The beginning of a new argument
Today, new research may trigger another debate about the relationship between brain volume and intelligence. Because new research shows that the bigger the brain, the smarter it is. Richard Haier of the University of California and Michael mcdaniel, an industrial and organizational psychologist at Virginia State University, hold this view. Moreover, they think this conclusion applies to all ages and all gender groups. Obviously, brain volume is closely related to intelligence.
It is not accurate to measure the circumference of a person's brain or the volume of his brain after death with a tape measure. In the past five years, different research groups have been able to use new imaging technology to measure the brain and get accurate results. Mcdaniel examined the brain volume of 26 people recently measured by imaging technology, and got a positive answer. The bigger the brain, the smarter the person is. However, the so-called intelligence standard is that IQ is questionable. Whether IQ really reveals intelligence and whether IQ can fully represent intelligence is still controversial.
For example, even from a biological point of view, the capacity of the brain is related to human intelligence, and there are great differences. For example, the brain contains cortex, including white matter and gray matter, as well as midbrain and brain stem. The capacity and structure of these parts may be related to IQ. It is difficult to fully understand human mind and wisdom. For example, a study in 2004 found that IQ is only related to the gray matter of the brain. However, many people believe that human intelligence is not only related to gray matter, but to the whole brain. However, it is important that the study in 2004 found that the rich gray matter in specific areas of the brain is closely related to IQ. This may explain why a person is good at math, but not at spelling. Another person with the same IQ is good at spelling, but not good at math. In addition, another study conducted by Haier in early 2005 found that men think more with gray matter, while women think more with white matter.
Researchers also found that smart people learn faster, make fewer mistakes and are more efficient. Therefore, they believe that IQ test is the only best indicator to determine whether a job seeker is competent, and the use of IQ test is of great economic value to companies and organizations.
Historical evolution of brain capacity and IQ
Today, the average human brain capacity is 1350- 1400 ml (cubic centimeter), while the brain capacity of modern apes such as chimpanzees is about 400 ml, the former is 3.5 times that of the latter.
Historically, the human brain has grown gradually. One theory about the evolution of human brain is that the brain capacity of homo habilis was 600 ml 2 million years ago, and it was not until Homo erectus that the brain capacity of human was increased to 900 ml 300,000 years later. Although it does not reach the level of modern people, it exceeds the brain capacity of existing non-human primates.
Another hypothesis is that about 3 million years ago, the human brain was only as big as today's chimpanzees. But since then, the brain has gradually expanded. About 2.6 million years ago, the human brain tripled in size. However, this enlarged brain capacity may not have produced smarter primitive people. Only in the era when tools can be made, there is little evidence that the human brain shows signs of enlargement.
Archaeological findings show that the human brain is gradually increasing, but the intelligence or IQ is developing by leaps and bounds. 50,000 to 70,000 years ago, there was a leap in human intelligence development, which led to the invention of bone tools, including bone sewing needles and throwing sticks, as well as simple works of art, such as collars, chains and murals. This tool has never appeared before.
However, this leap in human intelligence can hardly be explained by the increase in brain capacity, because about 654.38 million years or earlier before making tools and creating works of art, humans like modern people had brains as big as modern people. From this point of view, 70,000 years ago, human beings needed a huge brain capacity to create tools and works of art, but this alone was not enough.
Increasing brain means increasing IQ?
1964, Palmer Eldridge mentioned in his novel Three Marks that if a person wants to be smarter, he can achieve it by acquiring more brains. This therapy, called "electronic therapy", can increase people's brain capacity. In the past, this was completely an imagination or myth. But today, the development of biomedicine provides some practical cornerstones for this imagination. Researchers at the Massachusetts Institute of Technology believe that this hope of increasing brain capacity is entirely possible, because they have discovered a single gene called CPG 15, which can promote the growth of protein. Using this gene may lead to a new therapy to renew damaged or diseased brain tissue. CPG 15 is one of several molecules that play an important role in developing the viability of special brain cell groups in the brain. CPG 15 can expand the progenitor cell bank. Even in the exponential growth period of the brain, a little change in the capacity of the progenitor cell bank can greatly affect the final volume and shape of the cerebral cortex.
