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Biomedical subjects

M J Naus

Publications and source records attributed to M J Naus.

6 recordsLinked to original sources
PubMed1996

Cognitive correlates of long-term cannabis use in Costa Rican men.

BACKGROUND: Cognitive correlates of long-term cannabis use have been elusive. We tested the hypothesis that long-term cannabis use is associated with deficits in short term memory, working memory, and attention in a literate, westernized culture (Costa Rica) in which the effects of cannabis use can be isolated. METHODS: Two cohorts of long-term cannabis users and nonusers were studied. Within each cohort, users and nonusers were comparable in age and socioeconomic status. Polydrug users and users who tested positive for the use of cannabis at the time of cognitive assessment after a 72-hour abstention period were excluded. The older cohort (whose age was approximately 45 years) had consumed cannabis for an average of 34 years, and comprised 17 users and 30 nonusers, who had been recruited in San José, Costa Rica, and had been observed since 1973. The younger cohort (whose age was approximately 28 years) had consumed cannabis for an average of 8 years, and comprised 37 users and 49 nonusers. Short-term memory, working memory, and attentional skills were measured in each subject. RESULTS: Older long-term users performed worse than older nonusers on 2 short-term memory tests involving learning lists of words. In addition, older long-term users performed worse than older nonusers on selective and divided attention tasks associated with working memory. No notable differences were apparent between younger users and nonusers. CONCLUSION: Long-term cannabis use was associated with disruption of short-term memory, working memory, and attentional skills in older long-term cannabis users.

Adult↗
PubMed1985

Effects of the knowledge base on children's memory strategies.

In this article, the importance of examining the linkage between knowledge and strategic factors in children's memory has been suggested. Indeed, it has been argued that a more complete analysis of the development of remembering in children requires a consideration of the operation of memory strategies in the context of the growing knowledge base. The effects of the knowledge base were analyzed in terms of concurrent influences on the use of strategies and long-term consequences for the development of increasingly skilled memory processing. The available evidence suggests that age-related changes in the contents of the knowledge system, as well as increases in the ease with which information can be accessed, contribute to the strategies that are used by children of different ages, and influence the development of efficient modes of processing. Continued research on the concurrent effects of the knowledge base should provide a more complete account of children's memory than that currently available, taking into consideration knowledge of the materials, understanding of the task demands, as well as overall strategic abilities. Similarly, research on the long-term developmental effects of the knowledge base on memory strategies should facilitate an understanding of the mechanisms by which memory processing becomes more efficient and less effortful. Ideally, studies that examine these issues should be longitudinal in scope (Ornstein et al., 1985a), but even cross-sectional research that explores the interrelationships between strategies and knowledge will facilitate an understanding of the development of memory in children.

Adolescent↗
PubMed1976

Why a Y is not a V: a new look at the distinctive features of letters.

Although a feature detection theory of pattern recognition is consistent with many recent physiological and psychological findings, the specific rules governing the perception of the distinctive features of letters have not yet been determined. This article presente two new experimental procedures for determining these rules. Both procedures are demonstrated by the investigation of the specific rule involved in the perception of the letter attribute leg which distinguishes Y from V, F from C, and H from U. Whereas previous methods investigating the distinctive features of letters have focused primarily on archetypal letter forms, the present methods are based upon an investigation of ambiguous characters, those characters which can be assigned either of two letter labels with equal probability. One of these procedures allows for the investigation of these rules without the influence of external context, whereas the other allows for an investigation of the particular effects that external context can have on these rules.

Discrimination, Psychological↗