Why the friendships from your first job tend to be the strongest.

They say you can’t put a price on friendship. But last year researcher Nattavudh Powdthavee did just that. He suggested that having a friend you see most days – at work, for example – has value to the equivalent of a $138,000 pay rise.

According to Jane Garner, author of It’s Who You Know: How a Network of 12 Key People Can Fast-Track Your Success, the colleague who has brought six-figure value to your life is typically one you met early on in your career, most likely in your first ‘proper’ job.

“We often find it easier to connect with people who have the same knowledge, background or work focus as us. We tend to be drawn to clusters of sameness,” she explained in her book.

“When we start working in a new job or role, we mix mainly with co-workers in our department or those at a similar seniority to us.”

This “sameness” is most present at the bottom of the ladder, before your network begins to diversify: “As we stay longer in a company, opportunities arise to expand our network simply through promotion and tenure. We may be thrown into roles that force us to collaborate with other departments or companies. We may work with virtual teams including people based interstate and overseas.”

It’s also before the competition begins. When the stakes increase, workplace relationships become more fraught, more complex – especially for women. As researchers Katherine Crowley and Kathi Elster argued in their book Mean Girls at Work, “While men tend to compete in an overt manner – jockeying for position and fight to be crowned ‘winners’ – women often compete more covertly and behind the scenes.”

If a colleague isn’t a friend, do you still have to chip in for their pressie? (Post continues below.)

The friendships that a person forges prior to that, while within that bubble of professional parity, are therefore likely to be among the strongest and most enduring they’ll encounter in their adult life, Garner argues.

“These early friendships and shared life experiences can last for a long time, particularly if you stay in the same company, industry, city or even country,” she ELLE.

A very serious and scientific poll of Mamamia staffers, supported the theory. Several count their first colleagues among their best friends. Several have travelled together. Most at least still catch up regularly.

“After eight years working together in hospitality, I can’t imagine my life without the friends I made at my first cafe job. I have no doubt the reason we’re all so close is because of the avalanche of crap we suffered through together over the years,” said one.

“I met two of my bridesmaids in my first proper job,” added another. “I think we bonded because we spent so much time together, but also because it was local, it just felt like school again. We all lived close to each other so we could hang outside of work really easily. Also the culture was great there – it attracted people who had the same interests and personality.”

In the thick of those relationships, the benefits both in and away from the office are substantial.

A 2016 Gallup Poll found that those who had a close friend in the workplace were 43 per cent more likely to report having received recognition and praise for their work in the last week.

Another from 2012 found that 50 per cent of Americans with a best friend at work reported that they feel a strong connection with their company, while only 10 per cent of those without one could say the same.

And a Relationships at Work study by LinkedIn found that 46 per cent of professionals worldwide believe that work friends are important to their overall happiness.

According to Professor Christine M. Riordan of the University of Kentucky, it all hinges on camaraderie.

"Camaraderie is more than just having fun," she wrote for the Harvard Business Review blog. "It is also about creating a common sense of purpose and the mentality that we are in it together. Studies have shown that soldiers form strong bonds during missions in part because they believe in the purpose of the mission, rely on each other, and share the good and the bad as a team. In short, camaraderie promotes a group loyalty that results in a shared commitment to and discipline toward the work."

There really is a reason those first few years are referred to as "the trenches".