Let's face it - life is hard. As the most awkward day of the year approaches (that would be Valentine's Day, for those of you playing along at home), it's not unusual to reflect on whether or not we've made the right life decisions.

But wouldn't it be nice if scientists had done the hard work for you and studied a whole bunch of people throughout their lives to work out the key to happiness? Well, actually, they already have, and the results are in, as Vanessa explains in the latest episode of BrainCraft.

The Harvard Grant study began in 1938 and studied 268 male undergraduate students for the next 70 years, which was pretty much their entire lives.

The researchers measured plenty of psychological and physical traits during that time, such as personality, IQ, health.

And accordingly, they also came up with a lot of results, including the fact that the warmth of a man's relationships is more important to their success than their intelligence.

But when one of the lead researchers was asked what he thought the most important finding was, he answered:

"It was the capacity for intimate relations that predicted flourishing in all aspects of the men's lives… happiness is love."

But importantly, love doesn't necessarily mean marriage or a long relationship with a partner. It can also be a relationship with family or friends. In fact, the relationship men have with their mothers could predict their future income and their mental health as they age.

Of course, correlation doesn't equal causation, but other scientists have also gone on to measure whether there are factors in a relationship that can predict whether a couple will break up or stay together. They found that, surprisingly, they could actually see a physical difference between couples that would go on to live happily ever after, and those that wouldn't.

What they discovered was that the key to long-lasting relationships came down to two things. Of course, we don't want to give it all away - watch the episode of BrainCraft above to find out. And don't forget to find someone to love this Valentine's Day, even if it's just a pet, or yourself.

Source: BrainCraft