Universal interpretations of vocal music.

Despite the variability of music across cultures, some types of human songs share acoustic characteristics. For example, dance songs tend to be loud and rhythmic, and lullabies tend to be quiet and melodious. Human perceptual sensitivity to the behavioral contexts of songs, based on these musical features, suggests that basic properties of music are mutually intelligible, independent of linguistic or cultural content. Whether these effects reflect universal interpretations of vocal music, however, is unclear because prior studies focus almost exclusively on English-speaking participants, a group that is not representative of humans. Here, we report shared intuitions concerning the behavioral contexts of unfamiliar songs produced in unfamiliar languages, in participants living in Internet-connected industrialized societies (n = 5,516 native speakers of 28 languages) or smaller-scale societies with limited access to global media (n = 116 native speakers of three non-English languages). Participants listened to songs randomly selected from a representative sample of human vocal music, originally used in four behavioral contexts, and rated the degree to which they believed the song was used for each context. Listeners in both industrialized and smaller-scale societies inferred the contexts of dance songs, lullabies, and healing songs, but not love songs. Within and across cohorts, inferences were mutually consistent. Further, increased linguistic or geographical proximity between listeners and singers only minimally increased the accuracy of the inferences. These results demonstrate that the behavioral contexts of three common forms of music are mutually intelligible cross-culturally and imply that musical diversity, shaped by cultural evolution, is nonetheless grounded in some universal perceptual phenomena.

Discovering the unknown unknowns of research cartography with high-throughput natural description.

To succeed, we posit that research cartography will require high-throughput natural description to identify unknown unknowns in a particular design space. High-throughput natural description, the systematic collection and annotation of representative corpora of real-world stimuli, faces logistical challenges, but these can be overcome by solutions that are deployed in the later stages of integrative experiment design.

Subjective selection and the evolution of complex culture.

Why is culture the way it is? Here I argue that a major force shaping culture is subjective (cultural) selection, or the selective retention of cultural variants that people subjectively perceive as satisfying their goals. I show that people evaluate behaviors and beliefs according to how useful they are, especially for achieving goals. As they adopt and pass on those variants that seem best, they iteratively craft culture into increasingly effective-seeming forms. I argue that this process drives the development of many cumulatively complex cultural products, including effective technology, magic and ritual, aesthetic traditions, and institutions. I show that it can explain cultural dependencies, such as how certain beliefs create corresponding new practices, and I outline how it interacts with other cultural evolutionary processes. Cultural practices everywhere, from spears to shamanism, develop because people subjectively evaluate them to be effective means of satisfying regular goals.

Why is there shamanism? Developing the cultural evolutionary theory and addressing alternative accounts.

The commentators endorse the conceptual and ethnographic synthesis presented in the target article, suggest extensions and elaborations of the theory, and generalize its logic to explain apparently similar specializations. They also demand clarity about psychological mechanisms, argue against conclusions drawn about empirical phenomena, and propose alternative accounts for why shamanism develops. Here, I respond.

The cultural evolution of shamanism.

Shamans, including medicine men, mediums, and the prophets of religious movements, recur across human societies. Shamanism also existed among nearly all documented hunter-gatherers, likely characterized the religious lives of many ancestral humans, and is often proposed by anthropologists to be the "first profession," representing the first institutionalized division of labor beyond age and sex. In this article, I propose a cultural evolutionary theory to explain why shamanism consistently develops and, in particular, (1) why shamanic traditions exhibit recurrent features around the world; (2) why shamanism professionalizes early, often in the absence of other specialization; and (3) how shifting social conditions affect the form or existence of shamanism. According to this theory, shamanism is a set of traditions developed through cultural evolution that adapts to people's intuitions to convince observers that a practitioner can influence otherwise unpredictable, significant events. The shaman does this by ostensibly transforming during initiation and trance, violating folk intuitions of humanness to assure group members that he or she can interact with the invisible forces that control uncertain outcomes. Entry requirements for becoming a shaman persist because the practitioner's credibility depends on his or her "transforming." This contrasts with dealing with problems that have identifiable solutions (such as building a canoe), in which credibility hinges on showing results and outsiders can invade the jurisdiction by producing the outcome. Shamanism is an ancient human institution that recurs because of the capacity of cultural evolution to produce practices adapted to innate psychological tendencies.

