Relations between source amnesia and frontal lobe functioning in older adults

A study is reported in which the relations among normal aging, source amnesia, and frontal lobe functioning were explored. Twenty-four older adults (aged 60-84 years) were tested on their ability to remember where they had acquired new factual information; they were also given the Wisconsin Card Sorting Test (WCST), a test of verbal fluency, and other psychometric tests. The degree of source amnesia in this normal sample correlated with age, verbal fluency, and some measures from the WCST. Source amnesia was not related to Performance IQ, however, or to a measure of fact recall. The implications for the relations among aging, memory, and frontal lobe functions are discussed.     

An experimental approach to the design of cartographic symbols

Graphic designers and an experimental psychologist worked together to improve the design of two map symbols which are frequently confused: the symbols for cuttings and embankments on topographic maps. The problem was analysed in terms of the function of the symbols and their likely cognitive representations. Tests were developed to evaluate alternative designs, including an intervisibility task which requirred users to visualize the landform from the symbols viewed in the context of a map. Tests were given to schoolchildren and to experienced map users in order to compare the standard symbols with five alternative designs. Children's performance was strongly affected by the symbols they used, but experienced users were much less affected. After some refinement of the symbols a further experiment demonstrated the superiority of a number of alternative designs over the existing symbols on a range of test: scores were almost double on the intervisibility task. The paper makes recommendations to cartographers and argues for greater consideration of the inexperienced map user in the design process.     

Critical flicker fusion in normal elderly subjects; a cross-sectional community study

Critical Flicker Fusion Thresholds (CFFTs) were measured in 644 elderly people identified from community-based general practice records, and the relationship of CFFT with age was investigated. The CFFT was measured using the method of limits with mean scores for three ascending (flicker/fusion) and three descending (fusion/flicker) presentations being recorded. The difference between the ascending and descending means was found to be significantly correlated with age (r=−0.131,P<0.001) and may reflect a reduced sensitivity of the Central Nervous System to suprathreshold flicker with increasing age. The results suggest that CFFT measurement has an important role to play in gerontological research as an objective measure of cognitive aspects of the ageing process.     

Agricultural policy and strategic investment in information technology

In this article the perspective shifts to the “upstream” end of the agricultural knowledge and information system (AKIS). Because knowledge policy and strategic decision-making are not the prerogative of the public sector, organizations such as cooperative unions and multinational companies are included. After considering the influence of the changing environment on the nature of the AKIS, the role of knowledge management and policy in the emerging knowledge and information market is examined. Special attention is given to public and private R&D. The article then looks where information technology (IT) fits in and what considerations determine strategic investment in IT projects and sustained services. Some of the European experiences with this strategic investment are evaluated.     

Simple knowledge structures for perceptual classification expert systems

A new approach is described for the development and structure of perceptual knowledge-based systems. This systematic method for acquiring perceptual knowledge for use in knowledge-based systems and for representing perceptual knowledge within the systems has revealed that two broad classes of perceptual activity can each be characterized by a single logical operator. The number of rules necessary to accomplish particular perceptual tasks can also be estimated.     

CONVERGING METHODS FOR INVESTIGATING LEXICAL ACCESS

Abstract— In our discussion of the articles in this Special Section, we ask how well the various methods employed in these investigations can be made to converge on a common issue. We review how current evidence from positron emission tomography, studies of event-related potentials, cognitive methods, lesion studies, and network models relates to the mental processing of an ambiguous word. While many puzzles remain, we are impressed by the promising possibility of bringing these different methods together to deal with an issue central to cognition.     

HIV Disease: Current Concepts

The human immunodeficiency virus (HIV) causes a chronic, progressive, immune deficiency disease, the most severe phase of which is Acquired Immune Deficiency Syndrome (AIDS). HIV is a newly characterized human retrovirus transmitted only by direct exposure to blood or blood derivatives, certain acts of sexual intercourse, or transfer from infected mother to fetus or infant. In this article the author reviews the most important current epidemiologic, clinical, and virologic information about HIV and HIV disease and provides a factual framework for understanding the issues created by the epidemic.