Biological Psychology Links

by Michael Marshall Humans, apes and monkeys have their mothers to thank for their large brains. It takes a lot of energy to make and run a brain, so large ones should only have developed in animals with fast metabolisms. But according to Vera Weisbecker of the University of Cambridge and Anjali Goswami of University College London, that's only part of the story. The pair looked at the brains of 197 marsupials and 457 placental mammals, and could find a link between metabolic rate and brain size only in placental mammals. This suggests that parenting strategies play a key role. "Placental babies are connected to their mothers via the placenta for a long time," says Weisbecker. "So if she has a high metabolic rate, the baby is more likely to benefit." By contrast, marsupial babies are born while they are still very small, then spend a long time feeding off their mothers' milk – a slower way to grow a large brain. Placentas offer a continuous supply of rich nutrients. However, the pair found no difference in the average brain sizes of marsupials and placental mammals – as long as they excluded primates. These, it seem, got their disproportionately large brains from a double maternal boost. They are supplied with large amounts of energy by their mothers during gestation, and then receive additional months or even years of care after birth. Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0906486107 © Copyright Reed Business Information Ltd.

By Katherine Harmon Marine worms might seem like lowly, slow-witted creatures, but new gene mapping shows that we might share an ancient brainy ancestor with them. Human cognition is largely rooted in the cerebral cortex, the part of the brain that enables consciousness, language and other higher-level functions. We share the basic evolutionary underpinnings of our big brains with other vertebrates, which have a structure known as the pallium. Although lacking palliums, many invertebrates, such as insects, spiders and some worms, instead have what are know as mushroom bodies—sections of the brain so called because their shape resembles mushrooms. Mushroom bodies and vertebrate palliums are both responsible for some sensory integration and memory, and they have "long been noted and interpreted as convergent acquisitions," noted a team of researchers in a new study, published online September 2 in Cell. In other words, the thinking has been that these two kinds of brains evolved from independent paths. The team, however, has proposed instead that these two brain structures do share a single common ancestor, one that likely lived some 600 million years ago. The group based their conclusions on new gene expression maps—"molecular fingerprints"— gathered from the mushroom bodies in developing marine ragworms (Platynereis dumerilii) that could be compared with gene expression patterns of developing vertebrate palliums. © 2010 Scientific American,

by Kristen Minogue Most people don't want their parents meddling in their sex lives. But for one species of ape, having mom nearby can actually increase the odds of hooking up with an eligible mate. Bonobos—our closest living relatives, along with chimpanzees—aren't puritanical. Sex for these apes is a public, accepted form of social currency. They use it to acquire food from others, defuse conflicts, and ingratiate themselves with their superiors. But bonobos also live under a rigid social hierarchy. An ape retains its rank even when a community splits up into smaller groups to forage for food, which the primates do frequently. Normally with bonobos, the highest-ranking male in the group also mates the most, typically with the nubile females. But male bonobos also stick close to their mothers, sometimes spending as much as 90% of their time in their company. Because the mother-son bond is so strong, biologist Martin Surbeck of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and colleagues wondered whether having a mother close by could upset the mating hierarchy. For almost 2.5 years, the researchers observed a community of more than 30 wild bonobos in the Democratic Republic of the Congo's Salonga National Park, keeping a close eye on the adult and adolescent males—nine in all. When the apes split into small groups with fertile females but no moms, the highest-ranking male had about 40% of the intercourse with the females, the team will report online tomorrow in the Proceedings of the Royal Society B. But if every male's mom was also present, the top male managed only about 25% of the matings, leaving more for the subordinate males. Mom's presence didn't change the hierarchy, but it did level the playing field somewhat for the apes further down, says Surbeck. "The mother's like a social passport." © 2010 American Association for the Advancement of Science.

