Chapter 1. Biological Psychology: Scope and Outlook
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George Yancy: You have popularized the concept of speciesism, which, I believe was first used by the animal activist Richard Ryder. Briefly, define that term and how do you see it as similar to or different from racism? Peter Singer: Speciesism is an attitude of bias against a being because of the species to which it belongs. Typically, humans show speciesism when they give less weight to the interests of nonhuman animals than they give to the similar interests of human beings. Note the requirement that the interests in question be “similar.” It’s not speciesism to say that normal humans have an interest in continuing to live that is different from the interests that nonhuman animals have. One might, for instance, argue that a being with the ability to think of itself as existing over time, and therefore to plan its life, and to work for future achievements, has a greater interest in continuing to live than a being who lacks such capacities. If we were to compare attitudes about speciesism today with past racist attitudes, we would have to say that we are back in the days in which the slave trade was still legal. On that basis, one might argue that to kill a normal human being who wants to go on living is more seriously wrong than killing a nonhuman animal. Whether this claim is or is not sound, it is not speciesist. But given that some human beings – most obviously, those with profound intellectual impairment – lack this capacity, or have it to a lower degree than some nonhuman animals, it would be speciesist to claim that it is always more seriously wrong to kill a member of the species Homo sapiens than it is to kill a nonhuman animal. © 2015 The New York Times Company
Keyword: Animal Rights
Link ID: 20990 - Posted: 05.28.2015
Neurosurgeon Henry Marsh has opened heads, cut into brains and performed the most delicate and risky surgeries on the part of the body that controls everything — including breathing, movement, memory and consciousness. "What is, I think, peculiar about brain surgery is it's so dangerous," Marsh tells Fresh Air's Terry Gross. "A very small area of damage to the brain can cause catastrophic disability for the patient." Over the course of his career, Marsh, a consulting neurosurgeon at Atkinson Morley's/St. George's Hospital in London since 1987, has learned firsthand about the damage that his profession can cause. While many of the surgeries he has performed have been triumphs, there is always a risk of leaving the patient severely disabled. In the memoir Do No Harm, Marsh confesses to the fears and uncertainties he's dealt with as a surgeon, revisits his triumphs and failures and reflects on the enigmas of the brain and consciousness. Despite his decades on the job — or perhaps because of them — Marsh says that much of the brain remains beyond his grasp. He likens the mystery of the brain to that of the big-bang theory. "We're all sitting on an equally great mystery within ourselves, each of us, in this microcosm of our own consciousness, and I find that a quite nice thought," he says. You can nick the liver, you can remove bits of the lung, you can remove bits of the heart and the organ goes on working. But with the brain, although some areas can suffer some damage without terrible consequences for the patient, in general terms, it's very dangerous. Which means the decision-making is very important and ... in my experience over the years, when things have gone wrong, it's not because of [we] cut the wrong blood vessel or dropped an instrument or something like that. The mistakes made — the mistakes are in the decision-making — whether to operate or when to operate. © 2015 NPR
Link ID: 20987 - Posted: 05.27.2015
I’m fairly new to San Francisco, so I’m still building my mental database of restaurants I like. But this weekend, I know exactly where I’m heading to for dinner: Nick’s Crispy Tacos. Then, when I get home, I’m kicking back to a documentary I’ve never heard of, a Mongolian drama called The Cave of the Yellow Dog. An artificially intelligent algorithm told me I’d enjoy both these things. I’d like the restaurant, the machine told me, because I prefer Mexican food and wine bars “with a casual atmosphere,” and the movie because “drama movies are in my digital DNA.” Besides, the title shows up around the web next to Boyhood, another film I like. Nara Logics, the company behind this algorithm, is the brainchild (pun intended) of its CTO and cofounder, Nathan Wilson, a former research scientist at MIT who holds a doctorate in brain and cognitive science. Wilson spent his academic career and early professional life immersed in studying neural networks—software that mimics how a human mind thinks and makes connections. Nara Logics’ brain-like platform, under development for the past five years, is the product of all that thinking.. The Cambridge, Massachusetts-based company includes on its board such bigwig neuroscientists as Sebastian Seung from Princeton, Mriganka Sur from MIT, and Emily Hueske of Harvard’s Center for Brain and Science. So what does all that neuroscience brain power have to offer the tech world, when so many Internet giants—from Google and Facebook to Microsoft and Baidu—already have specialized internal teams looking to push the boundaries of artificial intelligence? These behemoths use AI to bolster their online services, everything from on-the-fly translations to image recognition services. But to hear Wilson tell it, all that in-house work still leaves a large gap—namely, all the businesses and people who could benefit from access to an artificial brain but can’t build it themselves. “We’re building a pipeline, and taking insights out of the lab to intelligent, applied use cases,” Wilson tells WIRED. “Nara is AI for the people.”
