News / Science & Technology

    Thieving Lemurs Teach Us About Evolution of Intelligence

    Ring-tailed lemurs quickly learn to only steal food from people who can’t see what they’re doing. Less social species have a hard time thinking this way. (credit: E. MacLean/Duke University)
    Ring-tailed lemurs quickly learn to only steal food from people who can’t see what they’re doing. Less social species have a hard time thinking this way. (credit: E. MacLean/Duke University)
    Megan McGrath
    As animals go, humans are very smart. After all, we discovered calculus, general relativity, and fire. Out of all the brains in nature, there is clearly something special about ours. But how did we get this way? As Dr. Evan MacLean, a senior researcher a Duke University, says, “What were the problems that nature posed for us that we needed these brains to solve?”

    Scientists like MacLean think that being very social - living in large groups and communicating, like humans do - might have led to the development of a bigger, more powerful brain. “When we’re in a social environment there are all kinds of dynamic things that we have to keep track of, like who’s friends with who, who’s enemies with who, and who knows what,” he said. “This kind of information processing is really hard for the brain to do.”

    Social primates, gifted thieves

    MacLean’s research team at Duke tested this theory in lemurs. These small primates, native to the Indian Ocean island nation of Madagascar, are our close evolutionary cousins. There are many different species of lemurs. Some are more social than others; for example, the colorful ring-tail lemur lives in groups of sixteen or more, whereas the mongoose lemur seldom congregate in groups of more than three. Also, some lemur species have larger brains than others.

    In their lab, the researchers tested six species on their ability to steal food from people. In some cases, the person was watching the bait, and would reach out and defend it from grasping lemur paws. In other cases, however, the person’s back was turned. In order to take the food, the thieving lemurs had to know whether the person was watching or not, and choose the right moment to pounce. They had to use what scientists call "social intelligence."

    “What we found,” said MacLean, “is that species that are characterized by living in large social groups in nature were very adept when it came to figuring out which piece of food they should steal.”

    However, when the lemurs were tested on their ability to obtain food in an indirect way - a problem that required planning, rather than interpreting social cues - the relatively antisocial lemurs performed just as well as the species that live in large groups.

    In other words, the solitary lemurs were less effective at using social information, but when it came to using general information, they were just fine. And, to the researchers' surprise, the size of their brains barely mattered at all.

    “It looks like species that have bigger brains were doing worse on this task, and I never would have really predicted that,” said MacLean.

    Many kinds of intelligence

    This tells us that different kinds of intelligence - like the ability to make decisions, or find food, or communicate and be social - can develop independently of each other. It’s true that humans are really smart, but different animals evolve to be smart in different ways, depending on what they need to be good at in order to survive.

    The study also adds to a growing body of evidence that when it comes to brains, bigger is not better. For centuries, scientists measured brain size to compare intelligence between species, but we now know that such measurements may not tell us much at all about how smart an animal is. Intelligence is complicated, and researchers are continually searching for better ways to measure and understand it.

    You May Like

    Turkey, US Splits Deepen Over Support for Kurdish Militants

    Ankara summons American ambassador to protest remarks by State Department spokesman who said Washington does not consider Syria's Kurdish Democracy Union Party (PYD) a terrorist organization

    Obama Seeking $19 Billion for National Cybersecurity

    Move, touted as attempt to build broad, cohesive federal response to cyberthreats, calls for increase in cybersecurity spending across all government agencies

    Video Foreign Policy Weighs Heavy for Some US Voters

    VOA talks to protesters in Manchester, New Hampshire, who sound off on foreign policy issues such as the Guantanamo Bay prison, the Israeli-Palestinian conflict and the wars in Iraq, Syria and Yemen

    Featured Videos

    Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
    Valentine's Day Stinks for Lebanese Clownsi
    X
    February 09, 2016 8:04 PM
    This weekend, on Valentine's Day in Lebanon, love is not the only thing in the air. More than half a year after the country's trash crisis began, the stink of uncollected garbage remains on the streets. Step forward "Clown Me In," a group of clowns who use their skills for activism. Before the most romantic day of the year the clowns have released their unusual take on love in Lebanon -- in a bid to keep the pressure up and get the trash off the streets. John Owens reports from Beirut.
    Video

    Video Valentine's Day Stinks for Lebanese Clowns

    This weekend, on Valentine's Day in Lebanon, love is not the only thing in the air. More than half a year after the country's trash crisis began, the stink of uncollected garbage remains on the streets. Step forward "Clown Me In," a group of clowns who use their skills for activism. Before the most romantic day of the year the clowns have released their unusual take on love in Lebanon -- in a bid to keep the pressure up and get the trash off the streets. John Owens reports from Beirut.
    Video

