The time that you are talking about is also the point at which examples of art start to appear, so a fair approximation of what was going on can be explored through looking at the emergence of this 'non-functional' aspect of human development
eg
http://en.wikipedia.org/wiki/Cave_painting
IMO people probably thought pretty much like they do now, but had a more specific set of problems to occupy them, like food, shelter and safety. It's heartening to think that even then music (and presumably dance) were important.