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PubMed1993

Responding changes systematically within sessions during conditioning procedures.

When the procedure is held constant within an experimental session, responding often changes systematically within that session. Many of these within-session changes in responding cannot be dismissed as learning curves or by-products of satiation. They have been observed in studies of positive reinforcement, avoidance, punishment, extinction, discrimination, delayed matching to sample, concept formation, maze and alley running, and laboratory analogues of foraging, as well as in the unconditioned substrates of conditioned behavior. When aversive stimuli are used, responding usually increases early in the session. When positive reinforcers are used, responding changes in a variety of ways, including increasing, decreasing, and bitonic functions. Both strong and minimal reinforcement procedures produce within-session decreases in positively reinforced behavior. Within-session changes in responding have substantial theoretical and methodological implications for research in conditioning.

Animals↗
PubMed1995

Anterior brain deficits in chronic alcoholism. Cause or effect?

To investigate the hypothesis of anterior brain involvement in alcoholism, nonfamilial short-term drinkers (STD) and long-term drinkers (LTD) were assessed using neuropsychological tests commonly related to frontal lobe functions. Both STDs and LTDs were similarly impaired on measures of visually mediated concept formation and flexibility of thinking. Results from other time-constrained tests that required good concentration and immediate memory, visual scanning, and visual-motor coordination were significantly lower in the LTD group as compared with STDs. The data suggest a dual-factor hypothesis of anterior cerebral dysfunctions in alcoholism: a preexisting deficit in conceptual thinking and consequential CNS abnormality (psychomotor slowing, decreased attentiveness, and immediate memory) associated with prolonged alcohol intake, and resembling signs of premature aging.

Alcohol Drinking↗
PubMed1986

Persistence of learned helplessness in humans.

The duration of the effects of a common learned helplessness induction procedure, exposure to insoluble concept-formation problems, was assessed by varying the interval between the induction procedure and subsequent exposure to soluble anagrams. Participants tested immediately or 30 min after the induction procedure exhibited reliable helplessness deficits on all dependent measures. These effects, relative to the performance of a nonhelpless control group, were absent in subjects who experienced delays of 2 or 6 hr before anagram testing. The implications of these results for the development of more enduring helplessness effects and for the conducting of research into analogue intervention are discussed.

Achievement↗
PubMed1985

Effects of flurazepam and triazolam on neuropsychological performance.

A double-blind study examined the effects of a single dose of either triazolam or flurazepam on measures of concept formation, attention, concentration, and motor function, the morning following drug ingestion. Subjects were 53 healthy university students, screened for history of neurological or psychiatric illness. In comparison to placebo-treated controls, there was no difference in the effects on neuropsychological performance, although subjects who received flurazepam reported more side effects. It was concluded that although these drugs may produce side effects, single doses do not appear to impair various aspects of neuropsychological ability the morning after ingestion.

Adolescent↗
PubMed1994

Predictions from uncertain categorizations.

Eleven experiments investigated how categorization influences feature prediction. Subjects were provided with sets of categorized exemplars, which they used to make predictions about properties of new exemplars. Because the categories were provided for subjects, this method allowed a test of categorization and prediction processes, bypassing initial concept formation and memory. The experiments tested a Bayesian rule of prediction according to which (1) predictions of an object's features are based on information from multiple categories, and (2) features are treated as independent of one another. With one exception, the studies found evidence against both of these claims. Subjects did not generally alter their predictions as a function of information outside the most likely "target" category. In addition, feature relations had reliable effects on these predictions. We discuss the implications of these results for understanding how categories are used in drawing inferences.

Concept Formation↗
PubMed1996

Neuropsychological aspects of frontal lobe epilepsy.

While most neuropsychological studies in focal epilepsies are concerned with temporal lobe epilepsy (TLE), only few investigations aim cognitive functioning in unresected patients with frontal lobe epilepsy (FLE). Following functional models arising from lesional studies, we evaluated patients with TLE (21 left, 17 right) and FLE (6 left, 17 right) with respect to attention and speed, motor coordination, verbal/nonverbal fluency, concept formation, response inhibition, anticipatory behavior and memory span. The following results were obtained. When compared to TLE, FLE was associated with significantly poorer results in almost all tests, fluency tests being the exception. No group differences were found with respect to the lateralization of the epileptic focus or the presence or absence of cerebral lesions. Factor analysis of the tests indicated that different subfunctions (speed, STM, motor coordination, response maintenance and inhibition) were assessed. A particular cognitive pattern of impaired motor coordination or response inhibition appeared to be characteristic for patients with FLE.

