People have shaped most of terrestrial nature for at least 12,000 years

From Ellis et al.L 

Significance

The current biodiversity crisis is often depicted as a struggle to preserve untouched habitats. Here, we combine global maps of human populations and land use over the past 12,000 y with current biodiversity data to show that nearly three quarters of terrestrial nature has long been shaped by diverse histories of human habitation and use by Indigenous and traditional peoples. With rare exceptions, current biodiversity losses are caused not by human conversion or degradation of untouched ecosystems, but rather by the appropriation, colonization, and intensification of use in lands inhabited and used by prior societies. Global land use history confirms that empowering the environmental stewardship of Indigenous peoples and local communities will be critical to conserving biodiversity across the planet.

Abstract

Archaeological and paleoecological evidence shows that by 10,000 BCE, all human societies employed varying degrees of ecologically transformative land use practices, including burning, hunting, species propagation, domestication, cultivation, and others that have left long-term legacies across the terrestrial biosphere. Yet, a lingering paradigm among natural scientists, conservationists, and policymakers is that human transformation of terrestrial nature is mostly recent and inherently destructive. Here, we use the most up-to-date, spatially explicit global reconstruction of historical human populations and land use to show that this paradigm is likely wrong. Even 12,000 y ago, nearly three quarters of Earth’s land was inhabited and therefore shaped by human societies, including more than 95% of temperate and 90% of tropical woodlands. Lands now characterized as “natural,” “intact,” and “wild” generally exhibit long histories of use, as do protected areas and Indigenous lands, and current global patterns of vertebrate species richness and key biodiversity areas are more strongly associated with past patterns of land use than with present ones in regional landscapes now characterized as natural. The current biodiversity crisis can seldom be explained by the loss of uninhabited wildlands, resulting instead from the appropriation, colonization, and intensifying use of the biodiverse cultural landscapes long shaped and sustained by prior societies. Recognizing this deep cultural connection with biodiversity will therefore be essential to resolve the crisis.

Motivated readers can obtain a PDF of the article by emailing me.

Sensitivity to geometric shape: A putative signature of human singularity

From Sablé-Meyer et al.:

Among primates, humans are special in their ability to create and manipulate highly elaborate structures of language, mathematics, and music. Here we show that this sensitivity to abstract structure is already present in a much simpler domain: the visual perception of regular geometric shapes such as squares, rectangles, and parallelograms. We asked human subjects to detect an intruder shape among six quadrilaterals. Although the intruder was always defined by an identical amount of displacement of a single vertex, the results revealed a geometric regularity effect: detection was considerably easier when either the base shape or the intruder was a regular figure comprising right angles, parallelism, or symmetry rather than a more irregular shape. This effect was replicated in several tasks and in all human populations tested, including uneducated Himba adults and French kindergartners. Baboons, however, showed no such geometric regularity effect, even after extensive training. Baboon behavior was captured by convolutional neural networks (CNNs), but neither CNNs nor a variational autoencoder captured the human geometric regularity effect. However, a symbolic model, based on exact properties of Euclidean geometry, closely fitted human behavior. Our results indicate that the human propensity for symbolic abstraction permeates even elementary shape perception. They suggest a putative signature of human singularity and provide a challenge for nonsymbolic models of human shape perception.

A graphic of the coming collapse of our marine ecosystems.

I've just done a slow read through a PNAS Perspective article authored by a collaborative of mainly European scientists on "The quiet crossing of ocean tipping points." The article describes how climate change in the ocean is clearly manifesting itself now with ocean deoxygenation and ocean acidification that will be irreversible for centuries to millennia.

Abrupt physical ocean changes due to marine heatwaves are expected with very high likelihood and high confidence concerning negative impacts on ecosystems. Increased heatwave occurrences are not reversible on short time scales and would persist from decades to centuries. The physical−chemical−biological ocean systems are at the verge of tipping into another state in many oceanic regions. Integrated over the world ocean, this adds up to a global issue of concern.

Here is a striking summary graphic that I want to pass on that shows candidates for high-probability high-impact marine tipping elements that concern warming, deoxygenation, and ocean acidification as well as their impacts. (Click to enlarge).

 

AND, I want to point you to a striking New York Times article that has amazing graphic animations showing the current dangerous weakening of the Gulf Stream that is generating a "cold blob" in the North Atlantic, threatening the normal warming effect of the Gulf Stream on the British Isles and northern Europe.

 

 

 

You've gotta watch this - A billion year journey of Earth's tectonic plates

The article by Andrews in the New York Times describes the history of tectonic plate theory and brings into vivid focus how us humans are just a transient eye blink in the history of our planet. I pass on a YouTube version of the fascinating animation in the article:

 

A broad approach to understanding emotions - Semantic Space Theory

I recently offered a 14-installment series of posts covering the ideas in Lisa Feldman Barrett’s book “How Emotions are Made: The Secret Life of the Brain. It's content centered around the debate of essentialist versus constructivist views of how we generate emotional behaviors, with Barrett presenting overwhelming data supporting the constructivist view. Cowen and Keltner now offer a alternative perspective, "semantic space theory" that encompases and expands beyond the more rigid definitions of essentialist basic emotion theory (BET, that claims that emotional feelings associated with specific cognitive appraisals and behaviors are biologically prepared and modified by experience) and constructivism (which takes certain valence/arousal responses to be biologically prepared, while specific emotions involve valence and arousal but are artifacts of language). From Cowen and Keltner:

Although these perspectives diverge on what emotions are, they converge in assuming that emotions solve a biological dilemma: that our brains are adapted for survival and reproduction, but our daily decisions are often many steps removed from these goals. This makes the evolutionary calculus of daily life – risk-taking, courtship, and tribal politics – immensely complex. The cognitive priors that enable our brains to approximate this calculus are, in most any theory of emotion, at the root of emotional behavior.

