Tag Archives: chimpanzee

Strikingly similar ape and human infant gestures hint to evolution of language

Psychologists closely studying chimpanzee, bonobo and human infants found striking similarities among the three species in terms of different types of gestures. Their findings seem to back-up the theory that claims language, as we know it, evolved from gesture-based communication first.

lexigramPanpanzee, a female chimpanzee (Pan troglodytes), and Panbanisha, a female bonobo (Pan paniscus) were raised together at the Language Research Center in Atlanta. Here, the caregivers taught them to communicate through visual symbols (geometric shapes called lexigrams), gestures and vocalization (non-speech sounds). In parallel, a human girl was followed who grew up in her parents’ home, along with her older brother. Video analysis for her began at 11 months of age and continued until she was 18 months old; video analysis for the two apes began at 12 months of age and continued until they were 26 months old.

For a few months, researchers  analyzed countless hours of footage and looked for telltale communicative signs and gestures exhibited by the infants, marking the first time such data have been used to compare the development of gestures across species.

“The similarity in the form and function of the gestures in a human infant, a baby chimpanzee and a baby bonobo was remarkable,” said Patricia Greenfield, a distinguished professor of psychology at UCLA and co-author of the study.

Gestures made by all three species included reaching, pointing with fingers or the head, and raising the arms to ask to be picked up – all communicative gestures, which make the findings even more revealing. It’s important to note here that chimpanzees and bonobos are our closet relatives in the evolutionary tree.




During the first half of the study, communicating with gestures was dominant in all three species. During the second half, all three species increased their symbol production — words for the child and lexigrams for the apes. However, the child progressed much more rapidly in the development of symbols. Words began to dominate her communication in the second half of the study, while the two apes continued to rely predominantly on gesture.

“Gesture appeared to help all three species develop symbolic skills when they were raised in environments rich in language and communication,” said Gillespie-Lynch, who conducted the research while she was at UCLA.


Seeing how the child transitioned at one point from a gesture-rich orientated mode of communication to a symbol-rich mode, this could be interpreted a developmental model of the evolutionary pathway to human language and thus evidence for the “gestural origins of human language,” Greenfield said.


What’s revealing about the findings ins’t necessary that they add weight to the claim that gestures signified the very first step in the evolution of human language, but rather the importance lies in the fact that a key link may have been uncovered: co-evolution of gestural and vocal communication. Most of the child’s gestures were accompanied by vocalization (non-language sounds); the apes’ gestures rarely were.

“This finding suggests that the ability to combine gesture and vocalization may have been important for the evolution of language,” Greenfield said.

The findings were reported in the journal  Frontiers in Psychology.

Don't panic! Some people's feet have a chimp-like feature, not chimp-like feet entirely.

One in thirteen people have chimp-like feet

Did you know you may have chimp-like feet? Apparently, following an anthropological study, one in every thirteen people has some of the features seen in chimp feet, adapted for climbing trees. If you ever found yourself at ease climbing trees, you might just be one of these people closer resembling our primate relatives, feet-wise at least.

Don't panic! Some people's feet have a chimp-like feature, not chimp-like feet entirely.

Don’t panic! Some people’s feet have a chimp-like feature, not chimp-like feet entirely.

Traditionally, the human foot has been viewed as a rigid part, allowing for more efficient walking. Jeremy DeSilva and Simone Gill at Boston University, however, found that this isn’t entirely true. They asked 400 adults to walk barefoot around the Boston Museum of Science, and filmed them with high-resolution cameras at the foot level. They found 8 percent of people have some mid-foot flexibility, akin to tree-climbing apes.

Want to check if you have a flexible foot? Well if you can bend the ball of your foot, as well as the region halfway between your heel and the ball of your foot then your foot is ape-like – mine isn’t. All human feet have a joint at this point, however, for most of us, a stiff ligament keeps it rigid. Some have this ligament more relaxed and have a superior mid-foot bend.

The feature is hardly noticeable, though, since most people involved in the study were not aware of anything unusual, nor was their gait any different.

