Discover surprising facts and myths about the brain

Dr Matt Roser guides us through five fascinating and surprising facts about the brain, and five things you may have heard that are, in fact, myths

5 min read

Neurons concept image.

Discover surprising facts and myths about the brain

Dr Matt Roser guides us through five fascinating and surprising facts about the brain, and five things you may have heard that are, in fact, myths

5 min read

Nervous systems serve vital functions in numerous species

The human brain is a remarkable organ which allows us to perceive and interact with the world, remember, think, communicate and plan. Ultimately, all human consciousness, action, and culture is a product of our brain.
At the Brain Research & Imaging Centre (BRIC) , based on the Plymouth Science Park, researchers from across the University are working with NHS staff to better understand how the brain works and how it is affected by disease and age.
Here are five fascinating and surprising facts about the brain, and five things you may have heard that are, in fact, myths.
 

Myths

We only use around 10% of our brain at any moment
This myth is widely believed, and is found in many popular movies (Limitless, 2011, Lucy, 2014) but is completely untrue. All neurons are constantly active, even if they are only firing (sending electrical signals) at a ‘resting’ rate. Multiple brain regions are involved in the most basic of processes, such as maintaining your breathing and heartrate. 

Some people are ‘left brained’ and some people are ‘right brained’
Studies of people who had the two hemispheres (halves) of the brain separated by surgery, people who have had unilateral (one-sided) brain damage, and studies using brain imaging have all found important differences between the two halves of the brain, both in structure and in function. 
There is no evidence though that individuals rely to a greater or lesser extent on one half of their brain, with corresponding individual differences1.

Left and right brain illustration.
The myth of strict lateralisation of function
Complex reality of relative lateralisation and interhemispheric interaction
Complex reality of relative lateralisation and interhemispheric interaction
We remember everything we experience
Many people claim to accurately remember events from long ago and the belief that everything that happed to us is somehow stored in our memory (perhaps to be recovered after long lying latent) is pervasive. 
In fact, studies of eyewitness testimony show that our memories are very unreliable and that they are reconstructed again and again over time and that this process is influenced by environmental factors2.
A grandmother and her granddaughter happily look through a family photo album together.
MRI Image Of Head Showing Brain
A pile of old pictures and a journal to document memories of past times.
 
Listening to classical music makes you smarter
This myth illustrates how many misperceptions about the brain arise from over simplification and over extension of minor findings. A study (Rauscher, 19933) in the early 1990’s found evidence for better performance on a spatial memory test after ten minutes of listening to Mozart than after ten minutes of listening to silence or to a monotone voice.
Despite this effect being small, specific to spatial memory, and short-lived (lasting only a few minutes) the study caught the imagination of the public and the ‘Mozart effect’ was born. 
In the years since, commercial exploitation has been built on claims that playing classical music to infants can significantly improve their general intelligence. In fact, a meta analysis (Pietschnig, et al., 20104) of numerous studies has shown no evidence for this claim.
Eduardo Miranda playing as part of an orchestra
Brain scan, MRI, neurology
Happy young child dancing in listening to music.
 
Our brain and mind are two different things
Most of us feel, intuitively, that we have a mind that interacts with our body or, in other words, that our mind and our body are two different realms. This is a philosophical stance known as dualism and was most clearly articulated by Rene Descartes. 
The psychologist Paul Bloom has argued (Bloom, 2005) that this tendency is innate and manifests at very early stages of development. He argues that this inbuilt model of the actions of others, and its extension to the movements of objects, helps infants to navigate a complex and dynamic world and is thus adaptive. 
While this may indeed be how we develop a mental model of the world that helps us to interact with it, and a model of ourselves, that doesn’t mean that dualism is true. The philosophical stance throws up all sorts of conundrums (how do the two realms of mind and body interact?) that are not satisfactorily answered. 
In the modern mind/brain sciences, researchers reject dualism and take a materialist or monist stance in which mind and body/brain are the same thing. Mind is brain. 
The challenge is to explain how mental processes, including conscious experience, are generated by the operation of a physical system. Current theories (Dehaene, et al., 2011) propose that consciousness at any one moment in time is defined as the ‘global neuronal workspace’ of processes that are linked in reciprocal networks of interaction and influence.
 

Facts

MRI Lab
Brain Stim
Brain Stim
 

It is estimated that the average adult brain contains around 100 billion brain cells

How many are neurons (that send signals to each other) and how many are supporting glial cells is debated. It is estimated that each neuron is connected to around 1,000 others, potentially totalling 100 trillion connections.5


The brain weighs around 1.5kgs, accounting for about 2% of body weight

but requires 20% of our blood supply our body’s energy.6


A threefold increase in brain size from that of our ancient ancestor, Homo habilis

began around two million years ago7


Information is encoded in the brain as patterns of electrical signals across a network of neurons 

and as patterns of connections of varying strength and effect (excitatory, inhibitory, or modulatory). 


Experience changes the brain by changing the strengths of connections between neurons

This affects the electrical signals sent across networks of neurons, changing behaviour, performance, perception and cognition.
 

Further resources

Cognitive Neuroscience on Box of Broadcasts (BoB)
The mysteries of how the brain gives rise to our mental life are rapidly being addressed by science, but much remains to be explained. This playlist curated by Dr Matt Roser includes two documentary series that cover the breadth of the mind/brain sciences, an entertaining magazine-style show and three-part live lecture series with demonstrations, and three personal stories of recovery from brain trauma. Together they show how investigations in Cognitive Neuroscience are building a picture of the complex organ that makes us who we are.
Box of Broadcasts (BoB) logo

Brain Research & Imaging Centre (BRIC)

The Brain Research & Imaging Centre is the most advanced multi-modal brain research facility in the South West and is at the forefront of the exploration of human brain structure, physiology and function in health and disease.
Seven specialised laboratories, clustered around a Siemens Prisma Magnetic Resonance Imaging (MRI) scanner allow for brain function to be experimentally manipulated using transcranial stimulation and cognitive tasks, and imaged using MRI and electrophysiology.

Discover more about BRIC

BRIC

References
1. This was demonstrated convincingly by: Nielsen, J. A., Zielinski, B. A., Ferguson, M. A., Lainhart, J. E., & Anderson, J. S. (2013). An evaluation of the left-brain vs. right-brain hypothesis with resting state functional connectivity magnetic resonance imaging. PloS one, 8(8), e71275.
2. Loftus, E. F., & Greenspan, R. L. (2017). If I’m certain, is it true? Accuracy and confidence in eyewitness memory. Psychological Science in the Public Interest, 18(1), 1-2.
3. Rauscher, F., Shaw, G. & Ky, C. (1993). Music and spatial task performance. Nature, 365, 611. 
4. Pietschnig, J., Voracek, M., & Formann, A. K. (2010). Mozart effect–Shmozart effect: A meta-analysis. Intelligence, 38(3), 314-323.
5. Zimmer, C. (2011). 100 trillion connections. Scientific American, 304(1), 58-61.
6. Owen, O. E. (1988, May). Resting metabolic requirements of men and women. In Mayo Clinic Proceedings (Vol. 63, No. 5, pp. 503-510). Elsevier.
7. Bruner, E., & Beaudet, A. (2023). The brain of Homo habilis: Three decades of paleoneurology. Journal of Human Evolution, 174, 103281.