Love is a complex mix of feelings, behaviors and beliefs associated with strong affection, protectiveness, warmth and respect for another person. It’s a cherished topic for philosophers, poets and writers. People also use the word to describe their feelings for non-human animals, for principles and even for religious beliefs.

When you say you love someone, what are you really saying? Is it simply that you find them attractive, or is it something more? How can we measure and understand this powerful emotion?

Although love is often a topic of debate, scientists have a few ideas about what it may mean. For one, the brain’s primary reward centers activate when we see someone we like. At the same time, a jumble of chemicals, including dopamine (pleasure), adrenaline (fight or flight) and norepinephrine (alertness), make us feel an intoxicating rush of euphoria. These feelings may be what we call romantic love.

Scientists believe that love can be broken down into three categories: lust, attraction and attachment. Lust is driven by sexual desire and an evolutionary need to pass on genes. During lust, parts of the brain that help us detect danger and make decisions become deactivated. It’s why you might do something silly, or perhaps dangerous, to impress someone you love.

As we fall deeper in love, our feelings of euphoria fade and are replaced with those of attachment. At this stage, the brain releases oxytocin (the “cuddle” hormone) and vasopressin (a chemical that generates feelings of bonding). These chemicals help us develop close relationships. They may also explain why you might spend all day thinking about your partner, or why your cheeks flush and palms sweat when you talk to him or her.

But the onset of attachment does not necessarily signal the end of romance. In fact, researchers have found that monogamous voles can continue to display a romantic preference for the familiar over the new, even after their brains are blocked from producing oxytocin and vasopressin. This is likely due to the innate sense of companionship that many people attribute to love.

There’s a lot more to happiness than feeling positive or laughing a lot. It’s also about knowing who you are and proactively making choices that align with your values. Happiness comes from contentedness, not always having things go your way, and being satisfied with your current life.

So if you’re looking for the next big thing, be careful not to miss out on the little pleasures in life that can make you just as happy. Sunshine, being able to climb into your clean bed, and seeing an old couple holding hands are all proven to make you happier. And don’t forget to tell those you love how much they mean to you! They’ll appreciate the reminder. It’s a small gesture that can have a big impact. Research has shown that people who are highly satisfied with their marriages live longer than those who are less happy in their relationships.