Chapter 6. Evolution of the Brain and Behavior

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Katharina Kropshofer Life is not so different beneath the ocean waves. Bottlenose dolphins use simple tools, orcas call each other by name, and sperm whales talk in local dialects. Many cetaceans live in tight-knit groups and spend a good deal of time at play. That much scientists know. But in a new study, researchers compiled a list of the rich behaviours spotted in 90 different species of dolphins, whales and porpoises, and found that the bigger the species’ brain, the more complex – indeed, the more “human-like” – their lives are likely to be. This suggests that the “cultural brain hypothesis” – the theory that suggests our intelligence developed as a way of coping with large and complex social groups – may apply to whales and dolphins, as well as humans. Writing in the journal, Nature Ecology and Evolution, the researchers claim that complex social and cultural characteristics, such as hunting together, developing regional dialects and learning from observation, are linked to the expansion of the animals’ brains – a process known as encephalisation. The researchers gathered records of dolphins playing with humpback whales, helping fishermen with their catches, and even producing signature whistles for dolphins that are absent – suggesting the animals may even gossip. Another common behaviour was adult animals raising unrelated young. “There is the saying that ‘it takes a village to raise a child’ [and that] seems to be true for both whales and humans,” said Michael Muthukrishna, an economic psychologist and co-author on the study at the London School of Economics. © 2017 Guardian News and Media Limited

Keyword: Evolution
Link ID: 24202 - Posted: 10.17.2017

Carl Safina Last week footage of five young elephants being captured in Zimbabwe to sell to zoos travelled round the world. Parks officials used helicopters to find the elephant families, shot sedatives into the young ones, then hazed away family members who came to the aid of the drugged young ones as they fell. The film, shared exclusively with the Guardian, showed the young captives being trussed up and dragged on to trucks. In the final moments of footage, two men repeatedly kick a small dazed elephant in the head. Removing young elephants from their parents and sending them into captivity is largely justified on the basis that they do not feel and suffer as we do. For decades we have been admonished against anthropomorphism – imbuing animals with human-type emotions such as sadness or love. But, actually, humans have these emotions because other animals do as well. Brain science, evolutionary biology, and behavioural science now show that elephants, humans, and many other animals share a near-identical nervous system and likely experience near-identical basic emotions. Human and elephant brains are bathed in the same chemicals that create mood and motivation in us. We are all mammals, and under the skin we are kin. Scientists have watched rats’ brains as they dream, and dogs’ brains showing love. In fact, sperm whales’ family structure is nearly identical to that of elephants. Animals living in stable social groups – apes and monkeys, wolves and wild dogs, hyenas and cats, various birds, some dolphins and others, know who they are and whom they are with. © 2017 Guardian News and Media Limited

Keyword: Emotions; Evolution
Link ID: 24197 - Posted: 10.16.2017

Rae Ellen Bichell Abstinence may have found its most impressive poster child yet: Diploscapter pachys. The tiny worm is transparent, smaller than a poppy seed and hasn't had sex in 18 million years. It's basically just been cloning itself this whole time. Usually, that's a solid strategy for going extinct, fast. What's its secret? "Scientists have been trying to understand how some animals can survive for millions of years without sex, because such strict, long-term abstinence is very rare in the animal world," says David Fitch, a biologist at New York University. Most plants and animals use sex to reproduce. As he and his colleagues report in the recent issue of Current Biology, this seemingly unimpressive roundworm seems to have developed a different way of copying its genes — one that leads to just enough mutations to give the worms room to adapt, but not enough to cause crippling defects. Sex is pretty great for a lot of reasons (unless, perhaps, you're a duck), but one is that's it's a good way to dodge the effects of bad mutations. "All organisms accumulate mutations," says Kristin Gunsalus, a developmental geneticist at New York University and a co-author of the study. Usually, the machinery that copies DNA makes a few mistakes each time a cell divides. In humans, says Gunsalus, there are about six errors per cell division. © 2017 npr

