Chapter 6. Evolution of the Brain and Behavior
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by Erika Engelhaupt Twerking is so 50 million years ago. In fact, it’s probably much older than that. Today, the provocative, butt-shaking dance move is enough of a social phenomenon to merit a word in the dictionary (with twerking defined about as tastefully as possible here by actor Morgan Freeman), but animals have been shaking their hindquarters for ages, for a variety of purposes (more on that below). Black widow spiders are the latest documented twerkers. In their case, it’s the males that shake their rears. Black widow females are aggressive predators and will immediately kill any prey detected in their webs. This presents a problem for males approaching a female to mate; in this case a literal misstep means becoming the female’s dinner. To figure out how the males avoid being eaten (at least before mating), researchers at Simon Fraser University in Canada measured vibrations created by males and by prey in webs of western black widows (Latrodectus hesperus). They compared the vibrations, and the females’ responses, to those of the hobo spider (Tegenaria agrestis), a species in which females rarely attack courting males. To capture the details of small vibrations, they used a fun tool called a laser Doppler vibrometer, which measures small changes in a laser beam aimed at a surface. Sure enough, black widow males appeared to have a death-avoidance strategy. They produced vibrations different from thrashing prey by means of “lengthy andrepeated bouts of abdominal tremulations” averaging 43 wiggles per second, the researchers report January 17 in Frontiers in Zoology. You can see a male's moves in this video: © Society for Science & the Public 2000 - 2014
Things are heating up in the world of genetics. The hot pepper (Capsicum annuum) is one of the most widely grown spice crops globally, playing an important role in many medicines, makeups, and meals worldwide. Although the plant’s so-called capsaicin chemical is well known for spicing things up, until now the genetic spark responsible for the pepper’s pungency was unknown. A team of scientists recently completed the first high-quality reference genome for the hot pepper. Comparing the pepper’s genome with that of its tame cousin, the tomato, the scientists discovered the gene responsible for fiery capsaicin production appeared in both plants. While the tomato carried four nonfunctioning copies of the gene, the hot pepper carried seven nonfunctioning copies and one functioning copy, the team reports online today in Nature Genetics. The researchers believe the pepper’s capsaicin-creating gene appeared after five mutations occurred during DNA replication, with the final mutation creating a functional copy. The mouth-burning chemicals likely protected the mutant pepper’s seeds from grazing land animals millions of years ago, giving the mutant a reproductive advantage and helping the mutant gene spread. The team says the finding could help breeders boost the pepper’s heat, nutrition, and medicinal properties. One researcher even suggests that geneticists could activate one of the tomato’s dormant genes, enabling capsaicinoid production and creating a plant that makes ready-made salsa. © 2014 American Association for the Advancement of Science.
Imagine a couple of million years ago, a curious young alien from the planet Zantar — let's call him a grad student — lands on Earth, looks around and asks, "Who's the brainiest critter on this planet? Relative to body size, who's got the biggest brain?" The answer, back then, would not have been us. (Two million years ago, apes — even walking ones — had much smaller brains.) The brainiest weren't ancestral crows or parrots or magpies or ravens or elephants or colonies of ants or bees or termites. The Earthlings with the biggest brains back then were dolphins (and certain whales). The Zantarian grad student would have wanted to meet them. A visitor from Zantar and a dolphin check each other out. But had the grad student arrived earlier, dolphins wouldn't have been the champs, because evolution is always changing life. , at Emory University in Atlanta, has been studying fossilized brains. And looking back, she sees sudden spurts of brain growth in different animals. "[T]he most dramatic increase in brain-to-body ratio in dolphins and toothed whales occurred 35 million years ago," she tells Chris Impey, the astronomer and writer, in Talking About Life. Something happened to make their medium-sized brains bigger, Lori says, then bigger still. For 20 million years certain dolphin species kept their brains growing until — just as mysteriously as it started — about 15 million years ago, they stopped. Why? Had the dolphins answered some secret dolphin question? Figured out a puzzle? Adapted to an environmental change? Gotten tired? Hit a limit? What? Dolphin says, "Enough." ©2014 NPR