Cowen and Keltner expand beyond the entrenched disagreements between essentialist and constructivist approaches to offer a more expansive and encyclopedic approach - semantic (def. meaning in language) space theory. Here is their description:

Our approach formalizes the study of emotion in the investigation of representational state spaces capturing systematic variation in emotion-related response (including experience and expression, as well as associated physiology, cognition, and motivation). We integrate computational studies of emotional experience, facial–bodily expression, and vocalization to visualize what one might think of as an emerging taxonomy of emotion. Next, we discuss how the brain represents these experiences in distinct configurations of activity across the default mode network and subcortical areas. Building upon these advances, we synthesize literatures on nonhuman emotion-like behavior and nervous system response, highlighting emerging evidence that emotional behaviors differentiated within a fine-grained taxonomy have animal homologies and evolved neural mechanisms. The implication of these developments is clear: moving beyond traditional models to a broad taxonomy of emotion (Figure 1) will provide for a richer, more comprehensive science of emotion.

The Figure 1 referenced is a real doozy. On request, I can send motivated readers a PDF of the whole article text. Here is the legend of Fig. 1 "Semantic Spaces of Experience and Expression" which contains links to many cloud based interactive maps showing an awesome amount of data. The actual six panel figure (A though F referred to in the legend) is too large to display in this post. Clicking the links below to go through the cloud based interactive graphics is interesting. One could spend a fair number of hours browsing the variety of emotional forms presented.

(A) The semantic space framework. A semantic space is described by (i) its dimensionality, or the number of distinct meanings of experiences or expressions within the space; (ii) the conceptualization of these meanings in terms of mental states, intentions, or appraisals; and (iii) the distribution of experiences or expressions within the space, capturing clusters or blends of states. (B) Semantic space of facial–bodily and vocal expression. A total of 3523 expressions are lettered, positioned, and colored according to 28 distinct emotions that people reliably attribute to them (28 in facial expression [42] and 24 in vocal expression [25]). Within the space are gradients in expression between emotions traditionally thought of as discrete, such as fear and surprise. To explore these expressions, see the interactive maps (face: https://s3-us-west-1.amazonaws.com/face28/map.html, voice: https://s3-us-west-1.amazonaws.com/vocs/map.html). (C) Semantic space of emotion evoked by 2185 brief videos. At least 27 distinct affective states are reliably captured in reports of emotional experience evoked by video, best conceptualized in terms of emotion concepts such as fear [26]. Again, gradients bridge emotion concepts traditionally thought of as discrete, such as fear and surprise. Interactive map: https://s3-us-west-1.amazonaws.com/emogifs/map.html. (D) Semantic space of emotional experience evoked by 1841 music samples in multiple cultures [36]. Music samples are positioned and colored according to 13 emotions with which they are reliably associated in both the USA and China. Within the space, we find gradients among these states. The similarities in affective response across cultures were most reliably revealed in the use of specific emotion concepts (e.g., desire and fear). Interactive map: https://s3.amazonaws.com/musicemo/map.html. (E) Semantic space of emotion conveyed by prosody in 2519 lexically identical speech samples. Across the USA and India, at least 12 kinds of emotion are preserved in the recognition of mental states from speech prosody, most reliably revealed in the use of emotion concepts [28]. Interactive map: https://s3-us-west-1.amazonaws.com/venec/map.html. (F) Emotional expression in Ancient American art [58]. Ancient American sculpture was found to portray at least five distinct kinds of facial expression that accord, in terms of the emotions they communicate to westerners, with western expectations for the emotions that might unfold in the eight contexts portrayed. Colors of individual faces (letters) are weighted averages of colors assigned to each kind of perceived facial expression. Eight example sculptures are shown. (To explore all 63 sculptures, see online map: https://s3.amazonaws.com/precolumbian/map.html.)

This post is already much too long, so I only mention section headings of the text following Fig. 1, with fragments of text:

Semantic Spaces of Emotion

Semantic spaces of emotion are defined by three properties (Figure 1A). The first is their dimensionality: how many different kinds of emotion are distinguished within the space? The second is the distribution of states within the space: are there discrete boundaries between emotion categories, or is there overlap? The third is the conceptualization of emotion: what concepts most precisely capture people’s implicit or explicit differentiation of subjective experiences and expressive behaviors?

Emotional experience and expression is high dimensional, categorical, and often blended

People reliably distinguish at least 27 distinct subjective experiences associated with video [26], 24 distinct emotions in nonverbal vocalizations [25,28], and 28 distinct emotions in the face and body (Figure 1B,C) [42]. These findings were observed using both traditional rating methods and open-ended free response. The specific numbers here matter less than the more general point that emotion is at least four times more complex than that represented in studies of six emotions. This finding, replicated across response systems of emotion, is not anticipated by BET, and stands in contrast to assumptions of low dimensionality – that emotion is largely reducible to valence and arousal – found in constructivist accounts

Extensions of an emergent taxonomy: patterns of brain response and mammalizn behavior...The primacy of specific emotions in neural response patterning.

