Chapter 6. Evolution of the Brain and Behavior
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By Erin Wayman Barbara J. King remembers the first time she met Kanzi the bonobo. It was the late 1990s, and the ape was living in a research center in Georgia. King walked in and told Kanzi she had a present. A small, round object created a visible outline in the front pocket of her jeans. Kanzi picked up a board checkered with colorful symbols and pointed to the one meaning “egg” and then to “question.” An egg? No, not an egg. A ball. But “he asked an on-point question, and even an extremely simple conversation was just amazing,” says King, a biological anthropologist at William & Mary in Williamsburg, Va. Born in 1980, Kanzi began learning to communicate with symbols as an infant. He ultimately mastered more than 300 symbols, combined them in novel ways and understood spoken English. Kanzi was arguably the most accomplished among a cohort of “talking” apes that scientists intensely studied to understand the origins of language and to probe the ape mind. He was also the last of his kind. In March, Kanzi died. “It’s not just Kanzi that is gone; it’s this whole field of inquiry,” says comparative psychologist Heidi Lyn of the University of South Alabama in Mobile. Lyn had worked with Kanzi on and off for 30 years. Kanzi’s death offers an opportunity to reflect on what decades of ape-language experiments taught us — and at what cost. A history of ape-language experiments Language — communication marked by using symbols, grammar and syntax — has long been considered among the abilities that make humans unique. And when it comes to delineating the exact boundary separating us from other animals, scientists often turn to our closest living relatives, the great apes. © Society for Science & the Public 2000–2025.
Keyword: Language; Evolution
Link ID: 29797 - Posted: 05.21.2025
By Mikael Angelo Francisco A comic explains the highs and lows of birdsong Mikael Angelo Francisco is a science journalist and illustrator from the Philippines who enjoys writing about paleontology, biodiversity, environment conservation, and science in pop culture. He has written and edited books about media literacy, Filipino scientists, and science trivia. © 2025 NautilusNext Inc.
Keyword: Language; Evolution
Link ID: 29794 - Posted: 05.21.2025
Gemma Conroy Researchers have identified a genetic dial in the human brain that, when inserted in mice, boosts their brain size by about 6.5%.Credit: Sergey Bezgodov/Shutterstock Taking a snippet of genetic code that is unique to humans and inserting it into mice helps the animals to grow bigger brains than usual, according to a report out in Nature today1. The slice of code — a stretch of DNA that acts like a dial to turn up the expression of certain genes — expanded the outer layer of the mouse brain by increasing the production of cells that become neurons. The finding could partially explain how humans evolved such large brains compared with their primate relatives. This study goes deeper than previous work that attempted to unpick the genetic mechanisms behind human brain development, says Katherine Pollard, a bioinformatics researcher at the Gladstone Institute of Data Science and Biotechnology in San Francisco, California. “The story is much more complete and convincing,” she says. How the human brain grew to be so big and complex remains a mystery, says Gabriel Santpere Baró, a neuroscientist who studies genomics at the Hospital del Mar Medical Research Institute in Barcelona, Spain. “We still do not have a definitive answer to how the human brain has tripled in size since our split from chimpanzees” during evolution, he says. Previous studies2,3 have hinted that human accelerated regions (HARs) — short snippets of the genome that are conserved across mammals, but which underwent rapid change in humans after they evolutionarily diverged from chimpanzees — could be key contributors to brain development and size. But the exact mechanisms that underlie the brain-building effects of HARs are yet to be uncovered, says study co-author Debra Silver, a developmental neurobiologist at Duke University in Durham, North Carolina. © 2025 Springer Nature Limited
Keyword: Development of the Brain; Evolution
Link ID: 29791 - Posted: 05.17.2025