Link ID: 20967 - Posted: 05.23.2015
An octopus filmed off the coast of Kalaoa in Hawaii has shown that even cephalopods can get into a game of peekaboo. In the footage, shot last month by the GoPro camera of diver Timothy Ewing, the octopus bobs up and down behind a rock as a Ewing does the same in an effort to take the animal's picture. It's clear from the video that the octopus is wary of Ewing and his big, light-equipped camera — but the animal is also very curious. “Octopus are one of the more intelligent creatures in the ocean. Sometimes they are too curious for their own good. If you hide from them they will come out and look for you," the diver wrote in his online posting of the video. Ewing explained to CaliforniaDiver.com that the encounter wasn't limited to the time captured on his GoPro. "I was interacting with that octopus for about 10 minutes before I took the video," Ewing told CaliforniaDiver.com. "I normally mount my GoPro to my big camera housing, however I always carry a small tripod with me to use with the GoPro for stationary shots like this or selfie videos." The octopus, found worldwide in tropical, subtropical and temperate areas, is known for its smarts and striking ability to camouflage itself. When it feels threatened, pigment cells in its skin allow it to change color instantly to blend in with its surroundings. The animals can also adapt their skin texture and body posture to further match their background. © 2015 Discovery Communications, LLC.
by Ashley Yeager New Caledonian crows are protective of their tools. The birds safeguard the sticks they use to find food and become even more careful with the tools as the cost of losing them goes up. Researchers videotaped captive and wild Corvus moneduloides crows and tracked what the birds did with their sticks. In between eating, the birds tucked the tools under their toes or left them in the holes they were probing. When higher up in the trees, the birds dropped the tools less often and were more likely to leave them in the holes they were probing than when they were on the ground. The finding, published May 20 in the Proceedings of the Royal Society B, shows how tool-protection tactics can prevent costly losses that could keep the crows from chowing down. © Society for Science & the Public 2000 - 2015
RACHEL MARTIN, HOST: For most of her life, Cole Cohen had a hard time with all kinds of things. She'd get lost all of the time. She couldn't do math to save her life. The whole concept of time was hard for her to grasp. Her parents took her to doctor after doctor, and there were all kinds of tests and experiments with medication, but no real diagnosis until she was 26 years old. Cole Cohen got her first MRI and finally, there was an explanation. There was a hole in her brain; a hole in her brain the size of a lemon. Her memoir, titled "Head Case," is a darkly funny exploration of what that discovery meant to her. Cole Cohen joins us now. Thanks so much for being with us. COLE COHEN: Thank you for having me, Rachel. MARTIN: Let's talk about what life was like before this revelation. I mentioned your propensity to get lost. We're not talking about being in a new place and getting confuses as a lot of us might do. You got lost in, like, big box stores that you had been to before. Can you describe that sensation, that feeling of not knowing where you are in a situation like that? COHEN: Yeah. I know that sensation every time I go grocery shopping. You know, you want to get a jar of peanut butter. You have a memory of where that jar of peanut butter is, and I just don't have that in my brain. I don't store that information. So it's like a discovery every time. MARTIN: I'd love for you to read an example of one of the symptoms. You have a hard time with numbers, even references to numbers. And you write about this in the book when you're taking driver's ed. Do you mind reading that bit? © 2015 NPR
Keyword: Learning & Memory
Link ID: 20942 - Posted: 05.18.2015
Barbara J. King Last Friday in the Washington Post, Charles Krauthammer asked which contemporary practices will be deemed "abominable" in the future, in the way that we today think of human enslavement. He then offered his own opinion: "I've long thought it will be our treatment of animals. I'm convinced that our great-grandchildren will find it difficult to believe that we actually raised, herded and slaughtered them on an industrial scale — for the eating." Krauthammer goes on to predict that meat-eating will become "a kind of exotic indulgence," because "science will find dietary substitutes that can be produced at infinitely less cost and effort." I don't often agree with Krauthammer's views, and his animal column is no exception. His breezy attitude on animal biomedical testing does animals no favors. (It's perhaps only fair to note that I have similar concerns about Alva's conclusions on animal testing from his 13.7 post published that same day.) But, still, Krauthammer does a terrific job of awakening people to many issues related to animals' suffering. And he's not alone. On April 17, I joined other scientists and activists on the radio show To the Point hosted by Warren Olney, to discuss this question: Is Animal Liberation Going Mainstream? In the 34-minute segment, we discussed the public outcry against SeaWorld's treatment of orcas, Ringling Bros.' plan to retire elephants from the circus in three years, and the rightness or wrongness of keeping animals in zoos — all issues brought up by Krauthammer in his column. © 2015 NPR
