Theories of Motivation: Why We Do What We Do

Why do humans do anything?

Seriously! Why do we get out of bed, chase careers, run marathons, or suddenly reorganize the spice rack at midnight?

The answer is motivation: the invisible engine that powers everything from survival to self‑expression.

Psychologists have spent decades trying to crack the code of motivation. The result? A whole buffet of theories, each offering a different explanation for why we do what we do. Some focus on survival needs, others on rewards, others on the joy of the task itself.

No single theory tells the whole story, but together they give us a fascinating map of human behavior.

This article is your guided tour through the major theories of motivation from the classics to the modern updates to the biological underpinnings, and even how they play out in the workplace (and your living room).

Along the way, we’ll also link to our deep dives where you can nerd out on each theory in detail.

Buckle up: science is about to explain why you’re reading this instead of folding your laundry.

What Are Theories of Motivation?

At their core, theories of motivation are frameworks that explain why we act the way we do.

They’re the “why” behind the “what.”

Why do you crave pizza? Why do you study for exams? Why do you keep checking your phone even when you know nothing new has happened?

Motivation theories matter because they help us understand behavior in real life, whether that behavior is happening in classrooms, in workplaces, in sports, or in our own personal goals.

They’re not just abstract psychology; they’re practical tools for making sense of ourselves and others!

So let’s take a tour of the greatest hits of motivation theory, starting with the classics that laid the foundation.

Classic Foundations of Motivation

Before psychology got all fancy with brain scans and acronyms, the earliest theories of motivation were focused on the basics: survival, performance, and why we sometimes act like hungry raccoons chasing shiny rewards.

These “classic” models may not explain everything, but they still nevertheless laid the groundwork for how we think about motivation today.

Maslow’s Hierarchy of Needs

Maslow’s pyramid is probably the most famous diagram in all of psychology.

At the bottom are the basics: food, water, shelter, and sleep. Once those are satisfied, we climb toward safety, belonging, esteem, and finally, self‑actualization: the pursuit of meaning and creativity.

Maslow’s big idea was that unmet lower needs block higher ones. For example, you’re unlikely to write a novel if you’re still worried about how you’re going to be able to pay rent.

Want the full breakdown? Check out our Maslow’s Hierarchy of Needs guide.

Drive Reduction Theory (Hull)

Drive Reduction Theory says we’re motivated to act when our body drifts out of balance.

Hungry? Eat. Tired? Sleep. Thirsty? Water.

It’s like your brain is constantly running a “balance check” and nudging you to fix the gaps. While it doesn’t explain why people chase goals beyond survival (like running ultramarathons), it’s still a cornerstone of motivation science.

Learn more in our Drive Reduction Theory article.

Incentive Theory of Motivation

Sometimes we’re not pushed by needs but pulled by rewards. Incentive Theory explains why bonuses, praise, or even pizza Fridays can get us moving.

It’s the carrot‑on‑a‑stick approach, though, let’s be honest, most of us prefer the carrot cake.

This theory helps explain why external rewards can be powerful… but also why they sometimes backfire.

Dive deeper in our Incentive Theory piece.

Arousal Theory & the Yerkes‑Dodson Law

Why do some people thrive under pressure while others crumble?

Arousal Theory explains that we all perform best at an “optimal” level of stimulation. Too little, and you’re bored. Too much, and you’re overwhelmed.

Meanwhile, the Yerkes‑Dodson Law charts this sweet spot: the Goldilocks zone of motivation. It’s why athletes talk about being “in the zone” and why cramming all night rarely works.

Modern Expansions and Refinements

As psychology matured, researchers realized motivation wasn’t just about hunger, rewards, or pressure. After all, humans also chase growth, purpose, and meaning!

These models dig into why we pursue goals, how we weigh effort against reward, and what makes us thrive.

Self‑Determination Theory (Deci & Ryan)

Forget carrots and sticks! This theory says we’re most motivated when three needs are met: autonomy (control over our choices), competence (feeling capable), and relatedness (connection to others).

For example, a job feels far more engaging if you have freedom, mastery, and supportive coworkers.

It’s like the holy trinity of motivation. Think about your favorite job or project: chances are, it ticked all three boxes.

Get the full story in our Self‑Determination Theory article.

Expectancy‑Value Theory

This one’s all about the mental math you may not realize that you do all the time!

Here, we weigh the value of a goal against how likely we are to succeed. If the reward feels worthwhile and achievable, we’re motivated. If not, we bail.

Sound familiar?

Think of it as the difference between “I’ll train for a 5K because I can do it” versus “I’ll never run a marathon, so why bother?”

Check out our Expectancy‑Value Theory deep dive.

Achievement Motivation Theory

Of course, some people are fueled by the challenge itself. They want to win, master, or outdo their past selves.

Achievement Motivation Theory explains this competitive spark. It’s why one student studies to ace the test while another just aims to pass.

It’s about the drive to excel, not just to get by.

Explore it in our Achievement Motivation Theory article.