Keyword: Evolution; Sexual Behavior
Link ID: 24179 - Posted: 10.12.2017

By Josh Gabbatiss Some female dolphins have evolved a secret weapon in their sexual arms race with males: vaginas that protect them from fertilisation by unwelcome partners. Penises come in a wide variety of shapes and sizes, especially in dolphins and other cetaceans. That seems to imply a similar diversity in vaginas, but Dara Orbach of Dalhousie University, Canada, says there is “a huge lag” in our understanding of female genitalia. That is partly because it is tricky to visualise vaginal structure. To overcome this problem, Orbach has created silicone moulds of cetaceans’ vaginas, revealing complex folds and spirals. “There’s this unparalleled level of vaginal diversity that we had no idea existed before,” Orbach says. Similarly complex vaginal structures are found in several species of duck. Orbach’s collaborator Patricia Brennan of Mount Holyoke College, Massachusetts, has previously found evidence that duck vaginas have evolved to make it harder for males to force copulation. So Orbach wondered if female cetaceans’ unusual vaginas had also evolved to keep out unwanted sperm. Orbach, Brennan and their colleagues obtained genitals from marine mammals that had died of natural causes: common and bottlenose dolphins, common porpoises and common seals. They inflated the males’ penises with saline to see how they looked when they were erect, and compared them with the vaginal moulds. They also took CT scans of penises inserted into the corresponding vaginas, to determine whether they fitted in easily and the best positions. © Copyright New Scientist Ltd.

Keyword: Sexual Behavior; Evolution
Link ID: 24170 - Posted: 10.11.2017

By Giorgia Guglielmi This mantis shrimp (Gonodactylus smithii) might have a much more elaborate brain than previously thought. That’s the conclusion of the first study to peer into the head of more than 200 crustaceans, including crabs, shrimp, and lobsters. Researchers discovered that the brain of mantis shrimp contains memory and learning centers, called mushroom bodies, which so far have been seen only in insects. The team also found similar structures in close relatives of these sea creatures: cleaner shrimp, pistol shrimp, and hermit crabs. This may not be a coincidence, the researchers say, because mantis shrimp and their brethren are the only crustaceans that hunt over long distances and might have to remember where to get food. But the finding, reported in eLife, is likely to stir debate: Scientists agree that mushroom bodies evolved after the insect lineage split off from the crustacean lineage about 480 million years ago; finding these learning centers in mantis shrimp means that either mushroom bodies are much more ancient than scientists realized and were lost in all crustaceans but mantis shrimp, or that these structures are similar to their counterparts in insects but have evolved independently. © 2017 American Association for the Advancement of Science.

Keyword: Learning & Memory; Evolution
Link ID: 24158 - Posted: 10.07.2017

By Ann Gibbons The insult "You're a Neandertal!" has taken on dramatic new meaning in the past few years, as researchers have begun to identify the genes many of us inherited from our long-extinct relatives. By sequencing a remarkably complete genome from a 50,000-year-old bone fragment of a female Neandertal found in Vindija Cave in Croatia, researchers report online today in Science a new trove of gene variants that living people outside of Africa obtained from Neandertals. Some of this DNA could influence cholesterol levels, the accumulation of belly fat, and the risk of schizophrenia and other diseases. The genome is only the second from a Neandertal sequenced to such high quality that it can reliably reveal when, where, and what DNA was passed from Neandertals to modern humans—and which diseases it may be causing or preventing today. "It's really exciting because it's more than two times better to have two Neandertal genomes," says evolutionary genomicist Tony Capra of Vanderbilt University in Nashville. The first Neandertal genome was a composite drawn from three individuals from Vindija Cave. Then, over the past few years, ancient DNA researchers sequenced two more Neandertal genomes, including another high-quality sequence from an individual that lived 122,000 years ago in the Altai Mountains of Siberia. Together, the genomes showed that living Europeans and Asians carry traces of DNA from Neandertals who mated with members of Homo sapiens soon after our species left Africa. (Most Africans lack Neandertal DNA as a result.) © 2017 American Association for the Advancement of Science.