By CARL ZIMMER Why are worker ants sterile? Why do birds sometimes help their parents raise more chicks, instead of having chicks of their own? Why do bacteria explode with toxins to kill rival colonies? In 1964, the British biologist William Hamilton published a landmark paper to answer these kinds of questions. Sometimes, he argued, helping your relatives can spread your genes faster than having children of your own. For the past 46 years, biologists have used Dr. Hamilton’s theory to make sense of how animal societies evolve. They’ve even applied it to the evolution of our own species. But in the latest issue of the journal Nature, a team of prominent evolutionary biologists at Harvard try to demolish the theory. The scientists argue that studies on animals since Dr. Hamilton’s day have failed to support it. The scientists write that a close look at the underlying math reveals that Dr. Hamilton’s theory is superfluous. “It’s precisely like an ancient epicycle in the solar system,” said Martin Nowak, a co-author of the paper with Edward O. Wilson and Corina Tarnita. “The world is much simpler without it.” Other biologists are sharply divided about the paper. Some praise it for challenging a concept that has outlived its usefulness. But others dismiss it as fundamentally wrong. “Things are just bouncing around right now like a box full of Ping-Pong balls,” said James Hunt, a biologist at North Carolina State University. Copyright 2010 The New York Times Company

By Larry O'Hanlon There are theories galore about why some dog breeds appear to be smarter than others, but new research suggests that size alone might make a difference. All larger dogs appear to be better at following pointing cues from humans than smaller dogs, which makes them appear smarter. It's possible that bigger dogs appear smarter not just because they are bred for taking orders, but because their wider set eyes give them better depth perception. As a result, they can more easily discern the direction a person is pointing. This latter hypothesis was tested by researchers in New Zealand, who think there might be something to it. "We do know that dog breeds are different," said William Helton of the University of Canterbury in Christchurch, New Zealand. Human breeding has created dogs with huge physical differences, like shorter snouts for more powerful bites. Even the internal structure of dogs eyes can vary among some breeds, he said. But can something as simple as the distance between the eyes be a factor too? To see if all larger dogs in general were better at discerning human pointing cues, Helton and his colleagues put 104 dogs to the test -- 61 large dogs (greater than 50 lbs) and 43 small dogs (less than 50 lbs). © 2010 Discovery Communications, LLC.

By Rebecca Kessler In greylag geese, nearly a fifth of all long-term couples are composed of two males. They're not alone: More than 130 bird species are known to engage in homosexual behavior at least occasionally, a fact that has puzzled scientists. After all, in evolutionary terms same-sex mating seems to reduce the birds' chances of reproductive success. But that's not necessarily so, according to a new study. In a given species, the sex with lighter parental duties tends to mate more, period whether with the same or the opposite sex. Birds engage in all kinds of same-sex hanky panky, from elaborate courtship displays to mounting and genital contact to setting up house together. In some species the same-sex pairs even raise young (conceived with outside partners, obviously) and stay together for several years. In 2007, a team led by Geoff MacFarlane, a biologist at the University of Newcastle in Australia, reported that male homosexual behavior was more common in polygynous bird species, where males mate with numerous females, and that female homosexual behavior was more common in monogamous species. Intrigued, MacFarlane looked for help explaining the pattern in a theory predicting that whichever gender spends less time caring for young tends to have sex with more partners. © 2010 LiveScience.com.

by Jon Cohen Thirty-five years ago, researchers studying chimpanzees in the wild noticed that neighboring communities had distinct grooming behaviors that could not be explained by differences in their environments. They contended that these behavioral idiosyncrasies were learned, or "cultural," and other scientists soon began noting group-specific tool uses and courting behaviors that also didn't appear to be environmental. But in a new study, researchers say some of these behaviors may be genetic after all. Before that 1975 revelation, few researchers had observed different communities of wild chimpanzees, and no one had even recognized that these behavioral differences existed. Investigators have been arguing about whether chimps truly have culture ever since. Proponents of culture published a landmark Nature paper in 1999 documenting 39 behaviors that were frequently observed in some communities and never seen in others. In the article's wake, a flood of reports began to appear about culture in other species, and the debates roiled on, with endless discussions about the meaning of the word itself. The new study, published online tomorrow in the Proceedings of the Royal Society B, examines partial sequences of the mitochondrial DNA (mtDNA) from wild chimpanzees in nine different groups. This DNA is handy because it's inherited only from mothers, and only chimp females typically move to new communities. Team members examined the links between the groups and 38 of the 39 supposed cultural variants documented in the earlier report. The study does not link behaviors to specific genes or even conclude that there is a genetic explanation. Rather, it assesses whether genetic differences can be excluded as an explanation for each behavior; it finds that they cannot more than half the time. © 2010 American Association for the Advancement of Science.