By Sydney Wyatt The red nucleus—a pale pink brainstem structure that coordinates limb movements in quadruped animals—also projects to brain areas that shape reward-motivated and action-based movements in people, according to a new functional imaging study. The finding suggests the region, like the cerebral cortex, took on a more complex role over the course of evolution. Many researchers had assumed that brainstem structures remained stuck in evolutionarily ancient roles, says Joan Baizer, professor of physiology and biophysics at the University at Buffalo. Activity in the red nucleus, a structure that emerged once animals began to use limbs for walking, coordinates the speed and accuracy of those movements in rats and helps to control posture in monkeys, previous electrophysiological recordings have shown. And in nonhuman primates, neurons in the red nucleus project to the motor cortex and spinal cord, anatomical studies have demonstrated, seemingly confirming the area’s role in motor function. By contrast, the human red nucleus primarily connects to cortical and subcortical regions involved in action control, reward and motivated behavior, the new work reveals. “If this is such a motor structure, why isn’t it projecting to the spinal cord? That doesn’t really fit with our notion of what this structure is supposed to be doing,” says study investigator Samuel Krimmel, a postdoctoral fellow in Nico Dosenbach’s lab. The new imaging suggests that, at least in people, the neural underpinnings of motivated movement—previously considered to be the role of higher-order brain areas—reach “all the way down into the brainstem,” says Dosenbach, professor of neurology at Washington University School of Medicine, who led the work. The findings were published last month in Nature Communications. © 2025 Simons Foundation
Keyword: Learning & Memory; Evolution
Link ID: 29790 - Posted: 05.17.2025
By Christa Lesté-Lasserre Can a robot arm wave hello to a cuttlefish—and get a hello back? Could a dolphin’s whistle actually mean “Where are you?” And are monkeys quietly naming each other while we fail to notice? These are just a few of the questions tackled by the finalists for this year’s Dolittle prize, a $100,000 award recognizing early breakthroughs in artificial intelligence (AI)-powered interspecies communication. The winning project—announced today—explores how dolphins use shared, learned whistles that may carry specific meanings—possibly even warning each other about danger, or just expressing confusion. The other contending teams—working with marmosets, cuttlefish, and nightingales—are also pushing the boundaries of what human-animal communication might look like. The prize marks an important milestone in the Coller Dolittle Challenge, a 5-year competition offering up to $10 million to the first team that can achieve genuine two-way communication with animals. “Part of how this initiative was born came from my skepticism,” says Yossi Yovel, a neuroecologist at Tel Aviv University and one of the prize’s organizers. “But we really have much better tools now. So this is the time to revisit a lot of our previous assumptions about two-way communication within the animal’s own world.” Science caught up with the four finalists to hear how close we really are to cracking the animal code. This interview has been edited for clarity and length. Cuttlefish (Sepia officinalis and S. bandensis) lack ears and voices, but they apparently make up for this with a kind of sign language. When shown videos of comrades waving their arms, they wave back.
Keyword: Language; Evolution
Link ID: 29788 - Posted: 05.17.2025
Nicola Davis Science correspondent Birds of a feather flock together, so the saying goes. But scientists studying the behaviour of starlings have found their ability to give and take makes their relationships closer to human friendships than previously thought. About 10% of bird species and 5% of mammal species breed “cooperatively”, meaning some individuals refrain from breeding to help others care for their offspring. Some species even help those they are unrelated to. Now researchers studying superb starlings have found the support cuts both ways, with birds that received help in feeding or guarding their chicks returning the favour when the “helper” bird has offspring of its own. Prof Dustin Rubenstein, a co-author of the study from the University of Colombia, said such behaviour was probably necessary for superb starlings as they live in a harsh environment where drought is common and food is limited. “Two birds probably can’t feed their offspring on their own, so they need these helpers to help them,” he said, adding that as each breeding pair produces few offspring, birds must be recruited from outside the family group to help the young survive. “What happens is the non-relatives come into the group, and they breed pretty quickly, usually in the first year, maybe the second year, and then they take some time off and some of the other birds breed – and we never understood why,” said Rubenstein. “But they’re forming these pairwise reciprocal relationships, in the sense that I might help you this year, and then you’ll help me in the future.” The results chime with previous work from Rubenstein and colleagues that found superb starlings living in larger groups have a greater chance of survival and of producing offspring, with the new work suggesting the give-and-take approach helps to stabilise these groups. © 2025 Guardian News & Media Limited
