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The adult human brain weighs on average about 1.2–1.4 kg (2.6–3.1 lb) which is about 2% of the total body weight, with a volume of around 1260 cm 3 in men and 1130 cm 3 in women. There is substantial individual variation, [4] with the standard reference range for men being 1,180–1,620 g (2.60–3.57 lb) [5] and for women 1,030–1,400 g ...
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The human brain is an amazing organ. It's capable of surprising feats of memory and learning. It's susceptible to damage, and yet remarkably adaptable to change. Considering all of its many capabilities, you may begin to wonder, how big is the human brain?
While the human brain has a structure similar to that of other mammals, what makes it different is it's size in relation to the rest of the human body.
Compared to the size of our bodies, humans have much larger brains than many other mammals—but not the largest. The brain makes up 2% of a human's body mass, while the shrew's brain is about 10% of its body mass.
In terms of sheer size, sperm whales and elephants take the top spots for weight at 18 and 11 pounds, respectively. But since even small elephants weigh 6,000 pounds or more, their brains are just 0.2% of their body weight. For the sperm whale, the brain is only about 0.06% of body weight.
The Brain and Behavior in Psychology
The average adult human brain weighs about 3 pounds (1300 to 1400 grams). A newborn baby's brain weighs approximately three-quarters of a pound (350 to 400 grams). On average, the human brain measures about 5.5 x 6.5 x 3.6 inches (140 x 167 x 93 mm).
The brain is considered fully formed at age 25. It develops from back to front, ending at the prefrontal cortex; this is the part of the brain that's responsible for decision-making and reasoning.
Men tend to have bigger brains than women. After taking overall body weight into account, men's brains tend to be approximately 100 grams larger than women's.
In women, parts of the frontal lobe and limbic cortex (areas associated with problem-solving and emotional regulation) tend to be bigger than those of men. In men, the parietal cortex (associated with the perception of space) and amygdala (involved in the processing of memory and emotional responses) tend to be larger than those in women.
Neurons are the building blocks of the brain and nervous system – they transmit and carry information, thus allowing different parts of the brain and body to communicate with one another. Researchers currently estimate that there are around 86 billion neurons in the human brain.
Parts of the Brain
All humans do not have the same size brain. Does that mean that highly intelligent people have bigger brains? In some cases, there might be a link.
Researchers have found brain size can be linked to certain diseases or developmental conditions.
Autistic children tend to have bigger brains (and earlier disproportionate brain growth) than non-autistic children. The hippocampus (an area of the brain strongly associated with memory) tends to be smaller in older adults with Alzheimer's disease.
What about intelligence? It depends on who you ask. According to an analysis done by Dr. Michael McDaniel, a professor at Virginia Commonwealth University, many studies have found a correlation between bigger brains and higher intelligence.
However, not all researchers agree with McDaniel's conclusions. Such studies also raise important questions about how intelligence is defined and measured, whether relative body size is taken into account when making such correlations, and which parts of the brain should be looked at when evaluating intelligence.
It is also important to note that variations in brain size between humans are relatively small. Other influences that could play a pivotal role in determining intelligence include the density of neurons in the brain, social and cultural factors, and other structural differences inside the brain.
Brain volume peaks at the teenage years, and after the age of 40 it begins declining at 5% per decade, speeding up around 70. Average adult male brain weight is 1,345 grams (47.4 oz), while an adult female has an average brain weight of 1,222 grams (43.1 oz).
May 28, 2021 · The human brain weighs about 3 lbs. (1.4 kilograms) and makes up about 2% of a human's body weight. On average, male brains are about 10% larger than female brains, according to...
4 days ago · Learn about the brain, the mass of nerve tissue in the anterior end of an organism that integrates sensory information and directs motor responses. The human brain weighs approximately 1.4 kg (3 pounds) and is made up of billions of cells called neurons.
- The Editors of Encyclopaedia Britannica
Feb 10, 2023 · An average adult brain weighs 3 pounds and is composed of 60% fat, with water, protein, carbohydrates, and salt accounting for the other 40%. The brain is an organ made up of neural tissue. It...
Jun 9, 2023 · The average human brain weighs in at 2.7 pounds, or 1,200 grams, which is about 2 percent of our body weight [source: Bryner]. Males, though, have about a 100 g advantage after accounting for differences in total body weight [source: Schoenemann ].
