09/05/2013 09:02 BST | Updated 08/07/2013 06:12 BST

Alex Ferguson Is an Alpha-Male Primate and This Is Why He Was a Great Manager

What is the secret of Manchester United's manager Alex Ferguson's success? No, it was not primarily the quality of his players nor the money he had to spend on attracting international stars. We know this because before he moved to Manchester more than a quarter of a century ago, he took the Scottish team Aberdeen, with its squad of mediocre players, to unprecedented heights of the Scottish league.

Alex Ferguson's gift is to be a dominant, alpha-male primate, who maintains the perfect balance between ensuring that his young male players pay proper obeisance to his dominant status on the one hand, while nurturing them like a protecting father on the other.

Anyone who threatened his absolute dominance of the primate troop which is the basis of all human groups, was expelled unceremoniously irrespective of their supposed skill and indispensability to the team: Jaap Stam, David Beckham, Ruud van Nistelrooy and Roy Keane were all swatted away like the junior male challengers to the primate throne which they were. (Although as a fellow Glaswegian, I have to say that my strong hunch is that wearing a hairband on the pitch was really what did for Beckham in Ferguson's mind).

Being a leader is stressful, and one of the best antidotes to stress is the power that goes with leadership. Power means having control over things which other people want, need or fear, and Ferguson had this in spades. Power makes you smarter, bolder, goal focussed, strategic in your thinking - as well as more confident, less depressed and less anxious. It does this by changing brain chemistry via the hormone testosterone.

The power and prestige which Ferguson accumulated over his years at Manchester United built all these capacities in him, leading to his team's huge success. But the more successful he became, the bigger the egos he had to deal with among his millionaire players. Success, like power, is a strong drug which inflates egos and can distort judgment and personality.

And this is why, no matter how good a player was, if they showed the slightest hint of failing to show total respect for Ferguson's authority, they were out. It doesn't matter how good a goal scorer Wayne Rooney was - if he hadn't showed absolute submission to the alpha male, he would have been out on his ear.

For a group to function well and survive in the wild - and premier league soccer is indeed the wild - there has to be a clear and indisputable hierarchy for the manager to get the best out of his team of testosterone-fuelled players. Ferguson could tolerate the most remarkably damaging behaviour of some players - Rio Ferdinand for instance missed a drug test in 2003 and may have lost his team a major opportunity in the European championship.

So, why did Ferguson keep Ferdinand, but not Beckham, Stam, van Nistelrooy or Keane? - Rio Ferdinand did not threaten Ferguson's alpha-male authority. He broke the rules and damaged the team, but he always deferred to the boss. He was the prodigal son whom the all-powerful but ultimately protective father brought back into the fold.

Teams with a strong hierarchy have a clear alpha male leader who has a mix of more or less dominant members below him - just like an army platoon. Adam Galinsky and his colleagues at Columbia University have shown that the best teams include a mix of testosterone levels and that teams with too many dominant players perform worse. Players like Beckham and Keane who got too big for their boots threatened not just Ferguson's ego, but more importantly from his point of view, threatened the efficient functioning of the team.

But Ferguson's management greatness was not just down to raw primate dominance. He managed his huge success and considerable power well, not allowing it to inflate his ego too much and avoiding the trap which befalls so many successful people - hubris. My hunch is that he was protected from the narcissism and ego-inflation that great power and success often bring, by his devotion to the greater cause which was Manchester United.

Leaders need to have an appetite for power, otherwise they find leadership too stressful. But power is a strong drug and can tip people into strange and self-defeating behaviours. The great social psychologist David McLelland showed that where the appetite for power was leavened with what he called 's-power' - an appetite for power for the greater good of a group or community - led to less susceptibility to power's addictive and corrupting properties. My hunch is that Ferguson's greatness and his having coped with so much power and success, is down to a health dose of 's-power'. @ihrobertson

But Alex will still be hooked on this powerful drug and he will find it very, very difficult to come off it, as we saw in his tears yesterday as he announced his departure. But ultimately, his devotion to the strange and wonderful cause which is Manchester United, will see him recover into the satisfying afterglow of leadership greatness.