Question: you spend two hours thinking a day, but surely there is something more productive towards your research you could do?

David Corne answered on 17 Jun 2011:

But the thinking I do is all about the research! Sorry if that wasn’t clear. I usually walk around a bit, sometimes in the woods near my office, sit by the lake, etc, thinking about how to solve the problem. This is very productive, since I sort out various ideas in my head which mean eventually I will make progress faster.