Neuroscience

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Posts tagged primates

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Brain Size Didn’t Drive Evolution, Research Suggests Brain organization, not overall size, may be the key evolutionary difference between primate brains, and the key to what gives humans their smarts, new research suggests. In the study, researchers looked at 17 species that span 40 million years of evolutionary time, finding changes in the relative size of specific brain regions, rather than changes in brain size, accounted for three-quarters of brain evolution over that time. The study, published today (March 26) in the Proceedings of the Royal Society B, also revealed that massive increases in the brain’s prefrontal cortex played a critical role in great ape evolution. "For the first time, we can really identify what is so special about great ape brain organization," said study co-author Jeroen Smaers, an evolutionary biologist at the University College London. Is bigger better? Traditionally, scientists have thought humans’ superior intelligence derived mostly from the fact that our brains are three times bigger than our nearest living relatives, chimpanzees. But bigger isn’t always better. Bigger brains take much more energy to power, so scientists have hypothesized that brain reorganization could be a smarter strategy to evolve mental abilities. To see how brain organization evolved throughout primates, Smaers and his colleague Christophe Soligo analyzed post-mortem slices of brains from 17 different primates, then mapped changes in brain size onto an evolutionary tree. Over evolutionary time, several key brain regions increased in size relative to other regions. Great apes (especially humans) saw a rise in white matter in the prefrontal cortex, which contributes to social cognition, moral judgments, introspection and goal-directed planning. "The prefrontal cortex is a little bit like the CEO of the brain," Smaers told LiveScience. "It takes information from other brain areas and it synthesizes them." When great apes diverged from old-world monkeys about 20 million years ago, brain regions tied to motor planning also increased in relative size. That could have helped them orchestrate the complex movements needed to manipulate tools — possibly to get at different food sources, Smaers said. Gibbons and howler monkeys showed a different pattern. Even though their bodies and their brains got smaller over time, the hippocampus, which plays a role in spatial tasks, tended to increase in size in relation to the rest of the brain. That may have allowed these monkeys to be spatially adept and inhabit a more diverse range of environments. Prefrontal cortex The study shows that specific parts of the brain can selectively scale up to meet the demands of new environments, said Chet Sherwood, an anthropologist at George Washington University, who was not involved in the study. The finding also drives home the importance of the prefrontal cortex, he said. "It’s very suggestive that connectivity of prefrontal cortex has been a particularly strong driving force in ape and human brains," Sherwood told LiveScience.

Brain Size Didn’t Drive Evolution, Research Suggests

Brain organization, not overall size, may be the key evolutionary difference between primate brains, and the key to what gives humans their smarts, new research suggests.

In the study, researchers looked at 17 species that span 40 million years of evolutionary time, finding changes in the relative size of specific brain regions, rather than changes in brain size, accounted for three-quarters of brain evolution over that time. The study, published today (March 26) in the Proceedings of the Royal Society B, also revealed that massive increases in the brain’s prefrontal cortex played a critical role in great ape evolution.

"For the first time, we can really identify what is so special about great ape brain organization," said study co-author Jeroen Smaers, an evolutionary biologist at the University College London.

Is bigger better?

Traditionally, scientists have thought humans’ superior intelligence derived mostly from the fact that our brains are three times bigger than our nearest living relatives, chimpanzees.

But bigger isn’t always better. Bigger brains take much more energy to power, so scientists have hypothesized that brain reorganization could be a smarter strategy to evolve mental abilities.

To see how brain organization evolved throughout primates, Smaers and his colleague Christophe Soligo analyzed post-mortem slices of brains from 17 different primates, then mapped changes in brain size onto an evolutionary tree.

Over evolutionary time, several key brain regions increased in size relative to other regions. Great apes (especially humans) saw a rise in white matter in the prefrontal cortex, which contributes to social cognition, moral judgments, introspection and goal-directed planning.

"The prefrontal cortex is a little bit like the CEO of the brain," Smaers told LiveScience. "It takes information from other brain areas and it synthesizes them."

When great apes diverged from old-world monkeys about 20 million years ago, brain regions tied to motor planning also increased in relative size. That could have helped them orchestrate the complex movements needed to manipulate tools — possibly to get at different food sources, Smaers said.

Gibbons and howler monkeys showed a different pattern. Even though their bodies and their brains got smaller over time, the hippocampus, which plays a role in spatial tasks, tended to increase in size in relation to the rest of the brain. That may have allowed these monkeys to be spatially adept and inhabit a more diverse range of environments.

Prefrontal cortex

The study shows that specific parts of the brain can selectively scale up to meet the demands of new environments, said Chet Sherwood, an anthropologist at George Washington University, who was not involved in the study.

The finding also drives home the importance of the prefrontal cortex, he said.