Keyword: Sexual Behavior; Evolution
Link ID: 29785 - Posted: 05.14.2025
By Jake Buehler Grunts, barks, screams and pants ring through Taï National Park in Cȏte d’Ivoire. Chimpanzees there combine these different calls like linguistic Legos to relay complex meanings when communicating, researchers report May 9 in Science Advances. Chimps can combine and flexibly rearrange pairs of sounds to convey different ideas or meanings, an ability that investigators have not documented in other nonhuman animals. This system may represent a key evolutionary transition between vocal communication strategies of other animals and the syntax rules that structure human languages. “The difference between human language and how other animals communicate is really about how we combine sounds to form words, and how we combine words to form sentences,” says Cédric Girard-Buttoz, an evolutionary biologist at CNRS in Lyon, France. Chimpanzees (Pan troglodytes) were known to have a particularly complicated vocal repertoire, with about a dozen single sounds that they can combine into hundreds of sequences. But it was unclear if the apes used multiple approaches when combining sounds to make new meanings, like in human language. In 2019 and 2020, Girard-Buttoz and his colleagues recorded 53 different adult chimpanzees living in the Taï forest. In all, the team analyzed over 4,300 sounds and described 16 different “bigrams” — short sequences of two sounds, like a grunt followed by a bark, or a panted hoo followed by a scream. The team then used statistical analyses to map those bigrams to behaviors to reveal some of the bigrams’ meanings. The result? Chimpanzees don’t combine sounds in a single, consistent way. They have at least four different methods — a first seen outside of humans. © Society for Science & the Public 2000–2025
Keyword: Language; Evolution
Link ID: 29781 - Posted: 05.11.2025
By Asher Elbein True friends, most people would agree, are there for each other. Sometimes that means offering emotional support. Sometimes it means helping each other move. And if you’re a superb starling — a flamboyant, chattering songbird native to the African savanna — it means stuffing bugs down the throats of your friends’ offspring, secure in the expectation that they’ll eventually do the same for yours. Scientists have long known that social animals usually put blood relatives first. But for a study published Wednesday in the journal Nature, researchers crunched two decades of field data to show that unrelated members of a superb starling flock often help each other raise chicks, trading assistance to one another over years in a behavior that was not previously known. “We think that these reciprocal helping relationships are a way to build ties,” said Dustin Rubenstein, a professor of ecology at Columbia University and an author of the paper. Superb starlings are distinctive among animals that breed cooperatively, said Alexis Earl, a biologist at Cornell University and an author of the paper. Their flocks mix family groups with immigrants from other groups. New parents rely on up to 16 helpers, which bring chicks extra food and help run off predators. Dr. Rubenstein’s lab has maintained a 20-year field study of the species that included 40 breeding seasons. It has recorded thousands of interactions between hundreds of the chattering birds and collected DNA to examine their genetic relationships. When Dr. Earl, then a graduate student in the lab, began crunching the data, she and her colleagues weren’t shocked to see that birds largely helped relatives, the way an aunt or uncle may swoop in to babysit and give parents a break. © 2025 The New York Times Company
Keyword: Evolution; Emotions
Link ID: 29780 - Posted: 05.10.2025
Freda Kreier Some people can function well on little sleep.Credit: Oleg Breslavtsev/Getty Most people need around eight hours of sleep each night to function, but a rare genetic condition allows some to thrive on as little as three hours. In a study published today in the Proceedings of the National Academy of Sciences1, scientists identified a genetic mutation that probably contributes to some people’s limited sleep needs. Understanding genetic changes in naturally short sleepers — people who sleep for three to six hours every night without negative effects — could help to develop treatments for sleep disorders, says co-author Ying-Hui Fu, a neuroscientist and geneticist at the University of California, San Francisco. “Our