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Referential communication abilities of learning-disabled, language-learning-disabled, and normal school-age children.

Past research in referential communication has indicated normally developing children show developmental progression in ability to communicate a specific referent to a listener. In one paradigm subjects were given lists of word-pairs in which one member of each pair was designated as the referent. It was shown that communicating about referents found in word-pairs associated in some way was more difficult than communicating about referents in dissimilar word-pairs. The present study extended this methodology to learning-disabled children. Learning-disabled, language-learning-disabled, and normally achieving children were asked to communicate about 30 pictured referents on three different tasks. On Tasks 1 and 2 each subject was asked to give a clue for the referent that would distinguish it from the other picture. Stimuli for Task 1 were 30 pairs of pictures that were related in some way and the stimuli for Task 2 were 30 pairs of unrelated pictures. Task 3 required the subjects to evaluate the adequacy of the examiner's clues for Task 1 stimuli. The disabled subjects were matched to the normally achieving subjects on the basis of receptive vocabulary age. Few differences were noted among the groups' performances on these referential communication tasks. Implications include the importance of vocabulary and concept development to referential communication.

Adolescent

Learning disabilities and learned helplessness: a heuristic approach.

This study investigated whether students with learning disabilities exhibited learned helpless behavior at a greater rate than their normal achieving peers when confronted with reading failure. Forty-five third grade students from a suburban elementary schools were participants in the study. Thirty of the subjects were classified as having a learning disability (LD) and the remaining 15 subjects were from regular education (RE) classrooms. Fifteen of the students with LD were placed in the treatment group and the remaining fifteen were placed in the control group. All the regular education students were placed in the treatment group. After randomly assigning the students with LD into either a treatment (stressed) group or a control (nonstressed) group, the stressed students were administered a reading instrument in order to measure how they dealt with failure. A one-way ANCOVA was conducted to determine whether significant differences existed between the groups based on their posttest scores. The results indicate that stressed students with LD have a significantly more difficult time recovering from stress than their regular education peers.

Child

Differential performance of learning disabled and non-learning disabled children on the McCarthy scales, WISC-R, and WRAT.

Individually administered the McCarthy Scales of Children's Abilities, WISC-R, and WRAT to 30 learning disabled and 30 non-learning disabled second-grade students. The McCarthy General Cognitive Index and the WISC-R Full Scale IQ scores were compared for both groups. In addition, correlations between the General Cognitive Index, WISC-R IQ, and mean WRAT achievement were reported. There was marginal support for previous studies that suggested that the McCarthy Scales are more consistent with the academic functioning of learning disable students. Implications and directions for future research were discussed.

Child

Ontogenesis of learning: III. Variation in the rat's differential reflexive and learned responses to sound frequencies.

The ontogenesis of the rat's differential response to variation in sound frequency was investigated. Two behavioral procedures were employed: (a) a differential Pavlovian conditioning procedure that provided a means of inferring the pup's capacity to learn to respond differentially on the basis of sound frequency (e.g., 2000 Hz vs 900 Hz), and (b) a habituation-generalization task that indexed the capacity to discriminate different sound frequencies from the pup's reflexive behavior. Pups less than 17 days old failed to learn to respond differentially to a 2000-Hz vs 900-Hz tone (Experiment I, IIA, IIB, and III). In contrast, pups only 14 days old discriminated tones that differed by as little as 200 Hz when the reflex-habituation-generalization procedure was employed (Experiment IV). This suggests that the reflexive and learned behaviors, potentially controlled by sound frequency, are dissociated during ontogenesis, the former emerging prior to the latter. These data were interpreted within a neurobiological framework that related ontogenetic changes in behavioral capacity to a caudal-to-rostral maturational sequence in the ascending auditory system of the components that contribute to these capacities.

Acoustic Stimulation

Analysis of associative learning in the terrestrial mollusc Limax maximus. II. Appetitive learning.

The odor and taste processing systems of the terrestrial mollusc Limax maximus have been shown capable of a number of complex computations. Most of the complex higher-order features of Limax learning have been demonstrated using differential aversive conditioning. The present experiments probe the appetitive learning ability of Limax. In the first experiment a differential appetitive classical conditioning procedure was used. An aversive CS+ odor was paired with an attractive taste while a CS- odor was explicitly unpaired with the attractive taste. This appetitive conditioning procedure dramatically increased the preference for the CS+ odor. Further experiments determined the time course of acquisition, the effect of an extinction procedure and long-term retention of the appetitive conditioning. Now that Limax has been shown capable of appetitive conditioning, the neural network simulation of Limax learning, called LIMAX, can be examined for its ability to display appetitive conditioning.