"It’s very suggestive that connectivity of prefrontal cortex has been a particularly strong driving force in ape and human brains," Sherwood told LiveScience.

Filed under brain evolution brain size prefrontal cortex cerebellum primates evolution neuroscience psychology science

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Reward linked to image is enough to activate brain’s visual cortex Once rhesus monkeys learn to associate a picture with a reward, the reward by itself becomes enough to alter the activity in the monkeys’ visual cortex. This finding was made by neurophysiologists Wim Vanduffel and John Arsenault (KU Leuven and Harvard Medical School) and American colleagues using functional brain scans and was published recently in the leading journal Neuron. Our visual perception is not determined solely by retinal activity. Other factors also influence the processing of visual signals in the brain. “Selective attention is one such factor,” says Professor Wim Vanduffel. “The more attention you pay to a stimulus, the better your visual perception is and the more effective your visual cortex is at processing that stimulus. Another factor is the reward value of a stimulus: when a visual signal becomes associated with a reward, it affects our processing of that visual signal. In this study, we wanted to investigate how a reward influences activity in the visual cortex.” Pavlov inverted To do this, the researchers used a variant of Pavlov’s well-known conditioning experiment: “Think of Pavlov giving a dog a treat after ringing a bell. The bell is the stimulus and the food is the reward. Eventually the dogs learned to associate the bell with the food and salivated at the sound of the bell alone. Essentially, Pavlov removed the reward but kept the stimulus. In this study, we removed the stimulus but kept the reward.” In the study, the rhesus monkeys first encountered images projected on a screen followed by a juice reward (classical conditioning). Later, the monkeys received juice rewards while viewing a blank screen. fMRI brain scans taken during this experiment showed that the visual cortex of the monkeys was activated by being rewarded in the absence of any image. Importantly, these activations were not spread throughout the whole visual system but were instead confined to the specific brain regions responsible for processing the exact stimulus used earlier during conditioning. This result shows that information about rewards is being sent to the visual cortex to indicate which stimuli have been associated with rewards. Equally surprising, these reward-only trials were found to strengthen the cue-reward associations. This is more or less the equivalent to giving Pavlov’s dog an extra treat after a conditioning session and noticing the next day that he salivates twice as much as before. More generally, this result suggests that rewards can be associated with stimuli over longer time scales than previously thought. Dopamine Why does the visual cortex react selectively in the absence of a visual stimulus on the retina? One potential explanation is dopamine. “Dopamine is a signalling chemical (neurotransmitter) in nerve cells and plays an important role in processing rewards, motivation, and motor functions. Dopamine’s role in reward signalling is the reason some Parkinson’s patients fall into gambling addiction after taking dopamine-increasing drugs. Aware of dopamine’s role in reward, we re-ran our experiments after giving the monkeys a small dose of a drug that blocks dopamine signalling. We found that the activations in the visual cortex were reduced by the dopamine blocker. What’s likely happening here is that a reward signal is being sent to the visual cortex via dopamine,” says Professor Vanduffel. The study used fMRI (functional Magnetic Resonance Imaging) scans to visualise brain activity. fMRI scans map functional activity in the brain by detecting changes in blood flow. The oxygen content and the amount of blood in a given brain area vary according to the brain activity associated with a given task. In this way, task-specific activity can be tracked.

Reward linked to image is enough to activate brain’s visual cortex

Once rhesus monkeys learn to associate a picture with a reward, the reward by itself becomes enough to alter the activity in the monkeys’ visual cortex. This finding was made by neurophysiologists Wim Vanduffel and John Arsenault (KU Leuven and Harvard Medical School) and American colleagues using functional brain scans and was published recently in the leading journal Neuron.

Our visual perception is not determined solely by retinal activity. Other factors also influence the processing of visual signals in the brain. “Selective attention is one such factor,” says Professor Wim Vanduffel. “The more attention you pay to a stimulus, the better your visual perception is and the more effective your visual cortex is at processing that stimulus. Another factor is the reward value of a stimulus: when a visual signal becomes associated with a reward, it affects our processing of that visual signal. In this study, we wanted to investigate how a reward influences activity in the visual cortex.”

Pavlov inverted

To do this, the researchers used a variant of Pavlov’s well-known conditioning experiment: “Think of Pavlov giving a dog a treat after ringing a bell. The bell is the stimulus and the food is the reward. Eventually the dogs learned to associate the bell with the food and salivated at the sound of the bell alone. Essentially, Pavlov removed the reward but kept the stimulus. In this study, we removed the stimulus but kept the reward.”

In the study, the rhesus monkeys first encountered images projected on a screen followed by a juice reward (classical conditioning). Later, the monkeys received juice rewards while viewing a blank screen. fMRI brain scans taken during this experiment showed that the visual cortex of the monkeys was activated by being rewarded in the absence of any image.