by Michael Balter Why cooperate when you can be selfish? Many animal behaviors are self-centered and apparently evolved to pass on an individual's genes to future generations. Yet cooperative breeding, in which some members of a group help others to raise their young, has evolved independently many times, especially in birds and insects. A new study of birds concludes that parents get more help when they are sexually faithful to each other. Cooperation has been called an evolutionary paradox, and cooperative breeding is relatively rare, with members of only 3% to 10% of bird species helping to raise one another's young. Among the apes, only humans are cooperative breeders, although monkeys such as marmosets and tamarins do it, too. In the 1960s, British biologist William Hamilton proposed that natural selection could favor cooperation if individuals pass on their own genes by helping relatives raise offspring. But Hamilton argued that cooperation can arise only if such helpers are closely related to recipients and if the benefits outweigh the costs. Over the past few years, Jacobus Boomsma, an evolutionary biologist at the University of Copenhagen, has argued that strict monogamous behavior, such as an ant queen mating for life, spurred the evolution of cooperative breeding in some social insects. Monogamy helps fulfill Hamilton's conditions, because all siblings are equally related to each other and to each parent. Promiscuity, on the other hand, leads to many half-siblings and lowers the relatedness of individuals in a group. © 2010 American Association for the Advancement of Science.

by Catherine de Lange They might not win any Oscars, but orang-utans can act. They have been caught on camera performing "pantomimes", in which they express their intentions and desires by acting them out. The finding challenges the view that these behaviours are exclusive to humans. Non-human great apes such as orang-utans and chimpanzees were already known to display meaningful gestures. They might throw an object when angry, for example. But that is a far cry from displaying actions that are intentionally symbolic and referential – the behaviour known as pantomiming. "Pantomime is considered uniquely human," says Anne Russon from York University in Toronto, Canada. "It is based on imitation, recreating behaviours you have seen somewhere else, which can be considered complex and beyond the grasp of most non-human species." Yet over years she has worked with great apes, Russon has seen several cases that she thought could be considered pantomiming. So to gather more concrete evidence, she and colleague Kristin Andrews searched through 20 years of data on the behaviour of free-ranging, rehabilitated orang-utans. They found 18 cases of orang-utans clearly acting out a message. Sometimes it was a simple mime, such as body-scratching using a stick, probably to encourage another orang-utan to groom the actor. © Copyright Reed Business Information Ltd.

By Bruce Bower For Lucy and her ancient hominid comrades, raw meat sliced off animal carcasses was what’s for dinner. That’s the implication of a new study, published in the Aug. 12 Nature, describing butchery marks made by stone implements on two animal bones from about 3.4 million years ago. If the new analysis holds up, it provides the oldest known evidence of stone-tool use and meat eating by members of the human evolutionary family. It’s also the first sign of such behavior in hominids preceding the Homo lineage, say anthropologist Shannon McPherron of the Max Planck Institute for Evolutionary Anthropology in Leipzig and her colleagues. McPherron’s group made the discovery in Ethiopia’s Dikika research area. Study coauthor Zeresenay Alemseged of the California Academy of Sciences in San Francisco previously unearthed a 3.3-million-year-old skeleton of an Australopithecus afarensis child at Dikika (SN: 9/23/06, p. 195). There’s no way to know whether the Dikika bones display marks made by intentionally produced stone tools or by sharp rocks found on the landscape. Until now, the oldest animal bones bearing stone-tool butchery marks came from another Ethiopian site, Bouri, and dated to 2.5 million years ago (SN: 4/24/99, p. 262). Researchers found the oldest known stone tools, estimated to be 2.6 million to 2.5 million years old, at nearby Gona, Ethiopia. Those implements were carefully fashioned from select types of rock, suggesting that stone toolmaking had begun much earlier (SN: 4/17/04, p. 254). © Society for Science & the Public 2000 - 2010