Flexible feet may be evolutionary remnants from our tree-dwelling times, and it’s likely that our feet had many more features adapted to climbing trees but were lost over time in favor of more efficient walking on two legs. Chimps’ legs, for instance, have  opposable toes for gripping. With this in mind, it’s peculiar that flexible feet still exist in such a large proportion today, considering humans have been walking for so long.

The researchers have a theory: flexible feet have resurfaced.  “My guess is that we are getting more variation than ever before, perhaps because shoes have impacted foot anatomy,” DeSilva says.

The findings were reported in the journal  Physical Anthropology.


Chimps also ‘think about thinking’ akin to humans


Our close primate relatives, chimpanzees, have been constantly amazing us with their incredible cognitive abilities and personality traits that are so similar to our own. If you believe much of what you undertake today is limited to human cognition only, think again. Chimps do it too – thinking about thinking that is, as the findings of a recent research by scientists at Georgia State University and the University at Buffalo show.

Chimps are our closest relatives, sharing 98% of the human genome, which might explain a bit why their social, cognitive and even emotional display is remarkably similar to that found in humans. Chimps have been shown to be self-aware (possess consciousness), have a sense of fairness, solve puzzles just for fun and even hold elections!

That’s remarkably human-like, however this recent demonstration of chimp metacognition – “thinking about thinking” or “knowing about knowing” – puts things into a whole new perspective.  Though a term that’s both thrown loosely in educational psychology discussions and discouraging at the same time, since not a lot of people know what it means, metacognition in itself represents nothing new, but highlights an important hallmark of intelligence. It’s believed metacognition plays a fundamental role in learning, since it’s only when you begin to rationalize your train of thought that you can begin to control what goes on in your environment and project your thoughts into actions. Activities such as planning how to approach a given learning task, monitoring comprehension, and evaluating progress toward the completion of a task are metacognitive in nature.

Existential chimps

In order to assess a chimps ability to recognize one’s own cognitive states, the researchers devised an experiment to query animals about their states of knowing or not knowing. Chimps at Georgia State’s LRC, like some in other labs, have been trained  to use a language-like system of symbols to name things, which came really handy later on in communicating their thoughts and ideas.

The chimps were tasked with naming which food was hidden in a particular location, by typing the symbol for the respective type of food. For instance, if a banana was hidden, the chimp would report this fact by pressing the banana symbol on symbols keyboard, and in the process would also gain the food.

But then, the researchers provided chimpanzees either with complete or incomplete information about the identity of the food rewards.

In some cases, the chimpanzees had already seen what item was available in the hidden location and could immediately name it by touching the correct symbol without going to look at the item in the hidden location to see what it was.

In other cases, the chimpanzees could not know what food item was in the hidden location, because either they had not seen any food yet on that trial, or because even if they had seen a food item, it may not have been the one moved to the hidden location.

So, basically the chimps named the food items when they that these were there, and sought them to be sure when they needed more information before naming them.

“This pattern of behavior reflects a controlled information-seeking capacity that serves to support intelligent responding, and it strongly suggests that our closest living relative has metacognitive abilities closely related to those of humans,” the researchers note.

The findings are important not just because it proves yet another important cognitive trait, thought to be solely reserved to humans, is present in non-human primates as well, but because it also may help shed light on the emergence of self-reflective mind during humans’ cognitive evolution. The paper was published in the the journal Psychological Science of the Association for Psychological Science.

Image Credit: Zoological Society of London

Chimps enjoy solving puzzles just for the thrill of it

Image Credit: Zoological Society of London

Image Credit: Zoological Society of London

Earlier today I wrote about some recent findings that suggest humans have evolved unique brain structures from other primates. Don’t be fooled however in thinking many of the activities we undertake every day are solely found in human culture. Dolphins communicate with each other much like humans do and besides tool use, chimps know that cooperation is key. The latest example of behavior that’s thought to be exclusive to humans, but encountered in other animals as well is puzzle solving.

We know that there a lot of animals that like to play, especially the young, however puzzle solving just for the thrill of it is typically thought to be an exclusive human trait. A recent experiment conduct by biologists Zoological Society of London (ZSL) showed, however, that chimps enjoy solving puzzles just for the gratification of having completed a challenge, without any other rewards.