This section discusses data on the brain representation of emotion.

Sixteen facial expressions occur in similar contexts worldwide .

I want to pass on this article by Cowen et al., which was the subject of a comment made on my December 2 post "Emotions are constructed, and are not universal." Here is the abstract:

Understanding the degree to which human facial expressions co-vary with specific social contexts across cultures is central to the theory that emotions enable adaptive responses to important challenges and opportunities. Concrete evidence linking social context to specific facial expressions is sparse and is largely based on survey-based approaches, which are often constrained by language and small sample sizes. Here, by applying machine-learning methods to real-world, dynamic behaviour, we ascertain whether naturalistic social contexts (for example, weddings or sporting competitions) are associated with specific facial expressions14 across different cultures. In two experiments using deep neural networks, we examined the extent to which 16 types of facial expression occurred systematically in thousands of contexts in 6 million videos from 144 countries. We found that each kind of facial expression had distinct associations with a set of contexts that were 70% preserved across 12 world regions. Consistent with these associations, regions varied in how frequently different facial expressions were produced as a function of which contexts were most salient. Our results reveal fine-grained patterns in human facial expressions that are preserved across the modern world.

Here is one fragment from the main text of the article:

Specific contexts including fireworks, weddings and sporting competitions are reliably and differentially associated with 16 patterns of dynamic facial expression, such as those often labelled awe, contentment and triumph by English speakers, in a similar manner across world regions. In total, 70% of the variance in the context–expression association was found to be preserved in all 12 world regions that we examined. In revealing universals in expressive behaviour throughout the modern world, our findings directly inform the origins, functions and universality of emotion.

It is important to note that the authors were careful to point out that these studies were done on behaviors throughout "the modern world" and used emotion categories defined in English. The results do not in fact contradict the assertions of Barrett that emotions do not have universal facial fingerprints, if data from the non-modern world of isolated tribes is taken into account. (see my post on chapter 3 of her book "Emotions are not universal")

Hallucinogens at a prehistoric rock art site.

Interesting work from Robinson et al. on stoned stone-age artists (open access article, see comment below)! 

Significance

Proponents of the altered states of consciousness (ASC) model have argued that hallucinogens have influenced the prehistoric making of images in caves and rock shelters. However, the lack of direct evidence for the consumption of hallucinogens at any global rock art site has undermined the ASC model. We present the first clear evidence for the ingestion of hallucinogens at a rock art site, in this case, from Pinwheel Cave, California. Quids in the cave ceiling are shown to be Datura wrightii, a Native Californian entheogen, indicating that, rather than illustrating visual phenomena caused by the Datura, the rock paintings instead likely represent the plant and its pollinator, calling into question long-held assumptions about rock art and the ASC model.

Abstract

While debates have raged over the relationship between trance and rock art, unambiguous evidence of the consumption of hallucinogens has not been reported from any rock art site in the world. A painting possibly representing the flowers of Datura on the ceiling of a Californian rock art site called Pinwheel Cave was discovered alongside fibrous quids in the same ceiling. Even though Native Californians are historically documented to have used Datura to enter trance states, little evidence exists to associate it with rock art. A multianalytical approach to the rock art, the quids, and the archaeological context of this site was undertaken. Liquid chromatography−mass spectrometry (LC-MS) results found hallucinogenic alkaloids scopolamine and atropine in the quids, while scanning electron microscope analysis confirms most to be Datura wrightii. Three-dimensional (3D) analyses of the quids indicate the quids were likely masticated and thus consumed in the cave under the paintings. Archaeological evidence and chronological dating shows the site was well utilized as a temporary residence for a range of activities from Late Prehistory through Colonial Periods. This indicates that Datura was ingested in the cave and that the rock painting represents the plant itself, serving to codify communal rituals involving this powerful entheogen. These results confirm the use of hallucinogens at a rock art site while calling into question previous assumptions concerning trance and rock art imagery.

Nature's lessons for a more kind society.

I recently came across this 2009 MindBlog post... relevant to our times. Here is a re-post (this link to the original post takes you to some comments.)

Blog reader Gary Olson has pointed me to his review of Franz De Waal's new book "The Age of Empathy: Nature’s Lessons For A Kinder Society." From that review:

de Waal provides compelling support for the proposition that humans are “preprogrammed to reach out.” From dolphins ferrying injured companions to safety and grieving elephants, baboons and cats (yes, even cats) to commiserating mice and hydrophobic chimps risking death to save a drowning companion, this is a major contribution to understanding the biological genesis of our inborn capacity for empathy, hence morality. In seven crisply written and wholly accessible chapters de Waal methodically demolishes the rationale behind Gordon Gekko’s admonition in the film "Wall Street" that greed “captures the essence of the evolutionary spirit.”...De Waal objects to an unrestrained market system, not capitalism itself. He prefers that the economic system be mitigated by more attention to empathy in order to soften its rough edges...Nevertheless, de Waal seriously underestimates certain capitalist imperatives and the role played by elites in cultivating callousness, thereby undermining social solidarity, reciprocity and empathy. Capitalist culture devalues an empathic disposition, and, as Erich Fromm argued some fifty years ago, there is a basic incompatibility between the underlying principles of capitalism and the lived expression of an ethos of empathy.

