Particle flow of scree in Gable Gill on Longside

We went up Longside direct up Gable Gill from Dodd Wood. The scree at the top seemed to present an easier option than knee-deep heather. I'd be instinctively wary of the bigger block scree but this turned out to be more stable than the smaller scree. Two possible ideas for why:
1. Smaller particles can pass each other more easily. Each one has a smaller surface area and thus will experience less friction so will flow more easily.
2. The larger blocks are heavier and have more inertia. Hence each individual block needs a bigger force to get it to move.
It's probably a combination of the two factors. We did make it to the top and here's the view...