Adult↗
PubMed1999

[Medicine with a human face--a scientific philosophic reflection].

The essay deals with the relationship between the scientific and humanistic social scientific aspects of medical concept formation and science. The first part focuses on methodological differences associated with the two forms of knowledge, emphasizing the distinction between quantitative and qualitative methods. The differences are traced back to type of phenomenon or object researched. On the basis of the special character of human beings and their illnesses it is then argued that scientific medicine necessarily will have to transcend the divide between the natural sciences on the one hand and the humanities and social sciences (the "human sciences") on the other. The unity in medicine is tied to its practice--the art of medicine as carried on in the clinical meeting between doctor and patient.

Concept Formation↗
PubMed1990

Neuropsychological assessment of monozygotic twins discordant for schizophrenia.

A comparison of monozygotic twins discordant for schizophrenia controls for genetic variance and reduces variance due to environmental circumstances, thus serving to highlight differences due to phenotypic-related variables. In this study, we assessed 16 such twin pairs on a wide range of neuropsychological tests. The affected twins tended to perform worse than their unaffected counterparts on most of the tests. Deficits were especially severe on tests of vigilance, memory, and concept formation, suggesting that dysfunction is greatest in the frontotemporal cortex. While manifest symptoms were not highly associated with neuropsychological scores, global level of functioning was. To address the issue of genetic liability, we also compared the sample of discordant unaffected twins with a sample of seven pairs of normal monozygotic twins. No significant differences between the groups were found for any neuropsychological test. In fact, the results suggest that neuropsychological dysfunction is a consistent feature of schizophrenia and that it is related primarily to the clinical disease process and not to genetic or nonspecific environmental factors.

Adult↗
PubMed1989

Frontal lobe dysfunction and memory impairment in patients with chronic progressive multiple sclerosis.

Deficits in semantic encoding have been described in patients with frontal lobe disease who also show memory impairments. As a group, patients with multiple sclerosis (MS) exhibit memory impairment, fail to make effective use of semantic encoding to aid memory, and perform poorly on verbal fluency and concept formation tests which are sensitive to frontal lobe damage. In the present study the semantic encoding capacity of MS patients was measured using a modification of Wicken's release from proactive interference (PI) paradigm. Individual patients varied considerably in the severity of their impairments on verbal fluency, verbal recognition memory and on Wisconsin Card Sorting Task, but even patients who evidenced both memory impairment and signs of frontal lobe dysfunction showed normal release from PI after a categorical shift. Memory disturbances in MS are unlikely to result from an incapacity for semantic encoding, which seems preserved in MS, but may arise instead from deficits in processing information rapidly.

Adult↗
PubMed1977

MMPI correlates of adaptive ability deficits in patients with brain lesions.

In the present study the relationship between MMPI variables and adequacy of function in verbal and performance intelligence, concept formation, sensory-perceptual and motor skills was examined in 129 subjects with definite evidence of cerebral lesions. Patients with greater impairment of abilities showed higher elevations on the MMPI variables, suggesting more emotional difficulties. Based on the present results and those of two previous studies by the same authors it was concluded that: a) MMPI variables are more closely related to measures of adequacy of function in adaptive abilities than they are to measures of lesion localization based upon pathoanatomical characteristics of the brain; and b) except for verbal skills the relationship between the MMPI variables and various adaptive skills is relatively minor. Interpretive limitations of the MMPI with brain-damaged patients and the need for devising other tests sensitive to the nuances of emotional difficulties of patients with brain lesions were discussed.

Adaptation, Psychological↗
PubMed2006

Neural markers of categorization in 6-month-old infants.

