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Anaerobic digesters converting manure to biogas reduce methane emissions from livestock, but incentives for them have encouraged factory farms to get bigger

Reader Simon called my attention to a new obituary in the Times of London of Robert Trivers, a giant in evolutionary biology (and a notorious eccentric) who died on March 12.  Because his death wasn’t announced immediately after he expired, this was bit late, but better late than never—especially given Trivers’s importance in the field. It’s a good obituary but the gold standard was Steve Pinker’s “in memoriam” article about Trivers published in Quillette on March 25.

Click the screenshot below to read, and if that doesn’t work,the article is archived here.

An excerpt:

In a burst of creativity in the early 1970s, Robert Trivers published a series of scientific papers that earned him a claim to being among the most important evolutionary theorists since Darwin. He was the first to fully appreciate how a gene-centric view of natural selection could explain some of the most puzzling and fundamental patterns in social life: the function of altruism, why males and females differ so much, the underpinnings of sibling rivalry and the delicate dynamic of conflict and co-operation that exists between parent and child.

Brilliantly original, Trivers was also an academic misfit: a foul-mouthed, pot-smoking individualist with a notable tendency to get into violent scrapes and an ungovernable character that eventually strained his relationship with the academy to breaking point.

Why do we ever behave altruistically? That is, why would an organism ever promote the reproductive success of another at some cost to its own? Since the work of the great evolutionist WD Hamilton, it had been appreciated that “kin selection” could explain why close relatives help one another out: doing so promotes an organism’s “inclusive fitness”, a measure accounting not only for an organism’s own genes but for copies of the same genes likely to be present in relatives. But why help non-kin? To Trivers, it was an obvious fact of life that we sometimes give priority to friends, and even strangers, over direct relatives.

Persuaded of the misguidedness of “group selectionist” theories that were fashionable at the time — according to which organisms sometimes sacrifice themselves for the “good of the species” — Trivers gave the central explanatory role to the gene. In his landmark 1971 paper, The Evolution of Reciprocal Altruism, Trivers argued that altruism depended on the possibility of reciprocity. As long as helping a non-relative is not too costly, and there is sufficient probability that the favour would one day be returned, genes coding for altruistic dispositions spread.

. . . Frustrated by the Harvard biology faculty’s delay in granting his tenure application in the late 1970s, he abruptly left with his young family to take up a position at the University of California, Santa Cruz, a decision he came to regard as a “once in a lifetime” mistake. There, he befriended Huey Newton, co-founder of the paramilitary Black Panther political party, who was a doctoral student at the university. They co-authored a paper on self-deception, and Trivers made Newton his daughter’s godfather. He joined the Panthers for a period and later confessed to doing “an illegal thing or two”, before Newton removed him from the group for his own safety.

In fact, what I recall in 1977 is that Harvard’s biology department recommended tenure for Trivers, but that recommendation was overturned by President Derek Bok.  I was there at the time and can vouch for that. Others say that Trivers asked for early tenure and was denied that, and then decided to leave Harvard. I also heard, and I can’t vouch for this, that Richard Lewontin (my Ph.D. advisor) and Dick Levins, both Marxists who despised sociobiology, went to President Bok to lobby him to deny Trivers tenure.  What we do know is that Trivers then moved to Santa Cruz, and later to Rutgers, where his academic turmoil continued:

. . . In 2015 he was suspended by Rutgers University for refusing to teach a course on human aggression, a field he claimed he was not expert in (despite its being a personal forte of his). He quit university life for good shortly after. Later, he was among the set of high-profile intellectuals pilloried for maintaining financial and social links to Jeffrey Epstein, even after the latter’s conviction for sex offences. Far from apologetic, Trivers, who accepted funding from Epstein to study the relationship between knee symmetry and sprinting ability, vouched for his integrity; in Trivers’s view, Epstein’s imprisonment was punishment enough and his crimes less “heinous” than they were made out to be.

It is testament to the depth and generality of Trivers’s discoveries that they could be applied so readily, as he unsparingly conceded, to his own case. As he understood, natural selection has built us, and it is to natural selection we must return “to understand the many roots of our suffering”.

Compared to Pinker’s piece, the Times obituary is light on Trivers’s scientific accomplishments, but all in all it’s pretty good.

Below is a NYT obituary, also delayed, that appeared on March 27 (click to read or find it archived here):

An excerpt (David Haig, who’s quoted, has written his own remembrance of Trivers, as the two were good friends; but I don’t think it’s yet been published):

“Robert Trivers was unlike any other academic I have known,” David A. Haig, an evolutionary biologist at Harvard, wrote in a remembrance of Professor Trivers for the journal Evolution and Human Behavior. “In another life, he might have been a hoodlum.”

