, again after one group, but not another, had been pre-exposed to the extra-maze landmarks. Here too, pre-exposure facilitated subsequent discrimination learning, unless the discrimination was made substantially easier by arranging that the two arms between which rats had to choose were always separated by 135 degrees. The results of both experiments can be explained by supposing that perceptual learning depends on the presence of features common to S+ and S-.

Observational learning in pigeons: The function of quality of observed performance in simultaneous discrimination

The present experiments investigated the role of quality of modeled performance on subsequent discrimination learning in pigeons and the function of observing a discriminating conspecific. Subjects either were exposed to the asymptotic performance of models proficient in a discrimination task (an erect vs. an inverted triangle) performing with few incorrect responses or observed the incremental performance of less proficient models with more error responding. Other groups of subjects in yoked compartments were exposed to pairings of stimulus and inaccessible grain at rates at which the respective models attained reinforcement. The results provide evidence for the beneficial effects of observing errors in performance; in addition, subjects exposed to apparatus operations in the absence of discriminating conspecifics appeared to benefit more from such observational experience than animals exposed to discriminating conspecifics.

Transfer of perceptual learning: role of tactual-kinesthetic feedback reexamined.

Albino rats were pre-exposed to stimuli in an otherwise visually sparse environment, with visibility and opportunity to manipulate the forms controlled during rearing. Analysis indicated that pre-exposing animals to stimuli which provided either tactual-kinesthetic feedback or highly visible forms significantly facilitated subsequent discrimination learning. The findings question the adequacy of either an attention-getting or tactual-kinesthetic feedback to account for differences in transfer effects in studies using two- and three-dimensional forms. It is suggested that the visibility of the forms and the opportunity to inspect the forms during pre-exposure is the important variable in studies of this type.

Facilitation and retardation of discrimination learning after exposure to the stimuli.

In three experiments, rats was required to learn a simultaneous discrimination in a jumping stand between horizontally and vertically striped objects. Experiment 1 showed that prior prolonged exposure to these stimuli in the rats' home cages helped them to learn the discrimination. Experiment 2 showed that a briefer period of exposure (1 hr per day for 50 days) was equally effective when the stimuli were presented in the home cage but produced a retardation of discrimination when the stimuli were presented in the jumping stand itself. Experiment 3 demonstrated that prior exposure to the jumping stand was not in itself enough to produce a retardation of subsequent discrimination learning. Some implications of these results for current theories of perceptual learning and latent inhibition are discussed.

Helplessness in the Rat: Interfering Response or Motivational/Cognitive Deficit?

An experiment showed that experience with an insoluble problem interfered with subsequent visual discrimination learning. Prior experience with a soluble problem significantly reduced the deleterious effects of the insoluble problem but this ‘immunization’ did not benefit subjects which were able to develop an incompatible position response in the insoluble problem. Implications of these and other recent results for the theory of learned helplessness are discussed.

The Effects of Prior Experience With Visual Shapes Under Differing Conditions of Reinforcement On Subsequent Discrimination Learning in the Rat

This experiment examined the effects of prior visual experience under varying conditions of reinforcement on learning of a circle/triangle discrimination. Albino rats were given nonreinforced, nondifferentially reinforced, or differentially reinforced experience with oval and rhombus forms in their home cages. Subsequent performance on circle/triangle discrimination was compared with that of animals given no prior experience with the shapes. The group given nonreinforced experience did not differ from the control group. The nondifferentially reinforced and differentially reinforced groups, while showing no significant effects in terms of trials to criterion, did show significantly enhanced performance during the early stages of learning, the effect being stronger for the differentially reinforced group. The results suggest that reinforcement is a significant factor in producing successful transfer of learning from prior visual experience.

Effects of previous exposure on olfactory discrimination in Acomys cahirinus.

EXPERIMENTS with chicks1–3, rats4,5, and rhesus monkeys6 indicate that previous exposure to a visual pattern facilitates subsequent discrimination learning involving that pattern and a novel visual stimulus. This facilitation of discrimination learning as a function of previous exposure has been found regardless of whether the exposure stimulus was the reinforced or the non-reinforced pattern in the subsequent discrimination task.

