Catching ourselves losing interest and motivation in doing things we normally enjoy is so common, yet so frustrating. Whether they are activities we are committed to for years or things we just started doing, everyone gets bored and unmotivated to pursue them for some period of time before they become interesting again. Maybe grabbing the book to read is not appealing lately. Not because the content of the book started going south, but because you don’t feel like reading these days. Normally you like going for a walk in the afternoons, but in the last few days it almost feels like a chore. Gym days used to be exciting and fun but now you look for excuses to skip it. Your favorite talk show seems to have lost its edge as if it doesn’t produce interesting stuff anymore.

Why is that? Are really books, walks, exercising, tv shows, social relationships and virtually any activity possible, doomed to become boring at some point? And more importantly, what can we do about it?

The molecule of drive.

Dopamine is a neurotransmitter produced in the brain that is associated with essential functions like reward anticipation, motivation and movement. Like all neurotransmitters, dopamine is constantly available in the brain, with dopaminergic neurons delivering this molecule in regular amounts. This is called baseline rate activity and the set point of this baseline differs from person to person. People with higher dopamine baseline, i.e. dopamine in abundance, are generally more motivated, in better spirits and more willing to work hard to achieve a goal. Conversely, low dopamine baseline is associated with depressive states, lack of motivation, tendency for quick and easy rewards, and reluctance to exert effort to obtain significant rewards. Hence, the dopamine baseline is a biomarker of how motivated someone is in general.

The role of dopamine in the experience of pain and pleasure.

When we are about to obtain something rewarding, like eating a chocolate, listen to a song we like, have sex etc, we get a dopamine release that exceeds the baseline and with the combination of other neurotransmitters that follow, we experience a euphoric feeling we call pleasure. Soon after the obtainment of that reward, the dopamine levels drop again, but crucially they don’t return to baseline. Instead, the dopamine levels crash below baseline. Since we have a finite amount of dopamine that is readily available each moment of time, using a little more than usual for the sake of a reward, will inevitably create a momentary shortage of dopamine. This will be experienced as a negative state. This will be the moment you feel you want to get a second bite of that chocolate. Pain and pleasure are the two sides of the same coin. This is also evident in neuroimaging data indicating overlapping neural networks between the two. Neuroscientists describe the pain-pleasure relationship like a seesaw. A tilt towards the pleasure side of the seesaw will lead to an inevitable return towards the side of pain with equal magnitude. In other words, getting a mild reward, like a piece of chocolate, will give back a mild irritation (manifested in the form of needing another piece), while getting a huge reward like winning a trophy or having a big birthday party, will give back a big, and potentially even longer lasting, sense of sadness. That also explains, atleast in part, why women experience depressive symptoms after giving birth. Of course how noticeable the experience of that pain/sadness will be, depends on how high or low the dopamine baseline was set in the first place. People with higher dopamine baseline are less likely to experience severe symptoms of this dopamine setback, but people with low dopamine baseline are at a greater risk of experiencing a more profound sense of emptiness afterwards.

So why do we lose motivation to pursue the activities we normally enjoy?

As stated before, one of the roles of dopamine is to anticipate rewards. The brain releases dopamine in order to learn and decode what a particular reward is all about and mark down the required steps that lead to that reward (create a habit). Consequently, any reward that gets repeated at predictable time intervals makes it easier for the brain to learn and decode it. That means less dopamine is required to be released next time, therefore less pleasure. Every next bite of that delicious chocolate tastes less good than the previous one, until the last piece, where you feel like eating one more will make you throw up. This transition from craving a piece to becoming sick of it, is partly because the brain is better prepared for what to expect from the upcoming bite and therefore less dopamine is released each time.
The effects of dopamine baseline drop can also manifest in longer time scales too, and can occur within any activity. Going to that amazing restaurant too often, or going to the movies every weekend, taking the exact same route for the afternoon walk or hanging out with only those same two people; all of these otherwise enjoyable activities can and will suffer from the dopamine aftereffects of using them too often. This is why we catch ourselves losing interest from time to time in doing things we normally enjoy. And this is also where the trap lies.
When exercising becomes a bit dull, people start bringing an energy drink, put on a song playlist or get a gym buddy to join for the work out. If the excitement from watching a sports game starts to fade, people combine it with some pizza, drinks, invite people over to watch together, bet on the match… In order to maintain the pleasure from an activity, people start to layer multiple rewards onto a single routine. Those multiple rewards combined in one, synergize to squeeze greater dopamine release than it would otherwise, providing a more profound sense of pleasure. Although that might sound harmless at first, combining multiple rewards is detrimental for our capacity to produce dopamine in the long run. That’s because by layering multiple rewards you essentially add new conditions to a single activity that will have to be met from now on in order to get the sense of pleasure. Simply watching a football match without any beers, pizza or betting, not only doesn’t feel good anymore, but it may even start to feel lame. No mobile phone, or having the gym buddy cancel for today, are good reasons for you to skip work out altogether. Multiple rewards entangled in a repetitive routine will have their effect on the dopaminergic system normalized, just like a single repetitive reward does. Layering rewards creates a vicious cycle of seeking more rewards for a burst of pleasure, only to soon leave us worse off than we started.

How to optimize the functionality of the reward system?

Short answer, randomize how often and how many rewards you allow to yourself during an activity.
The point is not to always avoid combining rewards. The point is to avoid combining the same rewards and regularly. Remember that if the reward becomes too predictable, that’s when the dopamine release becomes less and less. It’s not bad to go to the gym with a friend. It’s not bad to listen to music while taking your walk. It’s doing those things routinely and predictably that it’s not efficient. It’s by letting the brain predict what’s going to happen next that we start losing motivation. In general, the rule is to shuffle the routine often enough so we can keep doing what we enjoy, while making it too hard for the brain to predict. For example, if you like watching movies, you can choose how often you let yourself to have pop corn and soft drinks along. Allow your brain to experience that movies can also mean watching something alone on your couch without all your friends. If you like walking, exercising, reading, allow your brain to experience that these can also occur without coffee, energy drinks or mobile phones. Try to randomize how often you combine your daily activities with other rewards like food, drinks, friends etc. This strategy may sound like you’re undermining your favorite activities, but it actually does the opposite. Although counterintuitive, randomizing whether or not you will allow your brain to experience additional rewards during an activity, is the best tactic in order to optimize the neurophysiology of your dopaminergic system and keep you motivated and engaged in those activities in the long run. This is what makes industries like social media and betting companies, among others, so popular and sustainable. You can never know what card will be drawn next from that deck just like you can never know if and how much your next Instagram photo will be liked. The inability to predict those things is what keeps our interest burning, dragging us to keep coming back for more. This is also the foundation of how they become addictive.

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Bromberg-Martin, E., S., Matsumoto, M., Hikosaka, O. (2010). Dopamine in motivational control: rewarding, aversive, and alerting. Neuron. 68(5), 815–834.