The complexity model of societal collapse

Continuing in the thread of the previous MindBlog post describing Turchin's historical model, I want to point to Ben Ehrenreich's piece that also describes Joseph Tainter's model for the collapse of complex societies (PDF here). Some slightly edited clips:

Tainter’s argument rests on two proposals. The first is that human societies develop complexity, i.e. specialized roles and the institutional structures that coordinate them, in order to solve problems...large, heterogeneous, internally differentiated, class structured, controlled societies in which the resources that sustain life are not equally available to all...a delicate balance of symbolic and material benefits that Tainter calls “legitimacy,” the maintenance of which itself requires ever more complex structures, which become ever less flexible, and more vulnerable, the more they pile up.

His second proposal is based on an idea borrowed from the classical economists of the 18th century. Social complexity, he argues, is inevitably subject to diminishing marginal returns. It costs more and more, in other words, while producing smaller and smaller profits. “It’s a classic ‘Alice in Wonderland’ situation,” Tainter says. You’re “running faster and faster to stay in the same place.” Take Rome, which, in Tainter's telling, was able to win significant wealth by sacking its neighbors but was thereafter required to maintain an ever larger and more expensive military just to keep the imperial machine from stalling — until it couldn’t anymore.

Only complexity, Tainter argues, provides an explanation that applies in every instance of collapse. We go about our lives, addressing problems as they arise. Complexity builds and builds, usually incrementally, without anyone noticing how brittle it has all become. Then some little push arrives, and the society begins to fracture. The result is a “rapid, significant loss of an established level of sociopolitical complexity.” In human terms, that means central governments disintegrating and empires fracturing into “small, petty states,” often in conflict with one another. Trade routes seize up, and cities are abandoned. Literacy falls off, technological knowledge is lost and populations decline sharply. “The world,” Tainter writes, “perceptibly shrinks, and over the horizon lies the unknown.”

“The world today is full,” Tainter writes. Complex societies occupy every inhabitable region of the planet. There is no escaping. This also means, he writes, that collapse, “if and when it comes again, will this time be global.” Our fates are interlinked. “No longer can any individual nation collapse. World civilization will disintegrate as a whole.”...The quest for efficiency, he wrote recently, has brought on unprecedented levels of complexity: “an elaborate global system of production, shipping, manufacturing and retailing” in which goods are manufactured in one part of the world to meet immediate demands in another, and delivered only when they’re needed. The system’s speed is dizzying, but so are its vulnerabilities.

If you close your eyes and open them again, the periodic disintegrations that punctuate our history — all those crumbling ruins — begin to fade, and something else comes into focus: wiliness, stubbornness and, perhaps the strongest and most essential human trait, adaptability. Perhaps our ability to band together, to respond creatively to new and difficult circumstances is not some tragic secret snare, as Tainter has it, a story that always ends in sclerotic complexity and collapse. Perhaps it is what we do best. When one way doesn’t work, we try another. When one system fails, we build another. We struggle to do things differently, and we push on. As always, we have no other choice.

These few clips do not to justice to Ehrenreich's article, which notes the ideas of other thinkers, and contemporary research initiatives. I recommend you read the whole thing.

The pandemic exposes human nature: 10 evolutionary insights

The Nov. 10 issue of PNAS has a open source perspective article authored by an all star cast of prominent thinkers (including Steven Pinker, Same Harris, Paul Bloom, David Buss, David Sloan Wilson....and others). Here is the abstract, a list of the 10 insights and the scientific they suggest, and the article's conclusion.

Humans and viruses have been coevolving for millennia. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, the virus that causes COVID-19) has been particularly successful in evading our evolved defenses. The outcome has been tragic—across the globe, millions have been sickened and hundreds of thousands have died. Moreover, the quarantine has radically changed the structure of our lives, with devastating social and economic consequences that are likely to unfold for years. An evolutionary perspective can help us understand the progression and consequences of the pandemic. Here, a diverse group of scientists, with expertise from evolutionary medicine to cultural evolution, provide insights about the pandemic and its aftermath. At the most granular level, we consider how viruses might affect social behavior, and how quarantine, ironically, could make us susceptible to other maladies, due to a lack of microbial exposure. At the psychological level, we describe the ways in which the pandemic can affect mating behavior, cooperation (or the lack thereof), and gender norms, and how we can use disgust to better activate native “behavioral immunity” to combat disease spread. At the cultural level, we describe shifting cultural norms and how we might harness them to better combat disease and the negative social consequences of the pandemic. These insights can be used to craft solutions to problems produced by the pandemic and to lay the groundwork for a scientific agenda to capture and understand what has become, in effect, a worldwide social experiment.

Insight 1: The Virus Might Alter Host Sociability

 Insight 2: “Generation Quarantine” May Lack Critical Microbial Exposures

 Insight 3: Activating Disgust Can Help Combat Disease Spread

 Insight 4: The Mating Landscape Is Changing, and There Will Be Economic Consequences from a Decrease in Birth Rates

 Insight 5: Gender Norms Are Backsliding, and Gender Inequality Is Increasing

 Insight 6: An Increase in Empathy and Compassion Is Not Guaranteed

 Insight 7: We Have Not Evolved to Seek the Truth

 Insight 8: Combating the Pandemic Requires Its Own Evolutionary Process

 Insight 9: Cultural Evolutionary Forces Impact COVID-19 Severity

 Insight 10: Human Progress Continues

Conclusion

COVID-19 has brought radical change, through deaths, stress of extended quarantine, confusion that slowed adequate responding, social unrest at a massive scale, and a long and uncertain social and economic aftermath. This radical change is global—no human, anywhere, is unaffected by COVID-19.

