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Does A Bigger Brain Make You Smarter

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Does A Bigger Brain Make You Smarter When It Comes To Intelligence

Does a Bigger Brain Make You Smarter?

When it comes to the brain and the IQ, is bigger the better? Does size really matter? Is there really a connection between the size of your brain and intelligence? With the help of findings by neurologists and scientists, we seek to find out!

  • Ailments and the Brain: Scientists have found that children with autism have a brain that has grown in a disproportionate manner in the very first year of their life. This prevents the child from making connections with normal behaviour. On the other hand, children and adolescents who suffer from Attention Deficit Hyperactivity Disorder or ADHD have shown signs of having a much smaller brain size. Many scientists have shown that the size of the brain shrinks as we age, and this does not have any visible effect on our cognitive abilities.
  • It’s all Relative: The size of the brain does not really have a bearing on the way a person’s cognition gets shaped. Even large mammals like elephants and whales are finally hunted and tamed by humans who have smaller brains in comparison. The brain is made up of billions of neurons which need to function properly. It may be seen that scientists consider the brain mass in relation with the rest of the body so as to speculate about the cognitive abilities of the person. Why is this required? Large animals need a well functioning and proportionate brain size to control and run their organs with proper cognition for satisfactory results, which is what we humans seem to have done.
  • Brain Size And Body Size

    Body and brain weights of vertebrates refer to data from Jerison , Haug , Russell and van Dongen , while those of hominids and australopithecines are based on data from Jerison and Falk . Data for birds were taken from Jerison and Iwaniuk et al. .

    Mammals, like animals in general, vary enormously in body size . The smallest mammal is the Etruscan shrew Suncus etruscus with a body weight of 2 g, and the largest mammal and animal is the blue whale Balaenoptera musculus with a length of 33 m and a body weight up to 200 tons. The largest living terrestrial animal is the African elephant, Loxodonta africana, with a body weight up to 7.5 tons. Thus, among mammals there is a range in body size or weight of 8 orders of magnitude.

    The volumes or weights of brains likewise vary enormously. Among mammals, the smallest brain is found in the bat, Tylonycteris pachypus, which weighs 74 mg in the adult animal, and the largest brains of all animals are found in the sperm whale and killer whale , with up to 10 kg. African elephant brains weigh up to 6 kg. This is an again enormous range, here roughly 5 orders of magnitude.

    Within mammals, monkeys have much smaller brains than ungulates, and humans have much smaller brains than whales and elephants, while they are, without any doubt, more intelligent . However, there are groups like primates, where bigger is better appears to hold. Nevertheless, there remains the question: why are bigger brains not uniformly smarter?

    The Cortex As A Dominant Contributor To The Seat Of Intelligence And Mind

    Intelligence in the above-defined sense results from the interaction of a large number of forebrain structures , of which the cerebral cortex plays a dominant role . This neural network structure and its processing algorithms enable higher cognitive, executive and communicative functions including language and vocal learning .

    With increasing brain size in mammals, cortices increase in surface area as well as in volume. The smallest mammals, for example shrews, have a cortical surface of 0.8 cm2 or less, in the rat we find 6 cm2, in the cat 83 cm2, in humans about 2400 cm2, in the elephant 6300 cm2 and in the false killer whale a maximum of 7400 cm2. Thus, from shrews to false killer whale we find a nearly 10 000-fold increase in cortical surface area, following exactly the increase in brain volume at an exponent of two-thirds, as expected .

    In searching for a more direct neurobiological basis of intelligence, the number of neurons, particularly of cortical neurons as well as the effectiveness of their wiring and processing speed, comes to mind quite naturally. Brains and cortices of the same volume may contain very different numbers of neurons depending on their neuron packing density , whichamong othersdepends on the size of the neurons, including their dendritic trees. Processing speed depends on interneuronal distance and axonal conduction velocity, which in turn largely depend on the degree of myelination .

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    Are Big Brains Smarter

    Does the size of your brain say anything about your smarts?

