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Job performance testing: an alternative to age discrimination.

The Age Discrimination in Employment Act has raised the issue of Bona Fide Occupational Qualifications for employment in the public safety sector. Complicating the issue is the number of lawsuits filed for violation of the Age Discrimination in Employment Act. Physical performance testing as an alternative to arbitrary age limitations is considered for physically demanding tasks in fire fighting, law enforcement, and the military. Tests with criterion-related validity are presented that are useful for screening new applicants and for periodic re-evaluation of incumbents. Extensive testing in our laboratory, in concert with the literature review, support the observation that age is a poor predictor of performance across the full range of employment years. It is concluded that individuals who are otherwise healthy, with proper attention to their lifestyles, can develop and maintain the necessary physiological profile to successfully execute the duties of physically demanding jobs well into their advancing years.

Adult

Human learning and memory.

There have been several notable recent trends in the area of learning and memory. Problems with the episodic/semantic distinction have become more apparent, and new efforts have been made (exemplar models, distributed-memory models) to represent general knowledge without assuming a separate semantic system. Less emphasis is being placed on stable, prestored prototypes and more emphasis on a flexible memory system that provides the basis for a multitude of categories or frames of reference, derived on the spot as tasks demand. There is increasing acceptance of the idea that mental models are constructed and stored in memory in addition to, rather than instead of, memorial representations that are more closely tied to perceptions. This gives rise to questions concerning the conditions that permit inferences to be drawn and mental models to be constructed, and to questions concerning the similarities and differences in the nature of the representations in memory of perceived and generated information and in their functions. There has also been a swing from interest in deliberate strategies to interest in automatic, unconscious (even mechanistic!) processes, reflecting an appreciation that certain situations (e.g. recognition, frequency judgements, savings in indirect tasks, aspects of skill acquisition, etc) seem not to depend much on the products of strategic, effortful or reflective processes. There is a lively interest in relations among memory measures and attempts to characterize memory representations and/or processes that could give rise to dissociations among measures. Whether the pattern of results reflects the operation of functional subsystems of memory and, if so, what the "modules" are is far from clear. This issue has been fueled by work with amnesics and has contributed to a revival of interaction between researchers studying learning and memory in humans and those studying learning and memory in animals. Thus, neuroscience rivals computer science as a source of interdisciplinary stimulation. Research on topics such as memory for spatial location, the relation between memory and affect, and autobiographical memory reminds us that general theories of memory based on studies of verbal materials alone are limited. Investigating how people remember complex natural events should provide us with a larger set of memory phenomena to explain and consequently insight into a wider range of memory principles or a deeper understanding of the ones we already accept (e.g. the role of repetition, encoding specificity), including their functional significance for human behavior.(ABSTRACT TRUNCATED AT 400 WORDS)

Affect

Alcohol-related efficiency deficits using an ecologically valid test.

This study investigated whether male and female alcoholics and controls differed in their ability to solve an ecologically valid measure of abstraction. Ninety-one alcoholics (39 females, 52 males) and 61 community controls (36 females, 26 males) completed a battery of abstraction tasks including a Piagetian-type task, the Plant Task. The Plant Task demands that subjects predict the outcome of an unseen plant given a specific treatment regime. No group differences in the ability to correctly predict the unseen plant's outcome were obtained. Alcoholics were significantly poorer than controls in isolating the relevant variable (chi 2 (1) = 8.24, p = 0.004). There were no sex differences in the ability to isolate the relevant variable. However, there was a sex effect in the number of irrelevant explanations (chi 2 (3) = 15.58, p = 0.001) with females producing more than males and female alcoholics more than any of the other three cells. These data suggest that (1) alcoholics may exhibit subtle abstraction deficits most readily observed in tasks examining process as opposed to final performance, (2) males and females differ in their response patterns regarding irrelevant material, and (3) further empirical study of the Plant Task may support its use in experimental and clinical settings.

Adult

Regional cerebral blood flow correlates of language processes in reading disability.

This series of studies tests the hypothesis of abnormal left hemisphere activation in reading-disabled subjects during language task performance. First, a left superotemporal focus of activation, as measured by regional cerebral blood flow, was found to be positively correlated with task accuracy in a group of 69 normal adults. Next, that left superotemporal activation was replicated in a second group of 83 adults whose childhood reading ability was known from standardized tests given in childhood. Finally, in that latter group, childhood reading ability was also found to be inversely correlated with focal activation in a more posterior, temporoparietal area of cortex. Adult reading outcome was statistically unrelated to this finding. The results are interpreted as suggesting a trait anomaly of left hemisphere cerebral activation in adults who were dyslexic as children and as providing an existence proof of individual differences in focal cortical activation sites during constant task demands.

Adolescent

Valine, isoleucine, and leucine. A new treatment for phenylketonuria.