Experiments on mice show that if CPG 15 gene is expressed in large quantities in their brains, their brains can become bigger. These enlarged brains have the same grooves and circuits as those of mammals that evolved large surface areas. And the latter is an important factor that people agree to determine whether people are smart or not. Therefore, the brain must be large first (the first element of intelligence), and then it can develop into many ditches and circuits. These two factors and other factors can determine the IQ of a person or a creature.
The size of the brain is also related to β-catenin. Initially, researchers found that β -catenin is closely related to the occurrence, deterioration and metastasis of prostate cancer, and β -catenin also plays two roles in cells. One is that it can stick cells together, and the other is that it can promote the growth and survival of cells.
However, researchers at Harvard University in the United States found that β -catenin in selected mice showed enhanced activity through genetic engineering, which made the brain of mice almost twice as large as that of normal mice. The cerebral cortex of mice, which is the basis of determining human intelligence and language, has become almost as big as the human brain.
These studies show that if the brains of animals and people are enlarged, it is possible to change IQ. Because increasing the volume of the brain is not only a matter of the capacity of the central nervous system, but also can change its grooves and circuits, and even its structure, thus greatly increasing IQ.
Abstract thinking ability also determines IQ
So, how big a brain is suitable for humans? Is the average capacity of 1350- 1400 ml enough now? In fact, this question is very difficult to answer.
Some experts think that a bigger brain may be very important for our ancestors to hunt, because it helps them to throw more accurately, or such a brain enables people to create a language consisting of three words. Others think that a bigger brain has enough memory, so that early primitive people can distinguish those who are not trying but taking advantage. However, such a slight evolution is not enough to lead to the emergence of modern human behavior.
But only the appearance and development of language can really promote the development of the human brain and produce a high IQ superior to other creatures. For example, if you can't say more than two or three words at a time, just like drinking a glass of wine nonstop in summer, it is impossible for human beings to produce more complicated thoughts. Increasing sentence length or making multi-stage plans requires a structural understanding of the brain, which allows people to make tools and create works of art.
This structural ability of the brain comes from the language and thinking of early humans through trial and error. This is a leap in human intelligence. In the creation and application of language, a large number of such inventions may be unconscious, but occasionally a creative adult will try a new word or grammar, and then a child will hear it and integrate such usage into his or her language. The language of long sentences can spread like an infectious disease. If more children hear this structural sentence and use it skillfully, then he/she may become a super adult with complicated thinking.
The complexity of language and thinking leads to the fusion of culture and genes. The first is the invention of human behavior, such as expressing profound thoughts in complex language, and the second is a little genetic change. This may be the relationship between IQ and brain development. It can be predicted that the environment created by technology, medicine and better education will promote the second leap development of human brain.
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The brains of smart people and ordinary people
The more advanced an animal is, the greater the relative weight of its brain. For example, the brain of an orangutan weighs about 400g, the brain of an ape weighs about 850g, and the average weight of a human brain can reach 1350- 1400g. However, sometimes the brains of geniuses, smart people and great men are not as big as those of ordinary people.
1 April, 955/morning of kloc-0/8/morning of kloc-0/morning of kloc-0/5, Einstein died in Princeton Hospital, USA, at the age of 76. In the morning, Dr. Thomas S. Harvey, director of the Department of Pathology, conducted an autopsy. According to Harvey's record, Einstein's brain weighs1.230g, which is obviously lower than the average level of modern people. After Lenin's death, the data recorded in medical anatomy is that his brain is only 1340 grams, which is also lower than the average volume of human brain.
These facts show that a large brain capacity is a sign of intelligence, but it cannot be said that a small brain capacity is not a high IQ. In addition to brain capacity, there are several other factors that determine IQ.
First, the higher the proportion of brain weight to body weight, the higher the IQ may be. For example, the elephant's brain is twice as heavy as the human brain, but its weight is equivalent to 1/40 of the human weight, while the elephant's brain is only equivalent to 1/440 of its weight, and the orangutan's brain is only equivalent to1150 of its own weight.