bodies continue to work when we go to bed”, detoxifying themselves and repairing damage, she says. “These people, all these functions our bodies are doing while we are sleeping, they can just perform at a higher level than we can.” In the 2000s, Fu and her colleagues were approached by people who slept six hours or less each night. After analysing the genomes of a mother and daughter, the team identified a rare mutation in a gene that helps to regulate humans’ circadian rhythm, the internal clock responsible for our sleep–wake cycle. The researchers suggested that this variation contributed to the duo’s short sleep needs. That discovery prompted others with similar sleeping habits to contact the laboratory for DNA testing. The team now knows several hundred naturally short sleepers. Fu and her colleagues have so far identified five mutations in four genes that can contribute to the trait — although different families tend to have different mutations. Short sleeper In the latest study, the researchers searched for new mutations in the DNA of a naturally short sleeper. They found one in SIK3, a gene encoding an enzyme that, among other things, is active in the space between neurons. Researchers in Japan had previously found another mutation in Sik3 that caused mice to be unusually sleepy2. © 2025 Springer Nature Limited
Keyword: Sleep; Genes & Behavior
Link ID: 29778 - Posted: 05.07.2025
Logan S. James It is late at night, and we are silently watching a bat in a roost through a night-vision camera. From a nearby speaker comes a long, rattling trill. The bat briefly perks up and wiggles its ears as it listens to the sound before dropping its head back down, uninterested. Next from the speaker comes a higher-pitched “whine” followed by a “chuck.” The bat vigorously shakes its ears and then spreads its wings as it launches from the roost and dives down to attack the speaker. Bats show tremendous variation in the foods they eat to survive. Some species specialize on fruits, others on insects, others on flower nectar. There are even species that catch fish with their feet. At the Smithsonian Tropical Research Institute in Panama, we’ve been studying one species, the fringe-lipped bat (Trachops cirrhosus), for decades. This bat is a carnivore that specializes in feeding on frogs. Male frogs from many species call to attract female frogs. Frog-eating bats eavesdrop on those calls to find their next meal. But how do the bats come to associate sounds and prey? We were interested in understanding how predators that eavesdrop on their prey acquire the ability to discriminate between tasty and dangerous meals. We combined our expertise on animal behavior, bat cognition and frog communication to investigate. © 2010–2025, The Conversation US, Inc.
Keyword: Hearing; Development of the Brain
Link ID: 29768 - Posted: 05.03.2025
RJ Mackenzie Neuroscientists have identified a brain signal in mice that kick-starts the process of overwriting fearful memories once danger is passed — a process known as fear extinction. The research is at an early stage, but could aid the development of drugs to treat conditions, such as post-traumatic stress disorder (PTSD), that are linked to distressing past experiences. In a study published on 28 April in the Proceedings of the National Academy of Sciences1, the researchers focused on two populations of neurons in a part of the brain called the basolateral amygdala (BLA). These two types of neuron have contrasting effects: one stimulates and the other suppresses fear responses, says co-author Michele Pignatelli, a neuroscientist at Massachusetts Institute of Technology in Cambridge. Until now, scientists didn’t know what activated these neurons during fear extinction, although previous research implicated the neurotransmitter dopamine, released by a specific group of neurons in another part of the brain called the ventral tegmental area (VTA). To investigate this possibility, the authors used fluorescent tracers injected into the brains of mice to show that the VTA sends dopamine signals to the BLA, and that both pro- and anti-fear neurons in the BLA can respond to these signals. They then studied the effects of these circuits on behaviour, using mice that had been genetically modified so that dopamine activity in their brains produced fluorescent light, which allowed the researchers to record the activity of the VTA–BLA connections using fibre optics. They first placed these mice into chambers that delivered mild but unpleasant electrical shocks to their feet, which made them freeze in fear. The next day, they put the mice back in the chambers but did not give them any shocks. Although initially fearful, the mice began to relax after about 15 minutes, and the researchers saw a dopamine current surge through their ‘anti-fear’ BLA neurons. © 2025 Springer Nature Limited
