Researchers have discovered that the size of the human brain has tripled in the past 2 million years, growing faster than the brains of other mammals. University of Missouri scientists studied three popular explanations for why brains grow—climate change, ecological demands, and social competition—and determined that social competition is the primary reason for increased brain capacity.
According to David Geary, Curator’s Professor and Thomas Jefferson Professor of Psychosocial Sciences at the University of Missouri College of Arts and Science, “Our findings suggest brain size increases the most in areas with larger populations and this almost certainly increased the intensity of social competition. When humans had to compete for necessities and social status, which allowed better access to these necessities, bigger brains provided an advantage.”
Drew Bailey, University of Missouri, co-author of the study, added, “Brains are metabolically expensive, meaning they take lots of time and energy to develop and maintain, making it so important to understand why our brains continued to evolve faster than other animals. Our research tells us that competition, whether healthy or not, sets the stage for brain evolution.”
While competition may help encourage brain growth, aging takes its toll on brain size if people are not vigilant about maintaining it. The average brain is said to shrink by about 5% per decade after the age of 40.
There are actually ways to increase brain size and cognitive function, in the opinion of some researchers. Here are some lifestyle changes that may help to increase the size of your brain.
Meditation and Brain Size
Scientists at Harvard, Yale, and the Massachusetts Institute of Technology discovered meditation can change the physical structure of the human brain. They conducted brain scans showing that people experienced in meditation had increased thickness in brain areas responsible for attention and processing sensory input. In fact, one section of gray matter in the human cortex showed more pronounced thickening in older people than in younger people, an area thought to become thinner as people age.
As Sara Lazar, leader of the study and a psychologist at Harvard Medical School, explained, “Our data suggest that meditation practice can promote cortical plasticity in adults in areas important for cognitive and emotional processing and well-being. These findings are consistent with other studies that demonstrated increased thickness of music areas in the brains of musicians, and visual and motor areas in the brains of jugglers. In other words, the structure of an adult brain can change in response to repeated practice.”
Study participants, some of whom had been meditating for just a year and others for decades, spent approximately 40 minutes in meditation per day. Slowing of breathing rates determined the depth of the meditation. People who were most deeply involved in meditation demonstrated the largest changes in brain structure. Lazar concluded that “the differences in brain structure were caused by the meditation, rather than that differences in brain thickness got them into meditation in the first place.”
Game Playing and Brain Size
German research has made a connection between game-playing and larger brain volumes. In the study the researchers asked people to play video games for 30 minutes per day during a 2-month period and then compared their brain volumes to those of a control group. People who played the video games had larger gray matter structures in brain regions associated with spatial navigation, strategic planning, memory, and fine motor skills.
According to the lead author of the study, Simone Kühn, “While previous studies have shown differences in brain structure of video gamers, the present study can demonstrate the direct causal link between video gaming and a volumetric brain increase. This proves that specific brain regions can be trained by means of video games.”
Practicing and Brain Size
Researchers from the National Institutes of Health and McGill University found that consistency in the practice of just about any skill is relevant to brain size. More years of practice determine beneficial changes in the left hemisphere of the brain, such as amplifying gray matter volumes in clusters in the left insula, left frontal operculum, left orbitofrontal cortex, and right middle temporal gyrus. These parts of the brain are key components of cognitive abilities, interpersonal experience, perception, motor control, inhibition, self-awareness, and impulse control.
According to the researchers, how many hours a week you practice a skill influences gray matter volume in different regions of the brain, such as the hippocampus, primary visual cortex, primary somatosensory cortex/superior parietal lobule, and precuneus/posterior cingulate cortex. These sections of the brain control self-consciousness and self-awareness.
Musical Training and Brain Size
Researchers at Concordia University in Montréal, Québec, have theorized that learning to play a musical instrument increases the size of the brain, with the greatest effect taking place in young musicians. Long-term, high-level musical training gives musicians a better chance of integrating sensory information from seeing, hearing, and touching. The researchers have cited evidence for a possible sensitive period for musical training from a study showing that the anterior corpus callosum (CC) was larger in musicians than in non-musicians, and that the difference was greater for people who started training before the age of 7.
According to the study, brain circuits related to musical improvisation are formed by systematic training, resulting in less reliance on working memory and more extensive connectivity within the brain. “Some of the brain changes that occur with musical training reflect the automation of task (much as one would recite a multiplication table) and the acquisition of highly specific sensorimotor and cognitive skills required for various aspects of musical expertise,” said lead author Christopher J. Steele.
Exercise and Brain Size
According to a group of researchers from Australia’s National Institute of Complementary Medicine at Western Sydney University and the Division of Psychology and Mental Health at the University of Manchester in the UK, aerobic exercise can improve memory function and maintain brain health as people age. An article in the journal NeuroImage concluded that, although exercise had no effect on total hippocampal volume, it increased the size of the left region of the human hippocampus, the brain region responsible for memory and other functions.
The researchers examined the effects of aerobic exercise on the hippocampus, reviewing 14 clinical trials to analyze the brain scans of 737 people from ages 24 to 76—some healthy, some with cognitive impairment, and some with mental illness—before and after aerobic exercise programs or as part of a control group. Aerobic exercise included stationary cycling, treadmill running, and walking. They determined that exercise produces a chemical called brain-derived neurotrophic factor (BDNF), which could help to prevent age-related decline by reducing brain deterioration.
Eating and Brain Size
Another targeted lifestyle change could positively change brain size. Some foods can strengthen memory, improve problem-solving ability, and enable better multitasking.
Researchers from UCLA analyzed the role of omega-3 fatty acids in impacting brain function and general brain health. These studies, published in the journal Neurology, suggest that omega-3s improve cognitive function, especially visual memory and executive function, including problem-solving, multitasking, and abstract thinking. Working with 1,575 middle-aged and elderly participants, who were dementia and stroke-free, the researchers administered MRI brain scans and other evaluations of mental function, body mass, and omega-3 fatty acid levels in the participants’ red blood cells.
Participants whose DHA (a type of omega-3) levels were in the bottom 25% had lower brain volumes than participants with higher DHA levels, corresponding to 2 years of brain aging. They also had lower scores on brain function tests involving visual memory and executive function. Omega-3 fatty acids can be found in fish, flax seeds, walnuts, soybeans, and tofu.
Making New Neurons
Scientists at Columbia University Vagelos College of Physicians and Surgeons offered evidence that the human brain produces new neurons throughout life, including in the mature brain. While the hippocampus has been a key focus of studies on neurogenesis and stem cell biology and has been shown to grow throughout life, some researchers have said that this growth is fueled by existing neurons growing in size, or blood vessels or other internal support structures expanding, rather than the addition of new brain cells.
To test this theory, investigators dissected and analyzed a representative sample of human hippocampi. Samples came from 28 healthy donors ranging in age from 14 to 79 years old upon death. They also gathered medical records and conducted a “psychological autopsy.” Researchers accounted for whether the subject might have had a neurological or psychiatric disorder at the time of death and combined molecular probes and mathematical modeling to follow the path of neurogenesis in brains.
The study, published in the journal Cell Stem Cell, showed that neurogenesis did not decline with age. Both young and old brains make thousands of new neurons, but these neurons might not be as up to speed when it comes to making new connections in old brains. According to the researchers, the changes in older brains could be connected to cognitive-emotional changes that happen with aging. While exercise, diet, and medications may be beneficial, future studies will be needed to investigate these ideas.
One thing is for sure, however. Increasing the size of your brain is well within your control. Meditate, play games, take up an instrument, and exercise. And remember, practice makes perfect!