Little is known of the neural processes that underlie concept-formation abilities in human infants. We investigated category-learning processes in infants both by using a common behavioral measure and by recording the brain's electrical activity (event-related potentials, or ERPs). ERPs were recorded while 6-month-olds viewed cat images during training, followed by novel cat images interspersed with novel dog images during test. The data indicate that distinct neural signals correspond with learning of a category presented during familiarization, preferential responding to a novel category, and representation of category exemplars at multiple levels of inclusiveness. The results suggest that fundamental components of the neural architecture supporting object categorization are functional within the first half-year of postnatal life, before infants acquire language and young children engage in formal learning of semantic categories. The findings are discussed in terms of their implications for models of category learning and development.

Arousal↗
PubMed1991

Cognitive and behavioral effects of the coadministration of dextroamphetamine and haloperidol in schizophrenia.

OBJECTIVE: The authors sought to determine if an acute dose of dextroamphetamine might have positive effects on affect and cognition in schizophrenic patients maintained on a regimen of haloperidol and, if so, what variables might predict such improvements. METHOD: Twenty-one patients with chronic schizophrenia who were hospitalized on a research ward received a single oral dose of dextroamphetamine (0.25 mg/kg) in a double-blind, placebo-controlled, crossover study. All patients were receiving 0.4 mg/kg per day of haloperidol. Cognitive tests, motor tests, global ratings, mood ratings, and videotape ratings were used to determine the effect of the coadministration of these drugs. Ventricle-brain ratios derived from CT scans were used to predict response to the coadministration of these drugs. RESULTS: Amphetamine improved performance on a measure of concept formation on the Wisconsin Card Sorting Test but did not result in changes in performance on tests of memory or attention. As a group, the patients were more active and performed psychomotor tests more quickly while receiving amphetamine. Six patients were judged by clinical raters to have improved in terms of affect, cooperation, and engagement with the environment. Improvement was associated with enlarged cerebral ventricles and increases in blink rate from the placebo to the active drug condition. No patient unequivocally worsened. CONCLUSIONS: These results may be consistent with the theory that coadministration of amphetamine and haloperidol produces relatively selective enhancement of cortical dopaminergic activity. However, because of the acute nature of the trial and the specialized research environment in which it was conducted, the authors do not advocate amphetamine as a routine clinical treatment of schizophrenia.

Adult↗
PubMed1996

Issues in cognitive psychology: implications for professional education.

Education and cognitive psychology have tended to pursue parallel rather than overlapping paths. Yet there is, or should be, considerable common ground, since both have major interests in learning and memory. This paper presents a number of topics in cognitive psychology, summarizes the findings in the field, and explores the implications for teaching and learning. THE ORGANIZATION OF LONG-TERM MEMORY: The acquisition of expertise in an area can be characterized by the development of idiosyncratic memory structures called semantic networks, which are meaningful sets of connections among abstract concepts and/or specific experiences. Information (such as the assumptions and hypotheses that are necessary to diagnose and manage cases) is retrieved through the activation of these networks. Thus, when teaching, new information must be embedded meaningfully in relevant, previously existing knowledge to ensure that it will be retrievable when necessary. INFLUENCES ON STORAGE AND RETRIEVAL FROM MEMORY: A wide variety of variables affect the capacity to store and retrieve information from memory, including meaning, the context and manner in which information is learned, and relevant practice in retrieval. Educational strategies must, therefore, be directed at three goals--to enhance meaning, to reduce dependence on context, and to provide repeated relevant practice in retrieving information. PROBLEM SOLVING AND TRANSFER: Much of the development of expertise involves the transition from using general problem-solving routines to using specialized knowledge that reduces the need for classic "problem solving." Two manifestations of this specialized knowledge are the use of analogy and the specialization of general routines in specific domains. To develop these specialized forms of knowledge, the learner must have extensive practice in using relevant problem-solving routines and in identifying the situations in which a particular routine is likely to be useful. CONCEPT FORMATION: Experts possess both abstract proto-typical information about categories and an extensive set of separate, specific examples of categories, which have been obtained through individual experience. Both these sources of information are used in categorization and diagnostic classifications. Thus, it is important for educators to be aware that experience with sample cases is not just an opportunity to apply and practice the rules "at the end of the chapter." Instead, experience with cases provides an alternative method of reasoning that is independent of, but equally useful to, analytical rules. DECISION MAKING: Experts clearly do not use classic formal decision theory, but rather make use of heuristics, or shortcuts, when making decisions. Nonetheless, experts generally make appropriate decisions. This suggests that the shortcuts are useful more often than not. Rather than teaching learners to avoid heuristics, then, it might be more reasonable to help them recognize those relatively infrequent situations where their heuristics are likely to fail.

