scholarly journals Cryptic individual-level variation in propensity for selfing in a hermaphroditic snail

2021 ◽  
Author(s):  
Anja Felmy ◽  
Alena B Streiff ◽  
Jukka Jokela
Keyword(s):  
Population Density ◽  
Individual Variation ◽  
Statistical Power ◽  
Mating Behaviour ◽  
Empirical Support ◽  
Reproductive Assurance ◽  
Level Variation ◽  
Heritable Variation ◽  
Mate Availability ◽  
Individual Level

For mating-system evolution, individual-level variation is as important as variation among populations. In self-compatible hermaphrodites, individuals may vary in their lifetime propensity for selfing, which consists of a fundamental, likely genetic and an environmental component. According to the reproductive assurance hypothesis explaining partial selfing, a key environmental factor is mate availability, which fluctuates with population density. We quantified individual variation in selfing propensity in a hermaphroditic snail by manipulating mate availability in the laboratory, recording mating behaviour, estimating selfing rates from progeny arrays, and measuring female lifetime fitness. Our results revealed four classes of individuals with different selfing propensities: pure outcrossers, pure selfers, and two types of plastic individuals. These classes only became apparent in the laboratory; the field population is outcrossing. All classes were present both under low and increased mate availability; this large among-individual variation in selfing propensities meant that effects of the pairing treatment on the frequency and extent of selfing were non-significant despite large effect sizes and sufficient statistical power. We believe that selfing propensities may have a genetic component and when selected on cause mean selfing rates to evolve. We propose that heritable variation in selfing propensities offers a reconciliation between the reproductive assurance hypothesis and its weak empirical support: distributions of selfing propensities vary temporally and spatially, thus obscuring the relationship between population density and realised selfing rates.

The Bias of Individuals (In Crowds): Why Implicit Bias is Probably a Noisily-Measured Individual-Level Construct

2020 ◽  
Author(s):  
Paul Robert Connor ◽  
Ellen Riemke Katrien Evers
Keyword(s):  
Measurement Error ◽  
Present Article ◽  
Implicit Bias ◽  
Empirical Support ◽  
Simulated Data ◽  
Individual Level ◽  
Substantial Error

Payne, Vuletich, and Lundberg’s bias-of-crowds model proposes that a number of empirical puzzles can be resolved by conceptualizing implicit bias as a feature of situations rather than a feature of individuals. In the present article we argue against this model and propose that, given the existing evidence, implicit bias is best understood as an individual-level construct measured with substantial error. First, using real and simulated data, we show how each of Payne and colleagues’ proposed puzzles can be explained as being the result of measurement error and its reduction via aggregation. Second, we discuss why the authors’ counterarguments against this explanation have been unconvincing. Finally, we test a hypothesis derived from the bias-of-crowds model about the effect of an individually targeted “implicit-bias-based expulsion program” within universities and show the model to lack empirical support. We conclude by considering the implications of conceptualizing implicit bias as a noisily measured individual-level construct for ongoing implicit-bias research. All data and code are available at https://osf.io/tj8u6/.

scholarly journals A Multilevel Mixed Effects Analysis of Informal Carers Health in Australia: The role of Community Participation, Social Support and Trust at Small Area level.

2020 ◽  
Author(s):  
Itismita Mohanty ◽  
Theo Niyonsenga ◽  
Tom Cochrane ◽  
Debra Rickwood
Keyword(s):  
Mental Health ◽  
Social Support ◽  
Health Outcomes ◽  
Community Participation ◽  
General Health ◽  
Positive Influence ◽  
Mixed Effects ◽  
Level Variation ◽  
Individual Level ◽  
Informal Carers

Abstract Background: Informal carers suffer from worse health outcomes than non-carers due to their caregiving role. Yet, in a society carers health is as important as that of their care recipients. This study investigated the self-assessed mental and general health outcomes of informal carers in Australia. It evaluated the influence of carers’ personal social capital- a logically linked sequence of their social behaviour such as community participation, social support and trust in others- on their health outcomes. The study estimated the magnitude of small local area (SA1) level variation along with individual level variation in carers’ health outcomes.Methods: The study used a multilevel mixed effects cross-sectional design using data from the Household Income and Labour Dynamics of Australia survey, wave 14. It included Australians aged 15 years and older that were surveyed in the year 2014. The sample consisted of 12,767 individuals and 5004 SA1s. The outcome measures included- mental health, general health and physical functioning, domains of the Short Form 36 Questionnaire, a widely used multi-dimensional measure of health-related quality of life.Results: Informal carers suffered from poor mental (Beta = -0.587, p=0.003) and general health (Beta = -0.670, p=0.001) outcomes compared to non-carers in Australia. These health outcomes exhibited significant variation across small areas (SA1s) in Australia, with 12-13% variation in general and mental health. However, within small local areas, differences at the individual level, accounted for most of the variation in outcomes. Moreover, levels of community participation, personal social connection and trust, as perceived by individuals in the communities, had a positive influence on both mental and general health of carers and non-carers, and were more beneficial for carers compared to non-carers. Conclusion: It seems that the positive influence of social capital for carers helps them in coping with the negative impact of their caregiving duty on health outcomes. Findings suggested that some targeted community support programs for carers to build on their personal social cohesion and trust in their community could help in improving their poor health profiles. Moreover, improved informal carers’ health may help the health system in better managing their resources.

