The experimental evolution of human culture: flexibility, fidelity and environmental instability.

The past 2 Myr have seen both unprecedented environmental instability and the evolution of the human capacity for complex culture. This, along with the observation that cultural evolution occurs faster than genetic evolution, has led to the suggestion that culture is an adaptation to an unstable environment. We test this hypothesis by examining the ability of human social learning to respond to environmental changes. We do this by inserting human participants (n = 4800) into evolutionary simulations with a changing environment while varying the social information available to individuals across five conditions. We find that human social learning shows some signs of adaptation to environmental instability, including critical social learning, the adoption of up-and-coming traits and, unexpectedly, contrariness. However, these are insufficient to avoid significant fitness declines when the environment changes, and many individuals are highly conformist, which exacerbates the fitness effects of environmental change. We conclude that human social learning reflects a compromise between the competing needs for flexibility to accommodate environmental change and fidelity to accurately transmit valuable cultural information.

Foraging zebra finches (Taeniopygia guttata) are public information users rather than conformists.

Social learning enables adaptive information acquisition provided that it is not random but selective. To understand species typical decision-making and to trace the evolutionary origins of social learning, the heuristics social learners use need to be identified. Here, we experimentally tested the nature of majority influence in the zebra finch. Subjects simultaneously observed two demonstrator groups differing in relative and absolute numbers (ratios 1 : 2/2 : 4/3 : 3/1 : 5) foraging from two novel food sources (black and white feeders). We find that demonstrator groups influenced observers' feeder choices (social learning), but that zebra finches did not copy the majority of individuals. Instead, observers were influenced by the foraging activity (pecks) of the demonstrators and in an anti-conformist fashion. These results indicate that zebra finches are not conformist, but are public information users.

Biased transformation erases traditions sustained by conformist transmission.

Conformist transmission is a cognitively simple decision-making process by which observers are disproportionately likely to follow the majority. It has been studied in multiple species because theory suggests it can create stable cultural variation. However, the current theory assumes that while conformist transmission favours the majority, it is otherwise unbiased and does not systematically transform information, even though such biases are widely documented. Here, we relax this assumption, requiring conformist observers to infer the size of the majority from finite observations of their group mates. Because such inference can be subject to bias, it can lead to the biased transformation of transmitted information. We find that when individuals are biased (even weakly) the capacity of conformist transmission to sustain traditions is reduced and, in many cases, removed entirely. This suggests that the emphasis on conformist transmission as a source of stable cultural variation may be misplaced.

Acoustic localization and tracking of a multi-rotor unmanned aerial vehicle using an array with few microphones.

In recent years, the current technological improvements of unmanned aerial vehicles (UAV) have made drones more difficult to locate using optical or radio-based systems. However, the sound emitted by UAV motorization and the aerodynamic whistling of the UAVs can be exploited using a microphone array and an adequate real time signal processing algorithm. The proposed method takes advantage of the characteristics of the sound emitted by the UAV. The intrinsic harmonic structure of the emitted sound is exploited by a pitch detection algorithm coupled with zero-phase selective bandpass filtering to detect the fundamental of the signal and to extract its specific harmonics. Although three-dimensional position errors are less when signals are filtered within the antenna bandwidth, experimental measurements show that accurate estimates with only a few selected harmonics in the signal can be obtained with the localization process. Kalman filtering is used to smooth the estimates.

A theory limited in scope and evidence.

What promised to be a refreshing addition to cumulative cultural evolution, by moving the focus from cultural transmission to technological innovation, falls flat through a lack of thoroughness, explanatory power, and data. A comprehensive theory of cumulative cultural change must carefully integrate all existing evidence in a cohesive multi-level account. We argue that the manuscript fails to do so convincingly.

The development of adaptive conformity in young children: effects of uncertainty and consensus.