Cognition↗
PubMed2001

Attentional characteristics of schizophrenia patients differing in learning proficiency on the Wisconsin Card Sorting Test.

The Wisconsin Card Sorting Test (WCST), a test of concept formation, was given to 49 schizophrenia inpatients in three blocks of 64 cards each with the second block comprising special instructions and trial-by-trial feedback. With the help of a psychometric algorithm based on linear regression analysis, the patients were classified according to their response to these specific interventions. Results yielded 15 high scorers, 23 learners, and 11 nonlearners. This a priori classification was confirmed by cluster analysis. Next, these groups were further analyzed with the Degraded Stimulus Continuous Performance Test (DS-CPT), a test of target discrimination, and the Test of Attentional Style (TAS), which assesses habitual, subjectively experienced attentional problems. A significant difference between high scorers and nonlearners was found for discriminative sensitivity (d'), with the learners achieving intermediate scores. Results for only the DS-CPT response criterion (beta) and a TAS subscale (Distractibility) tended to be significant. Discriminant analysis also revealed that d' is the most powerful variable for discriminating among the subgroups. The article also addresses baseline versus dynamic assessment, specific rehabilitation needs in subgroups of schizophrenia patients different in learner status, and the neurocognitive characteristics of the subgroups.

Adult↗
PubMed1977

Adaptive training and individual differences in perception.

Four types of training techniques were compared in the training of a perceptual concept-formation task. Adaptive training, a technique in which one parameter in the learning situation is varied so that the difficulty of a learning task remains constant for that individual, was compared to three intermediate approaches to training (self-adaptive, in which the trainees could control their own pace of learning by indicating when they felt they had mastered the problem, fixed sequence, and fixed task). The relationship between individual trainee's perceptual style and various stages of training was also investigated. Perceptual style was measured by the Hidden Figures Test, the Rod-and-frame Test, a Distracting Context Test, and a Cancellation Test. Results showed a definite (time to perform the task) advantage in favor of the adaptive training method. Fewer errors were committed under the self-adaptive approach, but the task completion time was significantly higher. Further analysis showed that for the adaptive-training group, measures of perceptual style could be used as predictors of future task success. No such relationship was found for other training techniques. In particular, field-independence appears to be important early in training but becomes increasingly less important, and for the final training criterion trials, is not predictive of performance. In contrast, the Distracting Contest Test-II, early in training, is not an important predictor but is an important predictor for the final criterion trials.

Adult↗
PubMed2006

New scores for the Category Test: measures of interference for subtests 5 and 6.

The Category Test is a well-known neuropsychological instrument used to assess concept formation and higher executive abilities. The present study investigated the utility of additional scores for the Category Test. We used principles developed in cognitive psychology to create several new measures for subtests 5 and 6 of this test. These scores were primarily designed to be sensitive to interference effects of learning decision rules from subtest 2, subtest 3, and subtest 4. The new scores as well as the total error scores from subtests 5 and 6 were used to discriminate subjects with documented brain injury from subjects who were neurologically normal based on neuroimaging and neurologic evaluation. The Category Test was given following Reitan's (1979) instructions, with the exception that no additional prompting was given to participants who struggled early with the test in order to reduce the "executive" guidance of the examiner. Because any "interference" from earlier subtests on performance of subtest 5 and subtest 6 should be related to mastery of these earlier subtests, the normal group was matched to the brain-impaired group on which subtest(s) they learned. This resulted in four learning groups: (a) learned subtests 3 and 4; (b) learned subtest 4 but not 3; (c) learned subtest 3 but not 4; and (d) failed to learn either subtest. ANOVA analyses revealed that the three measures of interference were significantly greater in the brain-damaged group than in the normal controls. Also, specific interference measures were related to specific prior subtest mastery, thus providing support for a proactive interference effect. In addition, we have evidence that our new measures may be selectively sensitive to frontal system dysfunction.

Adult↗