scholarly journals Power analyses for moderator effects with (non)randomly varying slopes in cluster randomized trials

Methodology ◽  
2021 ◽  
Vol 17 (2) ◽  
pp. 92-110
Author(s):  
Nianbo Dong ◽  
Jessaca Spybrook ◽  
Benjamin Kelcey ◽  
Metin Bulus
Keyword(s):  
Statistical Power ◽  
Randomized Trials ◽  
Future Research ◽  
Size Difference ◽  
Detectable Effect ◽  
Cluster Randomized Trials ◽  
Individual Level ◽  
Moderator Effects ◽  
Cluster Randomized ◽  
Power Analyses

Researchers often apply moderation analyses to examine whether the effects of an intervention differ conditional on individual or cluster moderator variables such as gender, pretest, or school size. This study develops formulas for power analyses to detect moderator effects in two-level cluster randomized trials (CRTs) using hierarchical linear models. We derive the formulas for estimating statistical power, minimum detectable effect size difference and 95% confidence intervals for cluster- and individual-level moderators. Our framework accommodates binary or continuous moderators, designs with or without covariates, and effects of individual-level moderators that vary randomly or nonrandomly across clusters. A small Monte Carlo simulation confirms the accuracy of our formulas. We also compare power between main effect analysis and moderation analysis, discuss the effects of mis-specification of the moderator slope (randomly vs. non-randomly varying), and conclude with directions for future research. We provide software for conducting a power analysis of moderator effects in CRTs.

scholarly journals Honeybee dance-followers respond similarly to dances regardless of their spatial information content

2021 ◽  
Author(s):  
Matthew J. Hasenjager ◽  
William Hoppitt ◽  
Ellouise Leadbeater
Keyword(s):  
Information Content ◽  
Spatial Information ◽  
Empirical Support ◽  
Long Distance ◽  
Individual Level ◽  
Self Organized ◽  
Diffusion Analysis ◽  
Novel Targets ◽  
The Individual ◽  
Collective Influence

AbstractHoneybees famously use waggle dances to communicate foraging locations to nestmates in the hive, thereby recruiting them to those sites. The decision to dance is governed by rules that, when operating collectively, are assumed to direct foragers to the most profitable locations with little input from potential recruits, who are presumed to respond similarly to any dance regardless of its information content. Yet variation in receiver responses can qualitatively alter collective outcomes. Here, we use network-based diffusion analysis to compare the collective influence of dance information during recruitment to feeders at different distances. We further assess how any such effects might be achieved at the individual level by dance-followers either persisting with known sites when novel targets are distant and/or seeking more accurate spatial information to guide long-distance searches. Contrary to predictions, we found no evidence that dance-followers’ responses depended on target distance. While dance information was always key to feeder discovery, its importance did not vary with feeder distance, and bees were in fact quicker to abandon previously rewarding sites for distant alternatives. These findings provide empirical support for the longstanding assumption that self-organized foraging by honeybee colonies relies heavily on signal performance rules with limited input from recipients.

scholarly journals Evaluating the Evidential Value of Empirically Supported Psychological Treatments (ESTs): A Meta-Scientific Review

2019 ◽  
Author(s):  
John Kitchener Sakaluk ◽  
Alexander Williams ◽  
Robyn Kilshaw ◽  
Kathleen T. Rhyner
Keyword(s):  
Statistical Power ◽  
Empirical Support ◽  
Therapeutic Interventions ◽  
Scientific Review ◽  
Evidential Value ◽  
Empirically Supported ◽  
Research Findings ◽  
Almost All ◽  
Multiple Metrics ◽  
Statistical Criteria

