Phenotypes expressed in a social context are not only a function of the individual, but can also be shaped by the phenotypes of social partners. These social effects may play a major role in the ...evolution of cooperative breeding if social partners differ in the quality of care they provide and if individual carers adjust their effort in relation to that of other carers. When applying social effects models to wild study systems, it is also important to explore sources of individual plasticity that could masquerade as social effects. We studied offspring provisioning rates of parents and helpers in a wild population of long-tailed tits Aegithalos caudatus using a quantitative genetic framework to identify these social effects and partition them into genetic, permanent environment and current environment components. Controlling for other effects, individuals were consistent in their provisioning effort at a given nest, but adjusted their effort based on who was in their social group, indicating the presence of social effects. However, these social effects differed between years and social contexts, indicating a current environment effect, rather than indicating a genetic or permanent environment effect. While this study reveals the importance of examining environmental and genetic sources of social effects, the framework we present is entirely general, enabling a greater understanding of potentially important social effects within any ecological population.
Most humans are right‐handed and, like many behavioral traits, there is good evidence that genetic factors play a role in handedness. Many researchers have argued that non‐human animal limb or hand ...preferences are not under genetic control but instead are determined by random, non‐genetic factors. We used quantitative genetic analyses to estimate the genetic and environmental contributions to three measures of chimpanzee handedness. Results revealed significant population‐level handedness for two of the three measures—the tube task and manual gestures. Furthermore, significant additive genetic effects for the direction and strength of handedness were found for all three measures, with some modulation due to early social rearing experiences. These findings challenge historical and contemporary views of the mechanisms underlying handedness in non‐human animals.
Chimpanzees show population‐level handedness for two of three handedness measures. Both direction and strength of handedness are significantly heritable for each measure.
The heritability of Major Depressive Disorder (MDD) has been estimated at 37% based largely on twin studies that rely on contested assumptions. More recently, the heritability of MDD has been ...estimated on large populations from registries such as the Swedish, Finnish, and Chinese cohorts. Family-based designs utilise a number of different relationships and provide an alternative means of estimating heritability. Generation Scotland: Scottish Family Health Study (GS:SFHS) is a large (n = 20,198), family-based population study designed to identify the genetic determinants of common diseases, including Major Depressive Disorder. Two thousand seven hundred and six individuals were SCID diagnosed with MDD, 13.5% of the cohort, from which we inferred a population prevalence of 12.2% (95% credible interval: 11.4% to 13.1%). Increased risk of MDD was associated with being female, unemployed due to a disability, current smokers, former drinkers, and living in areas of greater social deprivation. The heritability of MDD in GS:SFHS was between 28% and 44%, estimated from a pedigree model. The genetic correlation of MDD between sexes, age of onset, and illness course were examined and showed strong genetic correlations. The genetic correlation between males and females with MDD was 0.75 (0.43 to 0.99); between earlier ( less than or equal to age 40) and later (> age 40) onset was 0.85 (0.66 to 0.98); and between single and recurrent episodic illness course was 0.87 (0.72 to 0.98). We found that the heritability of recurrent MDD illness course was significantly greater than the heritability of single MDD illness course. The study confirms a moderate genetic contribution to depression, with a small contribution of the common family environment (variance proportion = 0.07, CI: 0.01 to 0.15), and supports the relationship of MDD with previously identified risk factors. This study did not find robust support for genetic differences in MDD due to sex, age of onset, or illness course. However, we found an intriguing difference in heritability between recurrent and single MDD illness course. These findings establish GS:SFHS as a valuable cohort for the genetic investigation of MDD.
Differential psychologists rightly identified evolutionary theory as a unifying framework for explaining the origins and persistence of individual differences in a wide array of human psychological ...characteristics. Psychological diversity occurs on multiple levels, including between species, populations, generations, and individuals. Each level reveals the outcome of evolutionary processes at different temporal scales. I embrace a range of methods and results from quantitative and population genetics, developmental evolution, and phylogenetically grounded comparative psychology to explore how personality evolves in humans and nonhuman primates. At the level of species, I compared personality structure derived from rater assessments for four species of macaques and found a consistent, core set of personality dimensions (Dominance, Confidence, and Friendliness) describing these species. At the population level, I studied the relationship in humans between fertility/longevity trade-offs and the average personality of a country and found that Neuroticism and Agreeableness exhibit adaptively plasticity to life-history conditions. At the level of families, I estimated the quantitative genetic structure of personality in orang-utans and found that, like humans, a large portion of the phenotypic variance was explained by non-additive genetic effects. I examined between generation changes in personality by testing whether personality traits in humans are genetically correlated with fitness and found that in modern environments personality evolves very slowly. Finally, I translated current conceptual models of biological reactivity and stress response into mathematical models of developmental evolution and determined that evolution would select highly resilient phenotypes but that variation could be maintained by skew in the distribution of underlying genetic factors. From these results I broadly conclude that primate personality structure is generally conserved among species, mean personality levels change only very slowly between human generations, and that this evolution results in a genetic basis of personality that is characterized by epistasis. The evolution of individual differences has much to gain from the rigorous application of evolutionary methodology.
Differential psychologists rightly identified evolutionary theory as a unifying framework for explaining the origins and persistence of individual differences in a wide array of human psychological ...characteristics. Psychological diversity occurs on multiple levels, including between species, populations, generations, and individuals. Each level reveals the outcome of evolutionary processes at different temporal scales. I embrace a range of methods and results from quantitative and population genetics, developmental evolution, and phylogenetically grounded comparative psychology to explore how personality evolves in humans and nonhuman primates. At the level of species, I compared personality structure derived from rater assessments for four species of macaques and found a consistent, core set of personality dimensions (Dominance, Confidence, and Friendliness) describing these species. At the population level, I studied the relationship in humans between fertility/longevity trade-offs and the average personality of a country and found that Neuroticism and Agreeableness exhibit adaptively plasticity to life-history conditions. At the level of families, I estimated the quantitative genetic structure of personality in orang-utans and found that, like humans, a large portion of the phenotypic variance was explained by non-additive genetic effects. I examined between generation changes in personality by testing whether personality traits in humans are genetically correlated with fitness and found that in modern environments personality evolves very slowly. Finally, I translated current conceptual models of biological reactivity and stress response into mathematical models of developmental evolution and determined that evolution would select highly resilient phenotypes but that variation could be maintained by skew in the distribution of underlying genetic factors. From these results I broadly conclude that primate personality structure is generally conserved among species, mean personality levels change only very slowly between human generations, and that this evolution results in a genetic basis of personality that is characterized by epistasis. The evolution of individual differences has much to gain from the rigorous application of evolutionary methodology.
The piano puts whole worlds of musical sound at the fingertips of one player, evoking the singing of a solo voice, the textural richness of an orchestra, and the rhythmic impetus of a dance band. It ...has been background or center stage in concertgoing, parlor singing, choir rehearsals, theatrical tryouts, and many other activities, forging a common bond among people of very different social spheres. This delightfully written and copiously illustrated book examines the place of the piano in classical and popular musical cultures and the pianos changing cultural roles over the past three centuries.Eminent authorities discuss the impetus for the invention of the piano; the innovations in its design, manufacturing, and marketing that promoted its growing significance in concert life and domestic life; and the importance of the piano lesson in the upbringing of the youngespecially of girls. They explore the relationship between the piano on the public stage and the piano in the parlor; the spread of the piano to all parts of the world; and the images formed around the piano in literature, art, and movies. And they eloquently describe what the piano has meant to different eras, as it evolved from the plaything of European aristocrats to companion of people of all classes and cultures.
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