Within-individual Changes Research Articles

Reciprocal relation between authenticity and calling among Chinese university students: A latent change score approach

It is common to hear that following one's “true self” is an important means to find a calling, yet research has not directly examined this possibility. In this study, we investigate the change pattern between authenticity and calling. Specifically, we conducted a three-wave longitudinal study with 459 Chinese university students over one year and examined the reciprocal dynamic relation between authenticity (i.e., authentic living, self-alienation, and accepting external influence) and calling. Results of a bivariate latent change score model examining within-individual changes over time showed that increases in authentic living were positively correlated with increases in calling, while increases in self-alienation and accepting external influence negatively correlated with increases in calling. We also found that higher levels of authentic living significantly predicted an increase in calling over time. However, higher levels of calling predicted a decrease in authentic living. Our findings contribute to the literature on calling by suggesting a dynamic change pattern of authenticity and calling among Chinese university students.

Declining home range area predicts reduced late-life survival in two wild ungulate populations.

Demographic senescence is increasingly recognised as an important force shaping the dynamics of wild vertebrate populations. However, our understanding of the processes that underpin these declines in survival and fertility in old age remains limited. Evidence for age-related changes in foraging behaviour and habitat use is emerging from wild vertebrate studies, but the extent to which these are driven by within-individual changes, and the consequences for fitness, remain unclear. Using longitudinal census observations collected over four decades from two long-term individual-based studies of unmanaged ungulates, we demonstrate consistent within-individual declines in home range area with age in adult females. In both systems, we found that within-individual decreases in home range area were associated with increased risk of mortality the following year. Our results provide the first evidence from the wild that age-related changes in space use are predictive of adult mortality.

An Examination of Parental and Peer Influence on Substance Use and Criminal Offending During the Transition from Adolescence to Adulthood.

Although peer behavior and parent-child-conflict have been associated with adolescent and young adults' behavior, prior studies have not adequately controlled for selection effects and other confounders, or examined whether associations change across the transition to adulthood or by race. Using annual data from young men followed from 17-26, within-individual change models examined whether substance use or offending increased in the year after boys began affiliating with friends who engaged in substance use/offending and/or experienced increased parent-son-conflict. Moderation analyses tested whether associations varied by age or race. Alcohol use, marijuana use, and offending (Black participants only) increased in the year after boys began affiliating with more peers who engaged in similar behaviors. Associations were strongest during adolescence for substance use. Parent-son conflict was not associated with the outcomes. Findings underscore the importance of developmental and racialized differences in understanding the role of social influences on young men's substance use and offending.

Association of changes in work shifts and shift intensity with change in fatigue and disturbed sleep: a within-subject study.

Objectives The aim of this study was to examine whether changes in work shifts and shift intensity are related to changes in difficulties to fall asleep, fatigue, and sleep length. Methods Questionnaire responses of hospital employees (N=7727, 93% women) in 2008, 2012, 2014 and 2015 were linked to daily-based records of working hours during three months preceding each survey. We used conditional logistic regression and longitudinal fixed-effects analyses to investigate odds ratios (OR) and 95% confidence intervals (CI) for each 25% within-individual change in the proportion of working hour characteristics in relation to changes in fatigue, difficulties to fall asleep, and 24-hour sleep length. Results Change in night but not in morning or evening shifts was associated with parallel changes in odds for longer sleep length (OR 1.45, 95% CI 1.28-1.64) and fatigue during free days (OR 1.38, 95% CI 1.16-1.64). Similarly, short shift intervals and having >2 but not >4 consecutive night shifts were associated with increased odds of fatigue during work and difficulties to fall asleep (OR 1.42, 95% CI 1.19-1.72 and OR 1.10, 95% CI 1.05-1.19, respectively). Among workers aged ≥50 years, the associations were the strongest between night shifts and longer sleep (OR 2.24, 95% CI 1.52-3.81) and between higher proportion of short shift intervals and fatigue during free days (OR 1.68, 95% CI 1.10-2.54). Conclusions Among shift workers with fatigue or sleep problems, decreasing the proportion of night shifts and quick returns and giving preference to quickly forward-rotating shift systems may reduce fatigue.