    Plenty of brainy scientists have pondered the link between a person or animal’s grey matter and their cognitive skills.

    Perhaps fitting for a question about the human brain which packs in more than 100 billion neurons, according to the National Institutes of Health but the answer is mired in complexities and unknowns.

    For one, scientists still debate over the definition of intelligence. For any IQ definition, how do you measure it? Further, do differences in IQ show up in daily life? And finally, does more brain tissue or a heftier brain equate with higher IQ?

    One thing scientists do agree on: A big brain alone doesn’t equate with smarts. If it did, elephants and sperm whales would win all the spelling bees. Rather, scientists look at brain mass relative to body mass in order to make any speculation about a creature’s cognitive abilities.

    So while an elephant noggin, at 10.5 pounds , could squash a human think box in a purely physical battle of brains, you and I take the cake in a war of wits. Our brains, which weigh an average of 2.7 pounds , account for about 2 percent of body weight, compared with an elephant’s under one-tenth of a percent.

    And the debate continues

    Brain size seems to have nothing to do with scores on standardized intelligence tests, according to a brain-scan study of young children.

    Average brain weights for primates :

    Sizing up brains for the rest of the animal kingdom, would include:

    Better To Focus On Neurons And Synapses

    Does Having A Big Brain Actually Make You Smarter?

    However, comparing gray matter doesnt tell the whole story. The brain contains several different kinds of cells, not just neurons. The neurons may be the most prominent cells . But the brain includes several types of support cells called glial cells. Microglia, for example, are tiny cells that serve an immune-like function. One of their roles is to clear out debris in the event of a brain injury. Astrocytes are another type of support cell, which protects neurons by establishing a barrier between the neurons and blood. These cells dont seem to be tied directly to intelligence, though we cant be dogmatic.

    The key is to compare the number of neurons. Only 1050% of the cells in the human brain are neurons. The adult human brain has an estimated 100 billion neurons, beating almost every kind of animal except elephants and whales.

    So we need to look at another critical factor related to intelligence: neuron density. Neurons come in a variety of sizes. Where neurons are smaller, more can be found in the same amount of space. In contrast, if neurons are larger, then fewer will be present and the neuronal density lower. Humans stand out in their neuron density, but even here we arent the undisputed champs.

    Synaptic density is definitely correlated to intelligence. In fact, the loss of synaptic density is best correlated to the severity of dementia in Alzheimers diseasebetter than the loss of neurons and the decrease in brain weight.

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    Importance Of The Gray And White Matter On The Brain

    University Challenge star Bobby Seagull has an extremely average brain or even a little bit lower than average, according to Dr Cox after the scan results were out.

    When asked by BBC2’s Horizon host, Dr Hannah Fry if he meant that Seagull has a smaller brain, Dr Cox replied that Seagull indeed has a brain that is a little bit lower than the average.

    Dr Cox added, despite the size of Seagull’s brain, he has a very nice example of gray matter. These gray matter areas around the exterior part of the brain filled out into the skull, representing a very healthy brain.

    More so, it seems that people who have more gray matter in the brains have slightly higher cognitive ability as they play the most significant part in allowing humans to function normally every day. The gray matter serves to process signals and information in the brain.

    Equally important, Dr Cox noted based on his observations that the white matter of the brain, houses all of the diverse connections across all of the areas in the brain. White matter is located in the subcortical tissues of the brain, which contains the extensions of neurons, the nerve fibers or axons which are covered in myelin sheath that protects the axons from injury and speeds up the electrical transmission of nerve signals.

    Dr Cox added that the gray and white matter contains roots between different areas of the brain and how information is being transmitted from one neuron to another.

    Are Bigger Brains Smarter Barely Says Study Led By Penn Scholar

    Using MRIs from more than 13,000 people, the authors found that each additional “cupful” of brain volume was correlated with 5 additional months of educational attainment, on average.

      How often have you heard a smart person draw praise for having a big brain?

      It may be just an expression, but according to a new study led by a University of Pennsylvania researcher, that notion contains a glimmer of literal truth.