Importantly, these activations were not spread throughout the whole visual system but were instead confined to the specific brain regions responsible for processing the exact stimulus used earlier during conditioning. This result shows that information about rewards is being sent to the visual cortex to indicate which stimuli have been associated with rewards.

Equally surprising, these reward-only trials were found to strengthen the cue-reward associations. This is more or less the equivalent to giving Pavlov’s dog an extra treat after a conditioning session and noticing the next day that he salivates twice as much as before. More generally, this result suggests that rewards can be associated with stimuli over longer time scales than previously thought.

Dopamine

Why does the visual cortex react selectively in the absence of a visual stimulus on the retina? One potential explanation is dopamine. “Dopamine is a signalling chemical (neurotransmitter) in nerve cells and plays an important role in processing rewards, motivation, and motor functions. Dopamine’s role in reward signalling is the reason some Parkinson’s patients fall into gambling addiction after taking dopamine-increasing drugs. Aware of dopamine’s role in reward, we re-ran our experiments after giving the monkeys a small dose of a drug that blocks dopamine signalling. We found that the activations in the visual cortex were reduced by the dopamine blocker. What’s likely happening here is that a reward signal is being sent to the visual cortex via dopamine,” says Professor Vanduffel.

The study used fMRI (functional Magnetic Resonance Imaging) scans to visualise brain activity. fMRI scans map functional activity in the brain by detecting changes in blood flow. The oxygen content and the amount of blood in a given brain area vary according to the brain activity associated with a given task. In this way, task-specific activity can be tracked.

Filed under primates visual cortex visual perception selective attention neuroscience psychology science

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Origins of teamwork found in our nearest relative the chimpanzee Teamwork has been fundamental in humanity’s greatest achievements but scientists have found that working together has its evolutionary roots in our nearest primate relatives – chimpanzees. A series of trials by scientists found that chimpanzees not only coordinate actions with each other but also understand the need to help a partner perform their role to achieve a common goal. Pairs of chimpanzees were given tools to get grapes out of a box. They had to work together with a tool each to get the food out. Scientists found that the chimpanzees would solve the problem together, even swapping tools, to pull the food out. The study, published in Biology Letters, by scientists from Warwick Business School, UK, and the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, sought to find out if there were any evolutionary roots to humans’ ability to cooperate and coordinate actions. Dr Alicia Melis, Assistant Professor of Behavioural Science at Warwick Business School, said: “We want to find out where humans’ ability to cooperate and work together has come from and whether it is unique to us. “Many animal species cooperate to achieve mutually beneficial goals like defending their territories or hunting prey. However, the level of intentional coordination underlying these group actions is often unclear, and success could be due to independent but simultaneous actions towards the same goal. “This study provides the first evidence that one of our closest primate relatives, the chimpanzees, not only intentionally coordinate actions with each other but that they even understand the necessity to help a partner performing her role in order to achieve the common goal. “These are skills shared by both chimpanzees and humans, so such skills may have been present in their common ancestor before humans evolved their own complex forms of collaboration”

Origins of teamwork found in our nearest relative the chimpanzee

Teamwork has been fundamental in humanity’s greatest achievements but scientists have found that working together has its evolutionary roots in our nearest primate relatives – chimpanzees.

A series of trials by scientists found that chimpanzees not only coordinate actions with each other but also understand the need to help a partner perform their role to achieve a common goal.

Pairs of chimpanzees were given tools to get grapes out of a box. They had to work together with a tool each to get the food out. Scientists found that the chimpanzees would solve the problem together, even swapping tools, to pull the food out.

The study, published in Biology Letters, by scientists from Warwick Business School, UK, and the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, sought to find out if there were any evolutionary roots to humans’ ability to cooperate and coordinate actions.

Dr Alicia Melis, Assistant Professor of Behavioural Science at Warwick Business School, said: “We want to find out where humans’ ability to cooperate and work together has come from and whether it is unique to us.

“Many animal species cooperate to achieve mutually beneficial goals like defending their territories or hunting prey. However, the level of intentional coordination underlying these group actions is often unclear, and success could be due to independent but simultaneous actions towards the same goal.

“This study provides the first evidence that one of our closest primate relatives, the chimpanzees, not only intentionally coordinate actions with each other but that they even understand the necessity to help a partner performing her role in order to achieve the common goal.

“These are skills shared by both chimpanzees and humans, so such skills may have been present in their common ancestor before humans evolved their own complex forms of collaboration”

Filed under primates evolution teamwork intentional coordination psychology neuroscience science

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Transplanted brain cells in monkeys light up personalized therapy

For the first time, scientists have transplanted neural cells derived from a monkey’s skin into its brain and watched the cells develop into several types of mature brain cells, according to the authors of a new study in Cell Reports. After six months, the cells looked entirely normal, and were only detectable because they initially were tagged with a fluorescent protein.