Keyword: Obesity; Evolution
Link ID: 24156 - Posted: 10.06.2017

Christie Wilcox Many tadpoles ward off predators with potent poisons — but those toxins also seem to help win battles with their own kind, a new study finds. Tadpoles of common toads (Bufo bufo) are more poisonous when raised in crowded conditions, which may give them a competitive edge, according to the work published on 23 September in Functional Ecology1. Many noxious plant species are known to modulate their defences to fend off different threats2, but it is less clear whether animals possess similar toxin-tuning abilities. Although predation pressure is known to induce tadpole chemical defences3, the new findings are the first unequivocal evidence of toxin synthesis spurred by competition in vertebrate animals. Being poisonous can make a species essentially inedible to predators, but making potent toxins comes at a metabolic cost — so it’s best to make that investment count. “It would be very profitable for such animals to kill two birds with one stone by using their anti-predatory toxins as chemical weapons against their competitors, too,” says the study’s lead author, Veronika Bókony, an ecologist with the Hungarian Academy of Sciences in Budapest. Common toads are equipped with bufadienolides, potent toxins that cause harm by accelerating and disrupting the heart’s rhythms4. Field studies have found that common toad toxicity varies geographically, with the intensity of competition being the most reliable predictor5. But it has been unclear whether such patterns occur because populations are genetically isolated from one another in different ponds, or whether they reflect defences induced by environmental factors. © 2017 Macmillan Publishers Limited,

Keyword: Neurotoxins; Evolution
Link ID: 24124 - Posted: 09.30.2017

Barbara J. King In 1981, the evolutionary biologist Stephen Jay Gould's book The Mismeasure of Man hit the presses. A take-down of studies purporting to demonstrate that the intelligence of humans is genetically determined — and that some human groups (read "white Western Europeans") are innately superior — the book exposed interpretive bias and scientific racism in the measurement of human intelligence. Different environmental histories across human groups, in fact, affect testing outcomes in significant ways: There is no innate superiority due to genes. The Mismeasure of Man ignited ferocious discussion (and the occasional subsequent correction) that has continued even in recent years across biology, anthropology, psychology and philosophy: Its argument mattered not only for how we do science, but how science entangles with issues of social justice. Now, psychologists David A. Leavens of the University of Sussex, Kim A. Bard of the University of Portsmouth, and William D. Hopkins of Georgia State University have framed their new Animal Cognition article, "The mismeasure of ape social cognition," around Gould's book. Ape (especially chimpanzee) social intelligence, the authors say, has been routinely mismeasured because apes are tested in comprehensively different circumstances from the children with whom they are compared — and against whose performance theirs is found to be lacking. Leavens et al. write: "All direct ape-human comparisons that have reported human superiority in cognitive function have universally failed to match the groups on testing environment, test preparation, sampling protocols, and test procedures." © 2017 npr

Keyword: Evolution; Intelligence
Link ID: 24123 - Posted: 09.29.2017

By Mary Bates North American walnut sphinx moth caterpillars (Amorpha juglandis) look like easy meals for birds, but they have a trick up their sleeves—they produce whistles that sound like bird alarm calls, scaring potential predators away. At first, scientists suspected birds were simply startled by the loud noise. But a new study presented at the International Symposium on Acoustic Communication by Animals in Omaha in July suggests a more sophisticated mechanism: the caterpillar’s whistle appears to mimic a bird alarm call, sending avian predators scrambling for cover. “This is the first instance of deceptive alarm calling between an insect and a bird, and it’s a novel defense form for an insect,” says Jessica Lindsay, the study’s first author and a graduate student in the lab of Kristin Laidre at the University of Washington. “I think that’s pretty wild.” When pecked by a bird, the caterpillars whistle by compressing their bodies like an accordion and forcing air out through specialized holes in their sides. The whistles are impressively loud, considering they are made by a two-inch long insect. They have been measured at over 80 dB from 5 cm away from the caterpillar, similar to the loudness of a garbage disposal. In a laboratory experiment a few years ago, birds responded to caterpillar whistles by jumping away and abandoning their predation attempts. The authors of that study had attributed their behavior to a general startle response. © 1986-2017 The Scientist