Raised by a diplomat and a poet, and educated at Phillips Academy in Andover, Mass., and Harvard University, Professor Trivers thrived on challenging scientific orthodoxies, calling the field of psychology a “set of competing guesses.” (He also scorned physics, noting that its utility was “connected primarily to warfare.”)

In the early 1970s, as a graduate student at Harvard and later as an untenured professor there, he published a series of papers applying Darwin’s theory of natural selection to social behavior, arguing that science had failed to connect evolution to an understanding of everyday life.

“I was an intellectual opportunist,” he wrote in “Natural Selection and Social Theory: Selected Papers of Robert Trivers” (2002). “The inability of biologists to think clearly on matters of social behavior and evolution for over a hundred years had left a series of important problems untackled.”

The paper does a decent job in outlining Trivers’s contributions, the most important of which was his evolutionary explanation of “reciprocal altruism”, but again, see Pinker for a fuller explication.  A bit more about the situation at Harvard:

During this creative burst, Professor Trivers struggled with mental health issues and was hospitalized at least once for bipolar disorder. He applied for early tenure at Harvard, but the decision was postponed because of concerns about his mental health.

“He could be a brilliant and wonderful colleague,” Professor Haig said. “In a different mood, he could be unnecessarily hostile to those around him.”

That’s enough for now, save one I just found in Skeptic, a remembrance by Trivers’s only graduate student ever, Robert Lynch. Click below to read:

It ends this way:

One of the last times I spoke with Robert, a fall had left his right arm nearly useless. He described it as “two sausages connected by an elbow.” He was a chaotic and deeply imperfect man, but also one of the few people whose ideas permanently changed how we understand evolution, animal behavior, and ourselves. Steven Pinker wrote that “it would not be too much of an exaggeration to say that [Trivers] provided a scientific explanation for the human condition: the intricately complicated and endlessly fascinating relationships that bind us to one another.”  That seems just about right to me.

His ideas are some of the deepest insights we have into human nature, animal behavior, and our place in the web of life. The mark of a great person is someone who never reminds us of anyone else. I have never known anyone like him.

I’ll miss you, Robert. You asshole.

Japan’s space agency, JAXA, has been knocking it out of the park with small-body exploration missions for decades. They had historic successes with both Hayabusa and Hayabusa2, and they are going to visit the Martian Moons soon with the Martian Moons eXploration (MMX) mission. But after that, they are aiming for something much more pristine and arguably more difficult - a comet. The Next Generation Small-Body Return (NGSR) was recently described in a paper at the Lunar and Planetary Science Conference (LPSC), and is under assessment as a large-class mission for the 2030s.

Four NASA astronauts have now travelled further from Earth than any humans before them, as they flew around the moon during the Artemis II mission on 6 April

Popular influencers claim birth rates are declining disastrously. How true is that, and is it a disaster?

Learn about your ad choices: dovetail.prx.org/ad-choices

State legislatures are considering bills that would legitimize pseudoscience like reflexology and reiki by recognizing their practitioners as health care professionals.

The post Legislative Alchemy: Licensing reflexologists and other practitioners of pseudoscience first appeared on Science-Based Medicine.

A team of engineers has created a breakthrough memory device that keeps working at temperatures hotter than molten lava, shattering one of electronics’ biggest limits. Built from an unusual stack of ultra-durable materials, the tiny component can store data and perform calculations even at 700°C (1300°F), far beyond what today’s chips can handle. The discovery was partly accidental, but it revealed a powerful new mechanism that prevents heat-induced failure at the atomic level.

Earth may have won a cosmic chemistry lottery. Researchers found that during the planet’s earliest formation, oxygen had to be in an extremely narrow “Goldilocks zone” for two life-essential elements, phosphorus and nitrogen, to stay where life could use them. Too much or too little oxygen, and those ingredients could be lost or trapped deep inside the planet. This could reshape the search for life by showing that water alone is not enough.

A strange “forbidden” planet spotted by the James Webb Space Telescope is turning planetary science on its head. TOI-5205 b, a Jupiter-sized world orbiting a small, cool star, has an atmosphere surprisingly poor in heavy elements—even less enriched than its own star, which defies current theories of how giant planets form.

The water locked up in the Permanently Shadowed Regions (PSRs) of the Moon’s south pole is a critical resource if we are ever going to get a permanent lunar presence off the ground. But while we know the water ice there exists, we don’t really know how much. We have to move from general estimates to mineable-scale prospecting data. That is what Oasis-1, the newly proposed lunar prospecting mission from Blue Origin that was recently introduced at the 2026 Lunar and Planetary Science Conference (LPSC) is meant to do.

