Violence happened but was generally something to avoid in the paleolithic due to the risk. It was too costly and it wasn't until the neolithic were population sizes high enough to make that cost worth while, and grain and resource storage made a worthwhile reward. Systematic warfare didn't appear until the neolithic, that's when we begin finding mass graves of peoples slaughtered by weaponry and more depictions of warfare in art.

The reason for the mass graves of course, is the increase in human population as a result of agriculture. It's not necessarily that as a percentage, you were less likely to be a victim of violence in the Paleolithic era.