Keyword: Evolution
Link ID: 24112 - Posted: 09.26.2017

Robin Dunbar, Angela Saini, Ben Garrod, Adam Rutherford We were all gearing up for the summer of love when, in 1967, Desmond Morris’s The Naked Ape took us by storm. Its pitch was that humans really were just apes, and much of our behaviour could be understood in terms of animal behaviour and its evolution. Yes, we were naked and bipedal, but beneath the veneer of culture lurked an ancestral avatar. With his zoologist’s training (he had had a distinguished career studying the behaviour of fishes and birds at Oxford University as part of the leading international group in this field), he gave us a picture of who we really are. In the laid-back, blue-smoke atmosphere of the hippy era, the book struck a chord with the wider public – if for no other reason than that, in the decade of free love, it asserted that humans had the largest penis for body size of all the primates. The early 1960s had seen the first field studies of monkeys and apes, and a corresponding interest in human evolution and the biology of contemporary hunter-gatherers. Morris latched on to the fact that the sexual division of labour (the men away hunting, the women at home gathering) necessitated some mechanism to ensure the sexual loyalty of one’s mate – this was the era of free love, after all. He suggested that becoming naked and developing new erogenous zones (notably, ear lobes and breasts), not to mention face-to-face copulation (all but unknown among animals), helped to maintain the couple’s loyalty to each other. Morris’s central claim, that much of our behaviour can be understood in the context of animal behaviour, has surely stood the test of time, even if some of the details haven’t. Our hairlessness (at around 2m years ago) long predates the rise of pair bonds (a mere 200,000 years ago). It owes its origins to the capacity to sweat copiously (another uniquely human trait) in order to allow us to travel longer distances across sunny savannahs. But he is probably still right that those bits of human behaviour that enhance sexual experience function to promote pair bonds – even if pair bonds are not lifelong in the way that many then assumed. © 2017 Guardian News and Media Limited

Keyword: Sexual Behavior; Evolution
Link ID: 24107 - Posted: 09.25.2017

By Ann Gibbons Neandertals have long been seen as the James Deans of human evolution—they grew up fast, died young, and became legends. But now, a rare skeleton of a Neandertal child suggests that our closest cousins didn’t all lead such fast lives—and that our own long childhoods aren’t unique. The find may reveal how Neandertals, like humans, had enough energy to grow bigger brains. “We like the paper because it puts the idea of ‘Neanderthal exceptionalism’ to rest,” wrote anthropologist Marcia Ponce de León and neurobiologist Christoph Zollikofer from the University of Zurich in Switzerland (who are not authors of the new study) in an email. “RIP.” Researchers have long known that modern humans take almost twice as long as chimpanzees to reach adulthood and have wondered when and why our ancestors evolved the ability to prolong childhood and delay reproduction. Our distant ancestors, such as the famous fossil Lucy and other australopithecines, matured quickly and died young like chimps. Even early members of our own genus Homo, such as the 1.6-million-year-old skeleton of an H. erectus boy, grew up faster than we do. By providing your email address, you agree to send your email address to the publication. Information provided here is subject to Science's Privacy Policy. But by the time the earliest known members of our species, H. sapiens, were alive 300,000 years ago at Jebel Irhoud in Morocco, they were taking longer to grow up. A leading theory is that big brains are so metabolically expensive that humans have to delay the age of reproduction—and, hence, have longer childhoods—so first-time mothers are older and, thus, bigger and strong enough to have the energy to feed babies with such big brains after birth when their brains are doubling in size. © 2017 American Association for the Advancement of Science