The researchers tasked two female chimps and four males to place sticks into holes in simple hardware store plumbing pipes to change the direction of either red dice or Brazil nuts until they fell out into a container. With the dice, the goal was to move them into an exit chamber, but with the nuts, that chamber had been removed so they would fall out of the maze and become a tasty snack to reward the chimps for their work. The researchers even increased the challenge for the chimps by adding additional pipes and making the pipes opaque so the chimpanzees could not see what was inside.

“We noticed that the chimps were keen to complete the puzzle regardless of whether or not they received a food reward,” Fay Clark, a researcher with the Zoological Society, said Saturday in a statement. “This strongly suggests they get similar feelings of satisfaction to humans who often complete brain games for a feel-good reward.”

In the wild, chimps can be often see using tools like wooden sticks peering through various orifices in search of insects and other food. It seems, however, that they also enjoy the challenge of fulfilling a cognitive task just like a human.

“The chimps took part in the cognitive challenge as part of their normal daily routine and doing the brain teaser was completely voluntary,” they said. “This study suggests that like humans, chimpanzees are motivated to solve a puzzle when there is no food reward. They do so for the sake of the challenge itself. It also suggests that chimpanzee cognition can be measured on social groups under more naturalistic conditions.”

The findings were reported in the  American Journal of Primatology. 


NIH to retire most of its research chimps, report says

chimps-lab-researchClear and solid steps have been taken in the past few years to cancel research, experiments and drug testing on chimps, a practice which is still legal in only two countries in the world: the US and Ghana. Recently, the US National Institutes of Health (NIH) was advised to retire its decade-old, 360 chimpanzee-strong colony to a national sanctuary. Some 50 chimpanzees will continue to remain in research facilities, but only if the research performed on them is considered to render important benefits to mankind.

The long awaited announcement delivered from a working group of external agency advisors comes a year after an important report by the US Institute of Medicine condemned the use of chimps for medical research and recommended their dismantlement after much debate, in light of ever growing evidence that chimps are very similar to humans and fearsome ethical discussions.

“Clearly there is going to be a reduction in the use of chimpanzees in research,” says working group co-chair Kent Lloyd, the associate dean for research at the School of Veterinary Medicine at the University of California, Davis.

The NIH committee traces clear restrictions for chimp research, calling for the cancellation of about half of 21 existing biomedical and behavioural experiments and the establishment of sanctuary housing for the retiring animals “immediately”. The committee goes on to add that some 50 chimpanzees are enough for future research, and this only after an independent committee would vet individual study proposals after they first pass routine NIH scientific review. In short future research that includes chimpanzees would have to prove that no other animal or biological model is available and the potential benefits to mankind are of great importance.

With this in mind, three of nine ongoing invasive experiments, involving immunology and infectious diseases, could continue, because they meet the IOM criteria and eight of 13 behavioural or comparative genomics studies could be allowed to continue, but in some cases only conditionally.

Last month, the agency announced that it will retire 110 chimpanzees to the national Chimp Haven sanctuary in Keithville, Louisiana; these 360 chimpanzees come in addition.

Of course, the announcement was met with great enthusiasm by animal rights activists, while some scientists point out that currently chimpanzees are the only animals where important medical research testing can be performed; research that might offer solutions, treatment and cures to afflictions, infections and diseases that currently plague mankind causing millions of deaths every year.

via Nature

Chimpanzees have a sense of fairness

Chimpanzees have the same sense of fair-play as humans do, explain researchers who played the Ultimatum game with them – it’s the first time such a trait was observed in a non-human species.

Playing a fair game

Chimpanzees munch on leek at Tokyo's Tam

The Ultimatum game is a simple game often used in economy game theory in which the two players involved interact to decide how to split a sum of money that is given to them; the rules are simple: the first person decides on how to split a sum of money, and the second player can agree or decline. If the second player agrees, then they split it that way, but if he disagrees, none of them get anything.

The results suggest that much like humans, who as a species have an aversion towards unfairness (though as individuals, that can be quite different), chimps like fair play.

“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,” says Darby Proctor of the Yerkes National Primate Research Center at Emory University.

When humans play the game, they are quite generous, most of the time going for a 50-50 split, even though typically, the second player accepts any amount over 25 percent. The same thing was observed in chimps.

