191 research outputs found
Sex differences in intimate relationships
Social networks have turned out to be of fundamental importance both for our
understanding human sociality and for the design of digital communication
technology. However, social networks are themselves based on dyadic
relationships and we have little understanding of the dynamics of close
relationships and how these change over time. Evolutionary theory suggests
that, even in monogamous mating systems, the pattern of investment in close
relationships should vary across the lifespan when post-weaning investment
plays an important role in maximising fitness. Mobile phone data sets provide
us with a unique window into the structure of relationships and the way these
change across the lifespan. We here use data from a large national mobile phone
dataset to demonstrate striking sex differences in the pattern in the
gender-bias of preferred relationships that reflect the way the reproductive
investment strategies of the two sexes change across the lifespan: these
differences mainly reflect women's shifting patterns of investment in
reproduction and parental care. These results suggest that human social
strategies may have more complex dynamics than we have tended to assume and a
life-history perspective may be crucial for understanding them.Comment: 5 pages, 3 figures, contains electronic supplementary materia
The origins and function of musical performance
Music is widely recognised as a human universal, yet there is no agreed explanation for its function, or why and when it evolved. I summarise experimental evidence that the primary function of musicking lies in social bonding, both at the dyadic and community levels, via the effect that performing any form of music has on the brain’s endorphin system (the principal neurohormonal basis for social bonding in primates). The many other functions associated with music-making (mate choice, pleasure, coalition signalling, etc) are all better understood as derivative of this, either as secondary selection pressures or as windows of evolutionary opportunity (exaptations). If music’s function is primarily as an adjunct of the social bonding mechanism (a feature it shares with laughter, feasting, storytelling and the rituals of religion), then reverse engineering the problem suggests that the capacity for music-making most likely evolved with the appearance of archaic humans. This agrees well with anatomical evidence for the capacity to sing
Higher order intentionality tasks are cognitively more demanding
A central assumption that underpins much of the discussion of the role played by social cognition in brain evolution is that social cognition is unusually cognitively demanding. This assumption has never been tested. Here, we use a task in which participants read stories and then answered questions about the stories in a behavioural experiment (39 participants) and an fMRI experiment (17 participants) to show that mentalising requires more time for responses than factual memory of a matched complexity and also that higher orders of mentalising are disproportionately more demanding and require the recruitment of more neurons in brain regions known to be associated with theory of mind, including insula, posterior STS, temporal pole and cerebellum. These results have significant implications both for models of brain function and for models of brain evolution
Cognitive resource allocation determines the organization of personal networks
[Póster presentado a]: XXII Congreso de Física Estadística (FisEs'18), Madrid, 18-20 de octubre de 2018.The typical human personal social network contains about 150 relationships including kin, friends, and acquaintances, organized into a set of hierarchically inclusive layers of increasing size but decreasing emotional intensity. Data from a number of different sources reveal that these inclusive layers exhibit a constant scaling ratio of ∼3. While the overall size of the networks has been connected to our cognitive capacity, no mechanism explaining why the networks present a layered structure with a consistent scaling has been proposed. Here we show that the existence of a heterogeneous cost to relationships (in terms of time or cognitive investment), together with a limitation in the total capacity an individual has to invest in them, can naturally explain the existence of layers and, when the cost function is linear, explain the scaling between them. We develop a one-parameter Bayesian model that fits the empirical data remarkably well. In addition, the model predicts the existence of a contrasting regime in the case of small communities, such that the layers have an inverted structure (increasing size with increasing emotional intensity). We test the model with five communities and provide clear evidence of the existence of the two predicted regimes. Our model explains, based on first principles, the emergence of structure in the organization of personal networks and allows us to predict a rare phenomenon whose existence we confirm empirically
Cognitive resource allocation determines the organization of personal networks
The typical human personal social network contains about 150 relationships including kin, friends, and acquaintances, organized into a set of hierarchically inclusive layers of increasing size but decreasing emotional intensity. Data from a number of different sources reveal that these inclusive layers exhibit a constant scaling ratio of 3. While the overall size of the networks has been connected to our cognitive capacity, no mechanism explaining why the networks present a layered structure with a consistent scaling has been proposed. Here we show that the existence of a heterogeneous cost to relationships (in terms of time or cognitive investment), together with a limitation in the total capacity an individual has to invest in them, can naturally explain the existence of layers and, when the cost function is linear, explain the scaling between them. We develop a one-parameter Bayesian model that fits the empirical data remarkably well. In addition, the model predicts the existence of a contrasting regime in the case of small communities, such that the layers have an inverted structure (increasing size with increasing emotional intensity). We test the model with five communities and provide clear evidence of the existence of the two predicted regimes. Our model explains, based on first principles, the emergence of structure in the organization of personal networks and allows us to predict a rare phenomenon whose existence we confirm empirically.I.T., J.A.C., and A.S. were supported in part by Fundación Banco Bilbao Vizcaya Argentaria through Grant Los Números de Dunbar y la Estructura de las Sociedades Digitales: Modelización y Simulación; by Ministerio de Economía, Innovación y Competitividad (Spain) through Grants FIS2015-64349-P VARIANCE (Ministerio