Changes in Body Mass Index and Physical Activity Predict Changes in Vitality During a Weight Loss Trial in Breast Cancer Survivors.

Breast cancer survivors rank fatigue (e.g., decreased vitality) as their number one concern affecting quality of life. Excess adiposity is associated with decreased vitality in breast cancer survivors, yet weight loss intervention trials report inconsistent effects on this parameter. This is a secondary analysis of the Exercise and Nutrition to Enhance Recovery and Good Health for You trial, in which 692 overweight or obese breast cancer survivors ≤5 years from diagnosis, initiated weight loss interventions, and completed assessments semi-annually for 2 years. Assessments included the Godin Leisure-Time Exercise Questionnaire and the SF-36 MOS vitality subscale as an inverse measure of fatigue. Multilevel structural equation models estimated the direct effects of physical activity on vitality and indirect effects through body mass index (BMI) changes. Within-person findings show that at assessments with greater physical activity, BMI was significantly lower (B = -0.07, p < 0.001) and vitality was higher (B = 0.22, p < 0.001). However, there was no direct relationship between lower BMI and higher vitality (B = -0.11, p = 0.262) after controlling for the relationship of physical activity with BMI and physical activity with vitality. The between-person indirect effect of physical activity change through BMI change to vitality was significant (B = 0.03, p < 0.001). Participants whose physical activity was above the mean (B = 0.37, p < 0.001) and whose BMI was below the mean (B = -1.05, p < 0.001) were more likely to report greater vitality. Improvements in vitality are primarily associated with increases in physical activity rather than BMI changes in this trial. Vitality was lower among survivors with higher BMI, although within-individual changes in BMI had no effect on vitality. Physical activity and weight loss share mechanistic links to vitality with physical activity potentially increasing (e.g., in an additive or synergistic manner) the effect of BMI reduction on vitality.

Agricultural productivity shocks, labour reallocation and rural–urban migration in China

This article analyses the way households in rural China use rural–urban migration and off-farm work as a response to negative productivity shocks in agriculture. I employ various waves of a longitudinal survey to construct a panel of individual migration and labour supply histories, and match them to detailed weather information, which I use to instrument agricultural productivity. For identification, I exploit the year-by-county variation in growing season rainfalls to explain within-individual changes in labour allocation. Data on days of work supplied to each sector allow to study the responses to weather shocks along both the participation and the intensive margin. Results suggest that farming is reduced by 4.5% and migration increased by about 5% in response to a 1 standard deviation negative rainfall shock. Increase in rural–urban migration derives from both longer spells in the city and from increment in the likelihood to participate in the urban sector. I find interesting heterogeneous response across generations driven by age-specific productivities in the different sectors and migration costs. Finally, land tenure insecurity seems to partially prevent households from freely reallocating labour away from farming in bad times.

Men’s and Women’s Gender-Role Attitudes across the Transition to Parenthood: Accounting for Child’s Gender

Gender-role attitudes capture individuals’ degree of support for traditional divisions of paid and domestic work and have been linked to the production and reproduction of gender inequality in different social spheres. Previous research has established that life-course transitions are related to within-individual over-time change in gender-role attitudes. Most importantly, becoming a parent is associated with shifts toward more traditional viewpoints. Theories of attitude change suggest that the gender of children should influence the pattern of gender-attitude shifts that accompany parenthood, but very few studies have investigated this. We add to this literature using Australian panel data from the Household, Income, and Labour Dynamics in Australia Survey (n = 29,918 observations) stretching over 15 years and fixed-effects panel regression models. We find that men’s and women’s gender-role attitudes become more traditional when they become parents, with evidence that this process is more pronounced among men, parents of daughters and, most of all, male parents of daughters.