Self-interested agents create, maintain, and modify group-functional culture.

We agree that institutions and rules are crucial for explaining human sociality, but we question the claim of there not being "alternatives to CGS [that] can easily account for the institutionalized cooperation that characterizes human societies" (target article, sect. 7). Hypothesizing that self-interested individuals coercively and collaboratively create rules, we propose that agent-based hypotheses offer viable alternatives to cultural group selection (CGS).

Potential Leaders Trade Off Goal-Oriented and Socially Oriented Behavior in Mobile Animal Groups.

Leadership is widespread across the animal kingdom. In self-organizing groups, such as fish schools, theoretical models predict that effective leaders need to balance goal-oriented motion, such as toward a known resource, with their tendency to be social. Increasing goal orientation is predicted to increase decision speed and accuracy, but it is also predicted to increase the risk of the group splitting. To test these key predictions, we trained fish (golden shiners, Notemigonus crysoleucas) to associate a spatial target with a food reward ("informed" individuals) before testing each singly with a group of eight untrained fish who were uninformed ("naive") about the target. Informed fish that exhibited faster and straighter paths (indicative of greater goal orientation) were more likely to reach their preferred target and did so more quickly. However, such behavior was associated with a tendency to leave untrained fish behind and, therefore, with failure to transmit their preference to others. Either all or none of the untrained fish stayed with the trained fish in the majority of trials. Using a simple model of self-organized coordination and leadership in groups, we recreate these features of leadership observed experimentally, including the apparent consensus behavior among naive individuals. Effective leadership thus requires informed individuals to appropriately balance goal-oriented and socially oriented behavior.

Do institutions evolve like material technologies?

Norms and institutions enable large-scale human cooperation by creating shared expectations and changing individuals' incentives via monitoring or sanctioning. Like material technologies, these social technologies satisfy instrumental ends and solve difficult problems. However, the similarities and differences between the evolution of material technologies and the evolution of social technologies remain unresolved. Here, we review evidence suggesting that, compared to the evolution of material technologies, institutional and normative evolution exhibits constraints in the production of variation and the selection of useful variants. These constraints stem from the frequency-dependent nature of social technologies and limit the pace and scope of normative and institutional evolution. We conclude by reviewing research on the social transmission of institutions and norms and highlighting an experimental paradigm to study their cultural evolution.

The Putative Virulence Plasmid pYR4 of the Fish Pathogen Yersinia ruckeri Is Conjugative and Stabilized by a HigBA Toxin-Antitoxin System.

The bacterium Yersinia ruckeri causes enteric redmouth disease in salmonids and hence has substantial economic implications for the farmed fish industry. The Norwegian Y. ruckeri outbreak isolate NVH_3758 carries a relatively uncharacterized plasmid, pYR4, which encodes both type 4 pili and a type 4 secretion system. In this study, we demonstrate that pYR4 does not impose a growth burden on the Y. ruckeri host bacterium, nor does the plasmid contribute to twitching motility (an indicator of type 4 pilus function) or virulence in a Galleria mellonella larval model of infection. However, we show that pYR4 is conjugative. We also reveal, through mutagenesis, that pYR4 encodes a functional post-segregational killing system, HigBA, that is responsible for plasmid maintenance within Y. ruckeri. This is the first toxin-antitoxin system to be characterized for this organism. Whilst further work is needed to elucidate the virulence role of pYR4 and whether it contributes to bacterial disease under non-laboratory conditions, our results suggest that the plasmid possesses substantial stability and transfer mechanisms that imply importance within the organism. These results add to our understanding of the mobile genetic elements and evolutionary trajectory of Y. ruckeri as an important commercial pathogen, with consequences for human food production.

The Streptococcus phage protein paratox is an intrinsically disordered protein.