By Lesley Richardson, Press Association A framework to understand the emotional lives of animals was revealed today. Animal choices can be assessed objectively as evidence of pessimistic or optimistic decision-making which indicates their long-term mood. Professor Mike Mendl and Dr Liz Paul, from the University of Bristol, and Dr Oliver Burman, from the University of Lincoln, looked through papers by experts from Charles Darwin to Paul Ekman and Jaak Panksepp to create the framework which can be used in the field of animal welfare and neuroscience. Professor Mike Mendl, head of the Animal Welfare and Behaviour research group at Bristol University's School of Clinical Veterinary Science, said: "Because we can measure animal choices objectively, we can use optimistic and pessimistic decision-making as an indicator of the animal's emotional state which itself is much more difficult to assess. "Recent studies by our group and others suggest that this may be a valuable new approach in a variety of animal species. Public interest in animal welfare remains high, with widespread implications for the way in which animals are treated, used and included in society. We believe our approach could help us to better understand and assess an animal's emotion." ©independent.co.uk

by Alison Motluk OVERSIZED brains are to humans what trunks are to elephants and elaborate tail feathers are to peacocks - our defining glory. What would we be without our superlative, gargantuan, neuron-packed brains? Like Donald Trump without his towers, Simon Cowell without his sneering put-downs or Bridget Jones without her diaries. We would just be ordinary primates. Unquestionably smart ones, of course, just not special. Uncomfortable as it is to contemplate, it is looking increasingly likely that our brains are not something to write home about after all. One group of researchers has scrutinised the primate archaeological record and concluded that the human brain has evolved just as would be expected for a primate of our size. Meanwhile, a biologist who has compared the number of neurons in the brains of all sorts of animals says there is nothing special about the human brain compared with other primates. No one is doubting the fact of human intelligence, but they say it can no longer be attributed to a "supersized" brain. Humans, apparently, are no more than ordinary primates with ordinary-sized brains. These findings undermine a fundamental and long-standing belief about our place in the kingdom of life: that Homo sapiens is the greatest species ever to grace the Earth and that we have become the greatest because our brains are the best ever to have evolved. Admittedly, justifying this assertion has taxed our self-professed ingenuity. Clearly ours is not the biggest brain on the planet in absolute terms - whales and elephants outdo us by up to six times - but we counter this by arguing that bigger animals are bound to have bigger brains. And if you take body size into account our brain is exceptionally large, as much as seven times larger than those of other mammals (Science, vol 121, p 447). The underlying assumption is still that when it comes to intelligence, brain size matters. But does it? © Copyright Reed Business Information Ltd.

By Jesse Bering Last week, while in a drowsy, altitude-induced delirium 35,000 feet somewhere over Iceland, I groped mindlessly for the cozy blue blanket poking out beneath my seat, only to realize—to my unutterable horror—that I was in fact tugging soundly on a wriggling, sock-covered big toe. Now with a temperament such as mine, life tends to be one awkward conversation after the next, so when I turned around, smiling, to apologize to the owner of this toe, my gaze was met by a very large man whose grunt suggested that he was having some difficulty in finding the humor in this incident. Unpleasant, yes. But I now call this event serendipitous. As I rested my head back against that sanitation paper-covered airline pillow, my mid-flight mind lighted away to a much happier memory, one involving another big toe, yet this one belonging to a noticeably more good-humored animal than the one sitting behind me. This other toe—which felt every bit as much as its overstuffed human equivalent did, I should add—was attached to a 450-pound Western Lowland gorilla, with calcified gums, named King. When I was 19, and he was 27, I spent much of the Summer of 1996 with my toothless friend King, listening to Frank Sinatra and the Three Tenors (my bizarre foray into science, which you can read about here), playing chase from one side of his exhibit to the other, and tickling his toes. He’d lean back in his night house, stick out one huge ashen grey foot through the bars of his cage and leave it dangling there in anticipation, erupting in shoulder-heaving guttural “laughter” as I’d grab hold of one of his toes and gently give it a palpable squeeze. He almost couldn’t control himself when, one day, I leaned down to act as though I was going to bite on that plump digit. If you’ve never seen a gorilla in a fit of laughter, I’d recommend searching out such a sight before you pass from this world. It’s something that would stir up cognitive dissonance in even the heartiest of creationists. © 2010 Scientific American