The Criminogenic Influence of Family on Substance Use During Reentry: A Life-Course Perspective on Between Individual Differences and Within Individual Changes

A large body of prior research has demonstrated a clear link between family support and desistance from substance use during reentry. Emerging research also suggests that family conflict may play an independent role in this process. Accordingly, this study moves towards an understanding of how baseline between-individual differences in both family support and conflict prior to release interact with within-individual change in the respective constructs to affect substance use during the reentry time period. Results of cross-lagged dynamic panel models examining four waves of the Serious and Violent Offender Reentry Initiative data demonstrate baseline between-individual differences and within-individual changes in family conflict, but not support, significantly relate to polysubstance use. While these results suggest that families play a criminogenic role in reentry, a series of interaction terms demonstrates that within-individual increases in family support can help offset the negative influence of family conflict.

Within-individual Change in Social Support, Perceived Collective Efficacy, Perceived Disorder and Fear of Crime: Results From a Two-wave Panel Study

In this study, we untangle the relationships between fear of crime (perceived risk of victimization) and perceptions of, respectively, social support, collective efficacy and perceived disorder. We use a two-wave panel study with 356 respondents. Results show that prior perceptions of disorder have a positive effect on later levels of perceived risk of victimization, lending support to the hypothesis that fear of crime is, in part, determined by perceived disorder. Levels of social support negatively affected later levels of perceived risk of victimization. Neither perceived informal social control nor perceived social trust had any effect on later levels of perceived risk of victimization. Strengths, weaknesses and suggestions for further research are discussed.

Reciprocal Relations Between Parenting Behaviors and Conduct Disorder Symptoms in Preschool Children.

Reciprocal relations between children's conduct disorder (CD) symptoms and parenting behaviors were examined across the preschool years. Participants were 199 children (M = 44.26months, SD = 3.37; 92 girls) and their 199 mothers and 158 fathers. CD symptoms were assessed via structured interviews; parenting was assessed via observational and self-report measures. Fixed effects models were used to assess within-individual changes and traditional cross-lagged models were used to assess between-individual changes; comparisons by sex were also carried out. Increases in maternal overreactivity predicted increases in CD symptoms. During the later preschool years, decreases in maternal warmth predicted increases in CD symptoms and increases in CD symptoms predicted increases in paternal overreactivity. Reciprocal effects were found between girls' CD symptoms and paternal negative affect. Findings suggest maternal and paternal influence on the development of CD symptoms and suggest that CD symptoms influence fathers' parenting during the preschool years.

Gun- and Non-Gun–Related Violence Exposure and Risk for Subsequent Gun Carrying Among Male Juvenile Offenders

Although studies have found that youth exposed to violence are more likely to carry guns than non-exposed youth, this association could be due to common causal factors or other pre-existing differences between individuals. In this study, within-individual change models were used to determine whether juvenile offenders exhibit an increased propensity to carry a firearm after being exposed to gun violence and/or non-gun violence. The advantage of this approach is all time-invariant factors are eliminated as potential confounders. A sample of 1,170 racially/ethnically diverse male juvenile offenders was recruited in Arizona and Pennsylvania (14-19 years old at recruitment). Participants were interviewed every 6 months for 3 years followed by 4 annual assessments. The outcome was gun carrying and the primary predictors were exposure to gun violence and non-gun violence. Time-varying covariates included exposure to peers who carried guns, exposure to peers who engaged in other (non-gun) criminal acts, developmental changes in gun carrying, and changes in gun carrying from incarceration or institutionalization. Adolescent offenders were significantly more likely to carry a gun in recall periods after exposure to gun violence, but not after exposure to non-gun violence. Effect of gun violence on carrying was significant throughout adolescence and young adulthood and could not be accounted for by time-varying and time-invariant confounders. Interventions to decrease illegal gun carrying should target young men in medical and mental health settings who experience or witness gun violence and those living in communities with high rates of gun violence.

Developmental relations between alcohol expectancies and social norms in predicting alcohol onset.