Keyword: Animal Rights
Link ID: 20935 - Posted: 05.16.2015
Robin McKie The European parliament will on Monday debate a call – backed by a petition signed by 1.2 million people – to scrap animal research in the EU. The proposal has alarmed scientists, who worked for six years to set up the 2010 European directive that controls animal experimentation and welfare in the EU. Researchers fear that the petition, which was drawn up by the Italian-based Stop Vivisection European citizens’ initiative, could sway many newly elected MEPs who would then press the European commission into scrapping the directive which, in the UK, is enshrined in an amendment to the 1986 Animals (Scientific Procedures) Act. “Without the directive, research using animals would be blocked and that would have terrible consequences,” said Nancy Lee, senior policy adviser at the Wellcome Trust. “New medicines for Alzheimer’s, heart disease, cancer and other conditions could no longer be tested. Similarly, new drugs for animals would also be blocked.” This view is backed by Dame Kay Davies, director of the MRC functional genomics unit at Oxford University. “Removal of the directive would be a significant step backwards both for animal welfare in the EU and for Europe’s leading role in advancing human and animal health,” she said in last week’s Nature. Other citizens’ initiatives, which require a minimum of a million signatures before they are heard by the European parliament, have included calls for improved water supplies and stricter speed limits in Europe.
Keyword: Animal Rights
Link ID: 20905 - Posted: 05.11.2015
By Dialynn Dwyer @dia_dwyer Warning: The above video contains graphic images. Steven Keating says he fought his cancer with curiosity. The MIT doctoral student was diagnosed in the summer of 2014 with a baseball-sized brain tumor, and during his treatment he gathered his health data in order to understand the science behind what his body was going through. He even filmed his ten hour brain surgery. And though his surgery was performed and filmed last summer, it gained attention recently when Vox wrote about Keating and his surgery. Through his experience, Keating became passionate about more transparent health records. “Healthcare should be a two-way road, patients alongside doctors and researchers as a team,” he says on his website. “The future will be driven by networked healthcare, support communities, and I believe patient curiosity. I do believe learning, understanding, and access can heal.” Keating has given public talks about his experience, and he has shared all his findings, including the condensed video of his surgery, through his website for anyone to study.
Link ID: 20884 - Posted: 05.05.2015
By Gretchen Vogel BERLIN—A German neuroscientist who has been the target of animal rights activists says he is giving up on primate research. Nikos Logothetis, a director at the Max Planck Institute for Biological Cybernetics in Tübingen, Germany, says he will conclude his current experiments on macaques “as quickly as possible” and then shift his research to rodent neural networks. In a letter last week to fellow primate researchers, Logothetis cites a lack of support from colleagues and the wider scientific community as key factors in his decision. In particular, he says the Max Planck Society—and other organizations—should pursue criminal charges against the activists who target researchers. Logothetis’s research on the neural mechanisms of perception and object recognition has used rhesus macaques with electrode probes implanted in their brains. The work was the subject of a broadcast on German national television in September that showed footage filmed by an undercover animal rights activist working at the institute. The video purported to show animals being mistreated. Logothetis has said the footage is inaccurate, presenting a rare emergency situation following surgery as typical and showing stress behaviors deliberately prompted by the undercover caregiver. (His written rebuttal is here.) The broadcast triggered protests, however, and it prompted several investigations of animal care practices at the institute. Investigations by the Max Planck Society and animal protection authorities in the state of Baden-Württemberg found no serious violations of animal care rules. A third investigation by local Tübingen authorities that led to a police raid at the institute in late January is still ongoing. © 2015 American Association for the Advancement of Science.