Cornish sea salt crystals, pink Himalayan rock salt, smoked salt flakes – the use of gourmet salts is on the rise. But columnist Alice Klein finds it may be leading to a resurgence in iodine deficiency, with harmful consequences

Iodine deficiency is on the rise among people in the UK, the US and Australia. A century ago this led to drops in IQ, height and thyroid health – and the modern fancy salt fad may be leading to a resurgence, says columnist Alice Klein

For decades, scientists have tried and failed to explain how the force that binds the heart of atoms together really works. But new mathematical tools are finally prising the problem open

Once again we have an article about how science could be improved if only it incorporated indigenous “ways of knowing”—the “braiding of knowledge” referred to in the Guardian article below (click to read).  I often see another metaphor used to express the same thing: “two-eyed seeing”, with one eye seeing the way indigenous people do, and the other way modern science does. (I won’t use the term “Western science,” often used to denigrate it.) The implication is that modern science is half blind without indigenous knowledge.

And once again we see five things. The first is that indigenous knowledge is local knowledge, usually about how to grow food or harvest other things that enhance the lives of locals.

Second, indigenous “ways of knowing” are not science in the modern sense—the sense that involves hypothesis testing, doubt, controlled experiments, blind testing statistics, data analysis, and mathematics.  Indigenous “science” does not avail itself of these essential items in the toolkit of science.  Rather, it usually involves using trial and error (mainly about food), and if something works, it becomes “knowledge”. Such knowledge—like how to build the “clam gardens” copiously mentioned in the article below—may be true and may indeed be “knowledge” conceived of as “justified true belief”, but justification usually doesn’t involve replication.

Third, the “braiding” is asymmetrical: modern science can contribute much more to indigeous practices than the other way around. How to build clam gardens or harvest sweetgrass is, after all, not something that’s widely applicable, while principles of genetics, quantum mechanics, chemistry, and so on, are universal, and science can do a lot to help indigenous people with issues like medicine, probably the most important area of asymmetry.  We do not often adopt indigenous medical practices, but the other way around is pervasive, because modern medicine, based largely on science, works..

Fourth, examples of indigenous knowledge that are given in the article are few. These article are usually a lot more about people touting “other ways of knowing”, and calling attention to the past oppression of indigenous people, than they are about the expansion of human knowledge.

Finally, the article completely neglects examples of the damage done to the environment by indigeous people, and these examples are not rare. They cannot be mentioned because what indigenous people do must be uniformly regarded as good. But they are not, as the date below the fold show.

Click below to read; the author is Leila Nargi.

Examples of indigenous knowledge. I would be remiss if I neglected the “ways of knowing” that the article says should be braided with modern science. There are not many, but this list is pretty exhaustive from the article. Excerpts from it are indented, and my comments are flush left.

Clam gardens:

Beginning at least 4,000 years ago, Native communities built clam gardens into the intertidal zone from Washington state through coastal British Columbia, and into south-east Alaska. They are a unique form of mariculture that provide harvestable habitat for an array of tasty ocean creatures like butter clams – collected “in great numbers, then smoked and dried and stored and traded”, Hatch said. But they also yielded red rock crab, basket cockles, sea cucumbers, limpets, sea snails and seaweeds in a veritable smorgasbord for humans and marine mammals, such as otters.

These gardens change where sediment moves and may protect against increasing shoreline erosion; studies also show that clam productivity and populations are higher inside gardens than outside them.

Yes, this is an advance in growing clams, and may have other salubrious environmental effects, though they aren’t documented. At any rate, stemming erosion would be limited because clam gardens are restricted in size.

Sweetgrass harvesting:

Still, the necessity of “proving” the validity of longstanding Indigenous practices can frustrate. Suzanne Greenlaw, a citizen of the Houlton Band of Maliseet Indians, is an ecologist at the Schoodic Institute, a non-profit of the National Park Service (NPS) that supports Wabanaki-led research. She participated in a 2016 study to understand how sweet grass, which grows in salt marshes, rebounds after harvesting. The study was part of a Wabanaki bid to re-establish the right to gather sweet grass from NPS land. Though the Wabanaki have made baskets from sweet grass for centuries, they have been cut off from ancestral marshes in Maine’s Acadia national park for at least 100 years.

Non-Indigenous researchers planned to conduct an environmental assessment to gauge how well plants regrew after picking, choosing sweet grass plots that had no connection to those once used by the community. This led to a comparison study in which Wabanaki practitioners demonstrated their superior understanding of how and where to harvest for the greatest ecological benefit. (They may reclaim harvest rights later this year.)

Notice that modern science will be used to verify whether the way sweetgrass is harvested affects future harvests.  But that is not indigenous knowledge; rather, it’s an in-progress attempt to verify that knowledge, with the goal of helping indigenous people who have lost their right to harvest regain their rights.

Other stuff:

More Indigenous people – Robin Wall Kimmerer, author of Braiding Sweetgrass, is a notable example – are entering academia and changing it from the inside, while some tribal nations have hired their own scientists. Non-Native institutions are seeking to undo their erasure of Indigenous cultures; the Brooklyn Botanic Garden has started to include labeling that highlights Lenape names and uses for food plants like persimmons. International environmental organizations also increasingly recognize the importance of including Indigenous voices in discussions around the climate crisis. Since 2022, there’s even been federal funding to study ways to combine Indigenous and western sciences, so each part remains distinct while being strengthened by the other.