Empirically supported treatments (or therapies; ESTs) are the gold standard in therapeutic interventions for psychopathology. Based on a set of methodological and statistical criteria, the APA has assigned particular treatment-diagnosis combinations EST status and has further rated their empirical support as Strong, Modest, and/or Controversial. Emerging concerns about the replicability of research findings in clinical psychology highlight the need to critically examine the evidential value of EST research. We therefore conducted a meta-scientific review of the EST literature, using clinical trials reported in an existing online APA database of ESTs, and a set of novel evidential value metrics (i.e., rates of misreported statistics, statistical power, R-Index, and Bayes Factors). Our analyses indicated that power and replicability estimates were concerningly low across almost all ESTs, and individually, some ESTs scored poorly across multiple metrics, with Strong ESTs failing to continuously outperform their Modest counterparts. Lastly, we found evidence of improvements over time in statistical power within the EST literature, but not for the strength of evidence of EST efficacy. We describe the implications of our findings for practicing psychotherapists and offer recommendations for improving the evidential value of EST research moving forward.

The Importance of Bystanders in Threat Assessment and Management

2021 ◽  
pp. 423-436
Author(s):  
Randy Borum ◽  
Mary Rowe
Keyword(s):  
Decision Making ◽  
Family Members ◽  
Empirical Support ◽  
Threat Assessment ◽  
School Shootings ◽  
Mass Shootings ◽  
Individual Level ◽  
Targeted Violence ◽  
Intentional Acts ◽  
Common Barriers

Bystanders—those who observe or come to know about potential wrongdoing—are often the best source of preattack intelligence, including indicators of intent and “warning” behaviors. They are the reason that some planned attacks are foiled before they occur. Numerous studies of targeted violence (e.g., mass shootings and school shootings) have demonstrated that peers and bystanders often have knowledge of an attacker’s intentions, concerning communication, and troubling behavior before the attack occurs. This chapter describes—with empirical support—why threat assessment professionals should consider bystanders; outlines a model for understanding bystander decision-making; reviews common barriers to bystander reporting; and suggests ways to mitigate those barriers, to engage bystanders at an individual level, and to improve reporting. The principal aim of threat assessment is to prevent (primarily) intentional acts of harm. When tragic incidents of planned violence occur, however, it is almost always uncovered “that someone knew something” about the attack before it happened. This happens because, as attack plans unfold, people in several different roles may know, or come to know, something about what is happening before harm occurs. The perpetrators know, and so might others, including targets, family members, friends, coworkers, or even casual observers.

scholarly journals Proximity Interactions in a Permanently Housed Dairy Herd: Network Structure, Consistency, and Individual Differences

2020 ◽  
Vol 7 ◽  
Author(s):  
Kareemah Chopra ◽  
Holly R. Hodges ◽  
Zoe E. Barker ◽  
Jorge A. Vázquez Diosdado ◽  
Jonathan R. Amory ◽  
...  
Keyword(s):  
Individual Variation ◽  
Temporal Stability ◽  
Interaction Network ◽  
Dairy Herd ◽  
Individual Level ◽  
Local Positioning System ◽  
Functional Zones ◽  
Herd Structure ◽  
Using Data ◽  
Feeding Zone

Understanding the herd structure of housed dairy cows has the potential to reveal preferential interactions, detect changes in behavior indicative of illness, and optimize farm management regimes. This study investigated the structure and consistency of the proximity interaction network of a permanently housed commercial dairy herd throughout October 2014, using data collected from a wireless local positioning system. Herd-level networks were determined from sustained proximity interactions (pairs of cows continuously within three meters for 60 s or longer), and assessed for social differentiation, temporal stability, and the influence of individual-level characteristics such as lameness, parity, and days in milk. We determined the level of inter-individual variation in proximity interactions across the full barn housing, and for specific functional zones within it (feeding, non-feeding). The observed networks were highly connected and temporally varied, with significant preferential assortment, and inter-individual variation in daily interactions in the non-feeding zone. We found no clear social assortment by lameness, parity, or days in milk. Our study demonstrates the potential benefits of automated tracking technology to monitor the proximity interactions of individual animals within large, commercially relevant groups of livestock.

scholarly journals A multilevel mixed effects analysis of informal carers health in Australia: the role of community participation, social support and trust at small area level

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Itismita Mohanty ◽  
Theo Niyonsenga ◽  
Tom Cochrane ◽  
Debra Rickwood
Keyword(s):  
Health Outcomes ◽  
Community Participation ◽  
General Health ◽  
Small Area ◽  
Positive Influence ◽  
Mixed Effects ◽  
Level Variation ◽  
Individual Level ◽  
Small Area Level ◽  
Informal Carers

