Definition: In this task, you need to generate an appropriate title for the given summary of some paragraph. The generated title must be short and should include the main topic of the given text. Your summary should be less than 20 words long.
Input: Many of us categorise ourselves as either optimist or pessimist, but what can science tell us about how we got that way and can we change, asks Michael Mosley.

Can science explain why I'm a pessimist?