Because the cells were derived from adult cells in each monkey’s skin, the experiment is a proof-of-principle for the concept of personalized medicine, where treatments are designed for each individual.

And since the skin cells were not “foreign” tissue, there were no signs of immune rejection — potentially a major problem with cell transplants. “When you look at the brain, you cannot tell that it is a graft,” says senior author Su-Chun Zhang, a professor of neuroscience at the University of Wisconsin-Madison. “Structurally the host brain looks like a normal brain; the graft can only be seen under the fluorescent microscope.”

Marina Emborg, an associate professor of medical physics at UW-Madison and the lead co-author of the study, says, “This is the first time I saw, in a nonhuman primate, that the transplanted cells were so well integrated, with such a minimal reaction. And after six months, to see no scar, that was the best part.”

The cells were implanted in the monkeys “using a state-of-the-art surgical procedure” guided by an MRI image, says Emborg. The three rhesus monkeys used in the study at the Wisconsin National Primate Research Center had a lesion in a brain region that causes the movement disorder Parkinson’s disease, which afflicts up to 1 million Americans. Parkinson’s is caused by the death of a small number of neurons that make dopamine, a signaling chemical used in the brain.

The transplanted cells came from induced pluripotent stem cells (iPS cells), which can, like embryonic stem cells, develop into virtually any cell in the body. iPS cells, however, derive from adult cells rather than embryos.

In the lab, the iPS cells were converted into neural progenitor cells. These intermediate-stage cells can further specialize into the neurons that carry nerve signals, and the glial cells that perform many support and nutritional functions. This final stage of maturation occurred inside the monkey.

Zhang, who was the first in the world to derive neural cells from embryonic stem cells and then iPS cells, says one key to success was precise control over the development process. “We differentiate the stem cells only into neural cells. It would not work to transplant a cell population contaminated by non-neural cells.”

Another positive sign was the absence of any signs of cancer, says Zhang — a worrisome potential outcome of stem cell transplants. “Their appearance is normal, and we also used antibodies that mark cells that are dividing rapidly, as cancer cells are, and we do not see that. And when you look at what the cells have become, they become neurons with long axons [conducting fibers], as we’d expect. They also produce oligodendrocytes that are helping build insulating myelin sheaths for neurons, as they should. That means they have matured correctly, and are not cancerous.”

The experiment was designed as a proof of principle, says Zhang, who leads a group pioneering the use of iPS cells at the Waisman Center on the UW-Madison campus. The researchers did not transplant enough neurons to replace the dopamine-making cells in the brain, and the animal’s behavior did not improve.

Although promising, the transplant technique is a long way from the clinic, Zhang adds. “Unfortunately, this technique cannot be used to help patients until a number of questions are answered: Can this transplant improve the symptoms? Is it safe? Six months is not long enough… And what are the side effects? You may improve some symptoms, but if that leads to something else, then you have not solved the problem.”

Nonetheless, the new study represents a real step forward that may benefit human patients suffering from several diseases, says Emborg. “By taking cells from the animal and returning them in a new form to the same animal, this is a first step toward personalized medicine.”

The need for treatment is incessant, says Emborg, noting that each year, Parkinson’s is diagnosed in 60,000 patients. “I’m gratified that the Parkinson’s Disease Foundation took a risk as the primary funder for this small study. Now we want to move ahead and see if this leads to a real treatment for this awful disease.”

"It’s really the first-ever transplant of iPS cells from a non-human primate back into the same animal, not just in the brain," says Zhang. "I have not seen anybody transplanting reprogrammed iPS cells into the blood, the pancreas or anywhere else, into the same primate. This proof-of-principle study in primates presents hopes for personalized regenerative medicine."

(Source: news.wisc.edu)

Filed under stem cells embryonic stem cells pluripotent stem cells brain cells neural cells immune rejection cell transplants primates neuroscience science

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Nut-cracking monkeys use shapes to strategize their use of tools

Bearded capuchin monkeys deliberately place palm nuts in a stable position on a surface before trying to crack them open, revealing their capacity to use tactile information to improve tool use. The results are published February 27 in the open access journal PLOS ONE by Dorothy Fragaszy and colleagues from the University of Georgia.