Note that labeling plants with indigenous names is an exercise in linguistics and anthropology, not a “way of knowing”. And while indigenous people should not be excluded from discussions about practices that may affect their lives, that too is not “knowledge’ but inclusion.

More:

In fact, there are many proven correlations between Indigenous-managed food systems and ecological health. Researchers at Simon Fraser University have found that when Indigenous groups in British Columbia tended forest gardens, they not only produced an impressive biodiversity of food plants – from crabapple and hazelnut and wild plum to wild rice and cranberries – they also improved forest health.

Whyte, the University of Michigan professor, works with the Sault Ste Marie Tribe of Chippewa Indians in Michigan – one of many Native nations that used prescribed burns to boost populations of sharp-tailed grouse, snowshoe hare and deer, all of which declined after the federal government’s 1911 burning ban. Collaborating with US Forest Service researchers, they conducted more than 20 ecology surveys and other projects that proved their case for fire, in the interest of establishing a co-management plan that would allow them to reintroduce this tool.

The first part is absolutely expected: if you deliberately plant diverse plants to get fruits and nuts, and compare the biodiversity with that of native forests, yes, you’ll get a more diverse “ecosystem”. If you see that as a “healihier” ecosystem because it has more ethnobotanical assets, yes, that is also true.  But surely the author doesn’t mean to imply that all North American forest should be turned into “forest gardens” for growing food.

As for controlled burning, yes, that can be useful in replacing natural burns that are no longer permitted, but in the past burns set by indigenous people could become uncontrolled.  This was particularly dire in New Zealand, where 40% of native forest (30-35% of the total land area) was burned by Māori people within 200 years of their arrival on the two main islands in the 13th century. (There were of course no non-Polynesian “colonists” then.) See below the fold for more data.

All in all, it’s not an impressive record, and hardly one that enriches modern science. Indeed, modern science is making a large contribution to indigenous people than the other way around. Despite that,

Indigenous knowledge is sacralized and, the article implies, should be considered coequal with modern science.  Some quotes:

Rather than dismissing Indigenous knowledge, more western scientists are discovering its viability for themselves and adjusting their research goals to embrace it.

That represents a “massive shift”, according to Kyle Whyte, a professor of environmental justice at the University of Michigan and a member of the Citizen Potawatomi Nation. Historically, western scientists have considered themselves rigorous and empirical, while they have classified traditional Native thought as mythic, religious or plain made-up, he said.

It’s not false to say that a great deal of “traditional Native thought”, construed as “ways of knowing”, is indeed mythic, religious, or plain made-up.  But some of it is not, and insofar as this knowledge can be verified by modern science, that part is indeed “knowledge”.

Western science favors distinct disciplines – ecology, biology, geology and Supernant’s specialty, archaeology. But Indigenous knowledge considers “the earth and the water and the air and the plants and the animals as deeply interdependent and interconnected; to understand one is to understand all. And that has a lot to teach western science,” Supernant said of the importance of braiding these systems.

Notice the inaccurate term “Western science”.  And insofar as a system is dependent on other things, modern science has to deal with it. But, as my advisor Dick Lewontin said in an essay called “A reasonable skepticism“:

But this holistic world view is untenable. It is simply another form of mysticism and does not make it possible to manipulate the world for our own benefit. An obscurantist holism has been tried and it has failed. The world is not one huge organism that regulates itself to some good end as the believers in the Gaia hypothesis believe. While in some theoretical sense “the trembling of a flower is felt on the farthest star,” in practice my gardening has no effect on the orbit of Neptune because the force of gravitation is extremely weak and falls off very rapidly with distance. So there is clearly truth in the belief that the world can be broken up into independent parts. But that is not a universal direction for the study of all nature. A lot of nature, as we shall see, cannot be broken up into independent parts to be studied in isolation, and it is pure ideology to suppose that it can.

It is common to say that indigenous knowledge is superior to modern science because the former is more “holistic”.  Lewontin shows the fallacy of that claim.

Here’s another common claim you encounter in this kind of literature:

As opportunities for western and Indigenous collaborations multiply, it’s critical that Indigenous people maintain control over any knowledge gleaned and how it’s used, especially in light of western scientists’ historic penchant for extracting information that suited their own purposes and dismissing the rest. “Western science can help, as long as Native people are still decision makers. . . ” [quote from Suzanne Greenlaw, a Native American ecologist]

If this means anything beyond the way that published data is treated in modern science, then it is an unwarranted privilege. When science is published it becomes the property of humanity, and by and large those who produced the knowledge have no control about how it’s used—nor should they. If other people want to use what you’ve published for their own purposes, well, that’s the way science works. Indigenous people should have no more control over any knowledge they make public than should anybody else.