The bacteriophage protein paratox (Prx) blocks quorum sensing in its streptococcal host by directly binding the signal receptor and transcription factor ComR. This reduces the ability of Streptococcus to uptake environmental DNA and protects phage DNA from damage by recombination. Past work characterizing the Prx:ComR molecular interaction revealed that paratox adopts a well-ordered globular fold when bound to ComR. However, solution-state biophysical measurements suggested that Prx may be conformationally dynamic. To address this discrepancy, we investigated the stability and dynamic properties of Prx in solution using circular dichroism, nuclear magnetic resonance, and several fluorescence-based protein folding assays. Our work shows that under dilute buffer conditions Prx is intrinsically disordered. We also show that the addition of kosmotropic salts or protein stabilizing osmolytes induces Prx folding. However, the solute stabilized fold is different from the conformation Prx adopts when it is bound to ComR. Furthermore, we have characterized Prx folding thermodynamics and folding kinetics through steady-state fluorescence and stopped flow kinetic measurements. Our results show that Prx is a highly dynamic protein in dilute solution, folding and refolding within the 10 ms timescale. Overall, our results demonstrate that the streptococcal phage protein Prx is an intrinsically disordered protein in a two-state equilibrium with a solute-stabilized folded form. Furthermore, the solute-stabilized fold is likely the predominant form of Prx in a solute-crowded bacterial cell. Finally, our work suggests that Prx binds and inhibits ComR, and thus quorum sensing in Streptococcus, by a combination of conformational selection and induced-fit binding mechanisms.

Universality, domain-specificity, and development of psychological responses to music.

Humans can find music happy, sad, fearful, or spiritual. They can be soothed by it or urged to dance. Whether these psychological responses reflect cognitive adaptations that evolved expressly for responding to music is an ongoing topic of study. In this Review, we examine three features of music-related psychological responses that help to elucidate whether the underlying cognitive systems are specialized adaptations: universality, domain-specificity, and early expression. Focusing on emotional and behavioural responses, we find evidence that the relevant psychological mechanisms are universal and arise early in development. However, the existing evidence cannot establish that these mechanisms are domain-specific. To the contrary, many findings suggest that universal psychological responses to music reflect more general properties of emotion, auditory perception, and other human cognitive capacities that evolved for non-musical purposes. Cultural evolution, driven by the tinkering of musical performers, evidently crafts music to compellingly appeal to shared psychological mechanisms, resulting in both universal patterns (such as form-function associations) and culturally idiosyncratic styles.

Acute Subjective Effects of Psychedelics within and Beyond WEIRD Contexts.

Reports of psychedelic experiences may contain similarities and differences across cultural contexts, but most current characterizations and quantifications of psychedelic experiences come from Western medical and naturalistic settings. In this article, we begin with a brief history of the diversity of psychedelic use in non-Western settings. We then compare and contrast accounts of psychedelic experiences within and beyond Western, educated, industrialized, rich, and democratic (WEIRD) contexts. We focus on specific reports of direct testimony of the acute subjective effects of psychedelics experienced across these contexts. We compare themes from each of these various contexts, with special emphasis on psychometric measures such as the mystical experiences questionnaire (MEQ), the five-dimensional altered states of consciousness (5D-ASC) scale, the Survey of God Encounters, and the Survey of Entity Encounters, the Challenging Experiences Questionnaire, and the Inventory of Nonordinary Experiences (INOE). Finally, we offer recommendations for future research to quantify these similarities and differences across cultures to assess them empirically in the future.

Belief changes associated with psychedelic use.

