Research into smoking or nicotine and human cognitive performance: does the source of funding make a difference?

AIMS: To establish whether there is a relationship between tobacco industry support of basic research and the conclusions drawn by the authors of that research. DESIGN: A sample of 91 papers investigating the effects of tobacco or nicotine use upon cognitive performance was analyzed to see if the pattern of conclusions drawn by researchers acknowledging tobacco industry support differed from the pattern of conclusions drawn by researchers not acknowledging tobacco industry support. FINDINGS: Scientists acknowledging tobacco industry support reported typically that nicotine or smoking improved cognitive performance while researchers not reporting the financial support of the tobacco industry were more nearly split on their conclusions. CONCLUSIONS: While it is only possible to speculate on the possible reasons, the existence of a possible bias in the published literature according to funding source must be given serious consideration.

Cigarette smoking and cognitive performance.

While some investigations into the relationship between smoking and cognitive performance have reported that smoking facilitates performance, other research has come to the opposite conclusion. A review of the literature suggests that this variance in results may be due to differences among studies in design (comparing smokers only with deprived smokers rather than with non-smokers) and also to differences in task demands. Therefore, performance of smokers having just smoked, matched smokers deprived for a brief period, and also non-smokers was contrasted on a series of tasks which ranged from repetitive and perceptually-bound tasks to complex, dynamic tasks dependent upon long-term memory. It was found that while cigarette smoking had no negative effect upon performance for simple perceptual tasks, smoking was found to exert measurable negative effects upon performance for more complex information processing tasks.

Implications of cognitive change for gerontological pedagogical practice.

The focus of this paper is the problem of designing educational systems for the aged so as to maximize their potential for success. Relevant geropsychological literature is briefly summarized. It is proposed that complex changes in working memory occur with advanced age; and that by understanding the nature of these changes, educational materials can be designed which properly bring to the fore concepts, refresh memory, and guide the comprehension process. In this way, the aged are more likely to maintain their performance and to acquire new skills, to the benefit of society.

Contextual effects upon text memory for young, aged-normal, and aged memory-impaired individuals.

The purpose of the study was to assess contextual effects upon text memory for young, aged-normal, and aged memory-impaired individuals. Subjects read short passages which differed in their contextual relatedness to target sentences, and then recalled those target sentences. It was found that large differences distinguished the performance of the young from the elderly on the free recall task; that cueing aided the performance of the young and the elderly-normal more than the aged-impaired; and lastly, that no differences were found in recognition performance between young and aged normals whereas the performance of the aged-impaireds was significantly poorer than either the young or the aged-normal group. The results were interpreted in light of two hypothetical mechanisms; the first is labeled "normal" aging and the second, "pathological" aging.

Contextual effects upon text memory for young, aged-normal, and aged memory-impaired individuals.

The purpose of the study was to assess contextual effects upon text memory for young, aged-normal, and aged memory-impaired individuals. Subjects read short passages which differed in their contextual relatedness to target sentences, and then recalled those target sentences. It was found that large differences distinguished the performance of the young from the elderly on the free recall task; that cueing aided the performance of the young and the elderly-normal more than the aged-impaired; and lastly, that no differences were found in recognition performance between young and aged normals whereas the performance of the aged-impaireds was significantly poorer than either the young or the aged-normal group. The results were interpreted in light of two hypothetical mechanisms; the first is labeled "normal" aging and the second, "pathological" aging.

Some important methodological issues in the study of aging and cognition.

Despite extensive geropsychological research into cognitive change with advanced age, there is conflicting evidence regarding the nature of this change and even well developed arguments that no decrement with advanced age exists. A review of the field suggests that researchers have neglected certain important parameters which might greatly affect results Specifically, the following topics are examined: (1) determination as to what constitutes "young" and "old", (2) the source of the subjects in aging research, (3) methods of matching subject groups and (4) considerations of group heterogeneity. It was concluded that these issues are often confounded within research designs, that controlling them would help clarify theoretical issues, and that these parameters, when controlled, are themselves worthy of interest.