Animals

Synaptic plasticity and learning. II: Do different kinds of plasticity underlie different kinds of learning?

This paper discusses certain issues connected with the question of whether synaptic plasticity is involved in information storage by the brain. We begin by contrasting two well documented types of synaptic plasticity--activity-dependent modulation of presynaptic facilitation ("Kandel synapses") and NMDA receptor triggered alterations in excitatory amino acid transmission ("Hebb synapses"). We then propose that, embedded-into appropriate circuitry, these different forms of plasticity might underlie different kinds of learning. In partial support of this idea, we show that, in freely moving rats, intrahippocampal microinfusion of the NMDA-receptor antagonist D,L-AP5 causes a dose-dependent impairment of a type of spatial learning known to be sensitive to disruption by hippocampal lesions (water-maze place-navigation). In a second experiment, the same drug infusion protocol is shown to cause a blockade of hippocampal long-term potentiation in vivo across a comparable dose range. Finally, third, autoradiographic experiments indicate that diffusion of the drug was largely restricted to the hippocampus. Together, these results (1) suggest that blockade of hippocampal NMDA receptors, under conditions which leave baseline synaptic transmission relatively unaffected, blocks a type of learning with which the vertebrate hippocampus has been implicated on the basis of neuropsychological work; and (2) supports Abrams and Kandel's Trends Neurosci. 11 (1988) recent proposal that there may be several logically distinct forms of synaptic plasticity.

Animals

Forebrain serotonin and avoidance learning: behavioural and biochemical studies on the acute effect of p-chloroamphetamine on one-way active avoidance learning in the male rat.

The acute effects of p-chloroamphetamine (PCA) on one-way active avoidance learning and on central monoamine concentrations were examined in the male rat. The 5-HT specificity of the acute behavioural effect of PCA was examined in several experiments. PCA (0.08-5 mg/kg IP) injected 30-60 min before testing produced a dose-related impairment of both avoidance acquisition and retention. Pretreatment with the selective serotonin (5-HT) uptake inhibitors fluoxetine and zimelidine, but not the noradrenaline (NA) uptake inhibitor desipramine, resulted in a blockade of the avoidance deficit. Degeneration of brain 5-HT neurons by a high neurotoxic dose of PCA (2 x 10 mg/kg IP) 7 days prior to the administration of PCA also blocked the avoidance deficit. There was also a complete blockade of the PCA-induced avoidance deficit by pretreatment with metergoline, a central 5-HT receptor blocking agent. A 2.,5 mg/kg dose of PCA examined 60 min after injection produced regional changes in the 5-HT-levels preferentially in the forebrain region with significant reductions in the cerebral cortex, hippocampus and striatum while marginal effects were observed in the hypothalamus, midbrain and spinal cord. PCA failed to reduce dopamine and noradrenaline concentrations in the time- and dose-range of the avoidance deficit. Thus, the avoidance learning impairment appears to be specifically related to the acute release of endogenous 5-HT from presynaptic nerve endings possibly in the forebrain resulting in stimulation of postsynaptic 5-HT receptors. These findings indicate that 5-HT neurons in the forebrain play a role in active avoidance learning possibly by an involvement in memorial and/or retrieval processes.

Amphetamines

Learning from each other: peer teaching and learning in student nurse training.

From whom do student nurses learn practical skills? According to the small group of students questioned by the author they learn as much from fellow students as from staff nurses, and clinical teachers have little part in this type of learning. The author discusses this issue and asks whether teachers should be more involved in clinical practice.

Education, Nursing

Differential influences of corticotropin-releasing factor on memory retention of aversive learning and appetitive learning in rats.

The effects of intraamygdala injections of corticotropin-releasing factor (CRF) on memory retention of aversive and appetitive learnings were examined in the present study. Other than confirming the results of a previous study that a moderate dose of CRF (0.1 microgram) injected into the amygdala facilitated retention performance of an inhibitory avoidance task (electric shock punishment) 24 h after training, we have further found that this effect lasted for a week. However, CRF produced a differential dose-response effect upon memory of an appetitive learning paradigm (sexual reinforcement). CRF at 0.01 microgram enhanced retention at both 24-h and 1-week intervals, while CRF at 0.1 microgram impaired retention in the same task at 1 week only. These results confirm that the amygdala is important in memory processing and suggest that the mechanisms involved in the action of CRF on memory retention of aversive and appetitive learnings are different. The possible differences are also discussed.