BACKGROUND: Psychedelic use is anecdotally associated with belief changes, although few studies have tested these claims. AIM: Characterize a broad range of psychedelic occasioned belief changes. SURVEY: A survey was conducted in 2374 respondents who endorsed having had a belief changing psychedelic experience. Participants rated their agreement with belief statements Before and After the psychedelic experience as well as at the time of survey administration. RESULTS: Factor analysis of 45 belief statements revealed five factors: "Dualism," "Paranormal/Spirituality," "Non-mammal consciousness," "Mammal consciousness," and "Superstition." Medium to large effect sizes from Before to After the experience were observed for increases in beliefs in "Dualism" (ß = 0.72), "Paranormal/Spirituality" (ß = 0.90), "Non-mammal consciousness" (ß = 0.72), and "Mammal consciousness" (ß = 0.74). In contrast, negligible changes were observed for "Superstition" (ß = -0.18).). At the individual item level, increases in non-physicalist beliefs included belief in reincarnation, communication with the dead, existence of consciousness after death, telepathy, and consciousness of inanimate natural objects (e.g., rocks). The percentage of participants who identified as a "Believer (e.g., in Ultimate Reality, Higher Power, and/or God, etc.)" increased from 29% Before to 59% After." At both the factor and individual item level, higher ratings of mystical experience were associated with greater changes in beliefs. Belief changes assessed after the experience (an average 8.4 years) remained largely unchanged at the time of survey. CONCLUSIONS: A single psychedelic experience increased a range of non-physicalist beliefs as well as beliefs about consciousness, meaning, and purpose. Further, the magnitude of belief change is associated with qualitative features of the experience.

White Coat Effect: Is It Because of the Hospital Setting, or Is It Physician-Induced?

INTRODUCTION: White coat hypertension (WCH) patients are those individuals who have high blood pressure (BP) in the medical environment but are normal during their daily activities. White coat hypertensive patients with normal daytime ambulatory blood pressure monitoring (ABPM) rapidly progress to sustained hypertension. WCH is mainly treated with non-pharmacological methods. Alpha-1 agonists and beta blockers are logical treatment choices for patients with fixed hypertension with the White Coat Effect (WCE). Masked hypertension patients are those individuals who have normal values at the doctor's office but elevated BP at home or during 24-hour ABPM (24-hour or daytime). ABPM is a more practical and reliable method for detecting patients with WCH. MATERIAL AND METHODS: This observational study was conducted at Dayanand Medical College & Hospital, Ludhiana, over the course of one year (December 2015 to November 2016). The primary objective of the study was to determine whether there was a difference in blood pressure readings between the home setting and the hospital setting. The secondary objective was to determine whether the difference, if present, between the hospital and home readings was due to the hospital setting, physician presence, or a combination of both. Patients with stage 1 hypertension were included in the study, irrespective of antihypertensive treatment. Patients with ischemic heart disease, chronic liver failure, and chronic kidney disease who could not follow protocol instructions were excluded. RESULTS: In our study, the mean age of patients was 53.91±12.86 years. The patient's mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) readings at the hospital were higher than their home readings (p-0.012; p-0.001, respectively). Mean hospital SBP and DBP readings recorded by the physician were higher than readings recorded by patients alone at home (p-0.002; p-0.014, respectively) and alone at the hospital (p-0.004; p-0.001, respectively). BP readings taken by the physician with a manual sphygmomanometer were significantly lower than those taken with a digital sphygmomanometer by patients and physicians in all settings (p<0.05). The mean rise in BP was significant in both the physician's presence and the hospital environment (p<0.05 for both), and this rise was more significantly associated with the hospital effect than the physician effect (p<0.05). CONCLUSION: Misdiagnosis of hypertension results in inappropriate prescription and overuse of antihypertensive medications for individuals who are not persistently hypertensive. So it is very important to rule out WCH in both the hospital setting and the physician's presence, more precisely by ABPM. WCH can be diagnosed with regular BP monitoring by a digital sphygmomanometer at home.

Supernatural punishment beliefs as cognitively compelling tools of social control.

Why do humans develop beliefs in supernatural entities that punish uncooperative behaviors? Leading hypotheses maintain that these beliefs are widespread because they facilitate cooperation, allowing their groups to outcompete others in intergroup competition. Focusing on within-group interactions, we present a model in which people strategically endorse supernatural punishment beliefs as intuitive tools of social control to manipulate others into cooperating. Others accept these beliefs, meanwhile, because they are made compelling by various cognitive biases: they appear to provide information about why misfortune occurs; they appeal to intuitions about immanent justice; they contain threatening information; and they allow believers to signal their trustworthiness. Explaining supernatural beliefs requires considering both motivations to invest in their endorsement and the reasons others adopt them.

