Personality Trait Change Across a Major Global Stressor

The current research examined three related questions in a 21-month longitudinal study of a diverse sample of U.S. participants (N = 504): (a) How did Big Five traits change during the COVID-19 pandemic? (b) What factors were associated with individual differences in trait change? and (c) How was Big Five trait change associated with downstream well-being, mental health, and physical health? On average, across the 21-month study period, conscientiousness increased slightly, and extraversion decreased slightly. Individual trajectories varied around these average trajectories, and although few factors predicted these individual differences, greater increases in conscientiousness, extraversion, and agreeableness, and greater decreases in neuroticism were associated better well-being and fewer mental and physical health symptoms. The present research provides evidence that traits can change in the context of a major global stressor and that socially desirable patterns of trait change are associated with better health.

The relevance of perceived work environment and work activities for personality trajectories in midlife

OBJECTIVES

Work is an important developmental context in adulthood, yet little is known about how it contributes to personality trajectories in midlife. The present study examines how subjectively perceived work environment (autonomy, innovation, social integration, stress) and objectively measured work activities (activities related to information and people, physical/manual activities) are related to levels of Big Five personality traits at age 44 and to change over 20 years.

METHODS

We analyzed four-wave longitudinal data from N = 374 participants (born 1950-1952; Mage T1 = 44 years, SD = 1; 44% women) from the Interdisciplinary Longitudinal Study of Adult Development and Aging (ILSE) within the structural equation modeling framework.

RESULTS

At baseline, subjective perceptions of work environments showed a higher number of significant associations with personality than objective work activities. Over time, small declines in neuroticism and extraversion and small increases in agreeableness and conscientiousness were observed, which were largely independent of work characteristics.

CONCLUSIONS

Our findings show slight changes in most Big Five traits from age 44 to 64, which were mostly unrelated to work characteristics. More research is needed to uncover the sources and dynamics of personality trait change in midlife and the role of work for personality trajectories.

Eco-evolutionary contributions to community trait change in floating aquatic plants

An entire community of organisms may become modified when its environment changes. These modifications can happen through physiological processes (plasticity), evolutionary processes (adaptation) or shifts in species composition (sorting). The outcome of these three sources of change constitutes the community's phenotypic response, but how they combine to drive community trait dynamics is not currently well understood. We have conducted a community selection experiment in which communities of short-lived floating aquatic plants were grown in a range of stressful conditions, and measured changes in their body size. Determinants of phenotypic change were assessed with a full community reciprocal transplant which led to estimates of the contributions of plasticity, adaptation, and sorting. Species were modified during the experiment by both plasticity and adaptation, but in either case the magnitude and direction of change differed among species. Sorting and adaptation were of equal magnitude but tended to act in opposite directions: in conditions where species with large fronds prevailed, each species evolved smaller fronds, and vice versa. We conclude that community trait dynamics cannot be understood simply by extrapolating the adaptive response of any single species to the whole community. This article is protected by copyright. All rights reserved.

Higher fat stores contribute to persistence of little brown bat populations with white-nose syndrome

The persistence of populations declining from novel stressors depends, in part, on their ability to respond by trait change via evolution or plasticity. White-nose syndrome (WNS) has caused rapid declines in several North America bat species by disrupting hibernation behaviour, leading to body fat depletion and starvation. However, some populations of Myotis lucifugus now persist with WNS by unknown mechanisms. We examined whether persistence of M. lucifigus with WNS could be explained by increased body fat in early winter, which would allow bats to tolerate the increased energetic costs associated with WNS. We also investigated whether bats were escaping infection or resistant to infection as an alternative mechanism explaining persistence. We measured body fat in early and late winter during initial WNS invasion and 8 years later at six sites where bats are now persisting. We also measured infection prevalence and intensity in persisting populations. Infection prevalence was not significantly lower than observed in declining populations. However, at two sites, infection loads were lower than observed in declining populations. Body fat in early winter was significantly higher in four of the six persisting populations than during WNS invasion. Physiological models of energy use indicated that these higher fat stores could reduce WNS mortality by 58%-70%. These results suggest that differences in fat storage and infection dynamics have reduced the impacts of WNS in many populations. Increases in body fat provide a potential mechanism for management intervention to help conserve bat populations.

Personality Change at Mid-Life is Associated with Changes in Self-Rated Health: Evidence from the Hawaii Personality and Health Cohort

Personality traits change across the lifespan, and trait change, in addition to trait level, may be related to health. Longitudinal data from the Hawaii Personality and Health Cohort were used to investigate associations between changes in traits and self-rated health (SRH). Participants (N = 733, M_age = 44.4) completed measures of the Big Five personality traits and SRH twice approximately 3 years apart. Personality trait changes were associated with SRH change. Additionally, increases on Agreeableness, Conscientiousness, and Openness, and decreases on Neuroticism, predicted increases in SRH, even when controlling for gender and education. Relating correlated trait change at mid-life, when traits reach peak stability, to a consequential health outcome such as SRH change, demonstrates the value of treating both traits and health indicators as dynamic variables.

Temporal dynamics of inducible anti-herbivory defenses in the brown seaweed Ascophyllum nodosum (Phaeophyceae)(1)

Anti-herbivory defenses support persistence of seaweeds. Little is known, however, about temporal dynamics in the induction of grazer-deterrent seaweed traits. In two induction experiments, consumption rates of the periwinkle Littorina obtusata (L.) on the brown seaweed Ascophyllum nodosum (L.) Le Jolis were measured in 3-d intervals. Changes in palatability of directly grazed A. nodosum were tested every 3 d with feeding assays using fresh and reconstituted seaweed pieces. Likewise, assays with fresh A. nodosum assessed changes in seaweed palatability in response to water-borne cues from nearby grazed conspecifics. Consumption rates of L. obtusata varied significantly during the 27-d induction phase of each experiment. Direct grazing by L. obtusata lowered palatability of fresh and reconstituted A. nodosum pieces to conspecific grazers after 15 d as well as after 6 and 12 d, respectively. After 12, 18, and 24 d, fresh A. nodosum located downstream of L. obtusata-grazed conspecifics was significantly less palatable than A. nodosum located downstream of ungrazed conspecifics. Changes in L. obtusata consumption rates and A. nodosum palatability during both induction experiments suggest temporal variation of grazer-deterrent responses, which may complicate experimental detection of inducible anti-herbivory defenses.

The Relation of Change in Hostility and Sociability During Childhood to Substance Use in Mid Adolescence

In a cohort-sequential longitudinal study (N = 1,075), we related change in children's hostility and sociability assessed from 1(st)-8(th) grade to their use of cigarettes, alcohol, and marijuana assessed from 9(th)-12(th) grade. Children who were more hostile at 1(st) grade, and had higher rates of growth of hostility, used more of all three substances at 9(th) grade, and those with higher initial levels of hostility increased their use of cigarettes and marijuana from 9(th) to 12(th) grade. Children who were more sociable at 1(st) grade used more alcohol at 9(th) grade. These findings demonstrate the significance of individual differences in the development of personality traits for the prediction of later substance use and have implications for prevention.