    Video Rocky Year Ahead for Nigeria Amid Oil Price Crash

    The global fall in the price of oil has rattled the economies of many petroleum exporters, and Africa’s oil king Nigeria is no exception. As Chris Stein reports from Lagos, analysts are predicting a rough year ahead for the continent’s top producer of crude.
    Video

    Video Foreign Policy Weighs Heavy for Some US Voters

    VOA talks to protesters in Manchester, New Hampshire who sound off on foreign policy issues such as the Guantanamo Bay Prison, the Israeli-Palestinian conflict, Middle East Affairs and national security.
    Video

    Video 'No Means No' Program Targets Sexual Violence in Kenya

    The organizers of an initiative to reduce and stop rape in the informal settlements around Kenya's capital say their program is having marked success. Girls are taking self-defense classes while the boys are learning how to protect the girls and respect them. Lenny Ruvaga reports from Nairobi.
    Video

    Video New Hampshire Voters Are Independent, Mindful of History

    Once every four years, the northeastern state of New Hampshire becomes the center of the U.S. political universe with its first-in-the-nation presidential primary. What's unusual about New Hampshire is how seriously the voters take their role and the responsibility of being among the first to weigh in on the candidates.
    Video

    Video Chocolate Lovers Get a Sweet History Lesson

    Observed in many countries around the world, Valentine’s Day is sometimes celebrated with chocolate festivals. But at a festival near Washington, the visitors experience a bit more than a sugar rush. They go on a sweet journey through history. VOA’s June Soh takes us to the festival.
    Video

    Video 'Smart' Bandages Could Heal Wounds More Quickly

    Simple bandages are usually seen as the first line of attack in healing small to moderate wounds and burns. But scientists say new synthetic materials with embedded microsensors could turn bandages into a much more valuable tool for emergency physicians. VOA’s George Putic reports.
    Video

    Video Bhutanese Refugees in New Hampshire Closely Watching Primary Election

    They fled their country and lived in refugee camps in neighboring Nepal for decades before being resettled in the northeastern U.S. state of New Hampshire -- now the focus of the U.S. presidential contest. VOA correspondent Aru Pande spoke with members of the Bhutanese community, including new American citizens, about the campaign and the strong anti-immigrant rhetoric of some of the candidates.
    Video

    Video Researchers Use 3-D Printer to Produce Transplantable Body Parts

    Human organ transplants have become fairly common around the world in the past few decades. Researchers at various universities are coordinating their efforts to find solutions -- including teams at the University of Pennsylvania and Rice University in Houston that are experimenting with a 3-D printer -- to make blood vessels and other structures for implant. As VOA’s Greg Flakus reports from Houston, they are also using these artificial body parts to seek ways of defeating cancerous tumors.
    Video

    Video Helping the Blind 'See' Great Art

    There are 285 million blind and visually impaired people in the world who are unable to enjoy visual art at a museum. One New York photographer is trying to fix this situation by making tangible copies of the world’s masterpieces. VOA correspondent Victoria Kupchinetsky was there as visually impaired people got a feel for great art. Joy Wagner narrates her report.
    Video

    Video German Artists to Memorialize Refugees With Life Jacket Exhibit

    Sold in every kind of shop in some Turkish port towns, life jackets have become a symbol of the refugee crisis that brought a million people to Europe in 2015.  On the shores of Lesbos, Greece, German artists collect discarded life jackets as they prepare an art installation they plan to display in Germany.  For VOA, Hamada Elrasam has this report from Lesbos, Greece.
    Video

    Video E-readers Help Ease Africa's Book Shortage

    Millions of people in Africa can't read, and there's a chronic shortage of books. A non-profit organization called Worldreader is trying to help change all that one e-reader at a time. VOA’s Deborah Block tells us about a girls' school in Nairobi, Kenya where Worldreader is making a difference.
    Video

    Video Genius Lets World Share Its Knowledge

    Inspired by crowdsourcing companies like Wikipedia, Genius allows anyone to edit anything on the web, using its web annotation tool
    Video

    Video In Philippines, Mixed Feelings About Greater US Military Presence

    In the Philippines, some who will be directly affected by a recent Supreme Court decision clearing the way for more United States troop visits are having mixed reactions.  The increased rotations come at a time when the Philippines is trying to build up its military in the face of growing maritime assertiveness from China.  From Bahile, Palawan on the coast of the South China Sea, Simone Orendain has this story.