Human culture relies on extensive use of social transmission, which must be integrated with independently acquired (i.e. asocial) information for effective decision-making. Formal evolutionary theory predicts that natural selection should favor adaptive learning strategies, including a bias to copy when uncertain, and a bias to disproportionately copy the majority (known as 'conformist transmission'). Although the function and causation of these evolved strategies has been comparatively well studied, little is known of their development. We experimentally investigated the development of the bias to copy-when-uncertain and conformist transmission in children from the ages of 3 to 7, testing predictions derived from theoretical models. Children first attempted to solve a binary-choice quantity discrimination task themselves using asocial information, but were then given the decisions of informants, and an opportunity to revise their answer. We investigated whether children's revised judgments were adaptively contingent on (i) the difficulty of the trial and (ii) the degree of consensus amongst informants. As predicted, older but not younger children copied others more on more difficult trials than on easier trials, even though older children also showed a tendency to stick with their initial, asocial decision. We also found that older children, like adults, were disproportionately receptive to non-total majorities (i.e. were conformist) whereas younger children were receptive only to total (i.e. unanimous) majorities. We conclude that, whilst the mechanism for incorporating social information into decision-making is initially very blunt, across the course of early childhood it converges on the adaptive learning mechanisms observed in adults and predicted by cultural evolutionary theory. A video abstract of this article can be viewed at http://youtu.be/Qb6JINGYqVk.

Investigating the effects of social information on spite in an online game.

While humans are highly cooperative, they can also behave spitefully. Yet spite remains understudied. Spite can be normatively driven and while previous experiments have found some evidence that cooperation and punishment may spread via social learning, no experiments have considered the social transmission of spiteful behaviour. Here we present an online experiment where, following an opportunity to earn wealth, we asked participants to choose an action towards an anonymous partner across a full spectrum of social behaviour, from spite to altruism. In accordance with cultural evolutionary theory, participants were presented with social information that varied in source and content. Across six conditions, we informed participants that either the majority or the highest earner had chosen to behave spitefully, neutrally or altruistically. We found an overall tendency towards altruism, but at lower levels among those exposed to spite compared with altruism. We found no difference between social information that came from the majority or the highest earner. Exploratory analysis revealed that participants' earnings negatively correlated with altruistic behaviour. Our results contrast with previous literature that report high rates of spite in experimental samples and a greater propensity for individuals to copy successful individuals over the majority.

Homing characteristics of donor T cells after experimental allogeneic bone marrow transplantation and posttransplantation therapy for multiple myeloma.

Relapse and graft-versus-host disease remain major problems associated with allogeneic bone marrow (BM) transplantation (allo-BMT) and posttransplantation therapy in patients with multiple myeloma (MM) and other hematologic malignancies. A possible strategy for selectively enhancing the graft-versus-myeloma response and possibly reducing graft-versus-host disease is to increase the migration of alloreactive T cells toward the MM-containing BM. In the present study, we characterized the BM-homing behavior of donor-derived effector T cells in a novel allo-BMT model for the treatment of MM. We observed that posttransplantation immunotherapy consisting of donor lymphocyte infusion (DLI) and vaccination with minor histocompatibility antigen-loaded dendritic cells (DCs) was associated with prolonged survival compared with allo-BMT with no further treatment. Moreover, CD8(+) effector T cells expressing inflammatory homing receptors, including high levels of CD44, LFA-1, and inflammatory chemokine receptors, were recruited to MM-bearing BM. This was paralleled by strongly increased expression of IFN-γ and IFN-γ-inducible chemokines, including CXCL9, CXCL10, and CXCL16, especially in mice treated with DLI plus minor histocompatibility antigen-loaded DC vaccination. Remarkably, expression of the homeostatic chemokine CXCL12 was reduced. Furthermore, IFN-γ and TNF-α induced BM endothelial cells to express high levels of the inflammatory chemokines and reduced or unaltered levels of CXCL12. Finally, presentation of CXCL9 by multiple BM endothelial cell-expressed heparan sulfate proteoglycans triggered transendothelial migration of effector T cells. Taken together, our data demonstrate that both post-transplantation DLI plus miHA-loaded DC vaccination and MM growth result in an increased expression of inflammatory homing receptors on donor T cells, decreased levels of the homeostatic BM-homing chemokine CXCL12, and strong induction of inflammatory chemokines in the BM. Thus, along with increasing the population of alloreactive T cells, post-transplantation immunotherapy also might contribute to a more effective graft-versus-tumor response by switching homeostatic T cell migration to inflammation-driven migration.

Inferring the age and sex of ancient potters from fingerprint ridge densities: A data-driven, Bayesian mixture modelling approach.