By Felicity Muth Whether there exist differences between boys and girls is passionately debated (for example, see this debate about gender disparity between Stephen Pinker and Elizabeth Spelke). Some studies have found that girls are more sociable than boys, but prefer to play with just one other person, while boys prefer a larger group to play with. However, it is very difficult to say whether differences that we see in boys’ and girls’ behaviour has a biological basis, as boys and girls are also treated differently. Even before a baby is born, parents have often painted its room pink or blue, and bought gender-differentiated toys. A mother is more likely to under-estimate her female baby’s crawling abilities, and over-estimate her male baby’s (he’s a boy, of course he’s going to be stronger and better at crawling?!). Perceptions on the personality and abilities of a baby also differ depending on whether the adult is told that the child is male or female. Given these differences in how people treat male and female children, it can be difficult to say whether the behaviours we see are have a biological basis or not. However, we can look for certain clues to biological differences in child behaviour from our ‘cousins’ the chimpanzees. Chimpanzees live in communities of 20 to 180 individuals, with sub-groups within this. One recent study looked at the behaviour of eight female and twelve male chimpanzee infants to see if their behaviour differed from each other. They found that the young males were more sociable than the young females. © 2014 Scientific American
Ed Yong A marine iguana (Amblyrhynchus cristatus) at the Galapagos Islands National Park rests calmly as tourists walk by — a behaviour that may have evolved because of a lack of predators. Expand When Charles Darwin visited the Galapagos Islands, he noted that many of its animal inhabitants were so unafraid of people that “a gun is here almost superfluous”. He swatted birds with his hat, pulled the tails of iguanas and sat on giant tortoises. These antics fuelled his famous idea that animals become tame when they live on remote, predator-free islands. Now, William Cooper Jr of Indiana University–Purdue University in Fort Wayne has tested Darwin's hypothesis on 66 species of lizards from around the world and found that island dwellers tended to be more docile than their continental relatives — the strongest evidence yet for this classic idea. The results are published this week in Proceedings of the Royal Society B1. Several studies and unpublished reports have shown that particular species are more approachable on islands where there are fewer predators, or quicker to flee on islands that contain introduced hunters such as feral cats. But despite this largely anecdotal evidence for island tameness, “no one has ever established that it’s a general phenomenon in any group”, says Cooper. “We showed that for a large prey group — lizards — there really is a significant decline in wariness on islands.” © 2014 Nature Publishing Group
By GRETCHEN REYNOLDS African tribesmen walk through their landscape in a pattern that eerily echoes the movements of scavenging birds, flocking insects, gliding sharks and visitors to Disneyland, a new study finds, suggesting that aspects of how we choose to move around in our world are deeply hard-wired. For the new study, which appeared online recently in Proceedings of the National Academy of Sciences, researchers at the University of Arizona at Tucson, Yale University, the New York Consortium in Evolutionary Primatology and other institutions traveled to northern Tanzania to study the Hadza, who are among the last human hunter-gatherers on earth. The Hadza generally spend their days following game and foraging for side dishes and condiments such as desert tubers and honey, frequently walking and jogging for miles in the process. The ways in which creatures, including people, navigate their world is a topic of considerable scientific interest, but one that, until the advent of global positioning systems and similar tracking technology, was difficult to quantify. In the past decade, however, scientists have begun strapping GPS units to many varieties of animals and insects, from bumblebees to birds, and measuring how they move. What they have found is that when moving with a purpose such as foraging for food, many creatures follow a particular and shared pattern. They walk (or wing or lope) for a short time in one direction, scouring the ground for edibles, then turn and start moving in another direction for a short while, before turning and strolling or flying in another direction yet again. This is a useful strategy for finding tubers and such, but if maintained indefinitely brings creatures back to the same starting point over and over; they essentially move in circles. Copyright 2014 The New York Times Company