The researchers analyzed the monkeys’ tool-use skills by videotaping adult monkeys cracking palm nuts on a surface they used frequently for the purpose. They found that monkeys positioned the nuts flat side down more frequently than expected by random chance. When placing the nuts, the monkeys knocked the nuts on the surface a few times before releasing them, after which the nuts very rarely moved. The researchers suggest that the monkeys may have learned to optimize this tool-use strategy by repeatedly knocking the nut to achieve the stable position prior to cracking it. They conclude that the monkeys’ strategic placement of the nut reveals that the monkeys pay attention to the fit between the nut and the surface each time they place the nut, and adjust their actions accordingly.

In a parallel experiment, the scientists asked blindfolded people to perform the same action, positioning palm nuts on an anvil as if to crack them with a stone or hammer. Like the monkeys, the human participants also followed tactile cues to place the nut flat-side down on the anvil.

Filed under primates tool use animal behavior haptic perception psychology neuroscience science

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Chimps solve puzzles for the thrill of it The apes, which are our closest relatives in the animal kingdom, seem to get the same level of satisfaction out of solving brain teasers as their human evolutionary cousins. A study published by the Zoological Society of London shows that six chimpanzees who were given a game which involved moving red dice or Brazil through a maze of pipes enjoyed solving the puzzle whether they got a reward or not. The researchers claim this suggests they got the same kind of psychological reward as humans get when solving problems. Most problem solving witnessed in the animal kingdom, where animals use tools or navigate mazes, are with the aim of reaching food. Hyenas, octopuses and birds such as crows all show the ability to solve problems. Chimpanzees have also been witnessed in the wild using tools such as a stick to forage for insects or honey in hard to reach places like tree stumps. But ZSL researcher Fay Clark said their research said they could be motivated by more than just food. She said: “We noticed that the chimps were keen to complete the puzzle regardless of whether or not they received a food reward. "This strongly suggests they get similar feelings of satisfaction to humans who often complete brain games for a feel-good reward.”

Chimps solve puzzles for the thrill of it

The apes, which are our closest relatives in the animal kingdom, seem to get the same level of satisfaction out of solving brain teasers as their human evolutionary cousins.

A study published by the Zoological Society of London shows that six chimpanzees who were given a game which involved moving red dice or Brazil through a maze of pipes enjoyed solving the puzzle whether they got a reward or not.

The researchers claim this suggests they got the same kind of psychological reward as humans get when solving problems.

Most problem solving witnessed in the animal kingdom, where animals use tools or navigate mazes, are with the aim of reaching food. Hyenas, octopuses and birds such as crows all show the ability to solve problems.

Chimpanzees have also been witnessed in the wild using tools such as a stick to forage for insects or honey in hard to reach places like tree stumps.

But ZSL researcher Fay Clark said their research said they could be motivated by more than just food.

She said: “We noticed that the chimps were keen to complete the puzzle regardless of whether or not they received a food reward.

"This strongly suggests they get similar feelings of satisfaction to humans who often complete brain games for a feel-good reward.”

Filed under primates problem solving reward animal behavior cognitive challenge psychology neuroscience science

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Has evolution given humans unique brain structures? Humans have at least two functional networks in their cerebral cortex not found in rhesus monkeys. This means that new brain networks were likely added in the course of evolution from primate ancestor to human. These findings, based on an analysis of functional brain scans, were published in a study by neurophysiologist Wim Vanduffel (KU Leuven and Harvard Medical School) in collaboration with a team of Italian and American researchers. Our ancestors evolutionarily split from those of rhesus monkeys about 25 million years ago. Since then, brain areas have been added, have disappeared or have changed in function. This raises the question, ‘Has evolution given humans unique brain structures?’. Scientists have entertained the idea before but conclusive evidence was lacking. By combining different research methods, we now have a first piece of evidence that could prove that humans have unique cortical brain networks. Professor Vanduffel explains: “We did functional brain scans in humans and rhesus monkeys at rest and while watching a movie to compare both the place and the function of cortical brain networks. Even at rest, the brain is very active. Different brain areas that are active simultaneously during rest form so-called ‘resting state’ networks. For the most part, these resting state networks in humans and monkeys are surprisingly similar, but we found two networks unique to humans and one unique network in the monkey.” “When watching a movie, the cortex processes an enormous amount of visual and auditory information. The human-specific resting state networks react to this stimulation in a totally different way than any part of the monkey brain. This means that they also have a different function than any of the resting state networks found in the monkey. In other words, brain structures that are unique in humans are anatomically absent in the monkey and there no other brain structures in the monkey that have an analogous function. Our unique brain areas are primarily located high at the back and at the front of the cortex and are probably related to specific human cognitive abilities, such as human-specific intelligence.” The study used fMRI (functional Magnetic Resonance Imaging) scans to visualise brain activity. fMRI scans map functional activity in the brain by detecting changes in blood flow. The oxygen content and the amount of blood in a given brain area vary according to a particular task, thus allowing activity to be tracked.

Has evolution given humans unique brain structures?

