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First published online: January 2020 Growth models (GM) of the mixed-effects and latent curve varieties have become popular methodological tools in lifespan research. One of the major advantages of GM is their flexibility in studying individual differences in change. We scrutinized the change functions of GM used in five years of publications on cognitive aging. Of the 162 publications that we identified, 88% test linear or quadratic polynomials, and fewer than 5% apply functions that are nonlinear in their parameters, such as exponential decline. This apparent bias in favor of polynomial decomposition calls for exploring what conclusions about individual differences in change are likely to be drawn if one applies linear or quadratic GMs to data simulated under a conceptually and empirically plausible model of exponential cognitive decline from adulthood to old age. Hence, we set up a simulation that manipulated the rate of exponential decline, measurement reliability, number of occasions, interval width, and sample size. True rate of decline and interval width influenced results strongly, number of occasions and measurement reliability exerted a moderate effect, and the effects of sample size appeared relatively minor. Critically, our results show that fit statistics generally do not differentiate misspecified linear or quadratic models from the true exponential model. Moreover, power to detect variance in change for the linear and quadratic GMs is low, and estimates of individual differences in level and change can be highly biased by model misspecification. We encourage researchers to also consider plausible nonlinear change functions when studying behavioral development across the lifespan.

Poor subjective health has been associated with higher levels of inflammatory cytokines. We investigated whether such an association would apply to women of the general population. Levels of cytokines, affect and subjective health were assessed in 347 women of the general population aged 45 to 90 years. Higher levels of interleukin-6 were associated with poor subjective health, especially in participants over 65 years of age. Positive affect was a more robust determinant of subjective health than negative affect. The presence of low-grade inflammation and absence of positive affect, rather than presence of negative affect, may be important determinants of subjective health.

Rationale: To allow for interdisciplinary research on the relations between socioeconomic conditions and health in the ageing population, a new anonymized longitudinal database — the Linnaeus Database — has been developed at the Centre for Population Studies at Umeå University. This paper presents the database and its research potential. Design: Using the Swedish personal numbers the researchers have, in collaboration with Statistics Sweden and the National Board for Health and Welfare, linked individual records from Swedish register data on death causes, hospitalization and various socioeconomic conditions with two databases — Betula and VIP (Västerbottens Intervention Programme) — previously developed by the researchers at Umeå University. Whereas Betula includes rich information about e.g. cognitive functions, VIP contains information about e.g. lifestyle and health indicators. Population and sample size: The Linnaeus Database includes annually updated socioeconomic information from Statistics Sweden registers for all registered residents of Sweden for the period 1990 to 2006, in total 12,066,478. The information from the Betula includes 4,500 participants from the city of Umeå and VIP includes data for almost 90,000 participants. Both datasets include cross-sectional as well as longitudinal information. Potential: Due to the coverage and rich information, the Linnaeus Database allows for a variety of longitudinal studies on the relations between, for instance, socioeconomic conditions, health, lifestyle, cognition, family networks, migration and working conditions in ageing cohorts. Conclusions: By joining various datasets developed in different disciplinary traditions new possibilities for interdisciplinary research on ageing emerge.

Two experiments are reported which demonstrate the typical finding of better performance on responses given positive outcomes as compared to performance on responses given negative and neutral outcomes. These effects of reinforcement are studied in more detail in the context of storage and retrieval processes. “Right” or “wrong” and monetary gain or loss were used as outcomes in the experiments. Both these types of outcome were found to have similar effects on storage, while the former tended to affect retrieval more than the latter outcomes did. The results clearly reject the notion that an outcome is stored along with the response to facilitate retrieval. A prerequisite for such a facilitation is a presentation of cues for retrieval at the time of test.

Five experiments investigated the extent to which the exteroceptive context, present on a saccharin aversion conditioning trial with rats, controlled the resulting aversion on one-bottle extinction tests and subsequent preference tests. The presence or absence of the specific odour which had been present on the conditioning trial was found not to influence saccharin intake on extinction tests, whereas the presence of the particular compartment in which, and the bottle from which, the saccharin had been consumed greatly suppressed saccharin intake as compared to the absence of these elements. Preference tests, performed in the respective conditioning contexts, showed extinction to be specific to the compartment + bottle context: groups that had extinguished their saccharin aversion in a context different from the conditioning context, retained their aversion in the conditioning context. No such specificity was found for the odour context. However, in the absence of the taste stimulus during the extinction phase, the odour that had been present on the conditioning trial did control the amount of water consumed, whereas the compartment+bottle context did not. Moreover, on preference tests, groups that had consumed water during extinction in the presence of the odour context, evidenced a lesser saccharin aversion than groups not exposed to the odour. The results are interpreted as demonstrating that rats learn about taste, odour, cage and bottle stimuli on a taste-aversion conditioning trial, and that taste and bottle stimuli seem to be the most salient.