Keyword: Emotions; Stress
Link ID: 29766 - Posted: 04.30.2025
Hannah Thomasy, PhD In recent decades, scientists have demonstrated that prosocial behaviors are not unique to humans, or even to primates. Rats, in particular, have proved surprisingly sensitive to the distress of conspecifics, and will often come to the aid of a fellow rat in trouble. In 2011, researchers showed that when rats were provided with a clear box containing chocolate chips, they usually opened the box and consumed all the chocolate.1 But when one box contained chocolate and another contained a trapped cagemate, the rats were more likely to open both boxes and share the chocolate. But some rats didn’t play as nicely with others. In versions of the test that did not involve chocolate, only a rat and its trapped cagemate, researchers noticed that while some rats consistently freed their compatriots, others did not. In a new Journal of Neuroscience study, neuroscientists Jocelyn Breton at Northeastern University and Inbal Ben-Ami Bartal at Tel-Aviv University explored the behaviors and neural characteristics of helpers and non-helpers.2 They found that helper rats displayed greater social interactions with their cagemates, greater activity in prosocial neural networks, and greater expression of oxytocin receptors in the nucleus accumbens (NAc), providing clues about the mechanisms that govern prosocial behaviour. “We appear to live in an increasingly polarized society where there is a gap in empathy towards others,” said Bartal in a press release. “This work helps us understand prosocial, or helpful, acts better. We see others in distress all the time but tend to help only certain individuals. The similarity between human and rat brains helps us understand the way our brain mediates prosocial decisions.” To undertake these experiments, the researchers first divided the rats into pairs and allowed them to acclimatize to their cagemates for a few weeks. Then they placed the pair in the testing arena, where they allowed one rat to roam free and restrained the other in a clear box that could only be opened from the outside. While they were not trained to open the box, more than half of the rats figured out how to free their trapped companions and did so during multiple days of consecutive testing. © 1986-2025 The Scientist.
Keyword: Emotions; Evolution
Link ID: 29765 - Posted: 04.30.2025
By Nicole M. Baran One of the biggest misconceptions among students in introductory biology courses is that our characteristics are determined at conception by our genes. They believe—incorrectly—that our traits are “immutable.” The much more beautiful, complicated reality is that we are in fact a product of our genes, our environment and their interaction as we grow and change throughout our lives. Nowhere is this truer than in the developmental process of sexual differentiation. Early in development when we are still in the womb, very little about us is “determined.” Indeed, the structures that become our reproductive system start out as multi-potential, capable of taking on many possible forms. A neutral structure called the germinal ridge, for example, can develop into ovaries or testes—the structures that produce reproductive cells and sex hormones—or sometimes into something in between, depending on the molecular signals it receives. Our genes influence this process, of course. But so do interactions among cells, molecules in our body, including hormones, and influences from the outside world. All of these can nudge development in one direction or another. Understanding the well-studied science underlying this process is especially important now, given widespread misinformation about—and the politicization of—sex and gender. I am a neuroendocrinologist, which means that I study and teach about hormones and the brain. In my neuroendocrinology classroom, students learn about the complex, messy process of sexual differentiation in both humans and in birds. Because sexual differentiation in birds is both similar to and subtly different from that in humans, studying how it unfolds in eggs can encourage students to look deeper at how this process works and to question their assumptions. So how does sexual differentiation work in birds? Like us, our feathered friends have sex chromosomes. But their sex chromosomes evolved independently of the X and Y chromosomes of mammals. In birds, a gene called DMRT1 initiates sexual differentiation. (DMRT1 is also important in sexual differentiation in mammals and many other vertebrate animals.) Males inherit two copies of DMRT1 and females inherit only one copy. Reduced dosage of the gene in females leads to the production of the sex hormone estradiol, a potent estrogen, in the developing embryo. © 2025 Simons Foundation
