We All Share an Evolutionary Purpose
As human beings, we are all designed for a purpose. From an evolutionary perspective, that purpose is the same for all of us: to survive long enough to reproduce. In order to motivate us to achieve that goal, our bodies come hardwired with an internal reward system engineered to make us want to take the actions required to keep the species going. This reward system delivers a diverse menu of chemicals, but there is one that is fundamental to them all: dopamine.
Dopamine is commonly referred to as the “happy hormone,” but it does a lot more than just make you feel good. It provides motivation to take action, and actually is the precursor to the process that actually gets your muscles to move. It is also involved in the process of memory formation, but yes – it also makes you feel good because all of those functions are necessary to let your brain know that you are actually making progress on the path towards purpose.
How Dopamine Works
You can understand the way dopamine works within your own reward system by thinking about a process critical to survival and reproduction: eating.
When you get hungry, you feel motivated to find food: that’s dopamine. Once you find the food, you experience pleasure as you eat it: that’s also dopamine.
But the interesting thing about this reward system is that while it rewards you for the goals required to pursue your purpose, it doesn’t reward you for actually achieving that purpose.
The actual purpose of finding and eating food is to convert that food’s energy into the glucose needed to power your mind and muscles for another day. But that conversion process, which occurs during digestion, doesn’t even register on your reward system.
Whatever the goal, we receive our dopamine reward when we think about taking actions in the pursuit of an ultimate purpose – and as we execute the actions required to pursue that purpose – but not for the actual fulfillment of the purpose itself. The brain gives us dopamine to get what it needs from the body, but once it has what it wants it cuts off the reward source completely.

We All Have Our Own Personal Purpose
The human reward system evolved to make sure our ancient ancestors pursued necessary activities like eating and sex, but today most of us live well past the age where we are able to reproduce. But the internal mechanisms that keep us motivated and happy remain the same, and they are all based on the same chemical of dopamine.
Take your work, for example. When you land your first job, you have an idea of the type of value you want to create in the world, and you develop a mental image of what a successful career would look like. As you begin to take actions that move you toward that goal, you feel very motivated and have the energy to work hard in the pursuit of your dreams.
When that effort pays off in the form of pay raises and promotions, you feel extra good because you know that you are moving forward on the path towards your purpose.
But as you approach the latter part of your career, you may notice a lack of energy motivating you and instead you get a general feeling of angst about your job and even life in general.
That is because the dopamine reward structure that you built up over time was based on achievements that, by definition, had to occur before your career was over. As that end approaches, the dopamine reward structure begins to shut down, and the good feelings are replaced by stressful ones.
Whether evolutionary or personal, your goals are only rewarding as they are pursued, not after they are achieved.

There Are Actually Two Different Types of Dopamine
Because dopamine is based on the pursuit of a future purpose, Harvard professor Daniel Lieberman differentiates it from what he refers to as other “here and now” happy chemicals – such as oxytocin, serotonin and endorphins.
Based on the above understanding of how dopamine works during both the initiation and execution of goal pursuit, however, I would argue that there is also a “here and now” component to dopamine itself.
I refer to the future-oriented, motivating energy that comes from thinking about goal pursuit (like when we are hungry, horny or hired) as “On The Path” dopamine, or OTP dopamine for short. The present-tense, pleasurable energy that we receive from executing our goals (which we get from activities like eating, sex and a job well done), then, could be considered the “here and now,” or H&N dopamine.
Joy Comes From Balancing OTP and H&N Dopamine

Why differentiate between these two types of dopamine sources? If we are rewarded for pursuing goals, isn’t it enough to just set a goal and go after it?
If we were actually rewarded for goal completion, then the answer would be yes. But because our goals stop being rewarding after they are achieved, it’s necessary to understand how to react when we feel ourselves becoming less happy even as we are accomplishing the things we set out to pursue.
When the pleasure of “here and now” happiness subdues, it’s time to reassess how to get back on the path towards purpose. That requires setting new goals that extend beyond the timeline you had previously set for success.
As you play that process out towards the future, eventually that means coming up with an ultimate goal – a purpose which would establish a perpetual reward system because it could always be pursued.
It’s not enough to just think about doing the right thing. It’s not even enough to actually do it. You have to keep doing the right thing over and over again in order to live into your human design.
When you can intentionally articulate an overarching mission to guide your actions, and a set of values that keeps those actions aligned with a sense of purpose, you can tap into something far greater than the happiness of future motivation or the pleasure of the present moment.

You can experience the joy that comes from consistently living your ideal life.