The development of new ideas and more knowledge is the biggest growth accelator, for society and individuals alike. 

>> I’m not convinced this is correct. I think the incentives of the systems within which we operate are possibly more important than knowledge in terms of growth accelerants.

Therefore, please tell me, if your objective was economic growth, should you rather spend time with and talk to someone who was totally different from you, or with someone who was almost identical to you?

>> It depends. If the other person is ‘too different’ I may not be able to comprehend his outlook. The energy lost to the cognitive dissonance (when encountering someone wildly different) may detract from understanding the alternative views/methodologies on offer. 

 Yes, a bit of a chicken and egg problem.

Provided we could speak a common language, I would see more potential value in speaking with someone very different from me than someone who was very similar to me. Because it seems more likely we both would learn something new from each other and develop something new together than if we were almost the same. 

 People full of emotion. Me rather read and attempt objectivity.  

 I see, but progress also comes from copying people's behavior, which express actionable ideas. You don't learn that from books, at least not very efficiently.