      An analysis of MRIs from 13,600 people revealed a slight correlation between brain volume and scores on a test of fluid intelligence a measure of logic and reasoning ability.

      The bigger-is-smarter relationship held true regardless of socioeconomic status for the people in the study.

      But brain volume accounted for just 2.1 percent of the variation in how well the study participants performed on the intelligence test. And while men have larger brains than women on average, their test scores were no better.

      That suggests other factors play a much bigger role in intelligence, such as perhaps the size of certain regions of the brain or the quality of the connections between them a hypothesis the researchers plan to examine in future studies. For example, previous research has found that the cortex, an outer layer of gray matter in the brain, tends to be thicker in women, said lead author Gideon Nave, an assistant professor of marketing at Penns Wharton School.

      Penn psychology professor Joseph W. Kable, one of Naves co-authors, agreed.

      Said Mayer:

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      Human Brains Vs Animal Brains

      When we are taught about human anatomy in school, we are often told that humans have the largest brains of primates, which is a simple explanation for our advanced cognitive abilities. The physical aspect of that fact is true primates already have larger brains than most other mammals, but humans have even larger brains than other primates!

      For reference, the average human brain is roughly three pounds, and represents about 2% of our total body weight. In terms of those animals with significantly larger brains than ours, such as sperm whales and elephants , some might assume that they would be more intelligent, yet their brain-to-body mass ratio is sometimes as small as 0.1% . Mice, on the other hand, have a similar brain-to-body mass ratio as humans, while in other animals, such as certain voles and birds, that ratio could be as high as 10%! In other words, humans neither have the largest brains, nor the largest brain-to-body mass ratio. Claiming cognitive superiority based on these two metrics is therefore impossible for humans and we dont like to lose.

      Evolving A Bigger Brain Isn’t Always About Intelligence

      Does Having A Big Brain Actually Make You Smarter?

      Evolution does not consistently favour bigger brains. Instead, it’s more common for mammals to have evolved smaller body sizes which makes it look like the brain is getting bigger.

      A study of 1,400 living and extinct mammal brains, , has given researchers an in-depth timeline of how mammal brains and bodies have evolved over the last 150 million years.

      They have found a simple story, but one that completely changes our previously held perception that cognition is the primary driver of brain size evolution in mammals.

      Over nearly 200 million years of mammal evolution, the researchers have shown that brain size is actually secondary to body size. Their research also shows that there are many different evolutionary paths to having a big brain.

      Prof. Anjali Goswami, a Research Leader at the Natural History Museum and an author of the study, explains ‘A lot of the time where it looks like brain size in increasing, it’s actually not that brains are getting bigger, but evolution is acting to decrease body size.’

      Habitat, diet, reproduction and metabolism all impact body size and may be more consequential for survival compared to cognition and intelligence.

      The study included data from not just living mammals but also 107 mammal fossils including ancient whales and the oldest Old World monkey skull ever found. Looking at fossils gave the researchers a more accurate picture of how brain and body sizes have changed through time.

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      Bigger Brains Are Smarter But Not By Much

      Date:
      University of Pennsylvania
      Summary:
      Using a large dataset and controlling for a variety of factors, including sex, age, height, socioeconomic status, and genetic ancestry, scientists found that people with larger brains rated higher on measures of intelligence and educational attainment. Size was far from everything, however, explaining only about two percent of the variation in smarts.

      The English idiom “highbrow,” derived from a physical description of a skull barely able to contain the brain inside of it, comes from a long-held belief in the existence of a link between brain size and intelligence.

      For more than 200 years, scientists have looked for such an association. Begun using rough measures, such as estimated skull volume or head circumference, the investigation became more sophisticated in the last few decades when MRIs offered a highly accurate accounting of brain volume.

      Yet the connection has remained hazy and fraught, with many studies failing to account for confounding variables, such as height and socioeconomic status. The published studies are also subject to “publication bias,” the tendency to publish only more noteworthy findings.

