Chimps Outplay Humans in Brain Games

We humans assume we are the smartest of all creations. In a world with over 8.7 million species, only we have the ability to understand the inner workings of our body while also unraveling the mysteries of the universe. We are the geniuses, the philosophers, the artists, the poets and savants. We amuse at a dog playing ball, a dolphin jumping rings, or a monkey imitating man because we think of these as remarkable acts for animals that, we presume, aren’t smart as us. But what is smart? Is it just about having ideas, or being good at language and math?

Scientists have shown, time and again, that many animals have an extraordinary intellect. Unlike an average human brain that can barely recall a vivid scene from the last hour, chimps have a photographic memory and can memorize patterns they see in the blink of an eye. Sea lions and elephants can remember faces from decades ago. Animals also have a unique sense perception. Sniffer dogs can detect the first signs of colon cancer by the scents of patients, while doctors flounder in early diagnosis. So the point is animals are smart too. But that’s not the upsetting realization. What happens when, for just once, a chimp or a dog challenges man to one of their feats? Well, for one, a precarious face-off – like the one Matt Reeves conceived in the Planet of the Apes – would seem a tad less unlikely than we thought.

In a recent study by psychologists Colin Camerer and Tetsuro Matsuzawa, chimps and humans played a strategy game – and unexpectedly, the chimps outplayed the humans.

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(Image: Shutterstock)

The Universal ‘Anger Face’

SA’s Taung Child’s skull and brain not human-like in expansion

The Taung Child, South Africa’s premier hominin discovered 90 years ago by Wits University Professor Raymond Dart, never seizes to transform and evolve the search for our collective origins.

By subjecting the skull of the first australopith discovered to the latest technologies in the Wits University Microfocus X-ray Computed Tomography (CT) facility, researchers are now casting doubt on theories that Australopithecus africanus shows the same cranial adaptations found in modern human infants and toddlers – in effect disproving current support for the idea that this early hominin shows infant brain development in the prefrontal region similar to that of modern humans.

The results have been published online in the prestigious journal Proceedings of the National Academy of Sciences (PNAS) on Monday, 25 August 2014 at 21:00 SAST (15:00 EST), in an article titled: New high resolution CT data of the Taung partial cranium and endocast and their bearing on metopism and hominin brain evolution.

The Taung Child has historical and scientific importance in the fossil record as the first and best example of early hominin brain evolution, and theories have been put forward that it exhibits key cranial adaptations found in modern human infants and toddlers.

To test the ancientness of this evolutionary adaptation, Dr Kristian J. Carlson, Senior Researcher from the Evolutionary Studies Institute at the University of the Witwatersrand, and colleagues, Professor Ralph L. Holloway from Columbia University and Douglas C. Broadfield from Florida Atlantic University, performed an in silico dissection of the Taung fossil using high-resolution computed tomography.

"A recent study has described the roughly 3 million-year-old fossil, thought to have belonged to a 3 to 4-year-old, as having a persistent metopic suture and open anterior fontanelle, two features that facilitate post-natal brain growth in human infants when their disappearance is delayed," said Carlson.

Comparisons with the existing hominin fossil record and chimpanzee variation do not support this evolutionary scenario.

Citing deficiencies in how the Taung fossil material has been recently assessed, the researchers suggest physical evidence does not incontrovertibly link features of the Taung skull, or its endocast, to early prefrontal lobe expansion, a brain region implicated in many human behaviors.

The authors also debate the previously offered theoretical basis for this adaptation in A. africanus. By refuting the presence of these features in the Taung Child, the researchers dispute whether these structures were selectively advantageous in hominin evolution, particularly in australopiths.

Thus, results of the new study show that there is still no evidence for this kind of skull adaptation that evolved before Homo, nor is there evidence for a link between such skull characteristics and the proposed accompanying early prefrontal lobe expansion, Carlson said.

