If you’ve ever wondered why some people just seem happier than others, there may be an answer. Part of the difference comes from people’s feelings of control over their own lives. In fact, this idea of whether our lives are controlled by internal or external forces is part of our personalities. Thankfully, it is a part we can change.

When we talk about these ideas of control, we use two terms: internal locus and external locus. People who have an internal locus of control feel their actions are directly responsible for what happens in their lives. If their car breaks down in the middle of an intersection, they may say, “I should have done better routine maintenance” or “I didn’t do enough research before I bought this lemon.” On the other hand, people who have an external locus of control believe what happens to them occurs because of external factors. In the same situation, they would respond: “The guy who changed my oil probably screwed up my engine” or “The people at that car manufacturer make crappy vehicles.”

Of course, these loci of control don’t just involve who we blame when something goes wrong in our lives. It can also involve who we credit when something goes right. If you get a promotion, for example, is it become of your hard work over the years (internal locus) or because nobody else wanted the extra work (external locus)?

While it could be argued that in some cases, both the external and the internal loci arguments have validity (for instance, the car maker may build poor quality cars AND the buyer should have done more research), here’s why the internal locus people are happier: you can only control you.

People who have an external locus of control are always fighting a losing battle to control the actions of others in order for their happiness to be preserved. On the other hand, people who have an internal locus of control know they can make changes that can bring about their own happiness.

So which one are you? Spend some time listening to your own thoughts when things happen. If you find yourself pointing fingers at forces outside your control, then start changing your self-talk. If you start to blame the manufacturer for the car trouble, ask yourself what you should have done differently. In this way, you are taking back control over your life and your happiness.

As I said above, this is part of our personalities but it is not hard-wired into us. How we view the forces shaping and controlling our lives comes from our families, our friends, and our socialization. You are not pre-determined to have an external locus of control. By recognizing how your thinking could be hurting your ability to build real happiness for yourself, you can move forward and fight back against your old mode of thinking about the world. Then you are more likely to find happiness.