The density of epidermal ridges in a fingerprint varies predictably by age and sex. Archaeologists are therefore interested in using recovered fingerprints to learn about the ancient people who produced them. Recent studies focus on estimating the age and sex of individuals by measuring their fingerprints with one of two similar metrics: mean ridge breadth (MRB) or ridge density (RD). Yet these attempts face several critical problems: expected values for adult females and adolescent males are inherently indistinguishable, and inter-assemblage variation caused by biological and technological differences cannot be easily estimated. Each of these factors greatly decreases the accuracy of predictions based on individual prints, and together they condemn this strategy to relative uselessness. However, information in fingerprints from across an assemblage can be pooled to generate a more accurate depiction of potter demographics. We present a new approach to epidermal ridge density analysis using Bayesian mixture models with the following key benefits:•Age and sex are estimated more accurately than existing methods by incorporating a data-driven understanding of how demographics and ridge density covary.•Uncertainty in demographic estimates is automatically quantified and included in output.•The Bayesian framework can be easily adapted to fit the unique needs of different researchers.

A quantitative proteomic analysis of lung epithelial (A549) cells infected with 2009 pandemic influenza A virus using stable isotope labelling with amino acids in cell culture.

Influenza A virus is one of the world's major uncontrolled pathogens, causing seasonal epidemics as well as global pandemics. This was evidenced by the recent emergence and now prevalence of the 2009 swine origin pandemic H1N1 influenza A virus. In this study, quantitative proteomics using stable isotope labelling with amino acids in cell culture was used to investigate the changes in the host cell proteome in cells infected with pandemic H1N1 influenza A virus. The study was conducted in A549 cells that retain properties similar to alveolar cells. Several global pathways were affected, including cell cycle regulation and lipid metabolism, and these could be correlated with recent microarray analyses of cells infected with influenza A virus. Taken together, both quantitative proteomics and transcriptomic approaches can be used to identify potential cellular proteins whose functions in the virus life cycle could be targeted for chemotherapeutic intervention.

The addictive brain: all roads lead to dopamine.

This article will touch on theories, scientific research and conjecture about the evolutionary genetics of the brain function and the impact of genetic variants called polymorphisms on drug-seeking behavior. It will cover the neurological basis of pleasure-seeking and addiction, which affects multitudes in a global atmosphere where people are seeking "pleasure states".

Early intervention of intravenous KB220IV--neuroadaptagen amino-acid therapy (NAAT) improves behavioral outcomes in a residential addiction treatment program: a pilot study.

Substance use disorders (SUD) are inheritable and the culprit is hypodopaminergic function regulated by reward genes. We evaluated a natural dopaminergic agonist; KB220 intravenous (IV) and oral variants, to improve dopaminergic function in SUD. Our pilot experiment found a significant reduction of chronic symptoms, measured by the Chronic Abstinence Symptom Severity (CASS) Scale. The combined group (IV and oral) did significantly better than the oral-only group over the first week and 30-day follow-up period. Next, the combination was given to 129 subjects and three factors; Emotion, Somatic, and Impaired Cognition, with eigenvalues greater than one were extracted for baseline CASS-Revised (CASS-R) variables. Paired sample t-tests for pre and post-treatment scales showed significant declines (p = .00001) from pre- to post-treatment: t = 19.1 for Emotion, t = 16.1 for Somatic, and t = 14.9 for Impaired Cognition. In a two-year follow-up of 23 subjects who underwent KB220IV therapy (at least five IV treatments over seven days) plus orals for 30+ days: 21 (91%) were sober at six months, 19 (82%) having no relapse; 19 (82%) were sober at one year, 18 (78%) having no relapse; and 21 (91%) were sober two-years post-treatment, 16(70%) having no relapse. We await additional research and advise caution in interpreting these encouraging results.

A novel cosmetic approach to treat thinning hair.