By CARL ZIMMER There are many things that make humans a unique species, but a couple stand out. One is our mind, the other our brain. The human mind can carry out cognitive tasks that other animals cannot, like using language, envisioning the distant future and inferring what other people are thinking. The human brain is exceptional, too. At three pounds, it is gigantic relative to our body size. Our closest living relatives, chimpanzees, have brains that are only a third as big. Scientists have long suspected that our big brain and powerful mind are intimately connected. Starting about three million years ago, fossils of our ancient relatives record a huge increase in brain size. Once that cranial growth was underway, our forerunners started leaving behind signs of increasingly sophisticated minds, like stone tools and cave paintings. But scientists have long struggled to understand how a simple increase in size could lead to the evolution of those faculties. Now, two Harvard neuroscientists, Randy L. Buckner and Fenna M. Krienen, have offered a powerful yet simple explanation. In our smaller-brained ancestors, the researchers argue, neurons were tightly tethered in a relatively simple pattern of connections. When our ancestors’ brains expanded, those tethers ripped apart, enabling our neurons to form new circuits. Dr. Buckner and Dr. Krienen call their idea the tether hypothesis, and present it in a paper in the December issue of the journal Trends in Cognitive Sciences. “I think it presents some pretty exciting ideas,” said Chet C. Sherwood, an expert on human brain evolution at George Washington University who was not involved in the research. Dr. Buckner and Dr. Krienen developed their hypothesis after making detailed maps of the connections in the human brain using f.M.R.I. scanners. When they compared their maps with those of other species’ brains, they saw some striking differences. © 2013 The New York Times Company
By Melissa Hogenboom Science reporter, BBC News An analysis of a Neanderthal's fossilised hyoid bone - a horseshoe-shaped structure in the neck - suggests the species had the ability to speak. This has been suspected since the 1989 discovery of a Neanderthal hyoid that looks just like a modern human's. But now computer modelling of how it works has shown this bone was also used in a very similar way. Writing in journal Plos One, scientists say its study is "highly suggestive" of complex speech in Neanderthals. The hyoid bone is crucial for speaking as it supports the root of the tongue. In non-human primates, it is not placed in the right position to vocalise like humans. An international team of researchers analysed a fossil Neanderthal throat bone using 3D x-ray imaging and mechanical modelling. This model allowed the group to see how the hyoid behaved in relation to the other surrounding bones. Stephen Wroe, from the University of New England, Armidale, NSW, Australia, said: "We would argue that this is a very significant step forward. It shows that the Kebara 2 hyoid doesn't just look like those of modern humans - it was used in a very similar way." He told BBC News that it not only changed our understanding of Neanderthals, but also of ourselves. "Many would argue that our capacity for speech and language is among the most fundamental of characteristics that make us human. If Neanderthals also had language then they were truly human, too." BBC © 2013
By JOHN NOBLE WILFORD Early in the 20th century, two brothers discovered a nearly complete Neanderthal skeleton in a pit inside a cave at La Chapelle-aux-Saints, in southwestern France. The discovery raised the possibility that these evolutionary relatives of ours intentionally buried their dead — at least 50,000 years ago, before the arrival of anatomically modern humans in Europe. These and at least 40 subsequent discoveries, a few as far from Europe as Israel and Iraq, appeared to suggest that Neanderthals, long thought of as brutish cave dwellers, actually had complex funeral practices. Yet a significant number of researchers have since objected that the burials were misinterpreted, and might not represent any advance in cognitive and symbolic behavior. Now an international team of scientists is reporting that a 13-year re-examination of the burials at La Chapelle-aux-Saints supports the earlier claims that the burials were intentional. The researchers — archaeologists, geologists and paleoanthropologists — not only studied the skeleton from the original excavations, but found more Neanderthal remains, from two children and an adult. They also studied the bones of other animals in the cave, mainly bison and reindeer, and the geology of the burial pits. The findings, in this week’s issue of Proceedings of the National Academy of Sciences, “buttress claims for complex symbolic behavior among Western European Neanderthals,” the scientists reported. William Rendu, the paper’s lead author and a researcher at the Center for International Research in the Humanities and Social Sciences in New York, said in an interview that the geology of the burial pits “cannot be explained by natural events” and that “there is no sign of weathering and scavenging by animals,” which means the bodies were covered soon after death. © 2013 The New York Times Company