“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.”

Modifying the game

The team analyzed six adult chimpanzees and 20 human children aged 3-7 years old, creating a modified version of the Ultimatum game; one individual chose between two differently colored tokens that, with the partner’s cooperation, could be exchanged for rewards. A token offered equal rewards to both players while another favored the individual at the expense of the partner.

Both the chimpanzees and the children reacted in accord to their basic nature: if cooperation is involved, they would split the entire reward equally with their partner.  However, when the partner was passive and had no chance to reject the offer, both groups chose the selfish option – giving another indication of their basic nature.

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,” says Yerkes’s Frans de Waal. “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.”

(A) An adult male chimpanzee seen holding tools (anvil in left hand, hammer in left foot) and Coula edulis nuts (mouth and right hand) part of a nut-cracking session. (B) Adult male chimpanzee seen carrying three papayas (one in each hand and one in mouth) during crop-raiding. (c) W C M McGrew

Human ancestors started walking on two legs to carry more scarce resources, study suggests

One of the biggest anthropological mysteries scientists have been trying to unravel is the long put question of  how did humans develop bipedal movement. There have been many theories formulated hypothesizing why our ancestors eventually switched from four limbs walking to two – some appealing, some a bit too far the edge. A recent study performed by a joint team of biological anthropologists at University of Cambridge and Kyoto University claims, with experimental data to back-up as evidence, that our human forefathers might have switched to two legs because it made carrying valuable, scarce resources easier in one go.

The researchers sought to understand how our hominid ancestors developed bipedal movement by studying the chimpanzee’s walking behavior, our closest relative. The researchers found that chimpanzees tend to switch their movement on two limbs instead of the usual four in situations when they want to monopolize a resource and want to carry as much of it as possible in one go.

“Bipedality as the key human adaptation may be an evolutionary product of this strategy persisting over time. Ultimately, it set our ancestors on a separate evolutionary path,” said Professor William McGrew, from the Department of Archaeology and Anthropology, University of Cambridge.

To test their theory which simply states that bipedal movement resulted from the need to transport resources with maximum efficiency, the researchers performed two surveys. One was in a natural clearing in Bossou Forest, Guinea, where anthropologists exposed chimpanzees to three situations in which certain nuts were available in limited or abundant supply. The oil palm nut, is naturally widely available and the chimpanzees are fully aware of this, while the other resource used in the study, the coula nut, is considered to be a scarce or “unpredictable” resource, so the latter made for a perfect control factor.

A possible explanation as to how our early ancestors came to walk on two legs

Behavior was monitored in three separate instances:

  • when only oil palm nuts were available
  • when a small number of coula nuts was available
  • when coula nuts were the majority available resource

In the first situation, no significant alternation in their movement behavior occurred. In the second instance, however, the chimpanzes procedeed in transporting more coula nuts in one go. They proceeded much in the same why in the third instance as well, only this time they ignored the oil palm nuts altogether, since they saw the coula nuts as a much more valuable resource, deeming the current situation as a one time opportunity, unpredictable, from which they had to profit at maximum efficiency.

(A) An adult male chimpanzee seen holding tools (anvil in left hand, hammer in left foot) and Coula edulis nuts (mouth and right hand) part of a nut-cracking session. (B) Adult male chimpanzee seen carrying three papayas (one in each hand and one in mouth) during crop-raiding. (c) W C M McGrew

(A) An adult male chimpanzee seen holding tools (anvil in left hand, hammer in left foot) and Coula edulis nuts (mouth and right hand) part of a nut-cracking session. (B) Adult male chimpanzee seen carrying three papayas (one in each hand and one in mouth) during crop-raiding. (c) W C M McGrew

During the last two instances, the frequency with which the chimps switched from four to two limbs increased by a factor of four. Bipedal movement allowed the chimpanzees to carry much more resources (~around twice as much), but even so that didn’t seem enough as some were seen carrying nuts even in their mouths. It’s important to note that most transport overall was quadrupedal.