Keyword: Sexual Behavior; Evolution
Link ID: 29759 - Posted: 04.26.2025
By Michael Erard In many Western societies, parents eagerly await their children’s first words, then celebrate their arrival. There’s also a vast scientific and popular attention to early child language. Yet there is (and was) surprisingly little hullabaloo sparked by the first words and hand signs displayed by great apes. WHAT I LEFT OUT is a recurring feature in which book authors are invited to share anecdotes and narratives that, for whatever reason, did not make it into their final manuscripts. In this installment, author and linguist Michael Erard shares a story that didn’t make it into his recent book “Bye Bye I Love You: The Story of Our First and Last Words” (MIT Press, 344 pages.) As far back as 1916, scientists have been exploring the linguistic abilities of humans’ closest relatives by raising them in language-rich environments. But the first moments in which these animals did cross a communication threshold created relatively little fuss in both the scientific literature and the media. Why? Consider, for example, the first sign by Washoe, a young chimpanzee that was captured in the wild and transported in 1966 to a laboratory at the University of Nevada, where she was studied by two researchers, Allen Gardner and Beatrice Gardner. Washoe was taught American Sign Language in family-like settings that would be conducive to communicative situations. “Her human companions,” wrote the Gardners in 1969, “were to be friends and playmates as well as providers and protectors, and they were to introduce a great many games and activities that would be likely to result in maximum interaction.” When the Gardners wrote about the experiments, they did note her first uses of specific signs, such as “toothbrush,” that didn’t seem to echo a sign a human had just used. These moments weren’t ignored, yet you have to pay very close attention to their writings to find the slightest awe or enthusiasm. Fireworks it is not.
Keyword: Language; Evolution
Link ID: 29753 - Posted: 04.23.2025
By Gayoung Lee edited by Allison Parshall Crows sometimes have a bad rap: they’re said to be loud and disruptive, and myths surrounding the birds tend to link them to death or misfortune. But crows deserve more love and charity, says Andreas Nieder, a neurophysiologist at the University of Tübingen in Germany. They not only can be incredibly cute, cuddly and social but also are extremely smart—especially when it comes to geometry, as Nieder has found. In a paper published on Friday in Science Advances, Nieder and his colleagues report that crows display an impressive aptitude at distinguishing shapes by using geometric irregularities as a cognitive cue. These crows could even discern quite subtle differences. For the experiment, the crows perched in front of a digital screen that, almost like a video game, displayed progressively more complex combinations of shapes. First, the crows were taught to peck at a certain shape for a reward. Then they were presented with that same shape among five others—for example, one star shape placed among five moon shapes—and were rewarded if they correctly picked the "outlier." “Initially [the outlier] was very obvious,” Nieder says. But once the crows appeared to have familiarized themselves with how the “game” worked, Nieder and his team introduced more similar quadrilateral shapes to see if the crows would still be able to identify outliers. “And they could tell us, for instance, if they saw a figure that was just not a square, slightly skewed, among all the other squares,” Nieder says. “They really could do this spontaneously [and] discriminate the outlier shapes based on the geometric differences without us needing them to train them additionally.” Even when the researchers stopped rewarding them with treats, the crows continued to peck the outliers. © 2024 SCIENTIFIC AMERICAN,
Keyword: Evolution; Intelligence
Link ID: 29741 - Posted: 04.12.2025