Early treatment of phenylketonuria by dietary phenylalanine restriction prevents brain damage. Behavioral and cognitive deficits occur when serum phenylalanine levels increase. Administration of valine, isoleucine, and leucine to patients with phenylketonuria may inhibit entry of phenylalanine into the brain and reduce its toxic effects on the central nervous system. Sixteen adolescents and young adults with phenylketonuria participated in double-blind trials in which a valine, isoleucine, and leucine mixture or a control mixture was given for four 3-month periods. Biochemical and neuropsychologic tests were carried out before and at the end of each period. Time to completion of a test that required substantial attention with mental processing (Attention Diagnostic Method) was faster during the valine, isoleucine, and leucine periods than during the control mixture periods. Improvement with valine, isoleucine, and leucine on a less demanding task (Continuous Performance Test) approached significance. These data lent support to the hypothesis that a regimen of valine, isoleucine, and leucine may help individuals unable to maintain low serum phenylalanine levels.

Adolescent

P3 in schizophrenia is affected by stimulus modality, response requirements, medication status, and negative symptoms.

Eighteen schizophrenics who were not taking medication, 13 schizophrenics who were taking medication, and 37 age-matched controls were tested with event-related potential paradigms designed to elicit P3 response automatically or effortfully (ie, with a choice reaction time task). Electroencephalograms were recorded from the 19 standard 10-20 electrode sites. Compared with controls, both groups of schizophrenics had reduced P3 amplitudes for both effortful and automatic paradigms. P3 latencies were delayed relative to controls for the medication-taking schizophrenics in the effortful paradigms. Negative symptoms derived from the Brief Psychiatric Rating Scale within 1 week of event-related potential testing correlated negatively with both auditory and visual P3 amplitude in the subjects who were not taking medication. There was no evidence that P3 is smaller over left temporal electrode sites in schizophrenics, as has been reported by others. P3 amplitude reduction in schizophrenia is a robust psychobiological phenomenon that is present regardless of medication status or task demands.

Adult

A tactile maze test in unilateral spatial neglect: the influence of vision and recording technique.

Right brain-damaged patients with left spatial neglect were examined on a tactile maze task. They started to explore the right side of the maze and their search times were longer on the left side. Their performance was the same whether blindfolded or not, which contrasts with the results of other studies and probably reflects differences in task demand. The present results do not support a previous observation that visual neglect can be compensated through the tactile modality. Our patients had markedly longer search times than normal controls in the right as well as the left hemifield, and search times in both hemifields were positively correlated. The outcome of the maze test in this context may therefore depend to a large extent on impaired topographical processing.

Adult

Social communication patterns of attention-deficit-disordered boys.

This study was designed to compare the social communication patterns of attention-deficit-disordered (ADD) and normal boys. This was accomplished by employing a "TV Talk Show" social role-playing procedure in which the task required different strategies for the roles of "host" and "guest." Groups of ADD and normal elementary-age boys were formed, and each boy was paired with a normal class-mate. Measures of communication competence were coded from videotapes made of subject and partner social interactions while performing both roles. Results indicated that the ADD boys, in contrast to the control group, failed to modulate their social communication behaviors as task demands shifted. Additionally, the behavior of the ADD boys resulted in their normal partners' altering their response patterns in order to maintain the equilibrium in the dyadic interaction. These results suggest that the social behavior of ADD children is relatively independent of environmental requirements and may contribute to the inappropriate responding of others.

Attention Deficit Disorder with Hyperactivity

The effects of methylphenidate on levels of processing and laterality in children with attention deficit disorder.

Effects of stimulant medication (methylphenidate) on levels (feature, name, semantic) of word processing by the left and right hemisphere were assessed in 31 attention-deficit-disordered children. In a double-blind procedure, same-different decisions were made to tachistoscopically presented word pairs under medication and placebo. Analysis of manual response times failed to show any negative effects of medication. Feature decisions were faster than name decisions, which were faster than semantic decisions. Methylphenidate induced a right visual field advantage (left hemisphere) for the name decision, which was interpreted as a normalization effect. The results suggest that (1) methylphenidate may selectively improve the phonological level of word processing and (2) methylphenidate's favorable therapeutic effect is produced through inhibition of excessive right hemisphere activity in response to task demands that engage the left hemisphere.

Adolescent

Behavioral microanalysis of spatial delayed alternation performance: rehearsal through overt behavior, and effects of scopolamine and chlordiazepoxide.