To understand the virus and our response to it, we need to understand how viruses and humans evolve. We know that there is a long history of the coevolution of viruses and humans. Viruses evolve to exploit their hosts to encourage their own replication, but they also depend on hosts to survive. Humans can tolerate some manipulation by viruses, but we have also evolved to combat them. This delicate coevolutionary dance is why we often seem to be running as fast as we can, just to stay in the same place (90).

However, humans also possess the tool of scientific insight that gives us a broader view than what the virus can see. Perhaps this can help us stay one step ahead. By understanding the nature of viral strategies, we can better anticipate the spread of COVID-19 and try to block it. Likewise, by understanding human nature, we can try to activate evolved motivational systems that will help fight the virus, such as providing cues that trigger our behavioral immune system. Understanding human nature will also enhance our ability to address the aftermath of COVID-19, as it has disrupted so many of our fundamental human activities, such as mating, parenting, and simply maintaining social contact.

Herein, we have described 10 insights offered by a broad range of evolutionary thinkers, with expertise ranging from evolutionary medicine to broadscale cultural evolution. These insights offer possibilities for guiding science to address the spread of COVID-19 and its inevitable aftermath. However, these insights represent only a limited snapshot of this historic moment, and a selection of topics, although important, that an evolutionary perspective on the pandemic can provide.

The objective in providing these insights is to help make sense of the vast confusion that mars this pandemic and to illuminate paths for research. In addition to insights that can produce immediate action, the pandemic has provided us with unique opportunities to witness human nature as it unfolds, from changes in patterns of reproduction, shifting social norms, and curiosities of cognition that can warp our recognition of threat. This paper is a call to action in science—both in the application of existing knowledge about viral and human nature and also as an opportunity to make discoveries that would not be possible except when a global social experiment is underway.

Origins of human music - two perspectives

Because I wrote an article in Behavioral and Brain Sciences (coauthored with Vadim Arshavsky), that was published in 2010, I receive the journal's calls for commentaries on forthcoming articles. Here I pass on the abstracts of two articles proposing evolutionary rationales for the origins of our human musical abilities.  Because I am a recital pianist I have always been interested in the origins and neuroscience of our musical faculties. In 2015 I agreed to give a lecture on 'Music and the Mind', generated thirty pages of fairly lucid text, became overwhelmed by the complexity of the subject, and backed out of doing the talk.  I'm curious to see whether a careful reading of these articles confirms that decision or inspires me to try again. 

Music as a coevolved system for social bonding

Why do humans make music? Theories of the evolution of musicality have focused mainly on the value of music for specific adaptive contexts such as mate selection, parental care, coalition signaling, and group cohesion. Synthesizing and extending previous proposals, we argue that social bonding is an overarching function that unifies all of these theories, and that musicality enabled social bonding at larger scales than grooming and other bonding mechanisms available in ancestral primate societies. We combine cross-disciplinary evidence from archaeology, anthropology, biology, musicology, psychology, and neuroscience into a unified framework that accounts for the biological and cultural evolution of music. We argue that the evolution of musicality involves gene-culture coevolution, through which proto-musical behaviors that initially arose and spread as cultural inventions had feedback effects on biological evolution due to their impact on social bonding. We emphasize the deep links between production, perception, prediction, and social reward arising from repetition, synchronization, and harmonization of rhythms and pitches, and summarize empirical evidence for these links at the levels of brain networks, physiological mechanisms, and behaviors across cultures and across species. Finally, we address potential criticisms and make testable predictions for future research, including neurobiological bases of musicality and relationships between human music, language, animal song, and other domains. The music and social bonding (MSB) hypothesis provides the most comprehensive theory to date of the biological and cultural evolution of music.

Origins of music in credible signaling

Music comprises a diverse category of cognitive phenomena that likely represent both the effects of psychological adaptations that are specific to music (e.g., rhythmic entrainment) and the effects of adaptations for non-musical functions (e.g., auditory scene analysis). How did music evolve? Here, we show that prevailing views on the evolution of music — that music is a byproduct of other evolved faculties, evolved for social bonding, or evolved to signal mate quality — are incomplete or wrong. We argue instead that music evolved as a credible signal in at least two contexts: coalitional interactions and infant care. Specifically, we propose that (1) the production and reception of coordinated, entrained rhythmic displays is a co-evolved system for credibly signaling coalition strength, size, and coordination ability; and (2) the production and reception of infant-directed song is a co-evolved system for credibly signaling parental attention to secondarily altricial infants. These proposals, supported by interdisciplinary evidence, suggest that basic features of music, such as melody and rhythm, result from adaptations in the proper domain of human music. The adaptations provide a foundation for the cultural evolution of music in its actual domain, yielding the diversity of musical forms and musical behaviors found worldwide.

The Neurobiology of Social Distance

Bzdok and Dunbar (open source) do a definitive review of evidence that psychosocial embedding in interpersonal relationship is crucial for survival. Dunbar is well known for his demonstration of the correlation between the size of social groups and the brain size of their members, which places the natural size of groups of humans at ~150 (roughly the size of human hunter gatherer groups whose isolation has permitted them to survive into the modern era. The number of friends and family relationships we can manage at any given time is limited by our cognitive constraints to ~150). Their summary:

From babies to the elderly, psychosocial embedding in interpersonal relationships is crucial for survival.