Expectations about alcohol's effects and perceptions of peers' behaviors and beliefs related to alcohol use are each shown to strongly influence the timing of drinking onset during adolescence. The present study builds on prior work by examining the conjoint effects of within-person changes in these social-cognitive factors on age of adolescent drinking onset. We related youths' alcohol status (i.e., alcohol-naive, initiation during study, prior initiation) to increases in positive and negative alcohol outcome expectancies (AOEs), as well as increases in perceived peer/close friend alcohol use and acceptance, during adolescence. We also investigated whether changes in AOEs and perceived social norms prospectively predicted alcohol onset in alcohol-naïve adolescents. Participants were 1,023 adolescents aged 12.2 years on average at enrollment (SD = 0.98), 52% female, participating in an ongoing longitudinal survey on substance use and health behaviors. Positive AOEs, close friends' norms, and same-age peer norms increased linearly, whereas negative AOEs decreased linearly. Changes were attenuated for participants who remained alcohol-naïve and increased for participants who experienced initiation during the study. Furthermore, we found associations between individual changes in AOEs and perceived social norms. Finally, survival models revealed that onset of alcohol use was prospectively predicted by stronger initial positive AOEs, as well as increases in close friends' norms and decreases in negative AOEs over time. These findings emphasize codevelopment of AOEs and perceived social norms, coinciding with, and predictive of, onset of alcohol use, and point toward a unique role for within-individual changes in identifying youth at risk for early onset of alcohol use. (PsycINFO Database Record

Neighborhood Disadvantage and Body Mass Index: A Study of Residential Relocation.

Natural experiments, such as longitudinal observational studies that follow-up residents as they relocate, provide a strong basis to infer causation between the neighborhood environment and health. In this study, we examined whether changes in the level of neighborhood disadvantage were associated with changes in body mass index (BMI) after residential relocation. This analysis included data from 928 residents who relocated between 2007 and 2013, across 4 waves of the How Areas in Brisbane Influence Health and Activity (HABITAT) study in Brisbane, Australia. Neighborhood disadvantage was measured using a census-derived composite index. For individual-level data, participants self-reported their height, weight, education, occupation, and household income. Data were analyzed using multilevel, hybrid linear models. Women residing in less disadvantaged neighborhoods had a lower BMI, but there was no association among men. Neighborhood disadvantage was not associated with within-individual changes in BMI among men or women when moving to a new neighborhood. Despite a growing body of literature suggesting an association between neighborhood disadvantage and BMI, we found this association may not be causal among middle-aged and older adults. Observing associations between neighborhood socioeconomic disadvantage and BMI over the life course, including the impact of residential relocation at younger ages, remains a priority for future research.

The Development of Future Orientation is Associated with Faster Decline in Hopelessness during Adolescence.

Hopelessness is implicated in multiple psychological disorders. Little is known, however, about the trajectory of hopelessness during adolescence or how emergent future orientation may influence its trajectory. Parallel process latent growth curve modelling tested whether (i) trajectories of future orientation and hopelessness and (ii) within-individual change in future orientation and hopelessness were related. The study was comprised of 472 adolescents [52% female, 47% Caucasian, 47% received free lunch] recruited at ages 12-13 who completed measures of future orientation and hopelessness at five annual assessments. The results indicate that a general decline in hopelessness across adolescence occurs quicker for those experiencing faster development of future orientation, when controlling for age, sex, low socio-economic status in addition to stressful life events in childhood and adolescence. Stressful childhood life events were associated with worse future orientation at baseline and negative life events experienced during adolescence were associated with both an increase in the trajectory of hopelessness as well as a decrease in the trajectory of future orientation. This study provides compelling evidence that the development of future orientation during adolescence is associated with a faster decline in hopelessness.

No short-term physiological costs of offspring care in a cooperatively breeding bird.

