Posts tagged tool use
Articles and news from the latest research reports.
What happens in our brain when we unlock a door?
People who are unable to button up their jacket or who find it difficult to insert a key in lock suffer from a condition known as apraxia. This means that their motor skills have been impaired – as a result of a stroke, for instance. Scientists in Munich have now examined the parts of the brain that are responsible for planning and executing complex actions. They discovered that there is a specific network in the brain for using tools. Their findings have been published in the Journal of Neuroscience.
Researchers from Technische Universität München (TUM) and the Klinikum rechts der Isar hospital have analyzed the brain networks that control the use of tools or other utensils. Their chosen method of functional magnetic resonance imaging (fMRI) shows the areas of the brain that are activated when a person thinks, moves and performs actions.
The use of tools is an essential human skill. “Numerous studies are investigating the neural processes at play when we pick up a tool,” says Prof. Joachim Hermsdörfer from TUM’s Chair of Human Movement Science. “But many of these studies are restricted to test subjects observing an action, miming it, or simply visualizing it.” The aim of this latest study was to analyze the basic neural principles of tool use under the most realistic conditions possible.
In the MRI study, the subjects received ten everyday objects, including a hammer, a bottle-opener, a key, a lighter and a scissors as well as some unfamiliar objects. Their task was to either use the objects or simply lift them up and place them down again, first with the left and then with the right hand. When they analyzed the data, the scientists looked at the planning phase and the actual execution phase separately. In this way, they were able to identify the brain networks that were activated while the subjects planned and used a tool and those that controlled execution.
Tool-specific network in the brain
One important finding was that the left hemisphere was activated when the subjects planned to use a tool – regardless of the hand they held it in. In addition, the researchers recognized a distributed network responsible for both planning and execution. When working with unfamiliar objects, these regions of the brain were less activated.
The “tool network” consists of brain regions of the parietal and frontal lobes as well as regions in the posterior temporal lobe and another area in the lateral occipital lobe. What the researchers found, therefore, was a neural activation pattern that covered all elements of a complex action. This includes recognizing the objects as tools, understanding how they are used, and the motor action to actually use the tool.
“The study also allowed us to confirm that there are different streams of perception in the brain for different tasks,” explains Hermsdörfer. The dorsal stream of perception conducts signals to the posterior parietal lobe and is generally responsible for controlling actions. “It can be divided into two function-specific processing pathways. The dorso-dorsal stream controls basic gripping and movement processes, regardless of whether the person is familiar with the object or not. A second ventro-dorsal stream becomes active when we use tools that are familiar to us.
Armed with knowledge about the localization of these “action modules”, doctors could in future provide a more differentiated diagnosis of apraxia and develop improved therapeutic approaches.
Cockatoos pick up tool use and manufacture through social learning
Two years ago, we brought you the story of Figaro, a Goffin’s cockatoo that lived at a research center in Vienna. These birds don’t use tools in the wild—Figaro’s minders even argue that the cockatoo’s curved beak makes tool use rather difficult for them.
But Figaro’s environment, which features lots of wired mesh, apparently drove him to some novel behaviors. He was observed splitting off splinters from wooden material, and the bird used them to retrieve objects (generally food or toys) that were on the wrong side of the wire. Figaro was making tools.
Insect diet helped early humans build bigger brains
Figuring out how to survive on a lean-season diet of hard-to-reach ants, slugs and other bugs may have spurred the development of bigger brains and higher-level cognitive functions in the ancestors of humans and other primates, suggests research from Washington University in St. Louis.
“Challenges associated with finding food have long been recognized as important in shaping evolution of the brain and cognition in primates, including humans,” said Amanda D. Melin, PhD, assistant professor of anthropology in Arts & Sciences and lead author of the study.
“Our work suggests that digging for insects when food was scarce may have contributed to hominid cognitive evolution and set the stage for advanced tool use.”
Based on a five-year study of capuchin monkeys in Costa Rica, the research provides support for an evolutionary theory that links the development of sensorimotor (SMI) skills, such as increased manual dexterity, tool use, and innovative problem solving, to the creative challenges of foraging for insects and other foods that are buried, embedded or otherwise hard to procure.
Published in the June 2014 Journal of Human Evolution, the study is the first to provide detailed evidence from the field on how seasonal changes in food supplies influence the foraging patterns of wild capuchin monkeys.
The study is co-authored by biologist Hilary C. Young and anthropologists Krisztina N. Mosdossy and Linda M. Fedigan, all from the University of Calgary, Canada.