By Yasemin Saplakoglu Humans tend to put our own intelligence on a pedestal. Our brains can do math, employ logic, explore abstractions and think critically. But we can’t claim a monopoly on thought. Among a variety of nonhuman species known to display intelligent behavior, birds have been shown time and again to have advanced cognitive abilities. Ravens plan (opens a new tab) for the future, crows count and use tools (opens a new tab), cockatoos open and pillage (opens a new tab) booby-trapped garbage cans, and chickadees keep track (opens a new tab) of tens of thousands of seeds cached across a landscape. Notably, birds achieve such feats with brains that look completely different from ours: They’re smaller and lack the highly organized structures that scientists associate with mammalian intelligence. “A bird with a 10-gram brain is doing pretty much the same as a chimp with a 400-gram brain,” said Onur Güntürkün (opens a new tab), who studies brain structures at Ruhr University Bochum in Germany. “How is it possible?” Researchers have long debated about the relationship between avian and mammalian intelligences. One possibility is that intelligence in vertebrates — animals with backbones, including mammals and birds — evolved once. In that case, both groups would have inherited the complex neural pathways that support cognition from a common ancestor: a lizardlike creature that lived 320 million years ago, when Earth’s continents were squished into one landmass. The other possibility is that the kinds of neural circuits that support vertebrate intelligence evolved independently in birds and mammals. It’s hard to track down which path evolution took, given that any trace of the ancient ancestor’s actual brain vanished in a geological blink. So biologists have taken other approaches — such as comparing brain structures in adult and developing animals today — to piece together how this kind of neurobiological complexity might have emerged. © 2025 Simons Foundation
Keyword: Intelligence; Evolution
Link ID: 29738 - Posted: 04.09.2025
is a psychologist, writer and professor in the history and philosophy of science programme at the University of Melbourne. She is the author of Delusions of Gender: How Our Minds, Society, and Neurosexism Create Difference (2010), Testosterone Rex: Myths of Sex, Science, and Society (2017) and Patriarchy Inc.: What We Get Wrong About Gender Equality – and Why Men Still Win at Work (2025). She lives in Melbourne, Australia. Carole Hooven is a human evolutionary biologist with a focus on behavioural endocrinology. She is a nonresident senior fellow at the American Enterprise Institute, an associate in Harvard’s Department of Psychology, and the author of T: The Story of Testosterone, the Hormone That Dominates and Divides Us (2021). She lives in Cambridge, Massachusetts. Does biology determine destiny, or is society the dominant cause of masculine and feminine traits? In this spirited exchange, the psychologist Cordelia Fine and the evolutionary biologist Carole Hooven unpack the complex relationship between testosterone and human behaviour. Fine emphasises variability, flexibility and context – seeing gender as shaped by social forces as much as it is by hormones. By contrast, Hooven stresses consistent patterns; while acknowledging the influence of culture and the differences between individuals, she maintains that biology explains why certain sex-linked behaviours persist across cultures. © Aeon Media Group Ltd. 2012-2025.
Keyword: Sexual Behavior; Evolution
Link ID: 29733 - Posted: 04.09.2025
By Carl Zimmer After listening to hundreds of hours of ape calls, a team of scientists say they have detected a hallmark of human language: the ability to put together strings of sounds to create new meanings. The provocative finding, published Thursday in the journal Science, drew praise from some scholars and skepticism from others. Federica Amici, a primatologist at the University of Leipzig in Germany, said that the study helped place the roots of language even further back in time, to millions of years before the emergence of our species. “Differences between humans and other primates, including in communication, are far less distinct and well-defined than we have long assumed,” Dr. Amici said. But other researchers said that the study, which had been conducted on bonobos, close relatives of chimpanzees, had little to reveal about how we use words. “The present findings don’t tell us anything about the evolution of language,” said Johan Bolhuis, a neurobiologist at Utrecht University in the Netherlands. Many species can communicate with sounds. But when an animal makes a sound, it typically means just one thing. Monkeys, for instance, can make one warning call in reference to a leopard and a different one for an incoming eagle flying. In contrast, we humans can string words together in ways that combine their individual meanings into something new. Suppose I say, “I am a bad dancer.” When I combine the words “bad” and “dancer,” I no longer mean them independently; I’m not saying, “I am a bad person who also happens to dance.” Instead, I mean that I don’t dance well. Linguists call this compositionality, and have long considered it an essential ingredient of language. “It’s the force behind language’s creativity and productivity,” said Simon Townsend, a comparative psychologist at the University of Zurich in Switzerland. “Theoretically, you can come up with any phrase that has never been uttered before.” © 2025 The New York Times Company