Link ID: 19041 - Posted: 12.17.2013
By CARL ZIMMER Scientists have found the oldest DNA evidence yet of humans’ biological history. But instead of neatly clarifying human evolution, the finding is adding new mysteries. In a paper in the journal Nature, scientists reported Wednesday that they had retrieved ancient human DNA from a fossil dating back about 400,000 years, shattering the previous record of 100,000 years. The fossil, a thigh bone found in Spain, had previously seemed to many experts to belong to a forerunner of Neanderthals. But its DNA tells a very different story. It most closely resembles DNA from an enigmatic lineage of humans known as Denisovans. Until now, Denisovans were known only from DNA retrieved from 80,000-year-old remains in Siberia, 4,000 miles east of where the new DNA was found. The mismatch between the anatomical and genetic evidence surprised the scientists, who are now rethinking human evolution over the past few hundred thousand years. It is possible, for example, that there are many extinct human populations that scientists have yet to discover. They might have interbred, swapping DNA. Scientists hope that further studies of extremely ancient human DNA will clarify the mystery. “Right now, we’ve basically generated a big question mark,” said Matthias Meyer, a geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and a co-author of the new study. Hints at new hidden complexities in the human story came from a 400,000-year-old femur found in a cave in Spain called Sima de los Huesos (“the pit of bones” in Spanish). The scientific team used new methods to extract the ancient DNA from the fossil. “This would not have been possible even a year ago,” said Juan Luis Arsuaga, a paleoanthropologist at Universidad Complutense de Madrid and a co-author of the paper. © 2013 The New York Times Company
Barn owl nestlings recognise their siblings' calls, according to researchers. Instead of competing aggressively for food, young barn owls are known to negotiate by calling out. A team of scientists in Switzerland discovered that the owlets have remarkably individual calls. They suggest this is to communicate each birds' needs and identity in the nest. The findings were announced in the Journal of Evolutionary Biology by Dr Amelie Dreiss and colleagues at the University of Lausanne, Switzerland. Barn owls (Tyto alba) are considered one of the most widespread species of bird and are found on every continent except Antarctica. An average clutch size ranges between four and six eggs but some have been known to contain up to 12. Previous studies have highlighted how barn owl nestlings, known as owlets, negotiate with their siblings for food instead of fighting. While their parents search for food the owlets advertise their hunger to their brothers and sisters by calling out. "These vocal signals deter siblings from vocalizing and from competing for the prey at parental return," explained Dr Dreiss. "If there is a disagreement, they can escalate signal intensity little by little, always without physical aggression, until less hungry siblings finally withdraw from the contest." BBC © 2013
By Victoria Gill Science reporter, BBC News Great tits use different alarm calls for different predators, according to a scientist in Japan. The researcher analysed the birds' calls and found they made "jar" sounds for snakes and "chicka" sounds for crows and martens. This, he says, is the first demonstration birds can communicate vocally about the type of predator threatening them. The findings are published in the journal Animal Behaviour. From his previous observations, the researcher, Dr Toshitaka Suzuki, from the Graduate University for Advanced Studies in Kanagawa, found great tits appeared to be able to discriminate between different predators. To test whether they could also communicate this information, he placed models of three different animals that prey on nestlings - snakes, crows and martens - close to the birds' nest boxes. He then recorded and analysed the birds' responses. "Parents usually make alarm calls when they approach and mob the nest predators," said Dr Suzuki. "They produced specific 'jar' alarm calls for the snakes and the same 'chicka' alarm call in response to both the crows and martens," he said. But a closers analysis of the sounds showed the birds had used different "note combinations" in their crow alarm calls from those they had used for the martens. Dr Suzuki thinks the birds might have evolved what he called a "combinatorial communication system" - combining different notes to produce calls with different meanings. Since snakes are able to slither into nest boxes, they pose a much greater threat to great tit nestlings than other birds or mammals, so Dr Suzuki says it makes sense that the birds would have a specific snake alarm call. BBC © 2013