(Image caption: LB1 in three different views to illustrate facial asymmetry. A is the actual specimen, B is the Right side doubled at the midline and mirrored, and C is the left side doubled and mirrored. Differences in left and right side facial architectures are apparent, and illustrate growth abnormalities of LB1. Credit: A, E. Indriati, B and C, D.W. Frayer)

Flores bones show features of Down syndrome, not a new “hobbit” human

In October 2004, excavation of fragmentary skeletal remains from the island of Flores in Indonesia yielded what was called “the most important find in human evolution for 100 years.” Its discoverers dubbed the find Homo floresiensis, a name suggesting a previously unknown species of human.

Now detailed reanalysis by an international team of researchers including Robert B. Eckhardt, professor of developmental genetics and evolution at Penn State, Maciej Henneberg, professor of anatomy and pathology at the University of Adelaide, and Kenneth Hsü, a Chinese geologist and paleoclimatologist, suggests that the single specimen on which the new designation depends, known as LB1, does not represent a new species. Instead, it is the skeleton of a developmentally abnormal human and, according to the researchers, contains important features most consistent with a diagnosis of Down syndrome.

"The skeletal sample from Liang Bua cave contains fragmentary remains of several individuals," Eckhardt said. "LB1 has the only skull and thighbones in the entire sample."

No substantial new bone discoveries have been made in the cave since the finding of LB1.

Initial descriptions of Homo floresiensis focused on LB1’s unusual anatomical characteristics: a cranial volume reported as only 380 milliliters (23.2 cubic inches), suggesting a brain less than one third the size of an average modern human’s and short thighbones, which were used to reconstruct a creature standing 1.06 meters (about 3.5 feet tall). Although LB1 lived only 15,000 years ago, comparisons were made to earlier hominins, including Homo erectus and Australopithecus. Other traits were characterized as unique and therefore indicative of a new species.

A thorough reexamination of the available evidence in the context of clinical studies, the researchers said, suggests a different explanation.

The researchers report their findings in two papers published today (Aug. 4) in the Proceedings of the National Academy of Sciences (1, 2).

In the first place, they write, the original figures for cranial volume and stature are underestimates, “markedly lower than any later attempts to confirm them.” Eckhardt, Henneberg, and other researchers have consistently found a cranial volume of about 430 milliliters (26.2 cubic inches).

"The difference is significant, and the revised figure falls in the range predicted for a modern human with Down syndrome from the same geographic region," Eckhardt said.

The original estimate of 3.5 feet for the creature’s height was based on extrapolation combining the short thighbone with a formula derived from an African pygmy population. But humans with Down syndrome also have diagnostically short thighbones, Eckhardt said.

Though these and other features are unusual, he acknowledged, “unusual does not equal unique. The originally reported traits are not so rare as to have required the invention of a new hominin species.”

Instead, the researchers build the case for an alternative diagnosis: that of Down syndrome, one of the most commonly occurring developmental disorders in modern humans.

"When we first saw these bones, several of us immediately spotted a developmental disturbance," said Eckhardt, "but we did not assign a specific diagnosis because the bones were so fragmentary. Over the years, several lines of evidence have converged on Down syndrome."

The first indicator is craniofacial asymmetry, a left-right mismatch of the skull that is characteristic of this and other disorders. Eckhardt and colleagues noted this asymmetry in LB1 as early as 2006, but it had not been reported by the excavating team and was later dismissed as a result of the skull’s being long buried, he said.

A previously unpublished measurement of LB1’s occipital-frontal circumference — the circumference of the skull taken roughly above the tops of the ears — allowed the researchers to compare LB1 to clinical data routinely collected on patients with developmental disorders. Here too, the brain size they estimate is within the range expected for an Australomelanesian human with Down syndrome.

LB1’s short thighbones not only match the height reduction seen in Down syndrome, Eckhardt said, but when corrected statistically for normal growth, they would yield a stature of about 1.26 meters, or just over four feet, a figure matched by some humans now living on Flores and in surrounding regions.

These and other Down-like characteristics, the researchers state, are present only in LB1, and not in the other Liang Bua skeletal remains, further evidence of LB1’s abnormality.