Insufficient social stimulation affects reasoning and memory performance, hormone homeostasis, brain grey/white matter connectivity and function, as well as resilience to physical and mental disease.

Feelings of loneliness can spread through a social network, causing negatively skewed social perception, escalating morbidity and mortality, and, in older people, precipitating the onset of dementia (e.g., Alzheimer’s disease).

Cats associated with early human farming long before their domestication

As the herd of Abyssinian cats in my has grown, now numbering two 12 year olds and two kittens, I've become more curious about the origins of this breed and of domestic cats in general. It turn out, as shown in recent work by Jrahcarz et al., that cats were predators feeding on rodents in grain stores in Neolithic farming settlements for at least a thousand years before their domestication as house cats.

Most of today’s domesticates began as farm animals, but cat domestication took a different path. Cats became commensal of humans somewhere in the Fertile Crescent, attracted to early farmers’ settlements by rodent pests. Cat remains from Poland dated to 4,200 to 2,300 y BCE are currently the earliest evidence for the migration of the Near Eastern wildcat to Central Europe. Tracking the possible synanthropic origin of that migration, we used stable isotopes to investigate the paleodiet. We found that the ecological balance was already changed due to the expansion of Neolithic farmlands. We conclude that among the Late Neolithic Near Eastern wildcats from Poland were free-living individuals, who preyed on rodent pests and shared ecological niches with native European wildcats.

As regards the origins of my Abyssianians, I have always passed on the story that all of the current registered purebreds derive from a male brought to England by a British solider in the late 19th century. A quick google look, however, shows their origins to be far from clear.

Self, purpose, and tribal mentality as Darwinian adaptations (or…Why why aren’t we all enlightened?)

This is a post like the one I offered on March 13 that passes on a bit of writing that I think might develop into a longer piece of work. I hope the following ideas and assertions make some sense to readers:

One ultimate cause of human behaviors is the endless cycling of a “Darwin machine,” operating at the level of cells, individuals, and groups of humans. As entities - from the most simple virus particles to complex human cultures - reproduce or renew themselves to persist through time, small errors or variations that end up enhancing reproductive fitness become dominant in the population. The grand master is multilevel selection, and there is a conflict between individual-level selection (individuals competing with other individuals in the same group) and group-level selection (competition between groups). Within groups selfish individuals beat altruistic individuals, but groups of altruists beat groups of selfish individuals. E.O. Wilson risks the oversimplification of suggesting that individual selection promoted sin, while group selection promoted virtue.

The array of social emotions supporting tribal cultures that have occupied most of human history, as well as the more recent emergence of language, thought, and material culture, can be rationalized with this model. Taken together, they have enabled formation of large complex societies bonded together by laws, religions, and assumptions about purpose, meaning, and self that are unique to modern humans.

Nations and religions link language and meaning to more ancient evolved instinctive social emotional behaviors that bond groups of humans and other primates. This link is revealed when logic and language are turned inward (by both ancient meditative traditions as well as modern neuroscience) in a way that reveals that our common experiences of self or purpose are confabulations, or illusions - illusions nevertheless that have been necessary for forming complex human linguistic cultures, illusions which our emotional hormones and nerve circuitry have evolved to support.

Given the clear scientific evidence, why don’t we transcend these evolved linkages between our biology and our illusions? Why have those regarded as spiritually ‘enlightened’ throughout history remained a small minority of the population? Perhaps it is because those who become enlightened or awakened to the illusory nature of the self are granted a perspective on basic emotional drives that can divests them of much of their power. Enlightenment is subtle, not noisy, it doesn't engage the passions as well as blind devotion to nations and gods. This is why secular humanism, with its more muted versions of spirituality (‘I’m spiritual but not religious’) finds it difficult to compete with the ego-rich passions of nationalism and theism.

Because our evolved social brains incline us to cling to a complex array of nations, religions, and tribal identities that parse the world into ‘us’ and ‘them,’ we find it difficult to accept that we are a common humanity that would most effectively face our current pandemic and environmental crises by joining together.

Future of the Human climate niche

Sobering analysis from Xu et al. :

Significance

We show that for thousands of years, humans have concentrated in a surprisingly narrow subset of Earth’s available climates, characterized by mean annual temperatures around ∼13 °C. This distribution likely reflects a human temperature niche related to fundamental constraints. We demonstrate that depending on scenarios of population growth and warming, over the coming 50 y, 1 to 3 billion people are projected to be left outside the climate conditions that have served humanity well over the past 6,000 y. Absent climate mitigation or migration, a substantial part of humanity will be exposed to mean annual temperatures warmer than nearly anywhere today.

Abstract

All species have an environmental niche, and despite technological advances, humans are unlikely to be an exception. Here, we demonstrate that for millennia, human populations have resided in the same narrow part of the climatic envelope available on the globe, characterized by a major mode around ∼11 °C to 15 °C mean annual temperature (MAT). Supporting the fundamental nature of this temperature niche, current production of crops and livestock is largely limited to the same conditions, and the same optimum has been found for agricultural and nonagricultural economic output of countries through analyses of year-to-year variation. We show that in a business-as-usual climate change scenario, the geographical position of this temperature niche is projected to shift more over the coming 50 y than it has moved since 6000 BP. Populations will not simply track the shifting climate, as adaptation in situ may address some of the challenges, and many other factors affect decisions to migrate. Nevertheless, in the absence of migration, one third of the global population is projected to experience a MAT >29 °C currently found in only 0.8% of the Earth’s land surface, mostly concentrated in the Sahara. As the potentially most affected regions are among the poorest in the world, where adaptive capacity is low, enhancing human development in those areas should be a priority alongside climate mitigation.