By Emily Underwood NASA hopes to send the first round-trip, manned spaceflight to Mars by the 2030s. If the mission succeeds, astronauts could spend several years potentially being bombarded with cosmic rays—high-energy particles launched across space by supernovae and other galactic explosions. Now, a study in mice suggests that these particles could alter the shape of neurons, impairing astronauts’ memories and other cognitive abilities. The concern about cosmic rays is a long-standing one, prompting NASA (and science fiction writers) to spend a lot of time discussing ways of protecting astronauts from them. (A buffer of water around the spacecraft’s hull is one popular idea.) But scientists don’t really know how much of a threat the radiation poses. It’s not feasible to study the effects of cosmic rays on real astronauts, such as those living in the International Space Station, because many variables, including the stress of living on a spaceship, can affect cognition, says Patric Stanton, a cell biologist at New York Medical College in Valhalla. It’s also impossible to control the level of radiation astronauts are exposed to, making it difficult to do rigorous experiments, he says. To overcome those challenges, several NASA-funded research groups are testing cosmic radiation on mice. In the new study, published today in Science Advances, Charles Limoli, a molecular biologist at the University of California, Irvine, and colleagues took male mice to a particle accelerator at the NASA Space Radiation Laboratory in Upton, New York. There, they catapulted oxygen and titanium ions down a 100-meter transport tunnel and into the restrained rodents’ brains at roughly two-thirds the speed of light. The dose of high-energy particles resembled the radiation likely to pass through the unprotected hull of a spaceship over the course of a mission to Mars, Limoli says. © 2015 American Association for the Advancement of Science
Link ID: 20873 - Posted: 05.02.2015
By Laura Sanders Studying the human brain requires grandiose thinking, but rarely do actual theatrical skills come into play. In her latest stint as a video star, MIT neuroscientist Nancy Kanwisher does not buzz saw her skull open to give viewers a glimpse of her brain. But she does perhaps the next best thing: She clips off her shoulder-length gray hair and shaves her head on camera. Kanwisher’s smooth, bald head then becomes a canvas for graduate student and artist Rosa Lafer-Sousa, who meticulously draws in the brain’s wrinkles — the sulci and the gyri that give rise to thoughts, memories and behaviors. All the while, Kanwisher provides a voice-over describing which areas of the brain recognize faces, process language and even think about what another person is thinking. The video is the latest in Kanwisher’s occasional online series, Nancy’s Brain Talks. Pithy, clever and cleanly produced, the more than two dozen videos she has made so far bring brain science to people who might otherwise miss out. In another neurostunt, brain-zapping technology called transcranial magnetic stimulation makes Kanwisher’s hand jump involuntarily. These demonstrations capture people’s attention more than a dry scientific paper would. “I think scientists owe it to the public to share the cool stuff we discover,” Kanwisher says. Her own lab’s discoveries focus on how the brain’s disparate parts work together to construct a mind. Some brain areas have very specific job descriptions while others are far more general. Compiling a tally of brain regions and figuring out what they do is one of the first steps toward understanding the brain. “It starts to give us a set of basic components of the mind,” Kanwisher says. “It’s like a parts list.” © Society for Science & the Public 2000 - 2015.
Keyword: Brain imaging
Link ID: 20853 - Posted: 04.28.2015
Brendan Borrell A campaign by animal rights activists to establish the legal personhood of chimpanzees took a bizarre turn this week, when a New York judge inadvertently opened a constitutional can of worms only to clamp it shut a day later. On 20 April, New York Supreme Court Justice Barbara Jaffe signed an order forcing Stony Brook University to respond to claims by the Nonhuman Rights Project (NhRP) that two research chimpanzees, Hercules and Leo, were being unlawfully detained. The Coral Springs, Florida, organization declared victory, claiming that because such an order, termed a writ of habeas corpus, can only be granted to a person in New York state, the judge had implicitly determined that the chimps were legal persons. An eruption of news coverage on 21 April sparked a backlash by legal experts claiming the significance of the order had been overblown. By that evening, Jaffe had amended the order, letting arguments on the chimps’ detainment go forward but explicitly scratching out the words WRIT OF HABEAS CORPUS at the top of the document. Nature takes a look at the episode’s significance in the campaign to give animals legal rights and what it means for the research community. What is the basis for the idea of giving chimps personhood rights, rather than improving animal treatment laws? The NhRP stands apart from typical animal welfare and animal rights groups in that it narrowly focuses on getting the most intelligent, autonomous, self-aware animals recognized under the law as “persons” with specific rights, rather than things. “We are only asking for one legal right and that’s bodily liberty,” says the organization’s executive director, Natalie Prosin. Animal welfare laws in New York already allow people and organizations to obtain relief from the courts when animals are being abused or kept in poor conditions. The organization’s petition to the court, filed with affidavits from animal cognition researchers, states that keeping chimps in captivity is unlawful, independent of the conditions in which they are kept and whether animal welfare laws are being violated. © 2015 Nature Publishing Group,