Below we see the implication that indigenous knowledge should be considered coequal with modern science (the quote is from Kisha Supernant “Métis and Papaschase and the director of the University of Alberta’s Institute of Prairie and Indigenous Archaeology”):

What constitutes progress when it comes to braiding western and Indigenous science depends on whom you ask. “If the burden of proof remains on Indigenous communities to demonstrate, using western scientific methods, that their knowledge … is valid, I think we’re not at the place we need to be,” Supernant said. “It is difficult to braid two things together when they’re not given equal weight in the braid.”

Well, I’d say that given the toolkit that’s constitutes modern science and is used to establish “knowledge,” then yes, indigenous people should have to demonstrate that their knowledge really is knowledge in the modern sense before it’s used.  When the Māori want to play whale songs to infected kauri trees because whales and kauri trees were once seen as brothers, then they should have to demonstrate the phylogenetic affinity of trees and cetaceans as well as the efficacy of whale songs. (This is a real case based on mytic lore.)

Finally, the bit below strikes me as rather patronizing, treating Indigenous people like children. (“Whyte” is a “professor of environmental justice at the University of Michigan and a member of the Citizen Potawatomi Nation.”)

Whyte is encouraged that the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), which seeks to provide scientific evidence to inform government decision-making, included a chapter on Indigenous knowledge in its latest global assessment. But he sees plenty of opportunity for improvements to braiding. For starters, “Indigenous people need to be involved at the earliest stages of research,” he said. And that means western scientists “need to get into the habit of approaching potential [Indigenous] partners and saying ‘I’m interested in water. Are you interested in water?’ before any research questions have been created. Let’s just get excited together about the topic, and plan from the beginning.”

If they plan experiments on indigenous land, or experiments that affect indigenous people, then yes, there should be consultation.  But “getting excited together” before any research questions have been formulated is not the way that science works, nor should it.  Science is not an endeavor that involves research equity, and creating such equity must be an extracurricular activity. The job of science is to understand the Universe, not to create social justice or spread an ideology.

h/t Ron, Ginger K

Click “continue reading” to see what we know about the damage indigenous North Americans did to the environment. It gives the answer to a question I asked Grok.

The question I asked: What damage did indigenous North American people do to the environment? And Grok’s complete answer, with sources (the ones I got had links).

Indigenous North American peoples (pre-Columbian ancestors and later Native American groups) altered their environments in significant ways, as all human societies do when they hunt, farm, burn landscapes, or build settlements. This often caused localized environmental damage, including species declines or extinctions, soil degradation, erosion, and major shifts in vegetation. The notion of a “pristine wilderness” untouched by humans before Europeans is a myth; archaeological, paleoecological, and historical evidence shows active modification and overexploitation in many regions.

Impacts varied by group, region, time, and technology (e.g., hunter-gatherers vs. agricultural societies), and were generally smaller-scale and more reversible than industrial-era damage due to lower populations and simpler tools. Many practices were adaptive for the peoples involved (e.g., increasing game or crops), but they still produced clear negative effects on ecosystems, biodiversity, and long-term habitability in specific areas. Here are the main documented examples:

1. Contribution to Pleistocene Megafauna Extinctions (~13,000–11,000 years ago)The arrival of humans in North America coincided with the extinction of ~38 genera of large mammals (megafauna), including mammoths, mastodons, giant ground sloths, camels, horses, and saber-toothed cats. The “overkill hypothesis” (proposed by Paul Martin) argues that efficient human hunters rapidly drove these naïve animals to extinction through direct predation, especially as human populations grew and spread.

• Supporting evidence includes kill sites with Clovis points and megafauna bones, plus computer models showing hunting pressure could cause rapid collapse. Humans hunted/scavenged these species continent-wide, including in eastern North America. sapiens.org
• Counterarguments note climate change (end of the Ice Age) played a major role, with many species already declining; extinctions weren’t instantaneous “blitzkrieg.” Some studies suggest 75–90% of northeastern megafauna vanished before or without heavy human involvement. science.org

Consensus: Humans were a key driver (especially in the Americas, where losses were ~72% of large mammal genera), amplifying climate stress via overhunting and habitat disruption. This was the earliest major human-caused environmental shift on the continent.

ourworldindata.org

2. Agricultural Overexploitation and Landscape Degradation (Southwest and Other Farming Regions)Sedentary farming societies like the Ancestral Puebloans (Anasazi/Hohokam, ~AD 1–1500) in the arid Southwest cleared woodlands, built irrigation systems, and intensified agriculture, leading to deforestation, soil erosion, salinization, and arroyo (gully) formation. These contributed to regional collapses and site abandonments.