The cultural origins of metacognition.

I want to pass on this open source article in Trends in Cognitive Science by Heyes et al. Their summary:

Highlights

Human metacognition involves discrimination, interpretation, and broadcasting of subtle cues indicating the rightness of ongoing thought and behaviour.

We propose that human metacognition is made fit for purpose by cultural evolution rather than genetic evolution.

In particular, we present evidence that the effective discrimination, interpretation, and broadcasting of metacognitive cues depends on cultural learning.

The cultural origins hypothesis advances a programme of research on the development of metacognition, cultural variation, individual differences, and cross-species comparisons.

Metacognition – the ability to represent, monitor and control ongoing cognitive processes – helps us perform many tasks, both when acting alone and when working with others. While metacognition is adaptive, and found in other animals, we should not assume that all human forms of metacognition are gene-based adaptations. Instead, some forms may have a social origin, including the discrimination, interpretation, and broadcasting of metacognitive representations. There is evidence that each of these abilities depends on cultural learning and therefore that cultural selection might shape human metacognition. The cultural origins hypothesis is a plausible and testable alternative that directs us towards a substantial new programme of research.

Universality and diversity in human song

In the same vein as the previous post on cultural variation and universal structures in music, another massive research collective reports on their study of universality and diversity in human music, emphasizing different dimensions of experience. They provide interactive graphic tools providing detailed descriptions and samples of songs. The tools pointed to in this and the previous MindBlog post give readers access hundreds (probably thousands) of different music samples, and their variety is astonishing. Here is a summary description done by Science magazine:

It is unclear whether there are universal patterns to music across cultures. Mehr et al. examined ethnographic data and observed music in every society sampled (see the Perspective by Fitch and Popescu). For songs specifically, three dimensions characterize more than 25% of the performances studied: formality of the performance, arousal level, and religiosity. There is more variation in musical behavior within societies than between societies, and societies show similar levels of within-society variation in musical behavior. At the same time, one-third of societies significantly differ from average for any given dimension, and half of all societies differ from average on at least one dimension, indicating variability across cultures.

What music makes us feel - 13 cross cultural categories

From Cowen et al.:
(Be sure to check out their striking visualization of the data. By moving the cursor about the screen you can listen to the different emotional categories of music, each differently color coded).

Significance

Do our subjective experiences when listening to music show evidence of universality? And if so, what is the nature of these experiences? With data-driven methodological and statistical approaches, we examined the feelings evoked by 2,168 music excerpts in the United States and China. We uncovered 13 distinct types of experiences that people across 2 different cultures report in listening to music of different kinds. Categories such as “awe” drive the experience of music more so than broad affective features like valence. However, emotions that scientists have long treated as discrete can be blended together. Our results provide answers to long-standing questions about the nature of the subjective experiences associated with music.

Abstract

What is the nature of the feelings evoked by music? We investigated how people represent the subjective experiences associated with Western and Chinese music and the form in which these representational processes are preserved across different cultural groups. US (n = 1,591) and Chinese (n = 1,258) participants listened to 2,168 music samples and reported on the specific feelings (e.g., “angry,” “dreamy”) or broad affective features (e.g., valence, arousal) that they made individuals feel. Using large-scale statistical tools, we uncovered 13 distinct types of subjective experience associated with music in both cultures. Specific feelings such as “triumphant” were better preserved across the 2 cultures than levels of valence and arousal, contrasting with theoretical claims that valence and arousal are building blocks of subjective experience. This held true even for music selected on the basis of its valence and arousal levels and for traditional Chinese music. Furthermore, the feelings associated with music were found to occupy continuous gradients, contradicting discrete emotion theories. Our findings, visualized within an interactive map (https://www.ocf.berkeley.edu/∼acowen/music.html) reveal a complex, high-dimensional space of subjective experience associated with music in multiple cultures. These findings can inform inquiries ranging from the etiology of affective disorders to the neurological basis of emotion.

How trance states might have forged human societies

I want to pass on a series of clips I have made for my own use from an intriguing article by Mark Vernon in Aeon:

With anatomically modern humans comes culture in a way that had never happened before. And from that culture came religion, with various proposals to map the hows and whys of its emergence. Until recently, the proposals fell into two broad groups – ‘big gods’ theories and ‘false agency’ hypotheses. Big gods theories envisage religion as conjuring up punishing deities. These disciplining gods provided social bonding by telling individuals that wrongdoing incurs massive costs. The problem is that big gods are not a universal feature of religions and, if they are present, they seem correlated to big societies not causes of them. False agency hypotheses...assume that our forebears were jumpy and superstitious: they thought that a shrub swayed because of a spirit not the wind; and they were easily fooled, though their mistakes were evolutionarily advantageous because, on occasion, the swaying was caused by a predator. The false agency hypothesis has been tested and disconfirmed across many experiments.

...there is a need for a new idea, and coming to the fore now is an old one revisited...The explanation is resurfacing in what can be called the trance theory of religious origins, which proposes that our paleolithic ancestors hit on effervescence upon finding that they could induce altered states of consciousness...Effervescence is generated when humans come together to make music or perform rituals, an experience that lingers when the ceremonies are over. The suggestion, therefore, is that collective experiences that are religious or religious-like unify groups and create the energy to sustain them.