The cost of reproduction results in a life-history trade-off where investment in current reproduction via costly parental care decreases subsequent fitness. Although this trade-off is thought to occur ubiquitously across animals, there is equivocal evidence that parental care behaviours are costly. A major challenge of studying the cost of parental care has been a lack of consensus over which physiological mechanisms underlie this trade-off. Here, we compare four traits believed to mediate the cost of parental care by examining whether glucocorticoids, oxidative stress, immune function or body condition represent a cost of performing offspring care and shape subsequent fitness. We use a 4year dataset collected in free-living cooperatively breeding superb starlings (Lamprotornis superbus), a species in which parental and alloparental care effort varies widely among individuals and across years. Our results showed that within-individual change in physiology was unrelated to investment in offspring care, and physiological state during chick rearing did not predict the likelihood that an individual would breed in subsequent seasons. Instead, individuals that had elevated baseline corticosterone during incubation performed more nest guarding, suggesting that this hormone may play a preparatory role for investing in offspring care. Together, our results indicate that superb starlings modify their investment in offspring care according to their physiological state during incubation, despite there being no evidence of a short-term physiological cost of parental or alloparental care. Thus, breeding cooperatively appears to provide individuals with the flexibility to adjust their investment in offspring care and overcome any potential costs of reproduction.

The relationship between egg size and helper number in cooperative breeders: a meta-analysis across species.

BackgroundLife history theory predicts that mothers should adjust reproductive investment depending on benefits of current reproduction and costs of reduced future reproductive success. These costs and benefits may in turn depend on the breeding female’s social environment. Cooperative breeders provide an ideal system to test whether changes in maternal investment are associated with the social conditions mothers experience. As alloparental helpers assist in offspring care, larger groups might reduce reproductive costs for mothers or alternatively indicate attractive conditions for reproduction. Thus, mothers may show reduced (load-lightening) or increased (differential allocation) reproductive investment in relation to group size. A growing number of studies have investigated how cooperatively breeding mothers adjust pre-natal investment depending on group size. Our aim was to survey these studies to assess, first, whether mothers consistently reduce or increase pre-natal investment when in larger groups and, second, whether these changes relate to variation in post-natal investment.MethodsWe extracted data on the relationship between helper number and maternal pre-natal investment (egg size) from 12 studies on 10 species of cooperatively breeding vertebrates. We performed meta-analyses to calculate the overall estimated relationship between egg size and helper number, and to quantify variation among species. We also tested whether these relationships are stronger in species in which the addition of helpers is associated with significant changes in maternal and helper post-natal investment.ResultsAcross studies, there is a significant negative relationship between helper number and egg size, suggesting that in most instances mothers show reduced reproductive investment in larger groups, in particular in species in which mothers also show a significant reduction in post-natal investment. However, even in this limited sample, substantial variation exists in the relationship between helper number and egg size, and the overall effect appears to be driven by a few well-studied species.DiscussionOur results, albeit based on a small sample of studies and species, indicate that cooperatively breeding females tend to produce smaller eggs in larger groups. These findings on prenatal investment accord with previous studies showing similar load-lightening reductions in postnatal parental effort (leading to concealed helper effects), but do not provide empirical support for differential allocation. However, the considerable variation in effect size across studies suggests that maternal investment is mitigated by additional factors. Our findings indicate that variation in the social environment may influence life-history strategies and suggest that future studies investigating within-individual changes in maternal investment in cooperative breeders offer a fruitful avenue to study the role of adaptive plasticity.

During, After, or Both? Isolating the Effect of Religious Support on Recidivism During Reentry.

To examine the independent and interdependent roles of baseline religious support during incarceration and within-individual changes in religious support on recidivism during the prisoner reentry process. Using data from the Serious and Violent Offender Reentry Initiative, cross-lagged dynamic panel models are used to examine the respective roles of baseline differences and within-individual changes in religious support on two variety indices encompassing substance use and criminal offending while simultaneously controlling for pre-incarceration levels of substance use and offending. Findings show that within-individual increases in religious support protect against substance use post-release, while baseline levels of religious support do not significantly influence substance use. Additionally, baseline levels of religious support fail to condition this relationship. Findings assessing criminal offending demonstrate that baseline religious support and within-individual changes in religious support fail to relate to offending independently. However, an interaction term reveals that the combination of the two relates to significantly lower levels of offending post-release. Findings offer encouragement for those involved in the work of providing religious support to ex-offenders in the community, reaffirming that tailoring support programs to the religious or spiritual ways individuals make meaning in their lives can improve reentry outcomes. Methodologically, failing to distinguish between baseline levels of religious support and post-release changes in religious support fails to capture the complexity of religiosity on the reentry process.