Humans have at least two functional networks in their cerebral cortex not found in rhesus monkeys. This means that new brain networks were likely added in the course of evolution from primate ancestor to human. These findings, based on an analysis of functional brain scans, were published in a study by neurophysiologist Wim Vanduffel (KU Leuven and Harvard Medical School) in collaboration with a team of Italian and American researchers.

Our ancestors evolutionarily split from those of rhesus monkeys about 25 million years ago. Since then, brain areas have been added, have disappeared or have changed in function. This raises the question, ‘Has evolution given humans unique brain structures?’. Scientists have entertained the idea before but conclusive evidence was lacking. By combining different research methods, we now have a first piece of evidence that could prove that humans have unique cortical brain networks.

Professor Vanduffel explains: “We did functional brain scans in humans and rhesus monkeys at rest and while watching a movie to compare both the place and the function of cortical brain networks. Even at rest, the brain is very active. Different brain areas that are active simultaneously during rest form so-called ‘resting state’ networks. For the most part, these resting state networks in humans and monkeys are surprisingly similar, but we found two networks unique to humans and one unique network in the monkey.”

“When watching a movie, the cortex processes an enormous amount of visual and auditory information. The human-specific resting state networks react to this stimulation in a totally different way than any part of the monkey brain. This means that they also have a different function than any of the resting state networks found in the monkey. In other words, brain structures that are unique in humans are anatomically absent in the monkey and there no other brain structures in the monkey that have an analogous function. Our unique brain areas are primarily located high at the back and at the front of the cortex and are probably related to specific human cognitive abilities, such as human-specific intelligence.”

The study used fMRI (functional Magnetic Resonance Imaging) scans to visualise brain activity. fMRI scans map functional activity in the brain by detecting changes in blood flow. The oxygen content and the amount of blood in a given brain area vary according to a particular task, thus allowing activity to be tracked.

Filed under brain brain structure brain networks brain activity cerebral cortex primates evolution neuroscience science

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Chimpanzees have faster working memory than humans Chimpanzees have a faster working memory than humans according to a remarkable study showing that it takes them a fraction of a second to remember something that it would take several seconds for humans to memorise. A Japanese scientist has demonstrated the prowess of chimps in remembering in less than half a second the precise position and correct sequence of up to nine numbers on a computer screen. The numbers are shown together randomly distributed on a computer screen and as soon as the chimps press the number “one” the rest of the numerals are masked. However, they can almost invariably remember where each number was. It is impossible for people to do the same cognitive task that quickly, said Tetsuro Matsuzawa, a primatologist at Kyoto University. “They have a better working memory than us,” he told the American Association for the Advancment of Science meeting in Boston. Professor Matsuzawa had carried out the memory experiments on a female chimp called Ai, which means “love” in Japanese, and Ayumu, her son who was born in 2000 and has shown even better memory skills, he said. Professor Matsuzawa suggested that chimps have developed this part of their memory because they live in the “here and now” whereas humans are thinking more about the past and planning for the future.

Chimpanzees have faster working memory than humans

Chimpanzees have a faster working memory than humans according to a remarkable study showing that it takes them a fraction of a second to remember something that it would take several seconds for humans to memorise.

A Japanese scientist has demonstrated the prowess of chimps in remembering in less than half a second the precise position and correct sequence of up to nine numbers on a computer screen.

The numbers are shown together randomly distributed on a computer screen and as soon as the chimps press the number “one” the rest of the numerals are masked. However, they can almost invariably remember where each number was.

It is impossible for people to do the same cognitive task that quickly, said Tetsuro Matsuzawa, a primatologist at Kyoto University. “They have a better working memory than us,” he told the American Association for the Advancment of Science meeting in Boston.

Professor Matsuzawa had carried out the memory experiments on a female chimp called Ai, which means “love” in Japanese, and Ayumu, her son who was born in 2000 and has shown even better memory skills, he said.

Professor Matsuzawa suggested that chimps have developed this part of their memory because they live in the “here and now” whereas humans are thinking more about the past and planning for the future.