It notes that many human populations also eat embedded insects on a seasonal basis and suggests that this practice played a key role in human evolution.
“We find that capuchin monkeys eat embedded insects year-round but intensify their feeding seasonally, during the time that their preferred food – ripe fruit – is less abundant,” Melin said. “These results suggest embedded insects are an important fallback food.”
Previous research has shown that fallback foods help shape the evolution of primate body forms, including the development of strong jaws, thick teeth and specialized digestive systems in primates whose fallback diets rely mainly on vegetation.
This study suggests that fallback foods can also play an important role in shaping brain evolution among primates that fall back on insect-based diets, and that this influence is most pronounced among primates that evolve in habitats with wide seasonal variations, such as the wet-dry cycles found in some South American forests.
“Capuchin monkeys are excellent models for examining evolution of brain size and intelligence for their small body size, they have impressively large brains,” Melin said. “Accessing hidden and well-protected insects living in tree branches and under bark is a cognitively demanding task, but provides a high-quality reward: fat and protein, which is needed to fuel big brains.”
But when it comes to using tools, not all capuchin monkey strains and lineages are created equal, and Melin’s theories may explain why.
Perhaps the most notable difference between the robust (tufted, genus Sapajus) and gracile (untufted, genus Cebus) capuchin lineages is their variation in tool use. While Cebus monkeys are known for clever food-foraging tricks, such as banging snails or fruits against branches, they can’t hold a stick to their Sapajus cousins when it comes to the
innovative use and modification of sophisticated tools.
One explanation, Melin said, is that Cebus capuchins have historically and consistently occupied tropical rainforests, whereas the Sapajus lineage spread from their origins in the Atlantic rainforest into drier, more temperate and seasonal habitat types.
“Primates who extract foods in the most seasonal environments are expected to experience the strongest selection in the ‘sensorimotor intelligence’ domain, which includes cognition related to object handling,” Melin said. “This may explain the occurrence of tool use in some capuchin lineages, but not in others.”
Genetic analysis of mitochondial chromosomes suggests that the Sapajus-Cebus diversification occurred millions of years ago in the late Miocene epoch.
“We predict that the last common ancestor of Cebus and Sapajus had a level of SMI more closely resembling extant Cebus monkeys, and that further expansion of SMI evolved in the robust lineage to facilitate increased access to varied embedded fallback foods,
necessitated by more intense periods of fruit shortage,” she said.
One of the more compelling modern examples of this behavior, said Melin, is the seasonal consumption of termites by chimpanzees, whose use of tools to extract this protein-rich food source is an important survival technique in harsh environments.
What does this all mean for hominids?
While it’s hard to decipher the extent of seasonal dietary variations from the fossil record, stable isotope analyses indicate seasonal variation in diet for at least one South African hominin, Paranthropus robustus. Other isotopic research suggests that early human diets may have included a range of extractable foods, such as termites, plant roots and tubers.
Modern humans frequently consume insects, which are seasonally important when other animal foods are limited.
This study suggests that the ingenuity required to survive on a diet of elusive insects has been a key factor in the development of uniquely human skills:
It may well have been bugs that helped build our brains.
Study finds crocodiles are cleverer than previously thought
Turns out the crocodile can be a shrewd hunter himself. A University of Tennessee, Knoxville, researcher has found that some crocodiles use lures to hunt their prey.
Vladimir Dinets, a research assistant professor in the Department of Psychology, is the first to observe two crocodilian species—muggers and American alligators—using twigs and sticks to lure birds, particularly during nest-building time.
The research is published in the current edition of Ethology, Ecology and Evolution. Dinets’ research is the first report of tool use by any reptiles, and also the first known case of predators timing the use of lures to a seasonal behavior of the prey—nest-building.
Dinets first observed the behavior in 2007 when he spotted crocodiles lying in shallow water along the edge of a pond in India with small sticks or twigs positioned across their snouts. The behavior potentially fooled nest-building birds wading in the water for sticks into thinking the sticks were floating on the water. The crocodiles remained still for hours and if a bird neared the stick, they would lunge.
To see if the stick-displaying was a form of clever predation, Dinets and his colleagues performed systematic observations of the reptiles for one year at four sites in Louisiana, including two rookery and two nonrookery sites. A rookery is a bird breeding ground. The researchers observed a significant increase in alligators displaying sticks on their snouts from March to May, the time birds were building nests. Specifically, the reptiles in rookeries had sticks on their snouts during and after the nest-building season. At non-rookery sites, the reptiles used lures during the nest-building season.