Keyword: Evolution; Development of the Brain
Link ID: 24098 - Posted: 09.22.2017

By STEPH YIN Worms and fish do it. Birds and bees do it. But do jellyfish fall asleep? It seems like a simple question, but answering it required a multistep investigation by a trio of Caltech graduate students. Their answer, published Thursday in Current Biology, is that at least one group of jellyfish called Cassiopea, or the upside-down jellyfish, does snooze. The finding is the first documented example of sleep in an animal with a diffuse nerve net, a system of neurons that are spread throughout an organism and not organized around a brain. It challenges the common notion that sleep requires a brain. It also suggests sleep could be an ancient behavior because the group that includes jellyfish branched off from the last common ancestor of most living animals early on in evolution. Working together was natural for Claire Bedbrook, Michael Abrams and Ravi Nath. The three leading co-authors of the paper are all Ph.D. candidates in biology at the California Institute of Technology and close friends. The project started with an observation by Mr. Abrams that some upside-down jellyfish in his lab would immediately slow their pulsing when the lights were turned off. Over coffee one evening, he discussed this phenomenon with Mr. Nath, who had been studying sleep in roundworms and pondering whether other “simple” animals slept. The two decided to visit Mr. Abrams’s lab in the middle of the night, to see how the jellyfish were behaving. The Cassiopea, or upside-down, jellyfish, demonstrated patterns of behavior consistent with sleep, according to an experiment conducted by Caltech graduate students. Credit Jan Easter Photography In the darkened lab, they observed a tankful of jellyfish pulsing infrequently and staying still for long periods of time — jellyfish that looked, in other words, like they were sleeping. Ms. Bedbrook started to believe they were onto something. © 2017 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 24097 - Posted: 09.22.2017

Carrie Arnold The purpose and evolutionary origins of sleep are among the biggest mysteries in neuroscience. Every complex animal, from the humblest fruit fly to the largest blue whale, sleeps — yet scientists can’t explain why any organism would leave itself vulnerable to predators, and unable to eat or mate, for a large portion of the day. Now, researchers have demonstrated for the first time that even an organism without a brain — a kind of jellyfish — shows sleep-like behaviour, suggesting that the origins of sleep are more primitive than thought. Researchers observed that the rate at which Cassiopea jellyfish pulsed their bell decreased by one-third at night, and the animals were much slower to respond to external stimuli such as food or movement during that time. When deprived of their night-time rest, the jellies were less active the next day. “Everyone we talk to has an opinion about whether or not jellyfish sleep. It really forces them to grapple with the question of what sleep is,” says Ravi Nath, the paper’s first author and a molecular geneticist at the California Institute of Technology (Caltech) in Pasadena. The study was published on 21 September in Current Biology1. “This work provides compelling evidence for how early in evolution a sleep-like state evolved,” says Dion Dickman, a neuroscientist at the University of Southern California in Los Angeles. Nath is studying sleep in the worm Caenorhabditis elegans, but whenever he presented his work at research conferences, other scientists scoffed at the idea that such a simple animal could sleep. The question got Nath thinking: how minimal can an animal’s nervous system get before the creature lacks the ability to sleep? Nath’s obsession soon infected his friends and fellow Caltech PhD students Michael Abrams and Claire Bedbrook. Abrams works on jellyfish, and he suggested that one of these creatures would be a suitable model organism, because jellies have neurons but no central nervous system. Instead, their neurons connect in a decentralized neural net. © 2017 Macmillan Publishers Limited

Keyword: Sleep; Evolution
Link ID: 24096 - Posted: 09.22.2017

Amy Maxmen Male ducks respond to sexual competition by growing either an extra-long penis or a nub of flesh, a new study finds. The unusual phenomena occurred in two species studied: the lesser scaup (Aythya affinis) and the ruddy duck (Oxyura jamaicensis). It suggests that penis size — in line with many traits and behaviours meant to impress or allow impregnation of the opposite sex — involves a trade-off between the potential to reproduce and to survive. Patricia Brennan, an evolutionary biologist at Mount Holyoke College in South Hadley, Massachusetts, compared the penises of ducks kept in male–female pairs to those housed with multiple males per female. The findings are published in a study on 20 September in The Auk: Ornithological Advances1. “If they were alone with a female, the males just grew a normal-sized penis, but if there were other males around, they had the ability to change dramatically,” Brennan says. “So evolution must be acting on the ability to be plastic — the ability to invest only in what is needed in your current circumstance.” Because evolutionary success relies on reproduction, genitals are adapted to meet the varied circumstances that every animal faces. Some male ducks, for example, have penises in the shape of corkscrews to navigate the labyrinth-like vaginas of their female counterparts. An earlier study by Brennan found that females’ anatomy evolved to prevent access to undesirable males who force copulation2. To mate successfully with their chosen partners, Brennan says, female ducks assume a posture that allows males to enter them fully and deposit sperm near eggs. © 2017 Macmillan Publishers Limited,

