Before I get to the hard evidence, the best proof you can gather to answer this question is your own experience.

FORBES: Want Proof that Collaborative, Interest-Based Negotiation is More Durable?

One of the few exceptions was Sri Lanka, where the Colombo All Share Index rose, proof I guess that the Sri Lankans took a more benign view about whether Nick and Dave would get it together.

BBC: Go Figure: Are we related?