by Michael Marshall The selective breeding of some domestic dogs has made their brains rotate forwards, and relocated one key component. Michael Valenzuela at the University of New South Wales in Sydney, Australia, and colleagues, used a brain scanner to look at the heads of 11 dogs that had recently been put down, and two live ones. The dogs came from a variety of breeds, which have been bred over thousands of years to have – among other characteristics – snouts of different lengths. They found that dogs with shorter snouts had brains which were rotated forwards by up to 15 degrees. They also found that the olfactory lobe at the front of the brain, which processes the sense of smell, was shunted downwards. "As a dog's head or skull shape becomes flatter – more pug-like – the brain rotates forward and the smell centre of the brain drifts further down to the lowest position in the skull," Valenzuela says. "It's something that hasn't been documented in other species." "This is the first evidence to suggest that selective breeding to meet specific physical characteristics in breed standards has had an impact on brain organisation," says Lisa Collins of the Royal Veterinary College in Hatfield, UK. It might help explain why long-snouted dogs are better at scent work, such as sniffing out drugs, than short-snouted breeds, she says. © Copyright Reed Business Information Ltd.

By Tom Wilkinson, Press Association Pigs can feel optimistic and pessimistic according to how they are being treated, scientists revealed today. Experts from Newcastle University's School of Agriculture, Food and Rural Development found they were just as likely as humans to feel the glass was half empty or half full, depending on their living conditions, as hogs kept in piggy luxury were more likely to respond positively to a new experience than those in less stimulating pens. The scientists hoped the research, which shows pigs are capable of feeling complex emotions, will have an impact on animal welfare. Led by Dr Catherine Douglas, the team employed a technique to "ask" pigs if they are feeling optimistic or pessimistic about life as a result of the way in which they live. In an experiment reminiscent of Pavlov's dogs, pigs were taught to associate a note on a glockenspiel with a treat - an apple - and a dog training "clicker" with something mildly unpleasant - in this case rustling a plastic bag. Then they placed half the pigs in an enriched environment - with more space, freedom to roam in straw and play with toys - while the other half were placed in a smaller, boring environment with no straw and only one non-interactive toy. The team then played an ambiguous noise - a squeak - and studied how the pigs responded. ©independent.co.uk

By Matt Walker Bowhead whales have a previously undiscovered ability to smell the air. The finding could change our understanding of how baleen whales locate prey, as scientists suspect the bowhead whales sniff out krill swarms. The whales' sense of smell was revealed when scientists dissected their bodies and found olfactory hardware linking the brain and nose, and functional protein receptors required to smell. Previously, whales and dolphins were thought to lack the ability. Details are published in the journal Marine Mammal Science. Cetacean expert Professor Hans Thewissen of the Northeastern Ohio Universities College of Medicine and colleagues based in Japan and Alaska made the discovery while evaluating the brain size of bowhead whales. The whales had been landed as part of the biannual Inupiat subsistence hunt along the north coast of Alaska, and Prof Thewissen's team was allowed to dissect the brain cavities, to evaluate how much of the brain casing a bowhead whale's brain actually fills. "Upon taking a brain out, I noticed that there were olfactory tracts, which, in other mammals, connect the brain to the nose," Prof Thewissen told the BBC. "I followed those to the nose, and noted that all the olfactory hardware is there." BBC © MMX

by Dave Munger Imagine being trapped in a small pressurized underwater chamber (like a diving bell) where you were fed once a day by an octopus that tossed food in from the opening in the floor. Each day an octopus also reached in to poke you gently with a stick. Suppose this went on for two weeks. Do you think you’d be able to figure out that there were actually two octopuses—one “poker” and one “feeder”? Would you be able to tell the difference between the two? Octopuses are so different from humans that it might actually be rather difficult for you to tell them apart—especially since you would only be able to see them through the distorting lens of the water. On the other hand, if you did manage to figure out which octopus was which, you might be able to get out of the way of the stick when the “poker” showed up. You also might be able to demonstrate to the octopuses that you were “intelligent,” perhaps inspiring them to treat you better while in captivity. Obviously this is just a thought experiment, and the real research was done in reverse, but hopefully this example gives you some sense of how difficult the problem of octopus intelligence really is. Because octopus brains evolved independently from human brains, their anatomical structure is very different from our own, so understanding whether octopuses are “intelligent” is not a simple task. How would you tell if an eight-legged alien from another planet was intelligent? ©2005-2009 Seed Media Group LLC.

