It's an age-old battle. Pessimists think optimists are foolish; optimists think pessimists make themselves unnecessarily miserable. A lot of research has been done on this issue in the last 30 years. Have we answered the question yet? Is the glass half-full or half-empty?
Martin Seligman and his colleagues at the University of Pennsylvania found that optimistic people are happier than pessimists. When something bad happens, optimists think of it as temporary, limited in its effect, and not entirely their fault. Pessimists do the opposite. They consider the setback to be permanent, far-reaching and all their fault.
There are varying degrees of this, of course; it’s not black or white. Most people fall somewhere between the two extremes. The main difference between optimists and pessimists is how they explain setbacks to themselves. Using these definitions, researchers find that optimism contributes to good health and pessimism contributes to illness.
In several large-scale, long-term, carefully controlled experiments, Seligman discovered that optimists are more successful than pessimists - optimistic politicians win more elections, optimistic students get better grades, optimistic athletes win more contests, optimistic salespeople make more money.
Why would this be so?
Because optimism and pessimism both tend to be self-fulfilling prophecies. If you think a setback is permanent, why would you try to change it?
Pessimistic explanations tend to make you feel defeated - making you less likely to take constructive action.
Optimistic explanations, on the other hand, make you more likely to act.
If you think the setback is only temporary, you’re apt to try to do something about it, and because you take action, you make it temporary.
It becomes a self-fulfilling prophecy.