BACKGROUND: Many of today's treatments associated with 'thinning hair', such as female pattern hair loss and telogen effluvium, are focused on two of the key aspects of the condition. Over-the-counter or prescription medications are often focused on improving scalp hair density while high-quality cosmetic products work to prevent further hair damage and minimize mid-fibre breakage. Fibre diameter is another key contributor to thinning hair, but it is less often the focus of medical or cosmetic treatments. OBJECTIVES: To examine the ability of a novel leave-on technology combination [caffeine, niacinamide, panthenol, dimethicone and an acrylate polymer (CNPDA)] to affect the diameter and behaviour of individual terminal scalp hair fibres as a new approach to counteract decreasing fibre diameters. METHODS: Testing methodology included fibre diameter measures via laser scan micrometer, assessment of fibre mechanical and behavioural properties via tensile break stress and torsion pendulum testing, and mechanistic studies including cryoscanning electron microscopy and autoradiographic analysis. RESULTS: CNPDA significantly increased the diameter of individual, existing terminal scalp hair fibres by 2-5 µm, which yields an increase in the cross-sectional area of approximately 10%. Beyond the diameter increase, the CNPDA-thickened fibres demonstrated the altered mechanical properties characteristic of thicker fibres: increased suppleness/pliability (decreased shear modulus) and better ability to withstand force without breaking (increased break stress). CONCLUSIONS: Although cosmetic treatments will not reverse the condition, this new approach may help to mitigate the effects of thinning hair.

Neurogenetics and clinical evidence for the putative activation of the brain reward circuitry by a neuroadaptagen: proposing an addiction candidate gene panel map.

This document presents evidence supporting the role of the KB220/KB220Z neuroadaptagens consisting of amino-acid neurotransmitter precursors and enkephalinase-catecholamine-methyl-transferase (COMT) inhibition therapy called Neuroadaptagen Amino Acid Therapy (NAAT) in brain reward function. It is becoming increasingly clear that this novel formulation is the first neuroadaptagen known to activate the brain reward circuitry. Ongoing research repeatedly confirms the numerous clinical effects that ultimately result in significant benefits for victims having genetic antecedents for all addictive, compulsive and impulsive behaviors. These behaviors are correctly classified under the rubric of"Reward Deficiency Syndrome" (RDS). We are proposing a novel addiction candidate gene map. We present preliminary findings in the United States using qEGG and in China using Functional Magnetic Resonance Imaging (fMRI) regarding the effects of oral NAAT on the activation of brain reward circuitry in victims of SUD. In unpublished data utilizing an fMRI 2X2 design at resting state, NAAT in comparison to placebo shows activation of the caudate brain region and potentially a smoothing out of heroin-induced putamen (a site for emotionality) abnormal connectivity. Although awaiting final analysis, if confirmed by ongoing studies in China coupled with published qEEG results in America, showing an increase in alpha and low beta, NAAT may be shown to impact treatment outcomes.

H-Wave® effects on blood flow and angiogenesis in longitudinal studies in rats.

Effects of repeated H-Wave® device stimulation (HWDS) on blood flow and angiogenesis in the rat hind limb were studied. The hypothesis tested was that HWDS acutely increases hind limb blood flow, and that repeated HWDS would elicit angiogenesis. Animals were HWDS-conditioned (``Conditioned'') or sham-stimulated (``Sham'') (n = 5/group) daily for 3 weeks. The contralateral limb in both groups served as the control. Each animal was injected with bromodeoxyuridine (BrDU). After 3 weeks, rats were anesthetized and iliac artery blood flow was measured bilaterally before, during, and after acute HWDS. HWDS of the Conditioned limbs elicited a 247% increase in blood flow above resting conditions compared to a 200% increase in control legs. Sham animals did not demonstrate between-leg differences in flow. Hindlimb musculature staining for BrDU revealed angiogenesis in Conditioned versus Sham groups. Flow changes accompanying HWDS corroborated earlier microvascular findings demonstrating a significant striated muscle arteriolar dilation with HWDS.

Competition for priority harms the reliability of science, but reforms can help.

Incentives for priority of discovery are hypothesized to harm scientific reliability. Here, we evaluate this hypothesis by developing an evolutionary agent-based model of a competitive scientific process. We find that rewarding priority of discovery causes populations to culturally evolve towards conducting research with smaller samples. This reduces research reliability and the information value of the average study. Increased start-up costs for setting up single studies and increased payoffs for secondary results (also known as scoop protection) attenuate the negative effects of competition. Furthermore, large rewards for negative results promote the evolution of smaller sample sizes. Our results confirm the logical coherence of scoop protection reforms at several journals. Our results also imply that reforms to increase scientific efficiency, such as rapid journal turnaround times, may produce collateral damage by incentivizing lower-quality research; in contrast, reforms that increase start-up costs, such as pre-registration and registered reports, may generate incentives for higher-quality research.

Trusting the experts: The domain-specificity of prestige-biased social learning.