Second, different capacities in different areas of the brain affect IQ. The greater the proportion of the surface area of the cerebral cortex to the whole brain area, the smarter people are, and the more and deeper the grooves on the surface of the cerebral cortex, the greater the surface area of the cerebral cortex. In addition, the greater the proportion of frontal lobe area to the whole cerebral cortex, the smarter people are. The frontal lobe is closely related to many important psychological activities such as language, judgment and reasoning, and has specific functional areas. Different people's frontal lobe structure will have different degrees of intellectual activity. Sandra Wiltson, a female professor at McMaster University in Ontario, Canada, found that Einstein's left and right hemispheres were larger 15% than normal, which was very developed. The developed parietal lobe and inferior lobe in the posterior upper part of the brain play an important role in a person's mathematical thinking, imagination and visual space understanding, which also explains why Einstein has a unique thinking, that is, his brain tissue that controls mathematical operation and spatial reasoning ability is relatively developed, which is the physiological basis for his thinking and reasoning on three-dimensional concepts such as time, space and motion.
In addition, Dr. Daglia Zadel of the University of California, USA, compared Einstein's brain tissue with that of 10 ordinary people. The results show that the left nerve cells in Einstein's hippocampus are much larger than the right nerve cells, while the left and right nerve cells in the common hippocampus have little difference in size. In addition, the gray matter area of Einstein's brain is obviously different from that of ordinary people, which means that Einstein's brain is indeed very different from ordinary people. The neurons in the left hippocampus of Einstein's brain are larger than those on the right, which may indicate that the neurons in the left hippocampus are more closely connected with the cerebral cortex than the right brain.
Third, the structure of the brain is different. Wiltson also found that another feature of Einstein's brain is that there are no sulcus (sulcus gyrus) in many places on the surface. These grooves are like roadblocks in the brain, making it difficult for nerve cells to connect with each other. Without these obstacles in the brain, nerve cells can communicate unimpeded and make the brain's thinking more active.
Finally, some professionals believe that studying the weight and structure of the brain after death can't really get the mystery of the relationship between the brain and IQ, because the brain will produce all kinds of ideas when it is alive, so if you want to know how the brain works and how IQ is produced, you should study it before you die.
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A new syndrome with big brain and high IQ
Rushton, a professor of psychology at the University of Western Ontario, said
Rushton) published an investigation report entitled "A 30-year Study on the Differences of Cognitive Abilities among Different Ethnic Groups" in the journal Psychology, Public Policy and Law published by the American Psychological Association in June 2005. According to the report, IQ measurement shows that East Asians have the highest IQ, with an average of about 106. Caucasian person-times, about100; Black Americans 85; The number of black people in Sahara is 70. According to MRI, IQ is positively correlated with brain volume. The coefficient ratio of brain volume to IQ is 0.4. The bigger the brain capacity, the higher the IQ. Because a big brain has more nerve cells and neural networks, it can process information faster. A cubic inch of brain can hold millions of brain cells. After maturity, the brains of East Asians are bigger than those of whites, and whites are bigger than blacks. So brain volume can explain the difference in IQ scores.
As early as 65438+30s, German anatomist Frederick put forward the theory that "brain size is related to intelligence". This theory was recently supported by an American study. This study shows that people with larger brains usually score higher on standard IQ tests.
Dr Michael mcdaniel of virginia commonwealth university, who led the research, reported that since 1930s, scientists have done a lot of research to verify the correlation between brain size and intelligence. The initial research focused on the analysis of head size. In recent years, scientists have focused on measuring the size of the brain through magnetic resonance imaging. Mcdaniel analyzed more than 20 research results on the relationship between brain capacity and intelligence involving 1530 people, and concluded that people with large brain capacity generally have higher IQ.
Mcdaniel pointed out that in the correlation between brain capacity and intelligence, women are more obvious than men, and adults are more obvious than children. In addition, women's brains are generally smaller than men's, but this does not affect their scores in IQ tests. The expert also believes that the influence of brain size on intelligence is only an objective phenomenon, and people with smaller brain size need not worry about it. There are many examples of small brains but high IQ. The brain of scientist Einstein is "not particularly big".
In fact, it is not an absolute thing!
What matters is whether the brain is filled with paste or brains.