According to the website PsychMechanics, there are some basics about the psychology of selfishness that we all should know:

A selfish person is the one who puts his own needs first. He's primarily concerned with himself and seeks out only those activities that fulfill his own desires and wants. Anything wrong with that? I don’t think so.

Going by that definition, we're all selfish in one way or the other. All of us want to do things that are ultimately for our own good and well-being. This type of selfishness is good and desirable.

So far so good. The problem arises when we do things for ourselves and at the same time ignore the needs of those around us or when we fulfill our needs at the expense of others. When you make life difficult for others to meet your own ends, then that kind of selfishness is the selfishness that you’d like to avoid.

There are several reasons that could make someone selfish...

A person who holds on to his resources and doesn't give it to the needy can be considered a selfish person and this is the type of selfishness that we commonly refer to when we say that someone is selfish.

When we say that someone is selfish, we usually mean that he doesn't share his resources (money, time, etc.). Now, why won’t a person share his resources, even if it's the best thing to do in a given situation?

The biggest reason is that he thinks he doesn't have enough. A selfish person, therefore, is also likely to be stingy. This insecurity of not having enough motivates a person to hold on to his resources and not share them.

Another reason is a fear of losing control. If someone has many needs and goals, then he overvalues his resources because he thinks that these resources are going to help him reach his goals. If he loses his resources, he loses his goals and if he loses his goals he feels he has lost control over his life.

For example, a student who doesn't share his study notes with others is the one who has high academic goals and sharing notes could mean losing an important resource that could help him reach his goal. And not being able to reach your goals is a perfect recipe for a feeling of loss of control over your life.

In other cases, the way a person was raised can also make him act in selfish ways. The only child or the child whose every demand was met by his parents (spoilt child) learns to take as much as he can and give very little back.

Such children learn to care only for their needs with little empathy or consideration for others. As children, we were all like that to some extent but gradually we began to learn that other people have emotions too and so developed empathy.

Some people never learn empathy and therefore remain selfish, just like when they were kids.

The most important thing to do when dealing with a selfish reason is to figure out the reason for his selfishness and then work on eliminating that reason.

All other methods and efforts of dealing with him are going to be in vain. Ask yourselves questions like...Why is he being selfish? What is he feeling so insecure about? Are you making unrealistic demands of him? Is he really in a position to meet your demands?

We are often too quick to label someone ‘selfish’ instead of admitting that we failed to persuade them or that our demands are unreasonable.

But what if they are really being selfish and you're not just falsely labeling them?

Well then, help them get rid of their insecurity. Show them that they're not going to lose anything by giving you what you want. Or better yet, show them how they may benefit by helping you if there's a possibility of a win-win situation.