The importance of the first factor – motivation – is simple. If people do not want to change, then the chances are they will not. The research is pretty unanimous on this. When people are motivated to achieve a specific change, they are far more likely to succeed in this development. So one very powerful thing leaders can do is to make sure people feel motivated to develop.

There are two main ways to approach this. First, there is what is called intrinsic motivation. This is motivation that is fuelled not by external rewards but by internal feelings – by the fact that we find something in some way fulfilling or enjoyable. And generally speaking, this seems to be the most powerful type of motivation, so much so that recent years have seen a spate of popular books and some highly viewed TED talks on the subject.

There is second approach to motivating people though - extrinsic motivation such as incentives and praise. And while these have come in for some criticism in recent years, there is good evidence that they can still be highly effective motivators where intrinsic motivation is lacking, especially in helping people get started with development. So incentives too can be powerful tools for change.

The second element – ability – is a basic consideration in all development. People need to know what they have to do, and they need to be able to do it. Of all the factors in the model it is probably both the most straightforward and the one you are already most familiar with. In fact, it tends to be dealt with as part of the basic two-step method people use.

Usually when we talk about people's ability to develop, we mean one of three things, and if development is to be successful, leaders need to ensure that all three are in place.

• Opportunity – whether someone's role provides the opportunity to perform the new, desired behavior.
• Capability – whether someone has the necessary skills and knowledge to perform the behavior.
• Resources – whether someone has the physical resources required to learn and perform the new behavior – any equipment, time and money they may need.

The third element – psychological capital – may be a new phrase to you, but psychologists have been studying it for many years. Through this research, they have identified two key inner resources that significantly impact whether people can sustain behavior change: believing you can succeed (having self-confidence and optimism) and having the inner strength to see things through (having willpower and resilience).

So Psychological capital is about whether people have the self-belief they need to take on the challenge of developing themselves. It is about whether individuals will persevere, put in the necessary effort and, when necessary, adapt their approach in order to succeed. And it is about whether people have the resilience required to cope with the inevitable setbacks and challenges.

Moreover psychological capital is important for two main reasons. First, it has been shown to be a critical foundation for developing yourself. Those people who are more confident they can change, and are more able to persevere and cope with setbacks, are also more likely to succeed in changing their behavior.

Second, research shows that psychological capital can be changed and improved. And more easily than you might think. Of particular interest here are the studies showing what exactly contributes to people's levels of psychological capital. Unsurprisingly, individual factors such as personality and self-esteem have been found to be relevant. But the single biggest predictor of how much psychological capital people have is their manager's behavior and the type of work environment he or she creates. Not their life history or previous experience, but you – their manager. So as strange as it may sound, you are ideally placed to influence and improve your people's psychological capital.

The final element in our model is the external supporting environment. These are things outside individuals that you can change to help them change. This can include many different things. The physical environment, such as office design, can play a role. Team dynamics and organizational culture can be factors. Even work-life balance and the state of individuals' personal relationships outside of work can affect their ability to change behaviors in the workplace. The list of factors is long, because pretty much everything around individuals can affect them.

There are, however, three particular external factors that can both have a big influence on people's ability to develop and that can be easily improved or changed. The first is social support. Simply put, having people around you helps support you to change. Dieters and recovering drug addicts have known that for ages, which is why support groups for these individuals can be found in most cities. It is also why many of the new, emerging behavior change apps include an element of social support – connecting you with other people who are trying to change and develop.

The second factor is nudges. Nudging is a phrase commonly used to describe the techniques for changing behavior emerging from the field of behavioral economics. A nudge is simply a feature of the external environment that influences the choices people make without coercing them. Indirect suggestions, incentives and information are all examples of nudges.

For a good example of a nudge, just go into any shop. The way companies try to make product packaging attractive in order to encourage us to buy is a nudge. The way shops price items at $9.99 rather than $10, in order to make them sound cheaper and thereby influence our decision to buy, is a nudge. And the way they put chocolate in clear sight by the checkout, knowing that we are more likely to buy some if they do this, is also a nudge. Marketers are experts at nudging.

In recent years many of the techniques of nudging have been slowly working their way into the workplace. More and more business are using nudges not just with their customers, but also with their employees. And the good news for you as a leader supporting someone's development is that nudging techniques can be quick, easy and effective.

The third factor is habit structure. A habit is a routine way of behaving that tends to occur automatically and unconsciously. There have been a number books and TED talks on the subject of habits in recent years. The enthusiasm for them comes from the fact that they offer a way to turn a new behavior, which someone may be struggling to do, into a more or less automatic thing. And fortunately, habits consist of a number of very simple components - such as behavior triggers and reinforcers - that you can easily use to create a kind of supporting structure for behavior change.