"This work is not presented in the form of a fanciful story, but to test a hypothesis: Are the skeletons from Liang Bua cave sufficiently unusual to require invention of a new human species?" Eckhardt said.

"Our reanalysis shows that they are not. The less strained explanation is a developmental disorder. Here the signs point rather clearly to Down syndrome, which occurs in more than one per thousand human births around the world."

Brain of World’s First Known Predators Discovered

An international team of paleontologists has identified the exquisitely preserved brain in the fossil of one of the world’s first known predators that lived in the Lower Cambrian, about 520 million years ago. The discovery revealed a brain that is surprisingly simple and less complex than those known from fossils of some of the animal’s prey.

The find for the first time identifies the fossilized brain of what are considered the top predators of their time, a group of animals known as anomalocaridids, which translates to “abnormal shrimp.” Long extinct, these fierce-looking arthropods were first discovered as fossils in the late 19th century but not properly identified until the early 1980s. They still have scientists arguing over where they belong in the tree of life.

"Our discovery helps to clarify this debate," said Nicholas Strausfeld, director of the University of Arizona’s Center for Insect Science. "It turns out the top predator of the Cambrian had a brain that was much less complex than that of some of its possible prey and that looked surprisingly similar to a modern group of rather modest worm-like animals."

Strausfeld, a Regents’ Professor in the Department of Neuroscience in the UA College of Science, is senior author on a paper about the findings, which appear in the July 17 issue of Nature.

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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.

Anxiety in invertebrates opens research avenues

For the first time, CNRS researchers and the Université de Bordeaux have produced and observed anxiety-like behavior in crayfish, which disappears when a dose of anxiolytic is injected. This work, published in Science on June 13, 2014, shows that the neuronal mechanisms related to anxiety have been preserved throughout evolution. This analysis of ancestral behavior in a simple animal model opens up new avenues for studying the neuronal bases for this emotion.

Anxiety can be defined as a behavioral response to stress, consisting in lasting apprehension of future events. It prepares individuals to detect threats and anticipate them appropriately so as to increase their chances of survival. However, when stress is chronic, anxiety becomes pathological and may lead to depression.

Until now, non-pathological anxiety had only been described in humans and a few vertebrates. For the first time, it has been observed in an invertebrate. To achieve this, researchers at the Institut de Neurosciences Cognitives et Intégratives d’Aquitaine (CNRS/Université de Bordeaux) and the Institut des Maladies Neurodégénératives (CNRS/Université de Bordeaux) repeatedly exposed crayfish to an electric field for thirty minutes. They then placed the crayfish in an aquatic cross-shaped maze. Two arms of the maze were lit up (which repels the crustaceans) and two were dark—which they find reassuring.

The researchers analyzed the exploratory behavior of the crayfish. Those made anxious tended to remain in the dark areas of the maze, by contrast to control crayfish, which explored the entire maze. This behavior is an adaptive response to a felt stress: the animal aims to minimize the risk of meeting an attacker. This emotional state wore itself out after about one hour.

Anxiety in crayfish is correlated to increased serotonin concentration in their brains. Neurotransmitter serotonin is involved in regulating many physiological processes in both invertebrates and humans. It is released when stress is experienced and regulates several responses related to anxiety, such as increasing blood glucose levels. The researchers have also highlighted that injecting an anxiolytic commonly used in humans (benzodiazepine) stops the prevention behavior in crayfish. This shows how early neural mechanisms that trigger or inhibit anxiety-like behavior appeared in the evolutionary process and that they have been well preserved over time.

This work provides researchers specializing in stress and anxiety with a unique animal model. Crayfish have a simple nervous system whose neurons are easy to record, so they may shed light on the neuronal mechanisms at work when stress is experienced, as well as on the role of neurotransmitters such as serotonin or GABA. The team now plans to study anxiety in crayfish subject to social stress and the neuronal changes that occur when the anxiety is prolonged for several days.

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