Research to test and develop this idea is underway in a multidisciplinary team led by Robin Dunbar at the University of Oxford. The approach appeals to him, in part, because it seems to capture a crucial aspect of religious phenomena missing in suggestions about punishing gods or dangerous spirits. It is not about the fine details of theology, but is about the raw feelings of experience...this raw-feelings element has a transcendental mystical component – something that is only fully experienced in trance states...this sense of transcendence and other worlds is present at some level in almost all forms of religious experience.

...there’s evidence that monkeys and apes experience the antecedents to ecstasy because they seem to experience wonder...a few hundred thousand years ago, archaic humans took a step that ramped up this capacity. They started deliberately to make music, dance and sing. When the synchronised and collective nature of these practices became sufficiently intense, individuals likely entered trance states in which they experienced not only this-worldly splendour but otherworldly intrigue... What you might call religiosity was born. It stuck partly because it also helped to ease tensions and bond groups, via the endorphin surges produced in trance states. In other words, altered states proved evolutionarily advantageous: the awoken human desire for ecstasy simultaneously prompted a social revolution because it meant that social groups could grow to much larger sizes via the shared intensity of heightened experiences.

The trance hypothesis...rests on the rituals that produce peak experiences, which means it doesn’t require speculating about what ancient people did or didn’t believe about spirits and gods...Asking when religion evolved is not a good question because religion is more than one thing...asking when the various elements such as supernatural agents and moral obligations started to coalesce together is a better question. And they invariably start to coalesce around rituals.

...when villages and then towns appear...new techniques for managing social pressures are required...religious systems (Doctrinal religions) that include specialists such as priests and impressive constructions we’d call temples and/or domestic house-based shrines...sustain the prosocial effects of earlier types of religiosity for groups that are now growing very large indeed...a tension .. arises when religious experiences are institutionalised....what’s on offer is somewhat thinner than experiences gained in the immersive rites that precipitate altered states. Encountering spirit entities directly in a dance or chase is not the same as the uplift offered by a monumental building.

...religions are caught between the Scylla of socially useful but potentially dreary religious rites and the Charybdis of altered states that are intrinsically exciting but socially disruptive. It’s why they bring bloody conflicts as well as social goods. This way of putting it highlights another feature of the trance theory. It interweaves two levels of explanation: one focused on the allure of spiritual vitality; the other on practical needs.

..science cannot decide whether the claims of any one religion are true. But the new theory still makes quite a strong claim, which brings me back to the role of the supernatural, transcendence and religious gods that today’s secularists seem inclined to sideline. If the science cannot confirm convictions about any divine revelations received, it does lend credence to the reasonableness, even necessity, of having them. Where the big gods and false agency hypotheses seemed inherently sniffy about human religiosity, the trance hypothesis positively values it...The trance hypothesis is neutral about the truth claims of religions whether you believe or don’t, though it does suggest that transcendent states of mind are meaningful to human beings and can evolve into religious systems of belief.

And in this final observation there is, perhaps, some good news for us, whether we’re religious or not. It’s often said that many of today’s troubles, from divisive political debates to spats on social media, are due to our tribal nature. It’s added, somewhat fatalistically, that deep within our evolutionary past is the tendency to identify with one group and demonise another. We are destined to be at war, culturally or otherwise. But if the trance theory is true, it shows that the evolutionary tendency to be tribal rests on an evolutionary taste for that which surpasses tribal experience – the transcendence that humans glimpsed in altered states of mind that enabled them to form tribes to start with.

If we long to belong, we also long to be in touch with ‘the more’, as the great pioneer of the study of religious experiences William James called it. That more will be envisaged in numerous ways. But it might help us by prompting new visions that exceed our herd instincts and binary thinking, and ease social tensions. If it helped our ancestors to survive, why would we think we are any different?

Explaining the puzzle of human diversity in the Christian world

Fascinating work by Schulz et al. is reviewed by both Gelfand and also Zauzmer. Schultz et al. show how the specific practices of Medieval Christianity can in part explain widespread variation in human psychology around the world.

From Zauzmer:

The story begins with kinship networks — the tribes and clans of densely connected, insular groups of relatives who formed most human societies before medieval times. Catholic Church teachings disrupted those networks, in large part by vehemently prohibiting marriage between relatives (which had been de rigeur), and eventually provoked a wholesale transformation of communities, changing the norm from large clans into small, monogamous nuclear families.

The team analyzed Vatican records to document the extent of a country or region’s exposure to Catholicism before the year 1500, and found that longer exposure to Catholicism correlated with low measures of kinship intensity in the modern era, including low rates of cousins marrying each other. Both measures correlated with psychology, the researchers found by looking at 24 different psychological traits of people in different cultures: Countries exposed to Catholicism early have citizens today who exhibit qualities such as being more individualistic and independent, and being more trusting of strangers.

From Gelfand:

...the authors found that both longer exposure to the Western Church and weaker kinship intensity (which were negatively related, as expected) were associated with greater individualism and independence, less conformity and obedience, and greater prosociality toward strangers—relationships that mostly held when controlling for a range of geographic variables. The results were replicated across 440 regions in 36 European countries: Longer exposure to the Western Church was generally associated with the same WEIRD (Western, Educated, Industrialized, Rich and Democratic) psychological shifts, even when controlling for alternate explanations (e.g., the influence of Roman political institutions, schooling, migration).