It Really Does Pay to Be Nice -- Growing Research Links Friendship and SuccessScience has concluded that workplace friendships, far from being distractions, are essential to being effective on the job.

If you've read your share of popular business books over the past few years, you're probably familiar with the following suggestions for improving your performance at work.

Focus on the important, not the urgent.Cultivate smarter habits. Resist multitasking. Manage your energy, not your time.

Now, here's another piece of advice that's equally essential, though rarely dispensed:

Invest in building close workplace friendships.

Related:The Benefits of Having Friends in the Office (Infographic)

Over the past few decades, researchers have gathered compelling evidence that meaningful connections are vital to our psychological and physical well-being. As I describe ina new book on the science of top workplace performance, studies also suggest that feeling close to our colleagues is essential to being effective at work.

Now, let's face it: Many of us have a hard time taking the importance of colleague friendships seriously. After all, close workplace relationships are often a source of gossip, favoritism and distraction. It's also easy to confuse friends at the office with a lack of professionalism, or the notion of fooling around.

But studies suggest that's exactly the wrong way to think about what happens when we're working with friends. In fact, many scientists now believe it's impossible to perform at our bestunlesswe feel connected to others.

Here's why.

When we feel connected to our colleagues, we can pay less attention to whether or not we're fitting in and direct our full attention to actually doing our work. We experience less anxiety in the face of setbacks and perceive greater support from those around us. We're also more willing to ask for help when we need it, which gives us more resources for achieving our goals.

Still not convinced? Then consider what happens when people feel isolated from their colleagues on a daily basis. They experience loneliness, which can have a crippling effect on the human body, beyond regular work hours. Lonely people have more stress hormones coursing through their bloodstream, take longer to relax and struggle falling asleep. That is why extended bouts of loneliness can bring about memory and learning deficits.

To build closer friendships with your colleagues, consider these three tips, based on the research on lasting friendships:

Search for similarity.

Studies show that similarity is a basic building block of human friendship. Here's how you can put that insight to use: Strike up conversations about common interests you share with colleagues. Anything from rooting for the same sports team, binge-watching the same television show, or raising kids that are around the same age. Research shows that the more colleagues talk about non-work topics, the more likely they are to be friends.

Related:How Office Friendships Could Affect Your Bottom Line

Find areas of common struggle.

Look for collaborative assignments where you and your colleagues need each other to succeed. It's easier to connect with coworkers when it's clear you're both on the same side and neither one of you can get the job done alone.

Build friendships in the spacesbetweenwork.

Workplace friendships don't happen in the conference room. They emerge in the spacesbetweenwork, before and after team meetings, in the office kitchen, or on the walk to the subway or parking lot.

Now, what if you're a freelancer or business owner who spends all day working alone? Are you destined to underperform because you lack close workplace friends? Not necessarily. Here are three tips for expanding your network and avoiding the loneliness trap:

Meet your competitors.

It seems counterintuitive, but chances are you have a lot in common with rivals. After all, you're both doing the same for a living.

Meeting informally (say, for coffee) can be surprisingly fruitful on a personal level and almost certainly valuable on a professional level. It may lead to a referral in the future, and is likely to get you thinking of new business ideas.

Grow your friends network.

Carlin Flora, author ofFriendfluence, describes friends of friends as the "low-hanging fruit" of a budding network. Your future friends are probably not people you don't know at all, but rather people you currently know indirectly. Inviting a distant contact for a cup of coffee or lunch might feel temporarily awkward to you but is likely to be perceived as flattering by the recipient.

Find an interactive hobby.

We tend to form close relationships when we're doing things in the company of others. Consider signing up for a new class, or join a club that specializes in an activity you currently enjoy. All the better if it involves physical exercise.Studies showthat exercise can lift your mood, improve your creativity and boost your memory, benefiting your work in more ways than one.

Ultimately, how you choose pursue closer friendships is a matter of personal preference. The important thing to remember is this: All work all the time doesnotmake you a more productive. Quite the opposite. It may, in fact, be the very thing holding you back.

Related:How Important Your Workplace Friendships Are Depends on Your Age