de Economía y Empresa/Fondo Europeo de Desarrollo Regional, Unión Europea);
and by the European Commission through FET Open Research and
Innovation Action 662725 Bridging the Gap: From Individual Behaviour to
the Socio-Technical Man and FET Proactive RIA 640772 Distributed Global
Financial Systems for Society. R.I.M.D. was supported by the European
Research Council Advanced Investigator through Grant 295663
The role of religion in adolescent mental health: faith as a moderator of the relationship between distrust and depression
It has recently been shown that interpersonal distrust predicts depressive symptoms in middle adolescence, and this finding has been interpreted in light of Social Safety Theory, which views distrust as an index of social threat. Here we hypothesize that religiousness provides social safety and may counteract the sense of social threat indexed by distrust. Religiousness should therefore act as a moderator between interpersonal distrust and depression. Using a nationally representative birth cohort from the UK, we provide evidence in favor of this hypothesis, even after controlling for stratum disadvantage and socioeconomic characteristics, sex, ethnicity, and multiple confounders on the level of the individual (BMI, chronic illness, cognitive ability, risk-taking, experiencing bullying, dietary habits, chronotype, physical activity and screen time), family context (frequency of eating meals together, maternal mental health), and neighborhood ecology (NO2 levels of air pollution)
Stability of the personal relationship networks in a longitudinal study of middle school students
The personal network of relationships is structured in circles of
friendships, that go from the most intense relationships to the least intense
ones. While this is a well established result, little is known about the
stability of those circles and their evolution in time. To shed light on this
issue, we study the temporal evolution of friendships among teenagers during
two consecutive academic years by means of a survey administered on five
occasions. We show that the first two circles, best friends and friends, can be
clearly observed in the survey but also that being in one or the other leads to
more or less stable relationships. We find that being in the same class is one
of the key drivers of friendship evolution. We also observe an almost constant
degree of reciprocity in the relationships, around 60%, a percentage influenced
both by being in the same class and by gender homophily. Not only do our
results confirm the mounting evidence supporting the circle structure of human
social networks, but they also show that these structures persist in time
despite the turnover of individual relationships -- a fact that may prove
particularly useful for understanding the social environment in middle schools.Comment: 10 pages, 7 figures, requires wlscirep.cls, jabbrv.sty,
jabbrv-ltwa-all.ldf, and jabbrv-ltwa-en.ldf (included
Fractal structure of human and primate social networks optimizes information flow
Article describes how primate and human social groups exhibit a fractal structure that has a very limited range of preferred layer sizes. The authors calculate the size dependence of the scaling properties of complex social network models and argue that this aggregate behavior exhibits a form of collective intelligence
Daily Rhythms in Mobile Telephone Communication
Circadian rhythms are known to be important drivers of human activity and the recent availability of electronic records of human behaviour has provided fine-grained data of temporal patterns of activity on a large scale. Further, questionnaire studies have identified important individual differences in circadian rhythms, with people broadly categorised into morning-like or evening-like individuals. However, little is known about the social aspects of these circadian rhythms, or how they vary across individuals. In this study we use a unique 18-month dataset that combines mobile phone calls and questionnaire data to examine individual differences in the daily rhythms of mobile phone activity. We demonstrate clear individual differences in daily patterns of phone calls, and show that these individual differences are persistent despite a high degree of turnover in the individuals' social networks. Further, women's calls were longer than men's calls, especially during the evening and at night, and these calls were typically focused on a small number of emotionally intense relationships. These results demonstrate that individual differences in circadian rhythms are not just related to broad patterns of morningness and eveningness, but have a strong social component, in directing phone calls to specific individuals at specific times of day.TA and JS were funded by The Academy of Finland, project No. 260427 (http://www.aka.fi) and the computational resources were provided by Aalto 379 Science-IT project. The study was funded by a grant from the UK Engineering and Physical Sciences Research Council and Economic and Social Research Council (grant No. EP/D052114/2). RD is funded by European Research Council (grant no. 295663). The 380 collection of the data by SGBR and RD was made possible by a grant from the UK 381 EPSRC and ESRC research councils. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
A dominant social comparison heuristic unites alternative mechanisms for the evolution of indirect reciprocity
Cooperation is a fundamental human trait but our understanding of how it functions remains incomplete. Indirect reciprocity is a particular case in point, where one-shot donations are made to unrelated beneficiaries without any guarantee of payback. Existing insights are largely from two independent perspectives: i) individual-level cognitive behaviour in decision making, and ii) identification of conditions that favour evolution of cooperation. We identify a fundamental connection between these two areas by examining social comparison as a means through which indirect reciprocity can evolve. Social comparison is well established as an inherent human disposition through which humans navigate the social world by self-referential evaluation of others. Donating to those that are at least as reputable as oneself emerges as a dominant heuristic, which represents aspirational homophily. This heuristic is found to be implicitly present in the current knowledge of conditions that favour indirect reciprocity. The effective social norms for updating reputation are also observed to support this heuristic. We hypothesise that the cognitive challenge associated with social comparison has contributed to cerebral expansion and the disproportionate human brain size, consistent with the social complexity hypothesis. The findings have relevance for the evolution of autonomous systems that are characterised by one-shot interactions
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