What does it mean to experience pleasure? Thanks to neuroscience, some answers have come to light. With extensive research, scientists have been able to explain why some things bring us pleasure. The addictions, cravings and the desire for pleasure is one that everyone experiences in one form or the other. So, why does this happen? Why are some people addicted to heroin and others to chocolate?
Thanks to author and professor of neuroscience, Davis J. Linden, an explanation is given as to why we experience pleasure, the good and the bad, the way we do.
In this book summary readers will discover:
- The pleasure circuit
- The pleasure of addiction
- The difference between love and sex
- The good pleasures
Key lesson one: The pleasure circuit
No matter what brings you pleasure, they all have one thing in common. They all activate the pleasure circuit in the medial forebrain. So, whether it be a drug, food or sex, the science behind the feeling is exactly the same.
The brain is a fascinating organ and there are several interconnected structures that allow humans to experience pleasure. The ventral tegmental area or VTA is one of these structures and the amygdala is the part of the brain that controls emotions. The neurons in the VTA are responsible for the release of dopamine to the amygdala when we experience something pleasurable. The other structure that receives dopamine is the dorsal striatum, this is the part of the brain responsible for learning habits. This is why when we enjoy something, we feel the need to do it again. This need for a repeated pleasurable experience is what leads to habits and addictions.
Due to this effect, the medial forebrain pleasure circuit has a strong impact on our behaviour. This has led to it being the focus of many studies, the most controversial of which was conducted in the 1970s by Dr. Robert Galbraith Heath. To examine the relationship between behaviour and the pleasure circuit, doctors used to deliberately stimulate the circuit to gauge the effects. Heath chose to focus his studies on homosexual men. He deliberately stimulated the pleasure circuit whilst homosexual men had intercourse with women to see if they still experienced pleasure. To stimulate the circuit, Heath implanted electrodes in the subject’s brain. He later stated that by stimulating the pleasure circuit, the homosexual man was able to climax whilst having intercourse with a woman. Although the ethics of this study are questionable, at the time it proved that direct electrical stimulation of the brain’s pleasure circuit could have an effect on short-term behaviour.
Key lesson two: The pleasure of addiction
Even though all pleasurable activities begin at our pleasure circuit, not all trigger the circuit in exactly the same way. Some activities can have a stronger effect on the circuit which makes the activity more addictive than others. This is what happens when one consumes drugs. The drugs themselves vary in the way they stimulate the circuit. This is the exact reason why it is easier to become addicted to heroin as compared to weaker drugs like marijuana. Interestingly, LSD does not activate the pleasure centre at all. This means that the risk of addiction to LSD is extremely low.
However, the brain is not the only contributor to addiction. Just consider smoking. In the United States alone 80 per cent of people who try cigarettes develop an addiction compared to 35 per cent of all those who try heroin. This occurs as a result of two things. Firstly, heroin is an illegal drug whilst cigarettes are not. Therefore, cigarettes are easier to obtain and they will be less frowned upon by the people you are surrounded by. Secondly, the kind of pleasure that heroin produces is much different from that produced by cigarettes. Heroin produces a huge pleasure surge all at once while cigarettes will give us lighter rushes of pleasure even though we have to take quite a few puffs. This means that we are rewarded for the action of smoking more frequently making it much easier to become addicted.
Addiction does not just alter our behaviour, it physically changes our brains. This was shown in a study whereby rats were given a cocaine solution for 28 days. The extensions of nerve cells in their pleasure circuit were greatly altered as compared to before the experiment. But it’s not just drugs that can become an addiction. Since addiction is caused by activation and a consequent change in the pleasure circuit, things like gambling, food, sex and even video gaming have the same potential to become addictive. Gambling seems to be a strange addiction since the risk of losing money is anything but pleasurable but it may surprise you that nature has an effect. As it turns out, our brains find a specific level of uncertainty pleasurable. It is a characteristic that is also shown in some primates. This was proven by Wolfram Schultz when he conducted an experiment with monkeys. Monkeys were provided with a treat when shown a green light, none when shown a red light and 50 per cent of the time when shown a blue light. The monkeys were shown to start experiencing the release of dopamine when shown the blue light as there was a pleasure associated with the wait to find out if they received a treat. This is similar to what gamblers experience, pleasure in uncertainty.