Ewen Callaway New genome sequences from two extinct human relatives suggest that these ‘archaic’ groups bred with humans and with each other more extensively than was previously known. The ancient genomes, one from a Neanderthal and one from a different archaic human group, the Denisovans, were presented on 18 November at a meeting at the Royal Society in London. They suggest that interbreeding went on between the members of several ancient human-like groups living in Europe and Asia more than 30,000 years ago, including an as-yet unknown human ancestor from Asia. “What it begins to suggest is that we’re looking at a ‘Lord of the Rings’-type world — that there were many hominid populations,” says Mark Thomas, an evolutionary geneticist at University College London who was at the meeting but was not involved in the work. The first Neanderthal1 and the Denisovan2 genome sequences revolutionized the study of ancient human history, not least because they showed that these groups interbred with anatomically modern humans, contributing to the genetic diversity of many people alive today. All humans whose ancestry originates outside of Africa owe about 2% of their genome to Neanderthals; and certain populations living in Oceania, such as Papua New Guineans and Australian Aboriginals, got about 4% of their DNA from interbreeding between their ancestors and Denisovans, who are named after the cave in Siberia’s Altai Mountains where they were discovered. The cave contains remains deposited there between 30,000 and 50,000 years ago. © 2013 Nature Publishing Group
Link ID: 18946 - Posted: 11.20.2013
By EMILY ANTHES Humans have no exclusive claim on intelligence. Across the animal kingdom, all sorts of creatures have performed impressive intellectual feats. A bonobo named Kanzi uses an array of symbols to communicate with humans. Chaser the border collie knows the English words for more than 1,000 objects. Crows make sophisticated tools, elephants recognize themselves in the mirror, and dolphins have a rudimentary number sense. Anolis evermanni lizards normally attack their prey from above. The lizards were challenged to find a way to access insects that were kept inside a small hole covered with a tightfitting blue cap. And reptiles? Well, at least they have their looks. In the plethora of research over the past few decades on the cognitive capabilities of various species, lizards, turtles and snakes have been left in the back of the class. Few scientists bothered to peer into the reptile mind, and those who did were largely unimpressed. “Reptiles don’t really have great press,” said Gordon M. Burghardt, a comparative psychologist at the University of Tennessee at Knoxville. “Certainly in the past, people didn’t really think too much of their intelligence. They were thought of as instinct machines.” But now that is beginning to change, thanks to a growing interest in “coldblooded cognition” and recent studies revealing that reptile brains are not as primitive as we imagined. The research could not only redeem reptiles but also shed new light on cognitive evolution. Because reptiles, birds and mammals diverged so long ago, with a common ancestor that lived 280 million years ago, the emerging data suggest that certain sophisticated mental skills may be more ancient than had been assumed — or so adaptive that they evolved multiple times. © 2013 The New York Times Company
By Tanya Lewis and LiveScience SAN DIEGO — Being a social butterfly just might change your brain: In people with a large network of friends and excellent social skills, certain brain regions are bigger and better connected than in people with fewer friends, a new study finds. The research, presented here Tuesday (Nov. 12) at the annual meeting of the Society for Neuroscience, suggests a connection between social interactions and brain structure. "We're interested in how your brain is able to allow you to navigate in complex social environments," study researcher MaryAnn Noonan, a neuroscientist at Oxford University, in England, said at a news conference. Basically, "how many friends can your brain handle?" Noonan said. Scientists