Spartacus Blog
The Evolution of the Brain. Can you make yourself happy?
The reason why we feel happy or sad is because of the way certain chemicals are in the brain at the time. I want to look at the reasons why these chemicals behave in this way and if we can do anything to influence this process.
Creatures have existed on earth for 800 million years. About 50 million years ago our brains began to grow and develop a second layer. The initial reptilian brain controlled the body's vital functions such as heart rate, breathing, body temperature and balance. The reptilian brain is reliable but tends to be somewhat rigid and compulsive. Reptiles still have this type of brain.

The Limbic Brain emerged in the first mammals. It can record memories of behaviour that produced agreeable and disagreeable experiences. Its main function is to process and regulate emotion and memory.
About two million years ago some animals (primates) began to develop a third layer, known as the cerebral cortex (this makes up to two-thirds of the human brain). An important part of this is the neo-cortex. This is the kind of brain that humans have and is responsible for the development of language, abstract thought, imagination, and consciousness. The neo-cortex is what has enabled human cultures to develop.
Lizards have reptile brains. It starts running as soon as it is born. Lizards never trust other lizards. The only time happy chemicals are released in the brain of a lizard is during mating and egg laying.
All mammals have chemicals in the brain. They are there to help mammals survive and reproduce. With humans, because we have the neo-cortex, this is far more complicated.
The first chemical messenger in the brain I want to look at is Dopamine . It affects movement, motivation, and reward-seeking. It's also known as the "feel-good" hormone. Movement: Dopamine controls movement in the brain. Motivation: Dopamine helps you decide if a task is worth the effort. Memory: Dopamine helps consolidate memories. Mood: Dopamine can make you feel good after doing something enjoyable. Learning: Dopamine helps you associate stimuli with rewards.
Dopamine is released to help us carry out tasks that we believe will be rewarded. If you achieve something that you have been working on for some time, these happy chemicals will flood your brain. Unfortunately, in a short time, these happy chemicals will be reabsorbed, and you will get a feeling of anti-climax. This happens when we have individual success like passing examinations. However, it seems the pleasures from success as a member of a team lasts longer.
Dopamine plays a vital role in animals as it encourages them to search for food. However, for humans it is no longer needed for survival and so people therefore must construct their own objectives.
We also have the problems that drugs can create dopamine. Cocaine stimulates more dopamine than we can achieve in real life. After taking cocaine natural rewards feel less exciting. However, the second dose of cocaine will not give you the same pleasure ("high") as the first dose. To achieve something like the first "high" you will have to take a larger dose, and you are on the road to addiction.
Endorphins also play an important role in our feelings. Endorphins motivate you to ignore pain, so you can escape from harm when you're injured. They allow a zebra to wriggle out of the jaws of a lion. A greyhound will continue chasing a hare after breaking its leg.
Endorphins are produced in the brain and released when the body experiences pain or stress. They are also released during pleasurable activities like exercise, eating, and sex.
Exercise that leads to pain gives you endorphin rush. It makes you feel good as it fills your blood with oxygen that goes to your head. Endorphins therefore help to reduce symptoms of anxiety and stress. This is why doctors are likely to suggest exercise might help deal with depression.
Hormones are chemical substances that act as messengers in the body. Oxytocin is a hormone that plays a key role in shaping human behavior. Oxytocin influences social bonding, love, and long-term emotional attachment. It's also known as the "love drug" or "love hormone" because it promotes positive feelings, like endorphins or serotonin.
Mammals live in herds and packs because there is safety in numbers. Animals in the wild survive by trusting their herd mates. If an animal is separated from their group their oxytocin levels fall dramatically and will increase when reunited with the herd.
When a mammal gives birth, her oxytocin surges. It also surges in the offspring. Oxytocin is stimulated by holding, kissing, touching or licking. Bonds of attachment are a buildup of oxytocin circuits. Oxytocin motivates you to trust others, to find safety in companionship. It produces the feeling of being safe with others.
Oxytocin helps you relax when you are with someone you trust. This is also true when you are in a group where you feel safe. You give each other protection from the outside world.
Serotonin is a neurotransmitter that sends messages between nerve cells in the brain and body. In mammals, serotonin is the good feeling of having access to important resources. For example, the stronger mammals in a herd dominate food and mating opportunities.
Serotonin plays a slightly different role in humans. We gain food and sex in a different way to animals, but it is the same process that impacts on our mood.
Serotonin levels rise and fall with changes in status. For example, dominant male monkeys have twice as much serotonin in their blood as non-dominant males. In humans, people in leadership positions have higher serotonin levels than their subordinates.
Serotonin is produced when you feel satisfaction or importance and can help regulate sleep and appetite. Low levels of serotonin are linked to depression. The most used antidepressants like Prozac work by raising serotonin levels in the brain.
However, it is also possible to increase serotonin levels without taking medicine. One natural way to increase serotonin is by working out. When you pedal your bicycle or lift weights, your body releases more tryptophan, the amino acid your brain uses to make serotonin. This boost in serotonin (along with other endorphins and other neurotransmitters) is why many people get that feeling of euphoria after an intense workout.
Exposure to either the sun or to the bright lights meant to replicate it is another way to naturally increase serotonin levels. Light therapy is one of the main treatments for seasonal affective disorder (SAD), the winter blues that may be triggered by a drop in serotonin levels.
The final chemical I want to look at is cortisol. All creatures have cortisol hormones that are triggered when they encounter survival threats.
In humans, cortisol creates the feeling of pain. The brain strives to avoid pain by storing details of the experience, so you know what to look out for in the future. When cortisol surges, we call it fear, but when cortisol dribbles, we call it anxiety or stress. Sometimes these painful memories are located in our subconscious and are not easy to deal with in a rational way.
Happy moments in your past connected neurons that are there, ready to spark more happy chemicals creating pathways in the brain (like water creating rivers). These chemicals also help you to avoid whatever hurt in the past.
You are designed to survive by seeking happy chemicals and avoiding unhappy chemicals. Cortisol communicates pain and the expectation of pain. When a lunching gazelle smells a lion is in the area, cortisol motivates it to run even though it would rather keep eating.
Advertising is often used to manipulate these happy chemicals to make us want things that we do not really need and in the long term can be very damaging.
The food industry also uses chemicals to manipulate our decision-making. Monosodium glutamate (MSG) is a flavour enhancer that can cause your pancreas to release more insulin, which can make you feel hungrier. Advanced glycation end products (AGEs) are a group of molecules that form when proteins, fats, and sugars combine during cooking. AGEs can increase hunger and make it harder to resist unhealthy food choices.
Corporations are constantly manipulating the chemicals in your brain to their advantage. Can you do the same to make life better for you?
I have already discussed the way exercise can increase your happy chemicals. Setting yourself new achievable goals is another way of achieving higher levels of dopamine and serotonin.
Try to see yourself in a positive light (be kind to yourself). Being kind to others will also boost your levels of serotonin and oxytocin. Increase the amount of social contact you have with friends. A meta-study (68 different research projects) at Brigham Young University discovered that having good close friends was more important for health outcomes (high blood pressure, heart disease, depression, cancer, early deaths) than diet or exercise habits. A study of 280,000 people by researchers at Michigan State University indicated that having good friendships is a strong predictor of both health and happiness.
Collecting is a good hobby to have because it overcomes dopamine disappointment. A collector always has something to seek. When he finds it, he avoids dopamine droop by starting the next quest. You can also bond with other collectors to stimulate oxytocin. If you have a good collection, you will also enjoy a serotonin boast.
I want to finish by telling two stories about people from history. In the early 1870s Thomas Edison began working on a system of electrical illumination, something he hoped could compete with gas and oil-based lighting. Over the next few years, he carried out thousands of experiments that all ended in failure.
To do this he needed plenty of dopamine. He only had this because he was convinced, he would be successful. He was an optimistic person who did not fear failure. Edison devised the first commercially viable electric light bulb in October 1879. Straight away he began experimenting in developing a system for electricity distribution and therefore avoided a drop in dopamine levels.
Edison was an optimist. The usual defence of pessimism is that a pessimist is never disappointed and can only ever be pleasantly surprised. However, research shows that optimists live longer and have happier lives. Optimism and positive thinking are linked to the release of several chemicals in the brain, including dopamine, serotonin, oxytocin, and norepinephrine.
As a child of 19 months Helen Keller suffered acute congestion of the stomach and brain (probably scarlet fever) which left her deaf and blind. At the age of six the Perkins Institute for the Blind in Boston provided her with a teacher, Anne Sullivan. She not only taught her how to communicate, but the need to be optimistic.