Filed under primates memory working memory cognitive tasks psychology neuroscience science

100 notes

Bonobos predisposed to show sensitivity to others Comforting a friend or relative in distress may be a more hard-wired behavior than previously thought, according to a new study of bonobos, which are great apes known for their empathy and close relation to humans and chimpanzees. This finding provides key evolutionary insight into how critical social skills may develop in humans. The results are published in the online journal PLOS ONE. Researchers from the Yerkes National Primate Research Center, Emory University, observed juvenile bonobos at the Lola ya Bonobo sanctuary in the Democratic Republic of Congo engaging in consolation behavior more than their adult counterparts. Juvenile bonobos (ages 3 to 7) are equivalent to preschool or elementary school-aged children. Zanna Clay, PhD, a postdoctoral fellow in Emory’s Department of Psychology, and Frans de Waal, PhD, director of the Living Links Center at Yerkes and C.H. Candler Professor of Psychology at Emory, led the study. "Our findings suggest that for bonobos, sensitivity to the emotions of others emerges early and does not require advanced thought processes that develop only in adults," Clay says. Starting at around age two, human children usually display consolation behavior, a sign of sensitivity to the emotions of others and the ability to take the perspective of another. Consolation has been observed in humans, bonobos, chimpanzees and other animals, including dogs, elephants and some types of birds, but has not been seen in monkeys. At the Lola ya Bonobo sanctuary, most bonobos come as juvenile or infant orphans because their parents are killed for meat or captured as pets. A minority of bonobos in the sanctuary is second generation and raised by their biological mothers. The researchers found bonobos raised by their own mothers were more likely to comfort others compared to orphaned bonobos. This may indicate early life stress interferes with development of consolation behavior, while a stable parental relationship encourages it, Clay says. Clay observed more than 350 conflicts between bonobos at the sanctuary during several months. Some conflicts involved violence, such as hitting, pushing or grabbing, while others only involved threats or chasing. Consolation occurred when a third bonobo – usually one that was close to the scene of conflict – comforted one of the parties in the conflict. Consolation behavior includes hugs, grooming and sometimes sexual behavior. Consolation appears to lower stress in the recipient, based on a reduction in the recipient’s rates of self-scratching and self-grooming, the authors write. "We found strong effects of friendship and kinship, with bonobos being more likely to comfort those they are emotionally close to," Clay says. "This is consistent with the idea that empathy and emotional sensitivity contribute to consolation behavior." In future research, Clay plans to take a closer look at the emergence of consolation behavior in bonobos at early ages. A process that may facilitate development of consolation behavior is when older bonobos use younger ones as teddy bears; their passive participation may get the younger bonobos used to the idea, she says. (Image: Getty)

Bonobos predisposed to show sensitivity to others

Comforting a friend or relative in distress may be a more hard-wired behavior than previously thought, according to a new study of bonobos, which are great apes known for their empathy and close relation to humans and chimpanzees. This finding provides key evolutionary insight into how critical social skills may develop in humans. The results are published in the online journal PLOS ONE.

Researchers from the Yerkes National Primate Research Center, Emory University, observed juvenile bonobos at the Lola ya Bonobo sanctuary in the Democratic Republic of Congo engaging in consolation behavior more than their adult counterparts. Juvenile bonobos (ages 3 to 7) are equivalent to preschool or elementary school-aged children.

Zanna Clay, PhD, a postdoctoral fellow in Emory’s Department of Psychology, and Frans de Waal, PhD, director of the Living Links Center at Yerkes and C.H. Candler Professor of Psychology at Emory, led the study.

"Our findings suggest that for bonobos, sensitivity to the emotions of others emerges early and does not require advanced thought processes that develop only in adults," Clay says.

Starting at around age two, human children usually display consolation behavior, a sign of sensitivity to the emotions of others and the ability to take the perspective of another. Consolation has been observed in humans, bonobos, chimpanzees and other animals, including dogs, elephants and some types of birds, but has not been seen in monkeys.

At the Lola ya Bonobo sanctuary, most bonobos come as juvenile or infant orphans because their parents are killed for meat or captured as pets. A minority of bonobos in the sanctuary is second generation and raised by their biological mothers. The researchers found bonobos raised by their own mothers were more likely to comfort others compared to orphaned bonobos. This may indicate early life stress interferes with development of consolation behavior, while a stable parental relationship encourages it, Clay says.

Clay observed more than 350 conflicts between bonobos at the sanctuary during several months. Some conflicts involved violence, such as hitting, pushing or grabbing, while others only involved threats or chasing. Consolation occurred when a third bonobo – usually one that was close to the scene of conflict – comforted one of the parties in the conflict.

Consolation behavior includes hugs, grooming and sometimes sexual behavior. Consolation appears to lower stress in the recipient, based on a reduction in the recipient’s rates of self-scratching and self-grooming, the authors write.

"We found strong effects of friendship and kinship, with bonobos being more likely to comfort those they are emotionally close to," Clay says. "This is consistent with the idea that empathy and emotional sensitivity contribute to consolation behavior."

In future research, Clay plans to take a closer look at the emergence of consolation behavior in bonobos at early ages. A process that may facilitate development of consolation behavior is when older bonobos use younger ones as teddy bears; their passive participation may get the younger bonobos used to the idea, she says.