Single- vs Multiple-Problem Training in Subsequent Discrimination Learning

36 Grade 2 and 3 students were randomly assigned to one of 3 groups receiving single-problem training, multiple-problem training, or no training with intervening, pretest, and posttest exposure to selected plates of the Columbia Mental Maturity Scale. It was hypothesized that type of problem-solving training would influence subsequent ability to solve a novel problem-solving task with multiple training resulting in the greatest positive transfer. An analysis of variance applied to the number of successful choices indicated that the effects of groups and Group × Sex were significant. Further, orthogonal comparisons indicated that the combined mean for the groups receiving single- and multiple-problem training was significantly larger than the mean score for the control group and that the mean of the group receiving multiple-problem training differed significantly from the mean of the group receiving single-problem training.

Differential delay-of-reward training and subsequent discrimination learning in children

Four groups of 16 first-grade children were given 40 single-stimulus training trials and then 100 trials on a subsequent two-choice visual discrimination test which employed the previous stimuli as discriminanda. Two groups (D-0; D-10) experienced differential delays (either zero or 10 seconds) of reward following a response to each stimulus during the training trials. One Group (N-0) of nondifferentially trained Ss experienced a zero-second delay of reward, while Ss in the other nondifferential Group (N-10) experienced a 10-second delay, following a response to both stimuli. During the discrimination test the stimuli associated with zero delay in the differential conditions became positive for one group of subjects (D-0) and negative for the other (D-10). The positive discriminative stimuli in the nondifferential conditions were assigned randomly. Response speeds to the stimuli during training were inversely related to the delay of reward associated with that stimulus. Ss in Group D-10 began the discrimination with a significant number of incorrect responses. Their performance over trials, however, increased rapidly, and the overall level of discriminative performance for the differential Groups (D-0 and D-10) was superior to that following non-differential training (N-0 and N-10). Results were interpreted in terms of a mediating response model.

Effects of prior exploration on subsequent discrimination learning

Two groups of rats learned a positional discrimination task on an elevated “Y” maze. Prior to discrimination training the experimental group was allowed to explore the maze for nine days during which time the control group was given pre training on an elevated straightaway. It was found that the experimental group learned the discrimination task significantly faster than the control group. This superiority was interpreted as due to the fact that the experimental group started discrimination learning with an already formed habit strength (H), which by interacting with incentive motivation (K) in a multiplicative way produced a larger excitatory potential (E) than the control group which started discrimination learning with negligible habit strength.

DELAY OF REWARD AND DISCRIMINATION LEARNING IN CHILDREN.

An experiment was designed to test the hypothesis that the detrimental effects of delayed reward are due to the association of inhibitory responses with the conditioned stimulus. Kindergarten children were given differential delayed reward pretraining followed by either simultaneous or successive discrimination learning involving the same stimuli used during pretraining. Response speeds during pretraining were found to be related to the reward condition on the immediately preceding trial rather than to the stimulus associated with immediate or delayed reward. Pretraining had no significant effect on subsequent discrimination learning. These findings are interpreted as evidence that initially, at least, the effects of delayed reward are a result of frustration induced avoidance responses that were not necessarily associated with the conditioned stimulus. Simultaneous presentation of the stimuli during discrimination training resulted in faster learning as well as faster response speeds. This was interpreted as supporting the hypothesis that the successive discrimination problem elicits a greater degree of response competition.