The second leg of the study was concentrated around a 14-month long survey of Bossou chimpanzees and crop-raiding, where again high-value resources are obtained with unpredictable frequency. The researchers observed that 35% of their activity involved some sort of bipedal movement, and once again, this behavior appeared to be linked to a clear attempt to carry as much as possible in one go. When correlated with the first survey, these findings lead reseachers to claim that when faced with situations where scarced resources are available at an unpredictable frequency, most often chimpanzees will switch to bipedal movement so they might carry as much as possible.

Our former hominid ancestors were subjected to more or less similar situations, faced with both unpredictable resource frequency and changing climates. With this in mind, the researchers suggest that selection pressure towards the economically favorable bipedal movement might have lead our ancestors on a separate evolutionary path where bipedal movement became the dominant form of locomotion.

The findings were reported in the journal Current Biology.

The US is debating the use of chimps in medical research

The United States and Gabon are the only countries left in the world that are still using chimps for medical research. While research made on our closest relatives is considered invaluable by scientists studying deadly diseases such as HIV, animal rights activists are pressuring the authorities to ban the use of chimps in research labs, considered cruel by all means. This was the subject of debate opened at a Institute of Medicine (IOM) conference this weekend.

It’s well known that once chimps reach the confinements of a lab cell, they become socially withdrawn, agitated – most became traumatized. In the U.S. there are currently 1.000 medical research chimps. The European Union banned lab chimps last year, and pharmaceutical companies nowadays have almost exclusively turned to cheaper alternatives (chimps are the hardest lab animals to care for, and thus deemed expensive).

“If you’re a scientist, a chimp is really a sort of last resort,” said Harold Watson, who directs the chimpanzee research program at the National Institutes of Health, which manages 734 of the nearly 1,000 medical research chimps in the United States.

Now, the IOM debated the fate of nearly all the medical research chimps left in the world.

Through the constant experimentation on chimps along the years, significant progress has been made in the medical field, like vaccines against hepatitis A and B, in which chimp research was considered crucial. Scientists studying hepatitis C say that chimps are vital to their work as the only lab animal susceptible to the virus.

Just because chimpanzees have the closest matching DNA to humans, it doesn’t mean that they’re susceptible to the same diseases as humans, though. Although extensive HIV studies were made on chimps in the 1980s and 1990s, scientists have found that rhesus monkeys are more likely to mimic human-like HIV infections, for example. So, having a similar DNA, doesn’t necessarily mean that two species will be affected similarly by a disease.

Biomedical research chimp numbers have dramatically declined in recent years, as scientists turn to other alternatives like mice or other means that new technology has been able to offer. Actually, scientists have now been able to engineer mice with more human-like immunity for hepatitis studies, which might release chimps of their principal cause of use.

“We are more than halfway” to mice that could replace chimps in hepatitis studies, Alexander Ploss of Rockefeller University said. “Whether we have that mouse in two years, five years, 10 years . . . who knows?”

Ethics and medical science, acting in the most honest good interest of humankind, have clashed for a long time whenever chimp reserach was concerned. Both sides have a solid say, and the matter is far from an easy solving in the near future.

“We wouldn’t be having this meeting if ethics wasn’t an issue,” Frans de Waal told the IOM committee. The Emory University researcher, whose pioneering studies with captive chimpanzees have revealed their human-like empathy, continued, “We don’t have this kind of meeting about rats.”

Chimp self-awareness

New research shows chimps are self-aware

Until recently it was considered that only humans have the ability of being aware of the fact that they exist as an individual, but studies show that chimps as well as dolphins share this ability.

A recent research revolving around chimps strengthens the idea and shows that our close relatives are indeed self-aware and can anticipate the consequences of their actions upon their environment. The research was published in Proceedings of the Royal Society B and could prove to have a tremendous impact on what’s philosophically considered human and non-human, as well as provide an important first stepping stone for further study of the evolution of consciousness.

Past studies employed various tests to see how self-aware chimps. The most evident and effective of them involved painting a chimp’s face and then facing him against a mirror – if the chimp would have touched his face and try to scrub the paint off than it proves the chimp recognizes himself. A simple self-recognition isn’t evidence enough of self-awareness, though, so researchers sought to test even further.

Takaaki Kaneko and Masaki Tomonaga of the Primate Research Institute in Kyoto designed a series of three experiments to see if chimps, our closest cousins genetically, can reason like humans in certain tasks connected to individuality.