      Nave and Koellinger’s collaborators on the work, which is published in the journal Psychological Science, included Joseph Kable, Baird Term Professor in Penn’s Department of Psychology Wi Hoon Jung, a former postdoctoral researcher in Kable’s lab and Richard Karlsson Linnér, a postdoc in Koellinger’s lab.

      Story Source:

      Scientists Breed Smarter Fish But Reveal Costs Of Big Brains

      In a Swedish lab, Alexander Kotrschal has deliberately moulded the intelligence of small fish called guppies. From a starting population, he picked individuals with either unusually large or small brains for their bodies, and bred them together. Its what farmers and pet-owners have done for centuries, selectively breeding animals with specific traits, from shorter legs or more muscle.

      Or bigger and smaller brains. After just two generations, Kotrschal had one lineage of guppies with brains that were 9 percent bigger than the other. And these individuals proved to be smarterthey outclassed their peers at a simple learning task, where they learned to discriminate between two and four symbols. This may seem like childs play for us, but its a relatively advanced cognitive task for a fish, says Kotrschal.

      Their boosted smarts came at a pricethe big-brained fish developed smaller guts and produced fewer offspring. Brains are expensive energy-guzzling organs. Ours, for example, make up just 2 percent of our body weight but consume 20 percent of our energy. Many scientists think that to pay for our larger brains, we had to scale back other parts of our bodies like our guts or fat stores, and thats exactly what Kotrschal found in his guppies.

      Kotrschals study also reminds us that evolution cant just pull adaptations out of thin air. Theres always a cost. In the case of the guppies, that took the form of smaller guts and fewer young.

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      Do Bigger Brains Make Smarter Carnivores

      Scientists confirm that species with larger brain size are more intelligent

      A bat-eared fox tries to open a puzzle box during an experiment to test intelligence.

      Why do dolphins evolve large brains relative to the size of their bodies, while blue whales and hippos have brains that are relatively small?

      While there has been much speculation regarding brain size and intelligence, a new paper published in the journal Proceedings of the National Academy of Sciences confirms that species with brains that are large relative to their bodies are more intelligent.

      This research “represents a novel and rigorous experimental test of the relationship between brain size and problem-solving ability using mammalian carnivores as our test group,” said Kay Holekamp, an integrative biologist at Michigan State University and senior author of the paper. “Our results show that having a larger brain really does improve an animal’s ability to solve a problem it has never encountered before.”

      Brain size and cognitive ability

      Brain size is often used as a proxy for cognitive ability. Whether brain size can predict cognitive ability in animals has frequently been questioned, however, mainly because of the lack of any experimental evidence, Holekamp added.

      The study included polar bears, Arctic foxes, tigers, river otters, wolves, spotted hyenas and some rare, exotic species such as binturongs, snow leopards and wolverines.

      Larger brain, greater intelligence?

      Human Brains Vs Human Brains

      Bigger brain could make you only a little smarter than others ...

      While it is possible to measure the intelligence of certain animals with more complex tests, such as problem-solving activities, play opportunities, and social/behavioral analysis, most human-animal intelligence comparisons are based on the simpler metrics explained above.

      For a comparison between two different human brains, a more diverse and measurable range of variables is present. Most people are aware of the Intelligence Quotient , which has been a commonly used metric for intelligence for more than a century. Basically, this is a test that measures your capacity to learn, and analyzes a number of general areas, such as spatial reasoning, analytical thinking and short-term memory. This was largely trusted as a valid measurement tool for decades, but in recent years, its reliability has been questioned, as it doesnt take into account the environmental and cultural factors that may affect some people. In simple terms, it fails to consider educational availability, genetic factors, cultural norms related to education, socioeconomic levels.

      Emotional Intelligence is often seen as a complementary measurement to IQ. A persons emotional quotient is intended to measure ones ability to identify, process, analyze, respond, express and control their emotions. Unlike ones IQ, a person can work on their EQ and improve it over time, as they mature and experience more of the world.

      Highlighted in green is orbitofrontal cortexa major reward and pleasure region of the brain.

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