Everyone has his or her own personality. But a new study says most people’s personalities can fit into four types. They are optimistic , trusting, pessimistic and envious . The study was done by a group of Spanish scientists. They divided 541 volunteers into pairs, and put them in different situations, according to Science Daily. They wanted to see how the volunteers dealt with the difficult situations. For example in one situation, two people could hunt deer together, but could only hunt rabbit if they decided to hunt alone. Scientists then used computers to classify (分类) volunteers according to their behaviors. The result shows that 90 percent of the volunteers belong to the four types. Among them, the envious is the most common (30%). These people don’t care if they succeed, as long as they are better than the other person. In the hunting game, they will choose to hunt rabbits. That way they can hunt by themselves and try to catch more rabbits than the other person. The optimistic (20%) believe they and their partners will make the choices (选择) that are best for both of them. They will choose to hunt deer because that is the best for both hunters. The pessimistic (20%) don’t think any choices are good enough. They usually choose the one that is least harmful. So they will go for rabbits because that way he or she is more likely to catch something. And the trusting (20%) always work well with others, without worrying too much about whether they win or lose. So in the hunting game, they will choose to hunt deer without a second thought.