"This study changes the way crocodiles have historically been viewed," said Dinets. "They are typically seen as lethargic, stupid and boring but now they are known to exhibit flexible multimodal signaling, advanced parental care and highly coordinated group hunting tactics."
The observations could mean the behavior is more widespread within the reptilian group and could also shed light on how crocodiles’ extinct relatives—dinosaurs—behaved.
"Our research provides a surprising insight into previously unrecognized complexity of extinct reptile behavior," said Dinets. "These discoveries are interesting not just because they show how easy it is to underestimate the intelligence of even relatively familiar animals, but also because crocodilians are a sister taxon of dinosaurs and flying reptiles."
Dinets collaborated with J.C and J.D. Brueggen from the St. Augustine Alligator Farm Zoological Park in St. Augustine, Fla. More of his crocodile research can be found in his book “Dragon Songs.”
Striking Patterns: Skill for Forming Tools and Words Evolved Together
When did humans start talking? There are nearly as many answers to this perplexing question as there are researchers studying it. A new brain imaging study claims to support the hypothesis that language emerged long before Homo sapiens and coevolved with the invention of the first finely made stone tools nearly 2 million years ago. However, some experts think it’s premature to draw sweeping conclusions.
Unlike ancient bones and stone tools, language does not fossilize. Researchers have to guess about its origins based on proxy indicators. Does painting cave walls indicate the capacity for language? How about the ability to make a fancy tool? Yet, in recent years, scientists have made some progress. A series of brain imaging studies by Dietrich Stout, an archaeologist at Emory University in Atlanta, and Thierry Chaminade, a cognitive neuroscientist at Aix-Marseille University in France, have shown that toolmaking and language use similar parts of the brain, including regions involved in manual manipulations and speech production. Moreover, the overlap is greater the more sophisticated the toolmaking techniques are. Thus, there was little overlap when modern-day flint knappers were making stone tools using the oldest known techniques, dated to 2.5 million years ago and called the Oldowan technology. But when knappers used a more sophisticated approach, called Acheulean technology and dating to as much as 1.75 million years ago, the parallels between toolmaking and language were more evident. Stout and Chaminade have used functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) scans, although not on the same subjects at the same time.
In the new work, published online today in PLOS ONE, archaeologist Natalie Uomini and experimental psychologist Georg Meyer, both at the University of Liverpool in the United Kingdom, attempted to advance these earlier studies in several ways. They applied a technique called functional transcranial Doppler ultrasonography (fTCD), which measures blood flow to the brain’s cerebral cortex and which—unlike fMRI and PET—is highly portable and can be used on subjects in the field through a device attached to their heads (see video). The fTCD approach makes it much easier to monitor subjects’ brains during vigorous activity, such as the somewhat violent motions that are required to make stone tools. Uomini and Meyer are also the first to study both toolmaking and language tasks in the same subjects.
The researchers recruited 10 expert flint knappers and gave them two different tasks. In the first, the knappers crafted an Acheulean hand ax, a symmetrical tool that requires considerable planning and skill. The procedure involves shaping a flint core with another stone called a hammerstone. While wearing the fTCD monitor, the knappers worked on the tool for periods of about 30 seconds each, interspersed with control periods of about 20 seconds in which they simply struck the core with the hammerstone without trying to make a tool.
In the second task, the knappers were asked to silently think up words beginning with a given letter. The control periods consisted of simply resting quietly and not thinking of words.
The team found that the pattern of blood flow changes in the brain during the critical first 10 seconds of each experimental period—when the knappers were strategizing about how to shape the core or thinking up their first words—was very similar, again involving areas of the brain implicated in manual manipulations and language. Moreover, although there were some variations in the patterns between the 10 knappers, the toolmaking and language patterns within each individual were very closely aligned—suggesting, the team concludes, that the same brain areas recruited in both tasks.
The results, Uomini and Meyer argue, support earlier hypotheses that language and toolmaking coevolved, perhaps beginning as early as 1.75 million years ago. This doesn’t necessarily mean that early humans were talking in the same rapid-fire way that we do today, Uomini points out, but that “the circuits for both activities were there early on.”
Stout calls the new study “exciting work” that provides “one more piece of evidence supporting a link between stone-tool making and language evolution.” Yet a number of questions remain, he says, such as whether the correlation is between the motor skills involved in making tools and in making the sounds of speech, or whether toolmaking and language share higher cognitive functions such as those used in symbolic behavior.
