Sequential Performance in Young and Older Adults: Evidence of Chunking and Inhibition

ABSTRACT

Two experiments were conducted to examine possible sources of age-related decline in sequential performance: age differences in sequence representation, retrieval of sequence elements, and efficiency of inhibitory processes. Healthy young and older participants learned a sequence of eight animal drawings in fixed order, then monitored for these targets within trials of mis-ordered stimuli, responding only when targets were shown in the correct order. Responses were slower for odd numbered targets, suggesting that participants spontaneously organized the sequence in two-element chunks. Perseverations (responses to previously relevant targets) served as an index of inhibitory inefficiency. Efficiency of chunk retrieval and self-inhibition were lower for older than for younger adults. Increasing environmental support in Experiment 2 through overt articulation of current chunk elements showed a pattern of results similar to Experiment 1, with particular benefit for older adults. The findings suggest an underlying susceptibility to interference in old age.     

Adult age differences in subjective and objective measures of strategy use on a sequentially cued prediction task

Differences in strategy use are thought to underlie age-related performance deficits on many learning and decision-making tasks. Recently, age-related differences in learning to make predictions were reported on the Triplets Prediction Task (TPT). Notably, deficits appeared early in training and continued with experience. To assess if age differences were due to early strategy use, neural networks were used to objectively assess the strategies implemented by participants during Session 1. Then, the relationship between these strategies and performance was examined. Results revealed that older adults were more likely to implement a disadvantageous strategy early in learning, and this led to poorer task performance. Importantly, the relationship between age and task performance was partially mediated by early strategy use, suggesting that early strategy selection played a role in the lower quality of predictions in older adults.     

Work stress,work–home interference and perceptions of organisational culture amongst insurance employees in Zimbabwe

The objective of the study was to determine the relationship between work stress, work-home interference, and perceptions of organisational culture amongst insurance employees in the Zimbabwean context. Data were collected from a sample of 190 employees (females=46%) who completed the Occupational Stress Inventory-Revised (OSI-R), the Work-Home Interference Questionnaire (SWING), and the Organisational Culture Index (OCI). Data analysis consisted of correlational and standard multiple regression analyses. The results revealed significant positive correlations between the sub-scales Role Overload, Role Insufficiency, Role Ambiguity, Role Boundary, Responsibilities, and Physical Environment of the OSI-R, the sub-scales Positive Work-Home Interference and Negative Work-Home Interference of the SWING, and the sub-scales Bureaucratic, Innovative and Supportive Culture of the OCI. These findings contribute to new knowledge in terms of the work stress experienced by insurance employees who are always under continuous pressure from the industry. Furthermore, it could be used to gain insight to enhance the work-life balance of insurance employees and the effect of organisational culture as perceived by insurance employees.     

Body size and body esteem in women: The mediating role of possible self expectancy

We predicted that an expectancy of acquiring a feared fat self and an expectancy of acquiring a hoped-for thin self both mediate the impact of body size on women's body esteem. We also predicted that the mediating pathway through the feared fat self would be stronger than that through the hoped-for thin self. A community sample of 251 women reported their age, height, weight, and completed measures of body esteem and expectancy perceptions of acquiring the feared fat and hoped-for thin selves. Bayesian Structural Equation Modeling (SEM) demonstrated that expectancies about the feared fat self and about the hoped-for thin self mediated the relationship between body size and body esteem. Bayesian SEM also revealed that the pathway through the feared fat self was stronger than that through the hoped-for thin self. Implications for future research and the development of eating pathology are discussed.     

Umgang mit gefährlichen Straftätern in England und Wales

Forensic psychiatric institutions exist in all western European countries. Their organisation depends on a number of factors including the legal framework and societal attitudes towards mentally disordered offenders. This article describes and critically comments on the forensic psychiatric system in England and Wales, its legal framework and approaches to dealing with dangerous offenders. England and Wales have a long forensic psychiatric tradition with the first high security hospital, Broadmoor hospital, having been established in 1863. Evidence-based treatment approaches in forensic hospitals as well as in prisons, training of forensic psychiatrists and research in the field of forensic psychiatry have gained international recognition. However, there are some worrying aspects in the system of forensic psychiatric care and the criminal justice system more generally, in particular the high and still increasing number of prisoners in comparison with other European countries, the low age of criminal responsibility, long sentences, increasing length of stay in forensic care and the increasingly risk averse culture. A number of differences to the German system can be found; one such difference relates to the role of criminal responsibility which is irrelevant for decisions regarding commitment in England and Wales. Only the mental state and need for treatment at the time of trial (or later assessment in prison) determine whether an offender is admitted to psychiatric care or receives a prison sentence. A number of new initiatives have been launched in recent years resulting in an increasing number of individuals being detained in forensic psychiatric and criminal justice institutions, in particular the initiative for the detention and treatment of individuals with so-called dangerous and severe personality disorders, the sexual offenders register and the new sentence of indeterminate imprisonment for public protection. These initiatives have been the subject of a number of complaints to the European Court of Human Rights. Nevertheless, the trend towards a more and more risk averse culture continues.     