Rats were trained in an operant spatial delayed alternation task utilizing retention intervals from 2 to 32 s. In addition to response accuracy, operations of the levers during the retention intervals were recorded and analyzed. Animals were tested following the administration of the muscarinic antagonists scopolamine hydrobromide and methylbromide, and the benzodiazepine receptor agonist chlordiazepoxide. In vehicle-treated animals, the relative number of correct responses and correct rehearsal operations (operation of the forthcoming correct lever during retention intervals) varied with the length of the retention intervals, and these measures were correlated. The response rate for rehearsal operations increased with the length of the retention intervals. It is speculated that the delay-dependent increase in response rate reflects an effect of delayed reward that was also associated with a delay-dependent increase in the tendency to alternate between levers. The effects of delay on the accuracy of rehearsal operations may have contributed to the delay-dependent correct responding. Scopolamine hydrobromide (0.01, 0.03, 0.1, 0.3 mg/kg) and methylbromide (0.1, 0.3 mg/kg) impaired correct responding, but did not seem to interfere with the relative number of correct rehearsal operations. As only the presentation of the panel light indicated trial onset, it is speculated that the cholinergic receptor blockade resulted in an increase in the probability of a repositioning response that was triggered by light onset. Chlordiazepoxide (1, 3, 5, 10 mg/kg) did not affect behavioral performance. These results suggest that in tasks that allow the development of rehearsal operations, delay-dependent response accuracy does not represent a sufficient condition for conclusions on task demands on memory.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Expert control of the arterial blood pressure during surgery.

During and after many surgical procedures the patient's arterial blood pressure must be artificially decreased to a lower than normal level. Although there are alternatives, infusion of the drug sodium nitroprusside (SNP) is frequently the preferred technique to achieve this controlled hypotension. The fast action of the drug and the danger of a too low pressure make manual control of the SNP infusion flow rate, even if done by an expert, a difficult and demanding task. This is mainly due to an occasional large unpredictable variability over time of the patient's sensitivity to SNP, and to the fact that a multitude of other factors also influence the arterial pressure. Due to these and several other causes, current automatic controllers cannot handle all cases equally well. A new expert system based SNP controller was designed to perform well for all patients, regardless of their characteristics. It monitors and adjusts its own performance, employing a number of heuristics derived from a careful study of the properties of the arterial pressure signal, the effects of SNP and other clinical provocations on the arterial pressure, and the ways in which expert clinicians manually manage the SNP infusion. Expert systems technology allows the new controller to access and employ this type of expert medical knowledge, resulting in expert-level performance. The controller was tested on 30 patients undergoing cardiac surgery, both before, during and after bypass. It was safe, needed little attention, and performed well in all cases.

Animals

Analysis of demand conditions associated with reluctant speech.

An analysis of five demand conditions affecting the reluctant speech of a preschool child was conducted in the classroom. Results indicated that demand conditions that did not permit escape from academic demand tasks, ignored mute responses, prompted answers and enthusiastically praised verbal responses resulted in higher rates of speech. Further, replication of these procedures across escape conditions resulted in increased speech rates that approximated those of a non-mute peer in the same classroom. Follow-up data at 8 months indicated that in the classroom the subject spoke more often to more people using a greater number of words, subsequent to analysis and intervention. The classroom teacher also reported a marked improvement in speech rate and quality and considered the time spent in analysis worthwhile. The study provides a model for further analysis of conditions associated with reluctant speech.

Behavior Therapy

Event-related potentials in drug-naive schizophrenic patients.

Decreased amplitudes of late components of event-related potentials (ERPs) in schizophrenia were ascribed to either psychotic features or to neuroleptic treatment of the patients. To rule out the drug effect, ERPs to stroboscopic stimuli were recorded in drug-naive schizophrenics and control subjects during no-task and simple-task sessions. Patients had significantly lower amplitudes of the late ERP components during both sessions, thus confirming similar results with treated schizophrenics. On the other hand, drug-naive patients did not differ from controls in the task-related relative facilitation of late ERP components. These results differ from findings of minimal ERP facilitation to task in treated schizophrenics. This discrepancy is discussed in the context of the effects of neuroleptic treatment and task demands on ERPs.

Adult

U-shaped learning and frequency effects in a multi-layered perceptron: implications for child language acquisition.

