Lennie, who had been watching, imitated George exactly. He pushed himself back, drew up his knees, embraced them, looked over to George to see whether he had it just right. He pulled his hat down a little more over his eyes, the way George’s hat was.
– John Steinbeck
Of Mice and Men, Chapter 1. This shows George’s influence on Lennie. When George washes his face, Lennie mimics him exactly. George acts like a parent to Lennie, who looks up to him as a role model.