Evidence for third-party mediation but not punishment in Mentawai justice.

Researchers argue that third parties help sustain human cooperation, yet how they contribute remains unclear, especially in small-scale, politically decentralized societies. Studying justice among Mentawai horticulturalists in Indonesia, we examined evidence for punishment and mediation by third parties. Across a sample of 444 transgressions, we find no evidence of direct third-party punishment. Most victims and aggrieved parties demanded payment, and if a transgressor faced punishment, this was never imposed by third parties. We find little evidence of indirect sanctions by third parties. Nearly 20% of transgressions were followed by no payment, and as predicted by dyadic models of sanctions, payments were less likely when transgressions were among related individuals. Approximately 75% of non-governmental mediators called were third parties, especially shamans and elders, and mediators were called more as cooperation was threatened. Our findings suggest that, among the Mentawai, institutionalized penalties function more to restore dyadic cooperation than to enforce norms.

Acoustic regularities in infant-directed speech and song across cultures.

When interacting with infants, humans often alter their speech and song in ways thought to support communication. Theories of human child-rearing, informed by data on vocal signalling across species, predict that such alterations should appear globally. Here, we show acoustic differences between infant-directed and adult-directed vocalizations across cultures. We collected 1,615 recordings of infant- and adult-directed speech and song produced by 410 people in 21 urban, rural and small-scale societies. Infant-directedness was reliably classified from acoustic features only, with acoustic profiles of infant-directedness differing across language and music but in consistent fashions. We then studied listener sensitivity to these acoustic features. We played the recordings to 51,065 people from 187 countries, recruited via an English-language website, who guessed whether each vocalization was infant-directed. Their intuitions were more accurate than chance, predictable in part by common sets of acoustic features and robust to the effects of linguistic relatedness between vocalizer and listener. These findings inform hypotheses of the psychological functions and evolution of human communication.

Beyond social learning.

Cultural evolution requires the social transmission of information. For this reason, scholars have emphasized social learning when explaining how and why culture evolves. Yet cultural evolution results from many mechanisms operating in concert. Here, we argue that the emphasis on social learning has distracted scholars from appreciating both the full range of mechanisms contributing to cultural evolution and how interactions among those mechanisms and other factors affect the output of cultural evolution. We examine understudied mechanisms and other factors and call for a more inclusive programme of investigation that probes multiple levels of the organization, spanning the neural, cognitive-behavioural and populational levels. To guide our discussion, we focus on factors involved in three core topics of cultural evolution: the emergence of culture, the emergence of cumulative cultural evolution and the design of cultural traits. Studying mechanisms across levels can add explanatory power while revealing gaps and misconceptions in our knowledge. This article is part of the theme issue 'Foundations of cultural evolution'.

Why do religious leaders observe costly prohibitions? Examining taboos on Mentawai shamans.

Religious leaders refrain from sex and food across human societies. Researchers argue that this avoidance influences people's perceptions of leaders' underlying traits, but few, if any, quantitative data exist testing these claims. Here we show that shamans in a small-scale society observe costly prohibitions and that observers infer cooperativeness, religious belief, difference from normal humans and supernatural power from shamans' adherence to special taboos. We investigated costly prohibitions on shamanic healers, known as sikerei, among the rainforest horticulturalist Mentawai people of Siberut Island. We found that shamans must observe permanent taboos on various animals, as well as prohibitions on sex and food during initiation and ceremonial healing. Using vignettes, we evaluated Mentawai participants' inferences about taboo adherence, testing three different but not mutually exclusive hypotheses: cooperative costly signalling, credibility-enhancing displays and supernatural otherness. We found support for all three: Mentawai participants infer self-denying shamans to be (a) cooperative, (b) sincere believers in the religious rules and (c) dissimilar from normal humans and with greater supernatural powers. People's inferences about religious self-denial are multidimensional and consistent with several functional accounts.