Inhibition in the Learning of a Visual Habit

Gibson and associates (Gibson & Walk, 1956; Gibson, Walk, & Tighe, 1959; Walk, Gibson, Pick, & Tighe, 1958; Walk, Gibson, Pick, & Tighe, 1959) have demonstrated that early experience with particular geometric forms facilitates later discrimination learning involving these forms. It has also been shown (Gibson, Walk, Pick, & Tighe, 1958) that what is acquired in the exposure to the stimuli may facilitate the learning of a discrimination problem utilizing stimuli similar to but different from those employed in the inicial exposure. Although chis latter finding suggests chat what is learned in extra experience'' situations is not specific to the exposure patterns but is general in character, it may well be that the degree of similarity between exposure and rest siruarions is an important and limiting factor of such uansfer. The present study investigated whether exposure to extraneous stimuli following initial exposure to discrimination stimuli interfered with subsequent discrimination learning. In short, it was hypothesized that, if the increased discrimination learning ability resulting from early exposure to stimuli were an instance of perceptual learning, it should be subject to the same principles, e.g., retroactive and proactive inhibition, held to characterize other forms of learned behavior.

LEVEL OF STIMULUS PRETRAINING AND PAIRED-ASSOCIATE LEARNING1

Previous studies of the effects of varying amounts of stimulus pretraining on subsequent discrimination or paired-associate learning have yielded inconclusive results. Some reported significantly more facilitation following greater amounts of pretraining, but did not control for the effects of possible performance set differences in groups given different amounts of pretraining (e.g., 2, 5). Others controlled performance set, but found that different amounts of pretraining did not produce significantly different amounts of performance set or of acquired distinctiveness (1, 3). The Ss, stimuli, and task I responses were comparable in these studies, but the former studies used button-pushing or switch-throwing responses in task II, whereas the latter studies used the Star Discrimeter. In the present study, stimuli and responses comparable to those used in the former studies were used, but children were used as Ss because it was desired to simplify the tasks and to minimize the probability that Ss would have preexperimentally learned names for the stimuli used in the condition which controlled performance set effects. Two specific predictions were tested: (a) the higher the level of pretraining, the better the performance on task II will be; and (b) the higher the level of pretraining, the greater the difference between the experimental (acquired distinctiveness) and performance-set control conditions will be. In task I, Ss learned to associate distinctive nonsense syllables with two stimuli. Three groups were trained to a low, moderate, or high criterion.

Effects of reinforcing single stimuli upon subsequent discrimination learning by rhesus monkeys.

Effects of reinforcing single stimuli upon subsequent discrimination learning by rhesus monkeys.

THE EFFECTS OF TYPE OF STIMULUS PRETRAINING ON DISCRIMINATION PERFORMANCE IN PRESCHOOL CHILDREN

Several recent experiments have demonstrated that certain types of stimulus pretraining facilitate subsequent discrimination learning and performance. Using adult human Ss, Dysinger (3) and J. Cantor (2) have demonstrated that Ss taught to respond to a set of stimuli with distinctive verbal subsequently perform better in a task requiring the learning of other to this same set of stimuli than do Ss who were given the same pretraining with an irrelevant (different) set of stimuli. Gerjuoy (4) and G. Cantor (i) report similar findings with elementary school and preschool Ss. Lawrence (6) found that if rats had first learned a simultaneous discrimination problem involving a given pair of stimulus cues, they subsequently learned a successive problem with the same cues more rapidly than did rats that had been trained on a different pair of cues in the first problem. One interpretation of these results makes use of the hypothesis of acquired distinctiveness of cues. Briefly, it is assumed that making a distinctive response (e.g., a name) to a stimulus produces a distinctive stimulus which becomes part of the total stimulus complex. If a distinctive response is learned to each member of a set of similar stimuli, the effective similarity of these stimuli is reduced. This decreases the amount of generalization among them, which, in turn, decreases the difficulty involved in associating a new set of distinctive to the stimuli. Another interpretation has been suggested by Kurtz (5) in specific reference to the Rossman and Goss (7) findings but presumably applicable to other similar studies. Briefly, Kurtz suggested that the function of the verbal pretraining is to establish appropriate responses which transfer into the second task. The name-learning, then, is interpreted as merely a convenient criterion that E may use to determine when the appropriate observing have been set up. In his own experiment, Kurtz established observing with a familiarization procedure

The effects of training to approach vs. to escape from electric shock upon subsequent discrimination learning.

The effects of training to approach vs. to escape from electric shock upon subsequent discrimination learning.