Keyword: Sexual Behavior; Evolution
Link ID: 24086 - Posted: 09.21.2017

By Aylin Woodward HUMANS aren’t the only primate to have pushed their prey towards extinction. Monkeys have also over-exploited animals for food. Long-tailed macaques forage for shellfish on islands off Thailand, then crack them open with stone tools. They target the largest rock oysters, bludgeoning them with stone hammers, and pry open the meatiest snail and crab shells with the flattened edges of their tools. These macaques are one of three primates that use stone tools, alongside chimpanzees in Africa and bearded capuchins in South America. “Stone tools open up an opportunity for foods they otherwise wouldn’t even be able to harvest,” says Lydia Luncz at the University of Oxford. Luncz wanted to investigate the impact of the monkeys’ shellfish snacking on the prey themselves. Her team followed 18 macaques on their daily foraging routes along the shores of Koram and NomSao, two neighbouring islands off eastern Thailand, recording their tool selection and use. On Koram – the more densely populated island, home to 80 macaques compared with NomSao’s nine – Luncz’s group saw not only smaller oysters and snails, but also fewer of each species. Multiple prey species were less abundant on Koram than NomSao, with four times as many tropical periwinkles on NomSao as on Koram (eLife, © Copyright New Scientist Ltd.

Keyword: Evolution
Link ID: 24080 - Posted: 09.20.2017

By Michael Le Page We are still evolving – very slowly. In the 20th century, people in the UK evolved to be less likely to smoke heavily, but the effect was tiny. So claims a study of 200,000 genomes. A population can be described as evolving when the frequency of gene variants changes over time. Because most people in rich countries now live well beyond reproductive age, some argue that we have stopped evolving because natural selection has been weakened. But several recent studies claim we are still evolving, albeit slowly. Now Joseph Pickrell at Columbia University in New York and his team have analysed human genome sequences to spot gene variants that are becoming rarer. One variant, of a gene called CHRNA3, is associated with heavier smoking in those that smoke, raising their risk of a smoking-related death. Comparing people over the age of 80 with people over the age of 60, Pickrell estimates that the variant has declined by 1 per cent between generations. However, his team was not able to prove this, as they did not have any genomic data from people under the age of 40. A variant of the ApoE4 gene that is known to increase the risk of late-onset Alzheimer’s disease, as well as cardiovascular disease, may also be getting rarer. © Copyright New Scientist Ltd.

Keyword: Alzheimers; Genes & Behavior
Link ID: 24038 - Posted: 09.06.2017

By Andy Coghlan How and when did we first become able to speak? A new analysis of our DNA reveals key evolutionary changes that reshaped our faces and larynxes, and which may have set the stage for complex speech. The alterations were not major mutations in our genes. Instead, they were tweaks in the activity of existing genes that we shared with our immediate ancestors. These changes in gene activity seem to have given us flat faces, by retracting the protruding chins of our ape ancestors. They also resculpted the larynx and moved it further down in the throat, allowing our ancestors to make sounds with greater subtleties. The study offers an unprecedented glimpse into how our faces and vocal tracts were altered at the genetic level, paving the way for the sophisticated speech we take for granted. However, other anthropologists say changes in the brain were at least equally important. It is also possible that earlier ancestors could speak, but in a more crude way, and that the facial changes simply took things up a notch. Liran Carmel of the Hebrew University of Jerusalem and his colleagues examined DNA from two modern-day people and four humans who lived within the last 50,000 years. They also looked at extinct hominins: two Neanderthals and a Denisovan. Finally, they looked at genetic material from six chimpanzees and data from public databases supplied by living people. © Copyright New Scientist Ltd.