Amygdala

Learned helplessness and learned resourcefulness: effects of noncontingent success and failure on individuals differing in self-control skills.

We designed two experiments to investigate the role of self-control processes in learned-helplessness studies by assessing the differential reactions to uncontrollability of subjects who presumably had either a rich (high resourceful, or HR) or poor (low resourceful, or LR) repertoire of self-control skills. HR and LR subjects received noncontingent success feedback, failure feedback, or no feedback on a task that ostensibly assessed "therapeutic abilities." Subjects were subsequently tested on insolvable puzzles (Experiment 1) or on solvable anagrams (Experiment 2). According to Kanfer and Hagerman's (1981) self-regulation model, self-regulatory activities are evoked primarily in situations in which subjects are faced with repeated failure. Hence we predicted that individual differences in self-control would influence performance on the insolvable puzzles and not anagram performance after exposure to noncontingent failure. This prediction was confirmed: Only the performance of LR subjects on the insolvable puzzles was debilitated by the helplessness induction, whereas HR and LR subjects showed equal helplessness-induced deficits on the anagrams. The latter finding was interpreted in terms of the learned-helplessness model without the mediating effects of self-regulatory processes. As predicted from the self-control model, HR subjects more frequently checked statements indicating positive self-evaluations and task-oriented thoughts and less frequently checked negative self-evaluations than did LR subjects during exposure to uncontrollability in both experiments. We concluded that the self-control model accounts best for subjects' self-reactions during exposure to uncontrollability or failure, whereas the learned-helplessness model accounts for the generalization of helplessness from uncontrollable situations to controllable ones.

Environment

Effects of fantasy contexts on children's learning and motivation: making learning more fun.

Two studies examined the effects of embedding instructional materials in relevant fantasy contexts on children's motivation and learning. In Study 1, Ss showed marked preferences for computer-based educational programs that involved fantasy elements. In Study 2, Ss worked with these programs for 5 hr. One program presented purely abstract problems. Others presented identical problems within fantasy contexts. Some Ss chose among 3 fantasies; others were assigned identical fantasies. Tests on the material occurred before, immediately after, and 2 weeks after the experimental sessions. Ss showed significantly greater learning and transfer in the fantasy than in the no-fantasy conditions. Having a choice of fantasies made no difference. Motivational and individualization strategies for enhancing interest and promoting learning are discussed.

Achievement

Conditioned and latent inhibition in taste-aversion learning: clarifying the role of learned safety.

Experiments 1-3 investigated the applicability of the classical conditioning concept of conditioned inhibition to taste-aversion learning. Rats made ill after drinking saccharin and subsequently administered a "safe" exposure to saline (or casein hydrolysate) evidenced an enhanced preference for the safe fluid (relative to either a third, slightly aversive, solution or to water) when compared to controls in which saccharin was not previously poisoned. Such active condition inhibition was significantly reduced in Experiment 4 when two safe exposures to saline preceded saccharin-illness pairings. These results indicate that conditioned inhibition can be established in a taste-aversion procedure and that a latent inhibition manipulation reduces the ability of a taste to become a signal for safety. Implications of these findings for the learned safety theory of taste-aversion learning and the relevance to bait-shyness of principles established within the classical conditioning paradigm are considered.

Animals

Is tube-escape learning by protozoa associative learning?

The ciliate protozoa, Stentor and Paramecium, have been reported to escape from the bottom end of narrow capillary tubes into a larger volume of medium with increasing rapidity over the course of trials. This change in behavior has been considered an apparent example of associative learning. This decrease in escape time is not due to a change in the protozoa's environment, their swimming speed, frequency of ciliary reversals, or the proportion of time spent forward or backward swimming. Instead, most of the decrease results from a decrease in the proportion of time spent in upward swimming. However, a similar decrease in upward swimming occurs when the task is altered to require escape from the upper end of the capillary tubes. Because the protozoa exhibit the same change in behavior regardless of the reinforcing stimulus, tube-escape learning is not associative learning.

Animals

Learning and behavioral correlates in learning-disabled pupils prone to heterozygous thalassemia and sicklemia.