Interpersonal Relationships as Protective and Risk Factors for Psychopathy: A Follow-up Study in Adolescent Offenders.

Friendships and romantic relationships may function as protective and risk factors for psychopathic traits. To better understand potential causal associations, we investigated whether within-individual changes in relationship characteristics were related to changes in psychopathic traits over time. Data were derived from ten repeated measurements of the Pathways to Desistance longitudinal study of 1354 offending adolescents (14.3% female; 40.1% Black). Analyses were adjusted for age, gender, ethnicity, self-reported offending and living facilities. Relationships of high quality were associated with lower psychopathic traits, whereas antisocial behavior and antisocial influence in relationships were related to higher psychopathic traits. Within-individual analysis indicated that time-invariant individual characteristics did not confound these associations. The findings suggest that the quality and antisocial activities of interpersonal relationships can affect positively or negatively on the levels of psychopathy.

Exploring the impact of high intensity interval training on adolescents’ objectively measured physical activity: Findings from a randomized controlled trial

ABSTRACTHigh Intensity Interval Training (HIIT) may be effective for accumulating VPA. However, the contribution of HIIT to overall physical activity is unknown. Our primary aim was to explore the impact of school-based HIIT on physical activity. The secondary aim was to explore within-individual changes in physical activity after participating in HIIT. Participants [n = 65; 15.8(0.6)years] were randomized to a HIIT or control group. Intervention groups participated in three HIIT sessions/week. GENEActiv accelerometers assessed objective physical activity at baseline and week-one, to detect changes in MPA and VPA. Intervention effects were examined using linear mixed models and evidence of a change in physical activity (i.e., compensation) were examined using multilevel linear regression models. The group-by-time interaction effects for MPA and VPA were small and moderate, respectively. Adjusted difference between groups for VPA was 1.70 min/day, 95%CI –1.96 to 5.36; p = 0.354; d = 0.55). Embedding HIIT within the school-day had a moderate effect on VPA compared to controls. Compensation analyses (i.e., individual level) suggested that adolescents were more active on days when they participated in HIIT. Further studies are needed to test the effects of HIIT on adolescents’ physical activity over extended time periods.

Of Uberfleas and Krakens: Detecting Trade-offs Using Mixed Models.

All animals experience performance trade-offs as they complete tasks such as capturing prey, defending territories, acquiring mates, and escaping predators. Why then, is it so hard to detect performance trade-offs at the whole-organismal level? Why do we sometimes even obtain positive correlations between two performance traits that are predicted to be negatively associated? Here we explore two plausible explanations. First, most analyses are based on individual maximal values (i.e., personal best), which could introduce a bias in the correlation estimates. Second, phenotypic correlations alone may be poor indicators of a trade-off when contrasting processes occur at the among- versus within-individual levels. One such scenario is the "big houses big cars" model developed in life-history theory to explain the existence of "uberfleas" that are superior in all regards (because they acquire more resources than others). We highlight that the exact opposite scenario might occur for performance trade-offs, where among-individual trade-offs may be masked by within-individual changes in physical condition. One of the best ways to test among these alternative scenarios is to collect repeated pairs of performance traits and analyze them using multivariate mixed models (MMMs). MMMs allow straightforward and simultaneous examination of trait correlations at the among- and within-individual levels. We use a simple simulation tool (SQuID package in R) to create a population of Krakens, a mythical giant squid-like sea creature whose morphology generates a performance trade-off between swimming speed and strength or ability to sink ships. The simulations showed that using individual maximum values introduces a bias that is particularly severe when individuals differ in the number of repeated samples (ntrial). Finally, we show how MMMs can help detect performance (or any other type of) trade-offs and offer additional insights (e.g., help detect plasticity integration). We hope researchers will adopt MMMs when exploring trade-offs in whole-animal performances.