Keyword: Language; Evolution
Link ID: 24004 - Posted: 08.28.2017

By Sam Wong It seems you can judge an athlete by their face – if they are a man, that is. Male athletes with a higher world ranking tend to be judged as more attractive by women, but there is no such trend among women. Several studies have previously reported a link between facial attractiveness and sporting performance in men, leading to suggestions that women respond to facial cues that reflect athletic ability in potential partners. Some have suggested this is because, in our evolutionary past, women might have benefited from choosing a partner with speed, skill and endurance. As a better hunter, the idea goes, he would have brought home more food, and he might pass on his fitness to their children. But these studies have been criticised, notably for only looking at men. They also tended to focus on team sports, therefore failing to isolate individual performance. To find more evidence, Tim Fawcett and colleagues at the University of Exeter, UK, collected photos of 156 men and women who competed at the 2014 Winter Olympics in the biathlon – an event combining cross-country skiing and shooting. Each athlete was rated for their facial attractiveness by members of the opposite sex, who didn’t know the purpose of the study. © Copyright New Scientist Ltd.

Keyword: Sexual Behavior; Evolution
Link ID: 23992 - Posted: 08.25.2017

By Denise D. Cummins Looking directly at the camera, NPR's Skunk Bear host Adam Cole laments, "It's pretty clear that I'll never be able to have a real human-style conversation with an ape.” In his short and very entertaining video, Cole summarizes decades of research aimed at teaching apes human language, all of which, we are to understand, came to naught. But what the video actually shows us is how little the average person (and many scientists) understands about language. At one point, Cole tells his dog to sit, and the dog sits. This, he tells us, is not evidence that the dog knows English. But actually, it is. The dog's behavior shows us that he is capable of understanding the simple concept of sitting, that he is capable of distinguishing the verbal signal "sit" from other verbal signals, and that he is capable of connecting the two. This isn't rocket science, it isn't magic, and it isn't anthropomorphizing. It is just the way word learning works. In studies conducted at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, a border collie named Rico was taught the meanings of 200 words. He could even use theprocess of elimination to figure out unfamiliar words: If he already knew the word "ball,” and his trainer showed him a ball and a stick and told him to get the "stick,” he would bring the stick. He could remember new words even after a month of not hearing them. © 2017 Scientific American,

Keyword: Animal Communication; Language
Link ID: 23977 - Posted: 08.19.2017

By Kai Sinclair It’s hard to see underwater, and not just because of the chlorine. The image-producing light rays that enter our eyes have trouble bending and focusing when the water’s density is almost same as that of eye fluid. Sea creatures experience the same problem, but squid use a type of lens notorious for blurry images to correct that, researchers report today in Science. Spherical lenses, like the squids’, usually can’t focus the incoming light to one point as it passes through the curved surface, which causes an unclear image. The only way to correct this is by bending each ray of light differently as it falls on each location of the lens’s surface. S-crystallin, the main protein in squid lenses, evolved the ability to do this by behaving as patchy colloids—small molecules that have spots of molecular glue that they use to stick together in clusters. The S-crystallins feature a pair of loops that act as the proteins’ sticky patches and attract the loops of other S-crystallins. Globs of six proteins link together during the squid’s larval stage and form a gel that eventually becomes the center of the lens. As the gel becomes too dense with protein clumps, smaller particles struggle to diffuse through, and a new layer of protein packages forms with just under six S-crystallins in each clump. The process continues until the outer edge of the lens is formed with pairs of S-crystallins. This allows light rays to bend a little differently in each region of the lens, which yields a clearer image. Some fish eyes are nearly identical to squids’, but it’s unknown whether their eye proteins exhibit patchy colloidlike behavior. Other cephalopods, like octopuses and nautiluses, lack S-crystallin lens proteins. So they, unlike squid, likely have blurry vision. © 2017 American Association for the Advancement of Science

Keyword: Vision; Evolution
Link ID: 23945 - Posted: 08.11.2017