A three-layer back-propagation network is used to implement a pattern association task in which four types of mapping are learned. These mappings, which are considered analogous to those which characterize the relationship between the stem and past tense forms of English verbs, include arbitrary mappings, identity mappings, vowel changes, and additions of a suffix. The degree of correspondence between parallel distributed processing (PDP) models which learn mappings of this sort (e.g., Rumelhart & McClelland, 1986, 1987) and children's acquisition of inflectional morphology has recently been at issue in discussions of the applicability of PDP models to the study of human cognition and language (Pinker & Mehler, 1989; Bever, in press). In this paper, we explore the capacity of a network to learn these types of mappings, focusing on three major issues. First, we compare the performance of a single-layered perceptron similar to the one used by Rumelhart and McClelland with a multi-layered perceptron. The results suggest that it is unlikely that a single-layered perceptron is capable of finding an adequate solution to the problem of mapping stems and past tense forms in input configurations that are sufficiently analogous to English. Second, we explore the input conditions which determine learning in these networks. Several factors that characterize linguistic input are investigated: (a) the nature of the mapping performed by the network (arbitrary, suffixation, identity, and vowel change); (b) the competition effects that arise when the task demands simultaneous learning of distinct mapping types; (c) the role of the type and token frequency of verb stems; and (d) the influence of phonological subregularities in the irregular verbs. Each of these factors is shown to have selective consequences on both successful and erroneous performance in the network. Third, we outline several types of systems which could result in U-shaped acquisition, and discuss the ways in which learning in multi-layered networks can be seen to capture several characteristics of U-shaped learning in children. In general, these models provide information about the role of input in determining the kinds of errors that a network will produce, including the conditions under which rule-like behavior and U-shaped learning will and will not emerge. The results from all simulations are discussed in light of behavioral data on children's acquisition of the past tense and the validity of drawing conclusions about the acquisition of language from models of this sort.

Child, Preschool

Sex differences in the lateralization of language discrimination vs language production.

Two tachistoscopic studies employing normal males and females were done to investigate the inconsistency of obtained sex differences on visual laterality tasks to the extent that this inconsistency is task specific. Type of linguistic task (discrimination vs production) and control of attention were manipulated. Results showed that on language discrimination, the sexes were fairly equally lateralized, while on production tasks, females showed greater laterality differences. The attempt to control for attention resulted in higher field differences, but especially so for females. It is suggested that more consideration of task demands in laterality experiments should help clarify the nature of sex differences in laterality.

Adolescent

Effects of luminance and blur on hemispheric asymmetries in temporal integration.

A task involving temporal integration of form was employed to examine the effects of input characteristics on hemispheric asymmetries. In Experiment 1, decreases in luminance produced greater improvement of right hemisphere (RH) performance. In Experiment 2, dioptric blur produced greater impairment of left hemisphere (LH) performance. The results suggest that spatial frequencies below nine cycles per degree are processed more efficiently in the RH. In Experiment 3, effects of input characteristics on hemispheric asymmetry were found to be dependent on the spatial frequencies required for processing by task demands, as mediated by interflash interval (IFI) duration. Increased blur produced greater impairment of LH performance at short IFI duration; at a longer IFI duration, however, increased blur produced equal impairment of RH and LH performance.

Adult

Behavioral performance effects of nicotine in smokers and nonsmokers.

Performance on finger-tapping and handsteadiness, tasks opposite in response requirements, was compared between male smokers and nonsmokers (n = 10 each) on two occasions, once following intake of nicotine (15 micrograms/kg) by measured-dose nasal spray and once following placebo. Compared with nonsmokers, smokers had significantly greater increase in finger-tapping speed due to nicotine. On the other hand, smokers tended to have improved performance on handsteadiness (i.e., less involuntary movement) due to nicotine, while nonsmokers had impaired performance, although this difference was not significant. Nicotine-induced changes in performance on each task were inversely related, suggesting specificity of the behavioral effects of nicotine depending on task demands, rather than a generalized effect. These effects of nicotine on behavioral performance may be important in understanding the reinforcing value of nicotine intake, and differences in effects as a function of smoking history may suggest chronic adaptation to nicotine.

Adult

The relationship of patient difficulty to therapist performance in interpersonal psychotherapy of depression.

The efficacy of Interpersonal Psychotherapy (IPT) in the treatment of ambulatory major depression was demonstrated in the recently completed NIMH Treatment of Depression Collaborative Research Program (Elkin et al. 1986). Factors which enhance or impede the administration of the treatment delimit effective patient care and should therefore be understood. This report examines the relationship of pretreatment patient attitudes and in-treatment patient difficulty to the ability of therapists to competently conduct IPT, using data from a training program in IPT. The hypothesis was that the patient's ability and willingness to establish a relationship and undertake the task demands of therapy would influence the therapist's ability to administer treatment. Patient difficulty was found to be strongly related to both therapists' and supervisors' judgements of therapist performance during IPT sessions: when patients were more difficult, therapists were judged to have performed more poorly. Patients' preexisting negative expectations about the potential outcome of treatment were associated with patient difficulty and poorer therapist performance, while the level of presenting symptomatology was not. Thus, it appears that the patient's ability to engage in a productive therapeutic relationship rather than the severity of his presenting problems influenced the therapist's ability to competently perform IPT. The findings regarding the relationship of patient difficulty to ratings of therapist performance suggest that patient difficulty should be taken into account in assessing therapist competence, whether for studies of therapeutic efficacy or for clinical supervision and training in general.

Adult