• Chaco Canyon (Ancestral Puebloans): Massive wood harvesting for construction and fuel stripped local woodlands (piñon-juniper, ponderosa pine). This caused destabilization, soil erosion, reduced water retention, and increased environmental unpredictability during droughts. pmc.ncbi.nlm.nih.gov
• Hohokam (Arizona’s Salt and Gila River valleys): Long-term irrigation raised groundwater salinity, rendering fields infertile and contributing to agricultural failure and societal decline by the 15th century. acsess.onlinelibrary.wiley.com
• Similar issues elsewhere: Prehistoric farming caused accelerated soil erosion in some areas, outpacing natural rates. sciencedirect.com

These were human-induced changes that made recovery difficult without relocation—classic cases of local environmental collapse from overexploitation.

3. Widespread Controlled Burning and Vegetation Shifts

Indigenous groups across North America (and especially the Great Plains, California, and eastern woodlands) used frequent, low-intensity fires to manage landscapes: clear underbrush for travel/hunting, promote grasses and fire-tolerant plants (oaks, hickories), drive game, and enhance berry/root crops. This profoundly altered ecosystems from what they would have been under purely natural (lightning) regimes.

• Forests were converted to grasslands, savannas, or open woodlands with grassy openings. Fire-tolerant species increased near settlements (e.g., oaks rose dramatically in southern New England forests). psu.edu
• This created the “park-like” landscapes Europeans later described—not untouched wilderness. Post-contact fire suppression (after indigenous populations crashed) led to fuel buildup and today’s severe wildfires. en.wikipedia.org

While often sustainable and biodiversity-enhancing in a mosaic sense, it represented deliberate, large-scale human modification that reduced closed-canopy forests and favored human-preferred species over others.

4. Hunting and Local Overexploitation

Beyond megafauna, there is evidence of wasteful or unsustainable hunting:

• Buffalo jumps and communal hunts sometimes killed far more animals than needed (pre- and post-horse), leaving carcasses unused. thetedkarchive.com
• In some areas, deer, beaver, and other game were depleted locally through intensive harvesting (pre-contact for subsistence; later amplified by European trade).
• Shepard Krech’s The Ecological Indian (1999) documents cases where indigenous groups did not always act as perfect conservationists—e.g., selective use of animals or failure to limit impacts despite knowledge of ecology. thetedkarchive.com

Pre-contact populations peaked around AD 1150 before some regional declines (from drought, warfare, disease), showing societies weren’t always in perfect equilibrium.

dri.edu

Context and ScaleThese impacts were real but not uniform or continent-wide “destruction.” Many groups were mobile or low-density, allowing recovery over time. Practices often reflected deep ecological knowledge (e.g., fire as “medicine” for resilience). European contact later caused massive indirect changes via depopulation (~90% decline in some areas from disease), followed by reforestation—but the question focuses on indigenous actions.

theguardian.com

Scholarly views (e.g., Krech, paleoecological studies) reject romanticized “harmony with nature” as ahistorical. Indigenous peoples were sophisticated actors who shaped, exploited, and sometimes damaged environments for survival and advantage—just as humans everywhere have. Modern conservation draws useful lessons from their fire management, but facts show they were not uniquely non-impactful.

Many people might find this to be an easy question and simple concept – what is your favorite color? In fact it was used as the quintessential easy question by the bridge guardian in Monty Python and the Holy Grail. But it is a good rule of thumb that everything is much more complicated than you think or than it may at first appear, and this is no exception. We recently had a casual discussion about this topic on the SGU, and it left me unsatisfied, so I thought I would do a deeper dive. Perhaps there is a neuroscientific answer to this question.

The panel differed in their reactions to the question of favorite color (we were just giving our subjective feelings, not discussing research or evidence). Cara felt that “favorite color” is largely arbitrary. Kids are asked to pick a favorite color, which they do (under pressure) and then often just stick with that answer as they get older. She also felt the question was meaningless without context – are you referring to clothes, cars, house color, or something else? Jay was at the other end of the spectrum – he has a strong affiliation for the color orange which gives him a pleasant feeling. The rest were somewhere in between these two extremes.

I knew there had to be a science of “favorite color”, which I thought might be interesting. Indeed there is – and it is interesting.

First, what is the distribution of favorite color, across the world and demographically? Blue is, far and away, the most favorite color, in most countries across the world, so it seems to be very cross-cultural. It is also the favorite across age groups and gender. The second-most favorite color is either green, red, or purple. Brown is almost universally the least favorite color. Gender has an effect on favorite color, with more women favoring pink, and reds in general (but still preferring blue overall). Republicans still prefer blue over red, but more Republicans prefer red than Democrats. There are country-specific differences as well. Red is a higher preference in China than many other countries, for example.

The demographics of favorite color are clues as to potential underlying causes. Is favorite color purely a cultural phenomenon? It does not seem to be, but there are some minor cultural influences. Is it a neuro-biological phenomenon? It could be, but not purely. If it is partly neurological, what does it track with? How about personality. The evidence is, in short, mixed, and reveals the hidden complexity of seemingly straightforward questions.