That question is critical, some researchers say, because the knappers in this study and the ones that Stout conducted probably used a technique known as the Late Acheulean, dating from about 500,000 years ago, which put a much greater emphasis on symmetry and aesthetic considerations than did the earliest Acheulean, dating from 1.75 million years ago. “There is an enormous difference” between these varieties of Acheulean toolmaking, says Michael Petraglia, an archaeologist at the University of Oxford in the United Kingdom, who adds that “future experimental studies should thus examine the range of techniques and methods used.”
Thus the new work is “consistent with the hypothesis” of coevolution between language and toolmaking, “but not proof of it,” says Michael Corballis, a psychologist at the University of Auckland in New Zealand. “It is possible that language itself emerged much later, but was built on circuits established during the Acheulean” period.
Thomas Wynn, an archaeologist at the University of Colorado, Colorado Springs, is even more cautious about the results. He thinks that the fTCD technique, which measures blood flow to large areas of the cerebral cortex but does not have as high a resolution as fMRI or PET, “is a crude measure, even for brain imaging techniques.” As a result, Wynn says, he is “far from convinced” that the study has anything new to say about language evolution.
Research determines how the brain computes tool use
With a goal of helping patients with spinal cord injuries, Jason Gallivan and a team of researchers at Queen’s University’s Department of Psychology and Centre for Neuroscience Studies are probing deep into the human brain to learn how it manages basic daily tasks.
The team’s most recent research, in collaboration with a group at Western University, investigated how the human brain supports tool use. The researchers were especially interested in determining the extent to which brain regions involved in planning actions with the hand alone would also be involved in planning actions with a tool. They found that although some brain regions were involved in planning actions with either the hand or tool alone, the vast majority were involved in planning both hand- and tool-related movements. In a subset of these latter brain areas the researchers further determined that the tool was in fact being represented as an extension of the hand.
“Tool use represents a defining characteristic of high-level cognition and behaviour across the animal kingdom but studying how the brain – and the human brain in particular – supports tool use remains a significant challenge for neuroscientists” says Dr. Gallivan. “This work is a considerable step forward in our understanding of how tool-related actions are planned in humans.”
Over the course of one year, human participants had their brain activity scanned using functional magnetic resonance imaging (fMRI) as they reached towards and grasped objects using either their hand or a set of plastic tongs. The tongs had been designed so they opened whenever participants closed their grip, requiring the participants to perform a different set of movements to use the tongs as opposed to when using their hand alone.
The team found that mere seconds before the action began, that the neural activity in some brain regions was predictive of the type of action to be performed upon the object, regardless of whether the hand or tool was to be used (and despite the different movements being required). By contrast, the predictive neural activity in other brain regions was shown to represent hand and tool actions separately. Specifically, some brain regions only coded actions with the hand whereas others only coded actions with the tool.
“Being able to decode desired tool use behaviours from brain signals takes us one step closer to using those signals to control those same types of actions with prosthetic limbs,” says Dr. Gallivan. “This work uncovers the brain organization underlying the planning of movements with the hand and hand-operated tools and this knowledge could help people suffering from spinal cord injuries.”
The research was recently published in eLife.
(Source: queensu.ca)
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.
Orangutans Have a Big Idea
Even when they are very young, orangutans may start to form ideas about their world—specifically, how and when to use certain tools. That’s the conclusion of a new study, which indicates that ape cultural traditions may not be that different from our own.
Like humans, orangutans have behavioral traditions that vary by region. Orangutans in one area use tools, for example, whereas others don’t. Take the island of Sumatra, in western Indonesia. By the age of 6 or 7, orangutans from swampy regions west of Sumatra’s Alas River use sticks to probe logs for honey. Yet researchers have never observed this “honey-dipping” among orangutans in coastal areas east of the water.
How do such differences arise? Many experts say that social learning is key—that the apes figure out how to honey-dip by watching others. But even the most careful field researcher can have difficulty proving this, says Yale University anthropologist David Watts. Wild apes are always responding to their environment, he says. And it may be influencing their behavior far more than social learning.
Proving that robots aren’t just for people any longer, African grey parrot, Pepper, has learned to drive a robot that was specially designed for him. Pepper, whose wing feathers are clipped to preventing him from flying around his humans’ house and destroying their things, now manipulates the joystick on his riding robot to guide it to where ever he wishes to go.
This robotic “bird buggy” was the brainchild of his human companion, Andrew Gray, a 29-year-old electrical and computer engineering graduate student at the University of Florida.