A neurochemical hypothesis for the origin of hominids

It has always been difficult to account for the evolution of certain human characters such as language, empathy, and altruism via individual reproductive success. However, the striatum, a subcortical region originally thought to be exclusively motor, is now known to contribute to social behaviors and “personality styles” that may link such complexities with natural selection. We here report that the human striatum exhibits a unique neurochemical profile that differs dramatically from those of other primates. The human signature of elevated striatal dopamine, serotonin, and neuropeptide Y, coupled with lowered acetylcholine, systematically favors externally driven behavior and greatly amplifies sensitivity to social cues that promote social conformity, empathy, and altruism. We propose that selection induced an initial form of this profile in early hominids, which increased their affiliative behavior, and that this shift either preceded or accompanied the adoption of bipedality and elimination of the sectorial canine. We further hypothesize that these changes were critical for increased individual fitness and promoted the adoption of social monogamy, which progressively increased cooperation as well as a dependence on tradition-based cultural transmission. These eventually facilitated the acquisition of language by elevating the reproductive advantage afforded those most sensitive to social cues.

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Evolution of Sociality and Nonlinear Population Dynamics

Perturbation, Behavioural Feedbacks, and Population Dynamics in Social Animals ◽

10.1093/oso/9780198849834.003.0006 ◽

2020 ◽

pp. 100-113

Author(s):

Daniel Oro

Keyword(s):

Population Dynamics ◽

Cultural Transmission ◽

Life Histories ◽

Minimum Size ◽

Stable States ◽

Individual Fitness ◽

Social Species ◽

Strong Source ◽

Adaptive Behaviours ◽

Threshold Setting

Sociality appears in many life histories during evolution. Some eusocial bees show evolutionary reversions to solitary behaviour, and populations of the same species can be solitary or social, likely depending on local environmental features. Social species need a minimum size to perform adaptive behaviours, such as the search for resources, which is crucial especially under perturbations. This minimum size may become a threshold, setting a phase transition for separating two stable states, from disorganized and maladaptive to organized and adaptive, which also shows hysteresis. The chapter also explores evolution via facilitation or cooperation (e.g. social information) under the theoretical framework of multilevel selection, by which there is likely an effect of the social group’s genes on individual fitness. Perturbations appear as a strong source of evolutionary processes. In humans, warfare acts as a very powerful selective pressure for competition between groups and thus for cooperation. Sociality has also many costs, such as a higher risk for the spread of infectious disease, the appearance of traps by social haunting philopatry, stronger aggression and competition, and a higher risk of being attacked by predators. Finally, the evolution of cultures is explored; optimization of social learning, social copying, and cultural transmission may have nonlinear consequences for population dynamics.

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Ideological Asymmetries in Motivated Reasoning and the Mechanisms of Attitude Polarization: A Two-Wave Survey Experiment

10.31219/osf.io/agjz2 ◽

2020 ◽

Author(s):

Davide Morisi ◽

Matthew H. Goldberg ◽

John Jost

Keyword(s):

Social Networks ◽

Motivated Reasoning ◽

Social Cues ◽

Survey Experiment ◽

Social Conformity ◽

Political Issues ◽

Attitude Polarization ◽

Ideological Polarization ◽

Balanced Information ◽

The U.S

Are there specific motives that lead individuals to become extreme in their political attitudes after exposure to information? Can these motives explain recent evidence that attitude polariza-tion occurs more on the conservative than the liberal side? We propose that two mechanisms, related to relational motives to engage in social conformity and epistemic motives to reduce uncertainty, might contribute to answering these questions. We used experimental manipula-tions to induce relational and epistemic motives in a two-wave survey experiment, in which we exposed participants to balanced information pertaining highly salient political issues in the U.S. Our results suggest that relational motives to maintain homogenous social networks are highly pertinent to how people, especially political conservatives, process information and make up their minds about important social and political issues. When exposed to social cues indicating where liberals and conservatives stand on specific issues, the two groups became fur-ther apart in their attitudes. Furthermore, we observed that, in the presence of social cues, con-servatives were more likely to develop extreme attitudes than liberals, triggering asymmetric polarization. Contrary to our predictions, however, we did not obtain consistent evidence of in-creased ideological polarization when epistemic motives to reduce uncertainty were present, although we found that conservatives (and not liberals) displayed a stronger confirmation bias in the evaluation of political arguments when uncertainty was high (compared to low).