Prestige-biased social learning (henceforth "prestige-bias") occurs when individuals predominantly choose to learn from a prestigious member of their group, i.e. someone who has gained attention, respect and admiration for their success in some domain. Prestige-bias is proposed as an adaptive social-learning strategy as it provides a short-cut to identifying successful group members, without having to assess each person's success individually. Previous work has documented prestige-bias and verified that it is used adaptively. However, the domain-specificity and generality of prestige-bias has not yet been explicitly addressed experimentally. By domain-specific prestige-bias we mean that individuals choose to learn from a prestigious model only within the domain of expertise in which the model acquired their prestige. By domain-general prestige-bias we mean that individuals choose to learn from prestigious models in general, regardless of the domain in which their prestige was earned. To distinguish between domain specific and domain general prestige we ran an online experiment (n = 397) in which participants could copy each other to score points on a general-knowledge quiz with varying topics (domains). Prestige in our task was an emergent property of participants' copying behaviour. We found participants overwhelmingly preferred domain-specific (same topic) prestige cues to domain-general (across topic) prestige cues. However, when only domain-general or cross-domain (different topic) cues were available, participants overwhelmingly favoured domain-general cues. Finally, when given the choice between cross-domain prestige cues and randomly generated Player IDs, participants favoured cross-domain prestige cues. These results suggest participants were sensitive to the source of prestige, and that they preferred domain-specific cues even though these cues were based on fewer samples (being calculated from one topic) than the domain-general cues (being calculated from all topics). We suggest that the extent to which people employ a domain-specific or domain-general prestige-bias may depend on their experience and understanding of the relationships between domains.

Compatibility of omega-functionality in the electrochemically directed self-assembly of monolayers on gold from alkyl thiosulfates.

Self-assembled monolayers were formed on gold electrochemically from omega-functionalized alkyl thiosulfates (Bunte salts). The resulting SAMs were characterized using X-ray photoelectron spectroscopy (XPS), contact-angle goniometry, and ellipsometry. A range of terminal functionality was examined, including CH(3), perfluoroalkyl, CO(2)H, CO(2)CH(3), CONH(2), CH(2)OH, and vinyl groups. Side-reactions involving some of these functional groups were consistent with intermediates proposed in our earlier publications and begin to define the scope of this method for building chemical structures at interfaces.

Real-time near-field acoustic holography for continuously visualizing nonstationary acoustic fields.

Near-field acoustic holography (NAH) is an effective tool for visualizing acoustic sources from pressure measurements made in the near-field of sources using a microphone array. The method involving the Fourier transform and some processing in the frequency-wavenumber domain is suitable for the study of stationary acoustic sources, providing an image of the spatial acoustic field for one frequency. When the behavior of acoustic sources fluctuates in time, NAH may not be used. Unlike time domain holography or transient method, the method proposed in the paper needs no transformation in the frequency domain or any assumption about local stationary properties. It is based on a time formulation of forward sound prediction or backward sound radiation in the time-wavenumber domain. The propagation is described by an analytic impulse response used to define a digital filter. The implementation of one filter in forward propagation and its inverse to recover the acoustic field on the source plane implies by simulations that real-time NAH is viable. Since a numerical filter is used rather than a Fourier transform of the time-signal, the emission on a point of the source may be rebuilt continuously and used for other post-processing applications.

Cultural adaptation is maximised when intelligent individuals rarely think for themselves.

Humans are remarkable in their reliance on cultural inheritance, and the ecological success this has produced. Nonetheless, we lack a thorough understanding of how the cognitive underpinnings of cultural transmission affect cultural adaptation across diverse tasks. Here, we use an agent-based simulation to investigate how different learning mechanisms (both social and asocial) interact with task structure to affect cultural adaptation. Specifically, we compared learning through refinement, recombination or both, in tasks of different difficulty, with learners of different asocial intelligence. We find that for simple tasks all learning mechanisms are roughly equivalent. However, for hard tasks, performance was maximised when populations consisted of highly intelligent individuals who nonetheless rarely innovated and instead recombined existing information. Our results thus show that cumulative cultural adaptation relies on the combination of individual intelligence and 'blind' population-level processes, although the former may be rarely used. The counterintuitive requirement that individuals be highly intelligent, but rarely use this intelligence, may help resolve the debate over the role of individual intelligence in cultural adaptation.