In 1903, aged 23, Helen Keller wrote an essay entitled Optimism. "Once I knew only darkness and stillness. Now I know hope and joy. My life was without past or future; death, the pessimist would say, ‘a consummation devoutly to be wished'… Optimism, compels the world forward, and pessimism retards it". Pessimism for a nation, as for an individual, "kills the instinct that urges men to struggle against poverty, ignorance and crime, and dries up all the fountains of joy in the world". Optimism, by contrast, is "the faith that leads to achievement". Without it, nothing can be made better. Helen Keller spent the whole of her adult life campaigning on issues such as civil rights, world peace and gender equality.

We do not know what the future holds for us. There will be both good and bad things waiting in the years that follow. Some of those unknowns are positive and that we have some ability to steer towards those positives. Optimism encourages us to seek them out. If, on the other hand, we have no expectation that our lot in life can be improved, we are not motivated to put in the thought and effort needed to improve it and those solutions go undiscovered. Failure becomes a self-fulfilling prophecy.
Sumit Paul-Choudhury, who lost his young wife from cancer, wrote in his book, The Bright Side: Why Optimists Have the Power to Change the World (2025): "We can't control the happenstances that determine the course of our lives. But we can control how we respond to them, and we can carry on looking for the bright side, no matter how dark the future appears. We owe it to ourselves, to those around us, to those we have lost and those who have yet to come, to make the best of it that we can."
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