(Image: Getty)

Filed under primates bonobos empathy consolation evolution psychology neuroscience science

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Chimpanzees successfully play the Ultimatum Game Researchers at the Yerkes National Primate Research Center, Emory University, are the first to show chimpanzees possess a sense of fairness that has previously been attributed as uniquely human. Working with colleagues from Georgia State University, the researchers played the Ultimatum Game with the chimpanzees to determine how sensitive the animals are to the reward distribution between two individuals if both need to agree on the outcome. The researchers say the findings, available in an early online edition of the Proceedings of the National Academy of Sciences (PNAS) available this week, suggest a long evolutionary history of the human aversion to inequity as well as a shared preference for fair outcomes by the common ancestor of humans and apes. According to first author Darby Proctor, PhD, “We used the Ultimatum Game because it is the gold standard to determine the human sense of fairness. In the game, one individual needs to propose a reward division to another individual and then have that individual accept the proposition before both can obtain the rewards. Humans typically offer generous portions, such as 50 percent of the reward, to their partners, and that’s exactly what we recorded in our study with chimpanzees.” Co-author Frans de Waal, PhD, adds, “Until our study, the behavioral economics community assumed the Ultimatum Game could not be played with animals or that animals would choose only the most selfish option while playing. We’ve concluded that chimpanzees not only get very close to the human sense of fairness, but the animals may actually have exactly the same preferences as our own species.” For purposes of direct comparison, the study was also conducted separately with human children. In the study, researchers tested six adult chimpanzees (Pan troglodytes) and 20 human children (ages 2 – 7 years) on a modified Ultimatum Game. One individual chose between two differently colored tokens that, with his or her partner’s cooperation, could be exchanged for rewards (small food rewards for chimpanzees and stickers for children). One token offered equal rewards to both players, whereas the other token favored the individual making the choice at the expense of his or her partner. The chooser then needed to hand the token to the partner, who needed to exchange it with the experimenter for food. This way, both individuals needed to be in agreement. Both the chimpanzees and the children responded like adult humans typically do. If the partner’s cooperation was required, the chimpanzees and children split the rewards equally. However, with a passive partner, who had no chance to reject the offer, chimpanzees and children chose the selfish option. Chimpanzees, who are highly cooperative in the wild, likely need to be sensitive to reward distributions in order to reap the benefits of cooperation. Thus, this study opens the door for further explorations into the mechanisms behind this human-like behavior.

Chimpanzees successfully play the Ultimatum Game

Researchers at the Yerkes National Primate Research Center, Emory University, are the first to show chimpanzees possess a sense of fairness that has previously been attributed as uniquely human. Working with colleagues from Georgia State University, the researchers played the Ultimatum Game with the chimpanzees to determine how sensitive the animals are to the reward distribution between two individuals if both need to agree on the outcome.

The researchers say the findings, available in an early online edition of the Proceedings of the National Academy of Sciences (PNAS) available this week, suggest a long evolutionary history of the human aversion to inequity as well as a shared preference for fair outcomes by the common ancestor of humans and apes.

According to first author Darby Proctor, PhD, “We used the Ultimatum Game because it is the gold standard to determine the human sense of fairness. In the game, one individual needs to propose a reward division to another individual and then have that individual accept the proposition before both can obtain the rewards. Humans typically offer generous portions, such as 50 percent of the reward, to their partners, and that’s exactly what we recorded in our study with chimpanzees.”

Co-author Frans de Waal, PhD, adds, “Until our study, the behavioral economics community assumed the Ultimatum Game could not be played with animals or that animals would choose only the most selfish option while playing. We’ve concluded that chimpanzees not only get very close to the human sense of fairness, but the animals may actually have exactly the same preferences as our own species.” For purposes of direct comparison, the study was also conducted separately with human children.

In the study, researchers tested six adult chimpanzees (Pan troglodytes) and 20 human children (ages 2 – 7 years) on a modified Ultimatum Game. One individual chose between two differently colored tokens that, with his or her partner’s cooperation, could be exchanged for rewards (small food rewards for chimpanzees and stickers for children). One token offered equal rewards to both players, whereas the other token favored the individual making the choice at the expense of his or her partner. The chooser then needed to hand the token to the partner, who needed to exchange it with the experimenter for food. This way, both individuals needed to be in agreement.

Both the chimpanzees and the children responded like adult humans typically do. If the partner’s cooperation was required, the chimpanzees and children split the rewards equally. However, with a passive partner, who had no chance to reject the offer, chimpanzees and children chose the selfish option.

Chimpanzees, who are highly cooperative in the wild, likely need to be sensitive to reward distributions in order to reap the benefits of cooperation. Thus, this study opens the door for further explorations into the mechanisms behind this human-like behavior.

Filed under evolution primates sense of fairness ultimatum game animal behavior neuroscience science

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