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Two-year old children preferentially transmit simple actions but not pedagogically demonstrated actions

10.31234/osf.io/mvepf ◽

2020 ◽

Author(s):

Marina Bazhydai ◽

Priya Silverstein ◽

Eugenio Parise ◽

Gert Westermann

Keyword(s):

Learning Environment ◽

Information Transmission ◽

Cultural Transmission ◽

Social Cues ◽

Previous Literature ◽

Social Aspects ◽

Transmitted Information ◽

Preferential Transmission ◽

Transmission Of Knowledge ◽

Competing Hypotheses

Children are sensitive to both social and non-social aspects of the learning environment. Among social cues, pedagogical communication has been shown to not only play a role in children’s learning, but also in their own active transmission of knowledge. Vredenburgh et al. (2015) showed that 2-year-olds are more likely to demonstrate an action to a naive adult after learning it in a pedagogical than in a non-pedagogical context. This finding was interpreted as evidence that pedagogically transmitted information has a special status as culturally relevant. Here we test the limits of this claim by setting it in contrast with an explanation in which the relevance of information is the outcome of multiple interacting social (e.g., pedagogical demonstration) and non-social properties (e.g., action complexity). To test these competing hypotheses, we varied both pedagogical cues and action complexity in an information transmission paradigm with 2-year-old children. In Experiment 1, children preferentially transmitted simple non-pedagogically demonstrated actions over pedagogically demonstrated more complex actions. In Experiment 2, when both actions were matched for complexity, we found no evidence of preferential transmission of pedagogically demonstrated actions. We discuss possible reasons for the discrepancy between our results and previous literature showing an effect of pedagogical cues on cultural transmission and conclude that our results are compatible with the view that pedagogical and other cues interact, but incompatible with the theory of a privileged role for pedagogical cues.

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Do songbirds attend to song categories when selecting breeding habitat? A case study with a wood warbler

Behaviour ◽

10.1163/1568539x-00003461 ◽

2017 ◽

Vol 154 (11) ◽

pp. 1123-1144 ◽

Cited By ~ 5

Author(s):

Janice K. Kelly ◽

Michael P. Ward

Keyword(s):

Habitat Selection ◽

Social Cues ◽

Breeding Habitat ◽

Yellow Warbler ◽

Individual Fitness ◽

First Category ◽

Different Types ◽

Yellow Warblers ◽

Second Category

Breeding habitat selection strongly affects reproduction and individual fitness. Among birds, using social cues from conspecifics to select habitat is widespread, but how different types of conspecific social cues influence breeding habitat selection remains less understood. We conducted a playback experiment evaluating if the yellow warbler (Setophaga petechia), a species with two song categories linked to pairing status, uses categories differently when selecting breeding habitat. We hypothesized that yellow warblers use second-category singing mode, which is mostly sung by paired males, over first-category singing mode for habitat selection, as successfully paired males should indicate higher-quality habitat. We broadcast yellow warbler first-category singing mode, second-category singing mode, and silent controls at sites in Illinois. Yellow warblers were more abundant at sites treated with second-category singing mode compared other sites. Our results demonstrate that yellow warblers use social cues informing successful pairing over other types of social cues to select breeding habitat.

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Early hominids may have been weed species

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1719669115 ◽

2018 ◽

Vol 115 (6) ◽

pp. 1244-1249 ◽

Cited By ~ 4

Author(s):

Richard S. Meindl ◽

Morgan E. Chaney ◽

C. Owen Lovejoy

Keyword(s):

Common Ancestor ◽

Last Common Ancestor ◽

Social Monogamy ◽

Female Mortality ◽

Weed Species ◽

Early Hominid ◽

Early Hominids ◽

Female Survival ◽

Locomotor Patterns ◽

Birth Space

Panid, gorillid, and hominid social structures appear to have diverged as dramatically as did their locomotor patterns as they emerged from a late Miocene last common ancestor (LCA). Despite their elimination of the sectorial canine complex and adoption of bipedality with its attendant removal of their ready access to the arboreal canopy, Australopithecus was able to easily invade novel habitats after florescence from its likely ancestral genus, Ardipithecus sp. Other hominoids, unable to sustain sufficient population growth, began an inexorable decline, culminating in their restriction to modern refugia. Success similar to that of earliest hominids also characterizes several species of macaques, often termed “weed species.” We here review their most salient demographic features and find that a key element is irregularly elevated female survival. It is reasonable to conclude that a similar feature characterized early hominids, most likely made possible by the adoption of social monogamy. Reduced female mortality is a more probable key to early hominid success than a reduction in birth space, which would have been physiologically more difficult.