By Emily Anthes Perhaps the most unlikely hero to emerge from this summer’s World Cup was Paul the octopus, a lightly spotted invertebrate living in an aquatic center in Germany. Paul earned worldwide fame for successfully “predicting” the winner of eight out of eight soccer games, including the final match. Before each game, Paul’s keepers would place two food-filled boxes, each of which was decorated with one team’s national flag, in the creature’s tank. Whichever box Paul ate from first was considered to be his pick. The octopus nailed it all eight times. Though Paul’s success seems mainly to have been luck — evidence for psychic sports forecasting ability in octopuses is, well, somewhat lacking — if you were looking to consult a brainy animal, you could do worse than an octopus. Research is increasingly revealing that there’s something sophisticated going on inside the octopus’s soft and squishy head. The critters, it seems, are surprisingly smart. Octopuses “make decisions all the time, complicated decisions,” says Roger Hanlon, a senior scientist at the Marine Biological Laboratory in Woods Hole. “People don’t expect that from a creature related to an oyster.” What scientists are discovering about the octopus calls into question many of our assumptions about intelligence. Partly this is because the creatures are so different from the kinds of animals — social vertebrates, especially mammals — that have long been seen as having a monopoly on smarts. Octopuses are members of a class of creatures known as cephalopods, which appeared on the planet even before the first fish, and they are almost as far removed from us primates as another animal can get. And although it has long been theorized that intelligence evolved in social creatures as a way for species that live in groups to navigate the complex social world, the octopus leads a solitary life. © 2010 NY Times Co.

by Mairi Macleod FROM feckless fathers and teenaged mothers to so-called feral kids, the media seems to take a voyeuristic pleasure in documenting the lives of the "underclass". Whether they are inclined to condemn or sympathise, commentators regularly ask how society got to be this way. There is seldom agreement, but one explanation you are unlikely to hear is that this kind of "delinquent" behaviour is a sensible response to the circumstances of a life constrained by poverty. Yet that is exactly what some evolutionary biologists are now proposing. There is no reason to view the poor as stupid or in any way different from anyone else, says Daniel Nettle of the University of Newcastle in the UK. All of us are simply human beings, making the best of the hand life has dealt us. If we understand this, it won't just change the way we view the lives of the poorest in society, it will also show how misguided many current efforts to tackle society's problems are - and it will suggest better solutions. Evolutionary theory predicts that if you are a mammal growing up in a harsh, unpredictable environment where you are susceptible to disease and might die young, then you should follow a "fast" reproductive strategy - grow up quickly, and have offspring early and close together so you can ensure leaving some viable progeny before you become ill or die. For a range of animal species there is evidence that this does happen. Now research suggests that humans are no exception. © Copyright Reed Business Information Ltd.

by Catherine Brahic THE French have elevated it to an art form, and even the British have got better at it - but chimps can't cook at all. According to one controversial evolutionary theory, early humans developed a taste for cooked food around 2 million years ago, and this set in motion a series of changes that made us utterly different from any other animal. Now the proponents of the cooked-food hypothesis are presenting fresh evidence in support of the idea - and it all comes down to how you chew. The theory, championed by Richard Wrangham at Harvard University, has divided palaeoanthropologists. In an attempt to convince the doubters, Wrangham and his colleagues have been amassing empirical evidence, including evolutionary adaptations consistent with a diet of heated food, such as the small size of our guts. At the Evolution 2010 conference in Portland, Oregon, at the end of June, Christopher Organ of Harvard and Brown University in Providence, Rhode Island, presented what he and Wrangham say is the best evidence yet that we are adapted to eating cooked food, and that this is the result of events that occurred early on in human evolution. Organ and Charles Nunn, also of Harvard, had predicted that if humans are uniquely adapted to eating cooked food, then we should spend far less time chewing than other primates, as cooked food tends to be softer than raw food. To test this, they gathered data from various primate species and looked at the correlation between chewing time and body size, taking into account how the different species were related to each other. © Copyright Reed Business Information Ltd.

Chapter 6. Evolution of Brain and Behavior