Intracerebroventricular effects of angiotensin II on a step-through passive avoidance task in rats

A wealth of evidence indicates that angiotensin II (Ang II) is involved in learning and memory. However, the precise role of this peptide in these cognitive processes is still controversial, with data indicating either an inhibitory or an enhancing action. The present study was designed to further investigate the effects of intracerebroventricular injections of Ang II (0.5, 1 or 3nmol/5microl) on a step-through passive avoidance task in male adult Wistar rats. When administered pretraining, Ang II did not affect the acquisition of passive avoidance, but markedly improved avoidance performance when given before the retrieval test. The latter effect was observed in retest sessions performed up to 72h after training. Administration of the peptide five minutes after training impaired retention of inhibitory avoidance. Therefore, Ang II may exert opposite effects on passive avoidance memory according to its interference with brain mechanisms leading to the storage or retrieval of this aversively motivated task.     

Electroencephalographic registration of low concentrations of isoamyl acetate

Previous research has demonstrated electroencephalogram (EEG) changes in response to low-odor concentrations, resulting in near-chance detection. Such findings have been taken as evidence for olfaction without awareness. We replicated and extended previous work by examining EEG responses to water-water control, 0.0001, 0. 001, 0.01, and 1 ppm isoamyl acetate (IAA) in water paired with water only. Detection was above chance (>50%) for.001 and above, and alpha decreased only to those concentrations, suggesting that EEG changes corresponded to IAA awareness. However, when correct trial EEGs were compared to incorrect trial EEGs during.001 ppm, right posterior/central alpha decreased during incorrect trials and alpha decreased more globally (including frontal sites) during correct trials. These data may not reflect awareness or unawareness per se. Instead, results are discussed regarding activation of perceptual systems in the posterior region during incorrect trials and the activation of frontal action systems during a subset of correct trials.     

Visual awareness due to neuronal activities in subcortical structures: a proposal

It has been shown that visual awareness in the blind hemifield of hemianopic cats that have undergone unilateral ablations of visual cortex can be restored by sectioning the commissure of the superior colliculus or by destroying a portion of the substantia nigra contralateral to the cortical lesion (the Sprague effect). We propose that the visual awareness that is recovered is due to synchronized oscillatory activities in the superior colliculus ipsilateral to the cortical lesion. These oscillatory activities are normally partially suppressed by the inhibitory, GABAergic contralateral nigrotectal projection, and the destruction of the substantia nigra, or the sectioning of the collicular commissure, disinhibits the collicular neurons, causing an increase in the extent of oscillatory activity and/or synchronization between activities at different sites. This increase in the oscillatory and synchronized character is sufficient for the activities to give rise to visual awareness. We argue that in rodents and lower vertebrates, normal visual awareness is partly due to synchronized oscillatory activities in the optic tectum and partly due to similar activities in visual cortex. It is only in carnivores and primates that visual awareness is wholly due to cortical activities. Based on von Baerian recapitulation theory, we propose that, even in humans, there is a period in early infancy when visual awareness is partially due to activities in the superior colliculus, but that this awareness gradually disappears as the nigrotectal projection matures.     

Achieving congruence between employee interests and county jobs: a win‐win proposition

Assisting employees to explore internal job switches rather than leaving an organization is a positive measure aimed at enhancing employee retention and job satisfaction. This article describes how a municipal county government used J. L. Holland's (1992) occupational classification system to help employees achieve congruence between their interests and their job requirements.     

Culture,gender and self–close‐other(s) connectedness in Canadian and Chinese samples

Founded upon the theories of Independent–Interdependent Self‐Construal and I–C, the main goal of this study was to test, via an adapted IOS Scale, whether Anglo‐Canadians were more independent than Mainland Chinese in construing their relationship with family members and friends. Strong cultural differences were found in self–family connectedness, but not in self–friends connectedness. Chinese were closer to their family members than Canadians, but Canadians were as close to their friends as Chinese. In both samples, gender difference was found in self–friends connectedness, but not in self–family connectedness. In the Canadian sample, females were closer to their friends than males, while in the Chinese sample, males were closer to their friends than females. In conclusion, this study contributes to the field in three ways. First, the finding that Canadians are as connected as Chinese to their close friends unprecedentedly contests one fundamental assumption of the theories of independent‐interdependent self‐construal (Markus & Kitayama, 1991 ) and I–C (Hofstede, 1980 ; Triandis, Bontempo, Villareal, Asia & Lucca, 1988 ) that individualists (e.g. Anglo‐Canadians) are more independent than collectivists (e.g. Chinese) on all dimensions of human relations. Second, the proposition (Cross & Madson, 1997 ) that Western males and females differ in the same way individualists and collectivists differ in their self‐construal is not supported. Finally, the adaptation of the IOS Scale proposes a refreshing direction in cross‐cultural research. Graphic representations may be less susceptible to cross‐cultural misconstrual than verbal statements since the former involves little or no translation from one language to another. Copyright © 2002 John Wiley & Sons, Ltd.