When it comes to food, the pleasure circuit can overtake other systems in our brain. Did you know that our brains have their own weight management system? It seems like something made up but it is absolutely true – your body should control its own weight. The hypothalamus is what receives signals to let the brain know about weight gain and losses. If we put on weight, a hormone produced by fat cells called leptin increases. Leptin activates the neurons in the hypothalamus that will then increase energy expenditure and suppress appetite. This is what makes us stop eating when we are no longer hungry. However, this management system can stop working. Usually, in cases of people with obesity, leptin resistance could be the problem. Even though the hormone is released, it fails to suppress appetite. Other hormones could further complicate the issue.
And that’s what dopamine is, a hormone. Foods that are high in sugar and fat release higher levels of dopamine. The urge to continue activating our pleasure circuit may be much larger than our appetites. This is why some people continue to eat even if they are not hungry. The need for pleasure is greater than our brains weight management system.
Key lesson three: The difference between love and sex
The brain and pleasure circuit can actually prove that there is a clear difference between sex and love. Both sex and falling in love activate the pleasure circuit, but differently. Love deactivates the judgement and social cognition centres in the brain. This was proven by Lucy Brown when she took brain scans of people who were looking at images of their loved ones and then platonic acquaintances. Knowing this fact, you might have a different perspective as to why we behave the way we do when we fall in love.
Orgasms, on the other hand, has a completely different impact on the pleasure circuit. It is also considered an emotional and sensory experience and can be experienced without pleasure as well. Electrode stimulation can induce orgasms with the same physiological features as pleasurable orgasms but without stimulating the pleasure circuit. This could explain what sometimes happens during epileptic seizures and rape cases. Naturally, orgasms are a pleasurable experience because they produce a massive dopamine surge. So as much as love and sex produce pleasure, they do so differently and combining the two could explain the intensely pleasurable experience that occurs.
Key lesson four: The good pleasures
Sometimes it can feel like the only things that bring us pleasure are the bad stuff but this couldn’t be further from the truth. Healthy living, charitable giving and good behaviour can also activate our pleasure centres.
For example, runner’s high is a common occurrence that athletes enjoy – sometimes even when they are exhausted. The physical pain that they experience causes an increase in opioid release in the brain and a subsequent rise in endocannabinoids. That’s right, the brain has its own cannabis-like molecules which it can release into the bloodstream. But painful stimuli also release dopamine which is where the pleasure comes from. This occurrence is why we can experience pain and pleasure at the same time.
Some people can experience pleasure through altruism. Giving to charity activates the pleasure circuit much in the same way that receiving money does. Similarly, it has been proven that knowledge can also activate the pleasure circuit even without reward. This was proven by Ethan Bromberg-Martin and Okihide Hikosaka when they showed that monkeys and humans opted to receive information about a reward without receiving it.
The key takeaway from The Compass of Pleasure is:
Pleasure can be traced to the pleasure circuit found in the medial forebrain. Many activities can trigger this pleasure circuit, it just depends on the level of pleasure it brings. The dark side of pleasure is addiction and is associated with long-term alterations in the electrical, morphological and biochemical functions within the pleasure circuit. This is why addiction is so hard to walk away from. Addiction can come in many forms as associated with pleasure like drugs, sex, alcohol, gambling and even food. Fortunately, there are also good habits that also provide pleasure like learning, charitable giving and exercise without harmful implications. Neuroscience has made great headway in discovering the connections between pleasure, addiction and the brain and will continue to do so as technologies develop.
How can I implement the lessons learned in The Compass of Pleasure:
Addiction may be the result of chasing after pleasure but as it was created, you can train your brain out of it. It is difficult but if you begin to associate addiction with a negative experience, you could theoretically rewire your pleasure circuit to seek another pleasurable experience. This is the reason why smokers tend to pick up another habit when they quit smoking and why addicts are encouraged to try distracting themselves with a hobby.