Most people think of color preference as referring to hue, but saturation and brightness have just as much of an influence on color choice. When you consider all aspects of color, the picture becomes more complex. Extroverts, for example, prefer bright colors. Adults tend to prefer more saturated colors. The results of studies, therefore, depend on how the questions were asked. But an overall summary is – you can make some statistical predictions about the big five personality types (extroversion, openness, agreeableness, neuroticism, and conscientiousness) from color choice. But this is one factor among many, and depend on multiple factors (the context, the object, and all three color traits). There does seem to be an actual phenomenon here – an influence of personality on color choice – but it’s mixed and complicated.

So far we have mostly just been describing who has which color preferences, but not why or how. We have some clues from the demographics of color choice, but no answers. Given everything above, it is still possible that color choice is entirely learned, or partly learned but mostly an inherited trait. What does the evidence say about this question? Well, there is no current answer, but there is a strong theory that is a good fit to the evidence – the ecological valence theory.

According to this theory color preferences emerge from the totality of our life experience mainly through emotional association. We have a partly associatative memory, in that we tend to remember things partly by associating them with other things that occur together. This includes color. If green things tend to be associated with good experiences, then we will begin to associate the color green with good feelings. According to EVT blue is the most common favorite color because we associate with blue clear skies and clean water, which tend to be associated with happy experiences. We tend to associate brown with feces or rotten food, so that is consistently the least favorite color.

The strength of EVT is that it allows for biological, cultural, experiential, and personality factors all at once. They all can affect our associations with colors, and contribute to how they make us feel. Some associations may be natural, like blue skies, green vegetation, and putrid yellow and brown. Others can be purely cultural, like pink for girls or purple with royalty. Different personalities would be drawn to different colors that tend to be associated with congruent moods, like vibrant reds for extroverts, or calming blues for introverts. And then there are likely to be some quirky individual factors as well – extreme individual experiences, or social group sorting (which color wedge do you typically play in Trivial Pursuit).

Does neuroscience add anything to this picture? So far, neuroscientific studies have elucidated some of the underlying brain regions that relate to color preference and processing, but don’t really provide any insight into why color preferences exist. Here is the most relevant study I could find:

These results demonstrate that brain activity is modulated by color preference, even when such preferences are irrelevant to the ongoing task the participants are engaged. They also suggest that color preferences automatically influence our processing of the visual world. Interestingly, the effect in the PMC overlaps with regions identified in neuroimaging studies of preference and value judgements of other types of stimuli.

Sure – color preferences and experiences happen in the brain, and involve a brain region generally involved in value judgement. This is a piece to the puzzle, but itself does not really address the cause of color preferences, just some of the neurological mechanisms.

There is still a lot to learn about color preferences. The evidence does not support the notion that color preference is a purely arbitrary phenomenon, but rather that it has a psychological, cultural, and neurological basis. But there is still a lot of research to be done in terms of the nature and causes of color preferences.

 

The post What Is Your Favorite Color? first appeared on NeuroLogica Blog.

Today the Artemis 2 capsule with its four astronauts does its transit around the Moon, going further into space than any human have gone into space. They’ll also see parts of the Moon’s backside that have never been seen by the living human eye, though the backside has been amply photographed.

Shortly after midnight this morning, the capsule entered the Moon’s “sphere of influence,” meaning the part of space where the gravity of the Moon exceeds the gravity of Earth.  The schedule is below, and I’ve put a video of the live proceedings below.

From the Space.com site:

The Artemis 2 astronauts have arrived in the moon’s sphere of influence, and are now preparing for a very full day of lunar observations.

They crossed the celestial threshold early Monday morning (April 6), becoming the first people to do so since the crew of Apollo 17, in 1972.

The pull of the moon’s gravity on the Artemis 2 Orion capsule officially became stronger than Earth’s influence on the spcecraft at 12:37 a.m. EDT (0437 GMT), as Orion flew 39,000 miles (62,764 kilometers) above the moon and 232,000 miles (373,368 km) from Earth.

Today, they will break the distance record set by Apollo 13, which flew 248,655 miles (400,171 kilometers) from Earth. Artemis 2 reach that, and then some, but between breaking the record and setting their own, they will have hours of lunar observations to conduct as Orion makes its closest approach to the moon.

Here’s a full breakdown of what to expect today (all times in EDT):

There will be about a 40-minute communications blackout (starting at about 6:47 pm) when they go around the Moon. Here’s today’s schedule:

1 p.m.: NASA lunar flyby coverage begins.
1:56 p.m.: Apollo 13 distance record broken
2:10 p.m.: Crew remarks about record
2:15 p.m.: Crew configures Orion for flyby
2:45 p.m.: Lunar observation period begins
6:47 p.m.: Loss of communications (estimated 40-min.)
7:02 p.m.: Closest approach to the moon
7:05 p.m.: Maximum distance from Earth
8:35 p.m.: Orion enters solar eclipse period
9:20 p.m.: Lunar observation period ends
9:32 p.m.: Solar eclipse period concludes

Watching a bit this morning, I see there is a possible cabin leak, which is worrying, but it may have been a false alarm.