Keyword: Language; Evolution
Link ID: 29730 - Posted: 04.05.2025
By Nathan H. Lents For generations, anthropologists have argued whether humans are evolved for monogamy or some other mating system, such as polygyny, polyandry, or promiscuity. But any exploration of monogamy must begin with a bifurcation of the concept into two completely different phenomena: social monogamy and sexual monogamy. WHAT I LEFT OUT is a recurring feature in which book authors are invited to share anecdotes and narratives that, for whatever reason, did not make it into their final manuscripts. In this installment, author Nathan H. Lents, professor of biology at John Jay College, shares a story that didn’t make it into his recent book “The Sexual Evolution: How 500 Million Years of Sex, Gender, and Mating Shape Modern Relationships” (Mariner Books). Sexual monogamy is just what it sounds like: The restriction of sexual intercourse to within a bonded pair. Social monogamy, also known as economic monogamy, describes the bonding itself, a strong, neurohormone-driven attachment between two adults that facilitates food and territory sharing, to the exclusion of others, for at least one breeding season, and generally purposed towards raising offspring. Because these two aspects of monogamy are so often enjoined among humans, they are considered two sides of the same coin. But, as it turns out, they are entirely separable among animals. In fact, social monogamy is extremely common in birds and somewhat common in mammals, while sexual monogamy is vanishingly rare among any species. Because of the unique way their embryos develop — externally but with constant warmth required — birds are the real stars of monogamy and have thus borne the brunt of its misconceptions. The marriage (if you’ll pardon the pun) of two very different behaviors into one concept is — and always was — unsupported by evidence from the natural world. Monogamy, as it is commonly understood, was the invention of anthropomorphic bias. Naturalists in the 19th and 20th centuries documented how pairs of various bird species dutifully toiled together building a nest, protecting the eggs, mutually feeding each other and their offspring, before eventually flying off into the sunset together. These prim and proper Victorians didn’t have to squint very hard to see a perfect model in nature of what they valued most in human society — lifelong and sexually exclusive marriage.
Keyword: Sexual Behavior; Evolution
Link ID: 29728 - Posted: 04.05.2025
By Adam Nossiter Ralph Holloway, an anthropologist who pioneered the idea that changes in brain structure, and not just size, were critical in the evolution of humans, died on March 12 at his home in Manhattan. He was 90. His death was announced by Columbia University’s anthropology department, where he taught for nearly 50 years. Mr. Holloway’s contrarian idea was that it wasn’t necessarily the big brains of humans that distinguished them from apes or primitive ancestors. Rather, it was the way human brains were organized. Brains from several million years ago don’t exist. But Dr. Holloway’s singular focus on casts of the interiors of skull fossils, which he usually made out of latex, allowed him to override this hurdle. He “compulsively collected” information from these casts, he wrote in a 2008 paper. Crucially, they offered a representation of the brain’s exterior edges, which allowed scientists to get a sense of the brain’s structure. Using a so-called endocast, Dr. Holloway was able to establish conclusively, for instance, that a famous and controversial two-million-year-old hominid fossil skull from a South Africa limestone quarry, known as the Taung child, belonged to one of mankind’s distant ancestors. The Taung child’s brain was small, leading many to doubt the conclusion of Raymond Dart, the anatomist who discovered it in the 1920s, that it was a human ancestor. In 1969, Dr. Holloway took his family to South Africa to meet the elderly Dr. Dart, to examine the natural limestone endocast that the Taung child’s positioning in the quarry had created and to make an endocast of his own. “I became convinced that the Taung endocast needed independent study,” he wrote in 2008, in order to “find an objective method(s) for deciding whether the cortex was reorganized as Dart had previously claimed,” so many years before. Dr. Holloway focused on a crescent-shaped furrow, called the lunate sulcus, at the back of the endocast. In his view, it was positioned like a human’s, which suggested to him that Dr. Dart had been right all along. © 2025 The New York Times Company
Keyword: Evolution
Link ID: 29727 - Posted: 04.05.2025