Keyword: Animal Rights
Link ID: 20834 - Posted: 04.23.2015
By David Grimm In a decision that effectively recognizes chimpanzees as legal persons for the first time, a New York judge today granted a pair of Stony Brook University lab animals the right to have their day in court. The ruling marks the first time in U.S. history that an animal has been covered by a writ of habeus corpus, which typically allows human prisoners to challenge their detention. The judicial action could force the university, which is believed to be holding the chimps, to release the primates, and could sway additional judges to do the same with other research animals. “This is a big step forward to getting what we are ultimately seeking: the right to bodily liberty for chimpanzees and other cognitively complex animals,” says Natalie Prosin, the Executive Director of the animal rights organization, the Nonhuman Rights Project (NhRP), which filed the case. “We got our foot in the door. And no matter what happens, that door can never be completely shut again.” Richard Cupp, a law professor at Pepperdine University in Malibu, California, and a noted opponent of personhood for animals, cautions against reading too much into the ruling, however. “The judge may merely want more information to make a decision on the legal personhood claim, and may have ordered a hearing simply as a vehicle for hearing out both parties in more depth,” he writes in an email to Science. “It would be quite surprising if the judge intended to make a momentous substantive finding that chimpanzees are legal persons if the judge has not yet heard the other side’s arguments.” © 2015 American Association for the Advancement of Science
Keyword: Animal Rights
Link ID: 20822 - Posted: 04.21.2015
Daniel Cressey Experiments that use only a small number of animals are common, but might not give meaningful results. Replace, refine, reduce: the 3 Rs of ethical animal research are widely accepted around the world. But now the message from UK funding agencies is that some experiments use too few animals, a problem that leads to wastage and low-quality results. On 15 April, the research councils responsible for channelling government funding to scientists, and their umbrella group Research Councils UK, announced changes to their guidelines for animal experiments. Funding applicants must now show that their work will provide statistically robust results — not just explain how it is justified and set out the ethical implications — or risk having their grant application rejected. The move aims to improve the quality of medical research, and will help to address widespread concerns that animals — mostly mice and rats — are being squandered in tiny studies that lack statistical power. “If the study is underpowered your results are not going to be reliable,” says Nathalie Percie du Sert, who works on experimental design at the National Centre for the Replacement, Refinement and Reduction (NC3Rs) of Animals in Research in London. “These animals are going to be wasted.” © 2015 Nature Publishing Group
Keyword: Animal Rights
Link ID: 20798 - Posted: 04.15.2015
By David Grimm The U.S. Department of Agriculture has launched an investigation into Harvard University’s New England Primate Research Center after several suspicious deaths at the Southborough, Massachusetts, facility. The inquiry coincides with a series of articles published by The Boston Globe, which has uncovered a number of potential animal welfare violations at the center, including a dozen dehydrated squirrel monkeys found dead in their cages or euthanized because of poor health between 1999 and 2011. In several cases it appears that the animals were not given water or were unable to drink due to malfunctioning water lines. In one incident, a monkey’s tooth caught in her jacket, preventing her from drinking. Some of these animals were the subject of a 2014 Veterinary Pathology paper on the impact of dehydration on lab animals. The journal says it is now investigating this study. The primate center is set to close at the end of next month, though—according to the Globe—the university blames finances, not animal care problems. © 2015 American Association for the Advancement of Science
Keyword: Animal Rights
Link ID: 20791 - Posted: 04.14.2015
|By Gareth Cook The wait has been long, but the discipline of neuroscience has finally delivered a full-length treatment of the zombie phenomenon. In their book, Do Zombies Dream of Undead Sheep?, scientists Timothy Verstynen and Bradley Voytek cover just about everything you might want to know about the brains of the undead. It's all good fun, and if you learn some serious neuroscience along the way, well, that's fine with them, too. Voytek answered questions from contributing editor Gareth Cook. How is it that you and your co-author came to write a book about zombies? Clearly, it is an urgent public health threat, but I would not have expected a book from neuroscientists on the topic. Indeed! You think you're prepared for the zombie apocalypse and then—BAM!—it happens, and only then do you realize how poorly prepared you really were. Truly the global concern of our time. Anyway, this whole silly thing started when Tim and I would get together to watch zombie movies with our wives and friends. Turns out when you get some neuroscientists together to watch zombie movies, after a few beers they start to diagnose them and mentally dissect their brains. Back in the summer of 2010 zombie enthusiast and author—and head of the Zombie Research Society—Matt Mogk got in touch with me to see if we were interested in doing something at the intersection of zombies and neuroscience. © 2015 Scientific American