The first test involved three females. The chimps initiated a video game by placing a finger on a touch-sensitive screen and then used a trackball, similar to a computer mouse, to move one of two cursors. The second cursor was implemented to distract the chimps, and was a recording of gestures made earlier by the same animal and set in motion by the computer. As soon as a chimp hit a target or the time lapsed, the test would end. Here’s where the test becomes really interesting to the point of remarkable – each chimp had to point with his finger which of the two cursors he had been manipulating, and received a reward if she chose correctly. All three animals scored above 90 percent. Wow, right ?

“This indicates that the chimpanzees were able to distinguish the cursor actions controlled by themselves from those caused by other factors, even when the physical properties of those actions were almost identical,” the researchers said.

It was still not enough. Researchers couldn’t tell if the chimps showed evidence of self-awareness are they simply have the ability of observing visual cues and clues, so another set of tests were devised.

In the second test both cursors moved independently of efforts to control them, with the trackball being unplugged – one a repeat of movements the chimp had generated in an earlier exercise, and the other a repeat of an “decoy” cursor. If the animals performed well on the first test but poorly on the second, the scientists reasoned, it would suggest that they were not simply responding to visual properties but knew they were in charge.

On the third and final experiment, used only for the chimps who had very high scores, introduced a time delay between trackball and cursor, as if the two were out of sync, and a distortion in the direction the cursor moved on the screen.

Analyzing the results, researchers conclude that “chimpanzees and humans share fundamental cognitive processes underlying the sense of being an independent agent.”

“We provide the first behavioral evidence that chimpanzees can perform distinctions between self and other for external events on the basis of a self-monitoring process.”

How the human penis lost its spines

It’s been long theoretized by most women, and not only, that there is a connection between the penis and the brain – and research done by Gill Bejerano, a biologist at Stanford University School of Medicine, and colleagues seems to support that theory, at least in a way.

Let’s look at our close relatives, the chimpanzees. Humans and chimps share over 97% of DNA, but it’s safe to say that between them and (most) humans there are some major differences in terms of appearance, and especially intellect. For example, we know that humans have larger brains, and within the brain, specifically a bigger angular gyrus, a region associated with abstract concepts, among others.

We also know that chimps have smaller penises which also have spines; don’t think about hedgehogs or anything, but just enough to make it… a little bumpy.

The team of researchers in case wanted to have a deeper understanding (no pun intended) of why these differences appear, so they analyzed genomes of humans and closely related primates and discovered more than 500 regulatory regions (the points which tell genes what to do) that chimps and other primates have, and humans don’t. In other words, they found out what parts of the genome humans lost through millions of years of evolution.

Think about it in terms of lightbulbs and switches: the light bulbs are the genes, while the switches are these DNA controlling sequences. If you have no bulb, you can’t turn it on and off; now think about a bulb that has five different switches that control it and can turn it on in different places and at different times. If you take one of them away, the bulb still works in four situations, but not in the fifth.

The study basically looked at two of these switches, and in order to analyze them, they took the switch information from chimps and hooked it up to what is called a receptor gene, a gene whose effects can be easily tracked. They injected this information into a mouse egg, to track the progress. They found that one switch makes sensory whiskers develop on the face and spines on the penis.

“This switch controls the expression of a key gene that’s required for the formation of these structures,” said David Kingsley, a study co-author at Stanford University. “If you kill that gene — smash the lightbulb — which has been done previously in mouse genetics, the whiskers don’t grow as much and the penile spines fail to form at all.”

You can read the full article over at Nature.

“It is detective work and a great reminder that, in the course of evolution, information is both gained and lost,” said Sean Carroll, an expert in animal genetics and evolution at the University of Wisconsin, Madison.

“As so often with very good ideas, it seems almost obvious in hindsight,” said Svante Pääbo, who directs the genetics department of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and was part of the team that recently sequenced the Neanderthal genome. “Since two of the almost 500 deleted sequences they identified turn out to be interesting, I am sure that several other ones on their list will turn out to be interesting too,” he added. The researchers are continuing to analyse the remaining 508 DNA sequences.