If the video is not working, you can see it on the Space.com site: You can also scroll back and see what was going on previously.

h/t: Bat

Today’s photo come from reader Jan Malik, who took them in New Jersay. Jan’s captions are indented, and you can enlarge the photos by clicking on them.

As an appendix to the earlier Tree Swallow pictures, here are a few more from the New Jersey Botanical Garden. A walk in that park on the first day of spring is a ritual of mine—to ensure all observable phenomena related to spring are happening again and that the thermal death of the Universe is postponed for yet another year.

Red-bellied Woodpecker (Melanerpes carolinus) pausing mid-search for food. This is a female; in this species, the red plumage is restricted to the nape and the area above the bill, whereas males sport a continuous red cap:

Spring Snowflake (Leucojum vernum, possibly var. carpathicum), a Eurasian transplant. It looks succulent, but this perennial defends itself against mammalian browsing by producing bitter, poisonous alkaloids:

Eastern Cottontail (Sylvilagus floridanus) hiding in bearberry brambles. Against this notorious garden destroyer, only the Holy Hand Grenade of Antioch offers a true degree of protection:

Forsythia (Genus Forsythia) in bloom—the unmistakable sign that spring has arrived:

White-breasted Nuthatch (Sitta carolinensis). Like the woodpecker, it is a connoisseur of arthropods hiding in bark. however, by being equally adept at feeding head-down or head-up, it finds insects that a woodpecker might miss:

Common Water Strider (likely Aquarius remigis) emerged from its winter hiding. These are predators and scavengers of insects trapped on the surface of slow-flowing streams. As a “true bug,” it has evolved to exploit surface tension. However, surface tension alone doesn’t keep it dry; the secret lies in the dense, hydrophobic hairs on its tarsi. These trap air to act as tiny “dinghies,” preventing the legs from being wetted by capillary action:

Crocus flower (likely a Woodland Crocus, Crocus tommasinianus). The flowers emerge before the leaves, which then die back in late spring after accumulating enough biomass for the year. This adaptation to montane meadows and early forests allows them to bloom early, while withdrawing underground provides a defense against browsing:

Northern Mockingbird (Mimus polyglottos) picking bittersweet fruit (likely the introduced Oriental Bittersweet, Celastrus orbiculatus). The fruit is indeed slightly sweet—a fact I confirmed before spitting it out, as they are reportedly toxic to humans. As they say: don’t try this at home; try it in nature instead:

After the meal, the mockingbird sits quietly in a nearby bush. They mimic other birds’ calls, possibly to fool rivals into thinking a territory is already occupied. It doesn’t work on me, though—I can always tell the original bird from the imitation:

Snowdrop (Genus Galanthus), another Eurasian immigrant. Most of the plants in these pictures were introduced from Eurasia to the Americas; however, with the exception of the Bittersweet, they are generally not considered invasive:

A Jumping Spider. I can’t vouch for the exact ID, but it resembles Phidippus princeps. While not my best shot, it’s worth noting that, like all others in this series, it was taken with a single lens (Canon RF 100-500mm)—a blessing for a lazy photographer.

An Eastern Gray Squirrel (Sciurus carolinensis), looking lean after winter and digging for roots and grubs in the lawn. This species is an unwelcome sight in Europe, where its introduction is displacing the native Red Squirrel. But can we really blame them? They are simply good at being squirrels. It is entirely a human fault that geographical barriers are collapsing. In this “Homogecene” era of a connected world, the total number of species will inevitably decline:

Boosting the brain's waste-disposal system is increasingly showing promise for Alzheimer's disease, with a study now suggesting that a novel approach eases brain deficits and symptoms associated with the condition

Scientists have taken a major step toward probing one of physics’ biggest mysteries—how gravity and quantum mechanics fit together—by creating the first unified way to detect tiny “ripples” in spacetime itself. These subtle fluctuations, long predicted but poorly defined, are now organized into clear categories with specific signals that real-world instruments can search for. The breakthrough means powerful tools like LIGO and even small tabletop experiments could start testing competing theories of quantum gravity much sooner than expected.

Scientists have taken a major step toward probing one of physics’ biggest mysteries—how gravity and quantum mechanics fit together—by creating the first unified way to detect tiny “ripples” in spacetime itself. These subtle fluctuations, long predicted but poorly defined, are now organized into clear categories with specific signals that real-world instruments can search for. The breakthrough means powerful tools like LIGO and even small tabletop experiments could start testing competing theories of quantum gravity much sooner than expected.