Link ID: 20772 - Posted: 04.10.2015
Cari Romm “As humans, we can identify galaxies light-years away. We can study particles smaller than an atom,” President Barack Obama said in April 2013, “But we still haven’t unlocked the mystery of the three pounds of matter that sits between our ears.” The observation was part of the president’s announcement of the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative, an effort to fast-track the development of new technology that will help scientists understand the workings of the human brain and its diseases. With progress, though, comes a whole new set of ethical questions. Can drugs used to treat conditions like ADHD, for example, also be used to make healthy people into sharper, more focused versions of themselves—and should they? Can a person with Alzheimer’s truly consent to testing that may help scientists better understand their disease? Can brain scans submitted as courtroom evidence reveal anything about a defendant’s intent? Can a person with Alzheimer’s truly consent to testing that may help scientists better understand their disease? To address these questions, the Presidential Commission for the Study of Bioethical Issues, an independent advisory group, recently released the second volume of a report examining the issues that may arise as neuroscience advances. The commission outlined three areas it deemed particularly fraught: cognitive enhancement, consent, and the use of neuroscience in the legal system. © 2015 by The Atlantic Monthly Group
Christian Jarrett November 2013, I proudly launched the Brain Watch blog here at WIRED. This will be my final post. For seventeen months I’ve used the blog to report on new neuroscience findings, to reflect on how neuroscience is influencing the public and media, to investigate the claims of brain products, to explore neurological abnormality and death, and to debunk misconceptions about the brain. I loved reading your comments and I was thrilled when I found my ideas from here quoted in other publications. It’s been a lot of fun. Here’s some of what I learned: Brain myths die hard When the movie Lucy came out last year, it provided me an opportunity to challenge the 10% brain myth and explore its origins (the idea we only use 10% of our brains is a premise of the film). With such tired myths, it’s easy to wonder if anybody believes them anymore. Writing this blog, I learned not to underestimate their staying power! Consider the vitriol my 10% post attracted from a neuroscience grad student at Yale. In an email dripping with disdain she told me “You … should feel ashamed for releasing such a misinformed article. … There are misinformed and uneducated people all over the internet trying to disprove this 10% notion, but that is expected. This is certainly NOT something I expected from someone allegedly as well educated as yourself.” Brain science is confusing and complicated Hardly a revelation, you might say. But writing this blog brought home to me the messy reality of neuroscience. Consider how tabloid papers like dividing the world into those activities and technologies that cause brain shrinkage and those that cause brain growth – the implicit assumption always being that growth is good and shrinkage bad.
Link ID: 20706 - Posted: 03.21.2015
A long-term study has pointed to a link between breastfeeding and intelligence. The research in Brazil traced nearly 3,500 babies, from all walks of life, and found those who had been breastfed for longer went on to score higher on IQ tests as adults. Experts say the results, while not conclusive, appear to back current advice that babies should be exclusively breastfed for six months. But they say mothers should still have a choice about whether or not to do it. Regarding the findings - published in The Lancet Global Health - they stress there are many different factors other than breastfeeding that could have an impact on intelligence, although the researchers did try to rule out the main confounders, such as mother's education, family income and birth weight. Dr Bernardo Lessa Horta, from the Federal University of Pelotas in Brazil, said his study offers a unique insight because in the population he studied, breastfeeding was evenly distributed across social class - not something just practised by the rich and educated. Most of the babies, irrespective of social class, were breastfed - some for less than a month and others for more than a year. Those who were breastfed for longer scored higher on measures of intelligence as adults. They were also more likely to earn a higher wage and to have completed more schooling. Dr Horta believes breast milk may offer an advantage because it is a good source of long-chain saturated fatty acids which are essential for brain development. But experts say the study findings cannot confirm this and that much more research is needed to explore any possible link between breastfeeding and intelligence. © 2015 BBC.