Question

So I have an assignment in psychology to write an essay that "argues whether or not you feel it is more important that researchers focus on individual differences or individual similarities in their studies of personality and to guide their theories of personality. Cite specific theorists/theories."
To be clear, I am not asking for someone to write the essay. I am asking for opinions,advice, help,ideas? What are your guys' opinions and why? Can someone maybe give me ideas, or reword the question to help give me a better idea of what I should be arguing? Know of any good sources I could use?