still don't understand how the brain manages human behavior in increasingly complex social situations, or what parts of the brain are linked to deviant social behavior associated with conditions like autism and schizophrenia. Studies in macaque monkeys have shown that brain areas involved in face processing and in predicting the intentions of others are larger in animals living in large social groups than in ones living in smaller groups. To investigate these brain differences in humans, Noonan and her colleagues at McGill University, in Canada, recruited 18 participants for a structural brain-imaging study. They asked people how many social interactions they had experienced in the past month, in order to determine the size of their social networks. As was the case in monkeys, some brain areas were enlarged and better connected in people with larger social networks. In humans, these areas were the temporal parietal junction, the anterior cingulate cortex and the rostral prefrontal cortex, which are part of a network involved in "mentalization" — the ability to attribute mental states, thoughts and beliefs to another. © 2013 Scientific American
by Bob Holmes When it comes to evolution, there is no such thing as perfection. Even in the simple, unchanging environment of a laboratory flask, bacteria never stop making small tweaks to improve their fitness. That's the conclusion of the longest-running evolutionary experiment carried out in a lab. In 1988, Richard Lenski of Michigan State University in East Lansing began growing 12 cultures of the same strain of Escherichia coli bacteria. The bacteria have been growing ever since, in isolation, on a simple nutrient medium – a total of more than 50,000 E. coli generations to date. Every 500 generations, Lenski freezes a sample of each culture, creating an artificial "fossil record". This allows him to resurrect the past and measure evolutionary progress by comparing how well bacteria compete against each other at different points in the evolutionary process. No upper limit After 10,000 generations, Lenski thought that the bacteria might approach an upper limit in fitness beyond which no further improvement was possible. But the full 50,000 generations of data show that isn't the case. When pitted against each other in an equal race, new generations always grew faster than older ones. In other words, fitness never stopped increasing. Their results fit a mathematical pattern known as a power law, in which something can increase forever, but at a steadily diminishing rate. "Even if we extrapolate it to 2.5 billion generations, there's no obvious reason to think there's an upper limit," says Lenski. © Copyright Reed Business Information Ltd.
Link ID: 18937 - Posted: 11.16.2013
Helen Shen To researchers who study how living things move, the octopus is an eight-legged marvel, managing its array of undulating appendages by means of a relatively simple nervous system. Some studies have suggested that each of the octopus’s tentacles has a 'mind' of its own, without rigid central coordination by the animal’s brain1. Now neuroscientist Guy Levy and his colleagues at the Hebrew University in Jerusalem report that the animals can rotate their bodies independently of their direction of movement, reorienting them while continuing to crawl in a straight line. And, unlike species that use their limbs to move forward or sideways relative to their body's orientation, octopuses tend to slither around in all directions. The team presented its findings on 10 November at the annual meeting of the Society for Neuroscience in San Diego, California. The new description of octopus movement is “not how one would imagine that would happen, but it seems to give a lot of control to the animal", says Gal Haspel, a neuroscientist at the New Jersey Institute of Technology in Newark. Haspel studies worm locomotion, and he was also surprised by the researchers’ report that the octopus pushes itself with worm-like contractions of its tentacles. Different combinations flex together to produce movement in different directions. Levy, who began the research as part of a project to design and control flexible, octopus-like robots, says that the work could also help to uncover basic biological principles of locomotion. Levy’s team deconstructed octopus movement using a transparent tank rigged with a system of mirrors and video cameras, in which they tested nine adult common octopuses (Octopus vulgaris). © 2013 Nature Publishing Group