The pilot study was designed to vindicate planning for large-scale detection and management of two parallel genetic blood disorders occurring in large numbers of Mediterranean- and black Americans; the heterozygous minor traits of thalassemia (Cooley's anemia) and sicklemia (sickle-cell anemia). Referred pupils (N=191) matched on schools, age, and learning difficulties associated with learning disabilities were compared as to presumed ethnic origin (n Mediterranean = 80; n black = 64; n "others" = 47) and incidence of trait-related learning and behavioral characteristics. Group mean differences on the study's criteria were found to be significant. Both minor-trait prone groups equally indicated the associative effects, while the control group without tradt-predisposition showed a nonsignificant relationship, thus supporting the hypotheses and the need for large-scale research.

Achievement

Impact of age and situation-specific experience on maze learning and learning-sensitive open-field parameters in mice.

The effects of age and situation-specific experience on maze learning and learning-sensitive open-field parameters (OFP) in Swiss albino male mice were studied. We tested the mice longitudinally by means of repeated measures and in cross-section by taking independent samples between the ages of 1-16 months. Mice with situation-specific experience improved their performance up to the age of 11 months. For mice lacking prior experience there was a trend toward impaired performance with regard to error scores and running times with increasing age. The ages of 1, 8, and 10 months were most favorable for the occurrence of quantitative maze learning-sensitive OFP changes, and the ages of 1, 3, 4, 8, 9, 10, 12, and 13 months were most favorable for the appearance of qualitative changes. The effect of situation-specific experience was interpreted as indicative of decreased emotionality but increased reactivity to novel stimuli or enhanced territorial behavior at the age of 16 months.

Aging

Concept learning by retarded children: a comparison of three discrimination learning procedures.

The effectiveness of stimulus delay and stimulus fading procedures was compared with differential reinforcement only in training developmentally delayed children on a concept learning task. Twenty-four children were randomly assigned to one of the three treatment conditions. All three experimental conditions contained five discrimination programmes, each designed to teach the child to discriminate one pair of exemplars from the target concepts bottle and jar. Following successful completion of one training programme, a concept acquisition probe was administered to determine whether the target concepts had been engendered. Alternate presentations of successively different training programmes and concept acquisition probes were continued until the subject passed the probe, failed to complete a training programme, or completed all five training programmes. Five 'stimulus fading' subjects, three 'stimulus delay' subjects, and four 'reinforcement only' subjects learned the concepts. All children who learned to discriminate one pair of exemplars displayed conceptual behaviour after training on two or fewer pairs of exemplars. It was suggested that the absence of pronounced differences between conditions may have been due to the complexity of the task or the type of prompts employed.

Child, Preschool

A homogeneous group of persons with learning disabilities: adults with severe learning disabilities in vocational rehabilitation.

The results of a comprehensive psychoeducational assessment of adults having learning disabilities (LD) and participating in vocational rehabilitation are presented. The subjects were found to have low-average general intelligence; lower verbal than performance IQs; attention, reasoning, and auditory memory deficits; academic achievement at the fourth-/fifth-grade level; language problems; and low self-esteem. These results were contrasted with other studies of adults with LD in vocational rehabilitation, and all studies on this population reported similar findings. A comparison of studies of adults with LD who were clients of vocational rehabilitation with those in college or employed and with those who had been labeled as learning disabled in childhood indicated that the adults with LD in vocational rehabilitation seem to constitute a homogeneous group of persons with severe deficits. The need to subtype learning disabilities by severity and criteria for making such determinations are proposed.

Adult

Using informed strategies for learning to enhance the reading and thinking skills of children with learning disabilities.

The purpose of this study was to improve the reading performance of children with learning disabilities using a classroom-based metacognitive reading program. The participants were third- and fourth-level 8- and 9-year-olds (13 boys and 5 girls) at a school for children with learning disabilities. A cross-sectional time series design was used. During pre- and posttesting participants were assessed on two measures of strategy awareness and a measure of perceived self-competence. During the instructional phase the metacognitive reading program was introduced. Participants were assessed on measures of reading performance throughout the study. In general, the findings were positive: Students increased in performance and awareness of strategies from pre- to posttesting. In addition, participants were placed in subgroups based on pretesting assessments. The subgroups differed on their improvements over time. This study provides preliminary evidence that a metacognitive reading program can be used with children with learning disabilities to improve their awareness about reading and their comprehension skills.

Awareness