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Individual and collective encoding of risk in animal groups

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1905585116 ◽

2019 ◽

Vol 116 (41) ◽

pp. 20556-20561 ◽

Cited By ~ 10

Author(s):

Matthew M. G. Sosna ◽

Colin R. Twomey ◽

Joseph Bak-Coleman ◽

Winnie Poel ◽

Bryan C. Daniels ◽

...

Keyword(s):

Perceived Risk ◽

Structural Connectivity ◽

Group Living ◽

Natural World ◽

Social Cues ◽

Animal Groups ◽

Fish Schools ◽

Individual Fitness ◽

Increased Sensitivity ◽

Context Dependent

The need to make fast decisions under risky and uncertain conditions is a widespread problem in the natural world. While there has been extensive work on how individual organisms dynamically modify their behavior to respond appropriately to changing environmental conditions (and how this is encoded in the brain), we know remarkably little about the corresponding aspects of collective information processing in animal groups. For example, many groups appear to show increased “sensitivity” in the presence of perceived threat, as evidenced by the increased frequency and magnitude of repeated cascading waves of behavioral change often observed in fish schools and bird flocks under such circumstances. How such context-dependent changes in collective sensitivity are mediated, however, is unknown. Here we address this question using schooling fish as a model system, focusing on 2 nonexclusive hypotheses: 1) that changes in collective responsiveness result from changes in how individuals respond to social cues (i.e., changes to the properties of the “nodes” in the social network), and 2) that they result from changes made to the structural connectivity of the network itself (i.e., the computation is encoded in the “edges” of the network). We find that despite the fact that perceived risk increases the probability for individuals to initiate an alarm, the context-dependent change in collective sensitivity predominantly results not from changes in how individuals respond to social cues, but instead from how individuals modify the spatial structure, and correspondingly the topology of the network of interactions, within the group. Risk is thus encoded as a collective property, emphasizing that in group-living species individual fitness can depend strongly on coupling between scales of behavioral organization.

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Competitive advantage of rare behaviours induces adaptive diversity rather than social conformity in skill learning

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2020.1259 ◽

2020 ◽

Vol 287 (1933) ◽

pp. 20201259

Author(s):

Naama Aljadeff ◽

Luc-Alain Giraldeau ◽

Arnon Lotem

Keyword(s):

Social Learning ◽

Cultural Transmission ◽

Skill Learning ◽

Dependent Manner ◽

Social Conformity ◽

Frequency Dependent ◽

Adaptive Diversity ◽

Dependent Learning ◽

Foraging Specialization

Recent studies have emphasized the role of social learning and cultural transmission in promoting conformity and uniformity in animal groups, but little attention has been given to the role of negative frequency-dependent learning in impeding conformity and promoting diversity instead. Here, we show experimentally that under competitive conditions that are common in nature, social foragers (although capable of social learning) are likely to develop diversity in foraging specialization rather than uniformity. Naive house sparrows that were introduced into groups of foraging specialists did not conform to the behaviour of the specialists, but rather learned to use the alternative food-related cues, thus forming groups of complementary specialists. We further show that individuals in such groups may forage more effectively in diverse environments. Our results suggest that when the benefit from socially acquired skills diminishes through competition in a negative frequency-dependent manner, animal societies will become behaviourally diverse rather than uniform.

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Psychology in Outerspace

European Psychologist ◽

10.1027/1016-9040/a000023 ◽

2010 ◽

Vol 15 (3) ◽

pp. 220-228 ◽

Cited By ~ 5

Author(s):

Viren Swami ◽

Tomas Chamorro-Premuzic ◽

Manal Shafi

Keyword(s):

Individual Difference ◽

Sensation Seeking ◽

Structural Equation ◽

Political Orientation ◽

Equation Modeling ◽

Big Five Personality ◽

Social Conformity ◽

Extraterrestrial Life ◽

Paranormal Beliefs ◽

Future Work

Previous work has shown that is important to consider the disjunction between paranormal and nonparanormal beliefs about extraterrestrial life. The current study examined the association between both such beliefs and individual difference and demographic variables. A total of 555 British participants completed the Extraterrestrial Beliefs Scale, as well as measures of their Big Five personality scores, social conformity, sensation seeking, and demographics. Results showed no sex differences in ratings of paranormal and nonparanormal extraterrestrial beliefs, but participants rated nonparanormal beliefs more positively than paranormal beliefs. Results of structural equation modeling showed that individual difference factors (specifically, Openness, Conscientiousness, and social conformity) explained 21% of the variance in extraterrestrial beliefs, whereas demographic factors (specifically, education level, political orientation, and religiosity) explained 16% of the variance. Limitations and directions for future work are considered.

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