Ed Yong Humanity's success depends on the ability of humans to copy, and build on, the works of their predecessors. Over time, human society has accumulated technologies, skills and knowledge beyond the scope of any single individual. Now, two teams of scientists have independently shown that the strength of this cumulative culture depends on the size and interconnectedness of social groups. Through laboratory experiments, they showed that complex cultural traditions — from making fishing nets to tying knots — last longer and improve faster at the hands of larger, more sociable groups. This helps to explain why some groups, such as Tasmanian aboriginals, lost many valuable skills and technologies as their populations shrank. “For producing fancy tools and complexity, it’s better to be social than smart,” says psychologist Joe Henrich of the University of British Columbia in Vancouver, Canada, the lead author of one of the two studies, published today in Proceedings of the Royal Society B1. “And things that make us social are going to make us seem smarter.” “There were some theoretical models to explain these phenomena but no one had done experiments,” says evolutionary biologist Maxime Derex of the University of Montpellier, France, who led the other study, published online today in Nature2. Derex’s team asked 366 male students to play a virtual game in which they gained points — and eventually money — by building either an arrowhead or a fishing net. The nets offered greater rewards, but were also harder to make. The students watched video demonstrations of the two tasks in groups of 2, 4, 8 or 16, before attempting the tasks individually. Their arrows and nets were tested in simulations and scored. After each trial, they could see how other group members fared, and watch a step-by-step procedure for any one of the designs. © 2013 Nature Publishing Group
by Jennifer Viegas Music skills evolved at least 30 million years ago in the common ancestor of humans and monkeys, according to a new study that could help explain why chimpanzees drum on tree roots and monkey calls sound like singing. The study, published in the latest issue of Biology Letters, also suggests an answer to this chicken-and-egg question: Which came first, language or music? The answer appears to be music. "Musical behaviors would constitute a first step towards phonological patterning, and therefore language," lead author Andrea Ravignani told Discovery News. For the study, Ravignani, a doctoral candidate at the University of Vienna's Department of Cognitive Biology, and his colleagues focused on an ability known as "dependency detection." This has to do with recognizing relationships between syllables, words and musical notes. For example, once we hear a certain pattern like Do-Re-Mi, we listen for it again. Hearing something like Do-Re-Fa sounds wrong because it violates the expected pattern. Normally monkeys don't respond the same way, but this research grabbed their attention since it used sounds within their frequency ranges. In the study, squirrel monkeys sat in a sound booth and listened to a set of three novel patterns. (The researchers fed the monkeys insects between playbacks, so the monkeys quickly got to like this activity.) Whenever a pattern changed, similar to our hearing Do-Re-Fa, the monkeys stared longer, as if to say, "Huh?" © 2013 Discovery Communications, LLC.
by Sarah Zielinski If you put two birds together and gave them a problem, would they be any better at solving it than if they were alone? A study in Animal Behaviour of common mynas finds that not only are they no better at problem solving when in a pair than when on their own, the birds actually get a lot worse when put in a group. Andrea S. Griffin and her research team from the University of Newcastle in Callaghan, Australia, began by using dog food pellets as bait to capture common mynas (a.k.a. the Indian mynah, Acridotheres tristis) from around Newcastle. Then they gave each of the birds an innovation test, consisting of a box containing a couple of drawers and some Petri dishes. To get to the food hidden in spots in the box, the birds would have to get creative and figure out how to open one of the four containers by doing things like levering up a lid or pushing open a drawer. The scientists then ranked the birds by innovative ability before pairing them up. Half the pairs consisted of a high-innovation and a low-innovation myna, and the other half were pairs of medium-innovation birds. Then the pairs each received an innovation test similar to the one with boxes. Another experiment tested the birds in same-sex groups of five. On their own, 29 of 34 birds were able to access at least one container. But in pairs, only 15 of the 34 birds did so, and they took a lot longer. Performance dropped for both high- and medium-innovation birds, and it didn’t improve for the low-ranked ones, which had done so poorly the first time around that their results couldn’t get any worse. In groups of five, birds’ results fell even further: No mynas solved any of those tasks. © Society for Science & the Public 2000 - 2013