Abstract Background Informal carers suffer from worse health outcomes than non-carers due to their caregiving role. Yet, in a society carers health is as important as that of their care recipients. This study investigated the self-assessed mental and general health outcomes of informal carers in Australia. It evaluated the influence of carers’ personal social capital- a logically linked sequence of their social behaviour such as community participation, social support and trust in others- on their health outcomes. The study estimated the magnitude of small area level variation at Statistical Area Level 1 (SA1) along with individual level variation in carers’ health outcomes. Methods The study used a multilevel mixed effects cross-sectional design using data from the Household Income and Labour Dynamics of Australia survey, wave 14. It included Australians aged 15 years and older that were surveyed in the year 2014. The sample consisted of 12,767 individuals and 5004 SA1s. The outcome measures included- mental health, general health and physical functioning, domains of the Short Form 36 Questionnaire, a widely used multi-dimensional measure of health-related quality of life. Results Informal carers suffered from poor mental (Beta = − 0.587, p = 0.003) and general health (Beta = − 0.670, p = 0.001) outcomes compared to non-carers in Australia. These health outcomes exhibited significant variation acrossSA1s in Australia, with 12–13% variation in general and mental health. However, within small local areas, differences at the individual level, accounted for most of the variation in outcomes. Moreover, levels of community participation, personal social connection and trust, as perceived by individuals in the communities, had a positive influence on both mental and general health of carers and non-carers, and were more beneficial for carers compared to non-carers. Conclusion It seems that the positive influence of social capital for carers helps them in coping with the negative impact of their caregiving duty on health outcomes. Findings suggested that some targeted community support programs for carers to build on their personal social cohesion and trust in their community could help in improving their poor health profiles. Moreover, improved informal carers’ health may help the health system in better managing their resources.

Analysis of individual differences in behavioural responsiveness in pigs

1989 ◽  
Vol 1989 ◽  
pp. 92-92
Author(s):  
C. Terlouw ◽  
A.B. Lawrence ◽  
A.W. Illius
Keyword(s):  
Individual Differences ◽  
Individual Variation ◽  
Mating Behaviour ◽  
Individual Variability ◽  
General Description ◽  
Environmental Challenges ◽  
Group A ◽  
Considerable Individual Variation ◽  
Environmental Challenge

Animals show considerable individual variation in many behaviour patterns such as feeding and mating behaviour. Often, this individual variability is ignored in favour of a more general description of the population. However, this may mask important information regarding the causes and functions of this individual variability. Behavioural work on other species has suggested that individuals tend to respond actively or passively to environmental challenge. It is of interest to know if a similar dimension of responsiveness exists in pigs as it may serve, amongst other things, to explain the considerable individual variability in pigs responses to putitive stresses such as tethered housing. This paper describes a series of tests made of behavioural responsiveness in pigs to assess the extent of consistent variability in individuals responses to a wide variety of environmental challenges.The subjects were two groups [Group A and B: n = 26 and 36 respectively) of modern hybrid non-pregnant gilts [Cotswold Pig Development Company Ltd, UK). Initially, the gilts were subjected to a number of tests of behavioural responsiveness at the Cotswold unit.

Rainbow trout personality: individual behavioural variation in juvenile Oncorhynchus mykiss

Behaviour ◽  
2018 ◽  
Vol 155 (2-3) ◽  
pp. 205-230 ◽  
Author(s):  
Ashley Elias ◽  
Frank Thrower ◽  
Krista M. Nichols
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Life Histories ◽  
Behavioural Syndrome ◽  
Level Variation ◽  
Individual Level ◽  
Behavioural Syndromes ◽  
Multiple Hypotheses ◽  
Developmental Shift

Abstract We evaluated the variation in dispersal, exploration, and aggression across time in juvenile progeny produced from wild caught rainbow trout (Oncorhynchus mykiss) at a critical developmental shift associated with the highest mortality in fish. By testing multiple ecologically relevant behaviours repeatedly in the same individuals, we simultaneously tested multiple hypotheses regarding personality, plasticity, and behavioural syndromes to better understand the innate behavioural variation in a population containing both migratory and resident life histories. There were consistent behavioural differences, or personality, between individuals across time, for dispersal, aggression, and exploration, unrelated to size or sex. The significant repeatabilities (0.10–0.46) indicate that these traits are potentially heritable. Also, we found both habituation in all behaviours and significant differences between individuals in the rate of that habituation, despite no evidence of a behavioural syndrome. The identification of this individual level variation is a step towards understanding which heritable traits selection could influence.

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