Intrinsic Motivation Theory

But sometimes the motivation is the activity itself. For example, you might paint because you just genuinely love painting, not because you’re getting paid.

That’s intrinsic motivation in a nutshell: joy, curiosity, and passion as the fuel.

It’s what keeps hobbies alive long after the novelty wears off.

Read more in our Intrinsic Motivation Theory guide.

Goal‑Setting Theory

“Do your best” is vague and useless. However, “Finish the report by Friday at 3 p.m.” is specific, challenging, and motivating.

Goal‑Setting Theory shows why specific, difficult goals outperform fuzzy ones. It’s why athletes aim for personal records and why SMART goals are a staple in business.

It’s also why New Year’s resolutions often flop… More often than not, they’re too fuzzy!

More in our Goal‑Setting Theory article.

Biological Bases of Motivation

Of course, not all motivation is psychological. Biology has a starring role too!

Our brains and bodies are wired with systems that push us to survive and thrive. Hunger, thirst, sex, and sleep are obvious examples, but behind them are complex networks of hormones and neurotransmitters.

Dopamine, for instance, is deeply tied to reward and drive. Serotonin affects mood and persistence. The hypothalamus regulates hunger and thirst. Even evolutionary pressures shape what we’re motivated to do: seek safety, find partners, and protect our tribe.

In short, biology sets the stage for motivation while psychology adds the plot twists.

Learn more with our Biological Bases of Motivation article.

Motivation in Everyday Life

But let’s pump the brakes for just a moment here. At the end of the day, what do these theories even really mean?

Your head’s in the right place, friend!

Theories are great in textbooks, but they really come alive when you see them in action. Motivation isn’t just something psychologists study in labs, but rather it’s something we wrestle with every single day.

It’s the reason some people leap out of bed ready to conquer the world, while others hit snooze five times. It explains why some teams thrive at work while others limp along, and why working from home can feel like paradise one day and quicksand the next.

Motivation in the Workplace

In the office, motivation is the invisible ingredient that separates thriving teams from disengaged ones. Paychecks matter, sure, but so do recognition, growth opportunities, and a sense of purpose!

Maslow’s hierarchy helps explain why employees need security before they can focus on creativity. Self‑Determination Theory highlights why autonomy and competence matter for engagement. Incentive Theory explains why bonuses and perks can boost performance, but also why they sometimes flop if they don’t align with deeper needs.

Think about it: one employee might be motivated by climbing the career ladder, another by mastering their craft, and another by feeling like their work makes a difference.

A manager who understands these different motivational levers can build a team that’s not just productive, but genuinely energized.

See our full guide: Motivation in the Workplace.

Motivation While Working From Home

Now let’s take away the office, the water cooler, and the boss walking by your desk.

Motivation suddenly looks a lot different, right?

Working from home can feel like freedom: no commute, more flexibility, pajamas all day. But it can also feel like a motivational minefield. The fridge is close, the couch is oh-so-tempting, and Zoom fatigue is real.

Here, theories like Goal‑Setting and Expectancy‑Value become lifesavers.

Clear, specific goals keep the day from dissolving into a blur. Incentives (like rewarding yourself with a walk or a snack) can help, but only if you don’t let the reward swallow the work.

And Self‑Determination Theory reminds us that connection still matters, even if it’s through a screen.

Motivation at home isn’t automatic. It takes boundaries, structure, and sometimes a little creativity (like inventing a “fake commute” or working in superhero capes).

We unpack it all in Motivation While Working From Home.

Why So Many Theories?

If you’re thinking, “Wow, that’s a lot of theories,” you’re absolutely right.

But here’s the thing: human behavior is seriously messy. No single explanation can cover why we chase promotions, binge TV, or suddenly decide to take up sourdough baking.

Motivation is multi‑layered, and each theory captures a different slice.

Maslow gives us the big pyramid picture. Drive Reduction zooms in on survival. Self‑Determination Theory highlights autonomy and connection, while Goal‑Setting shows the power of clarity. Even biology gets a seat at the table!

Sometimes these theories overlap, sometimes they contradict, and sometimes they explain totally different slices of life.

But that’s the point: motivation isn’t one neat formula. It’s a patchwork of needs, rewards, passions, biology, and context.

The beauty of having so many theories is that together, they give us a richer, more flexible map of what drives us. And the closer we get to understanding motivation, the better we can design workplaces, schools, and even personal habits that actually work instead of leaving us stuck reorganizing the spice rack at midnight.

Tomato Takeaway

Motivation is the science of what gets us moving, whether it’s survival, rewards, growth, curiosity, or connection. Theories of motivation are our best attempts to explain it, and while none are perfect, each one adds an important piece to the puzzle.

So for today’s Tomato Takeaway, here’s a challenge for you:

Think about what’s motivating you right now. Are you chasing safety, rewards, mastery, connection, or just the joy of learning? Then explore the linked articles to see which theory fits your personal drive.

Because the better we understand motivation, the better we can understand ourselves!