What is Lennie's personality like throughout the 1 & 2 chapters?

In the beginning of John Steinbeck's "Of Mice and Men," Lennie and George are introduced.  As George walks like a man, Lennie plods behind him,

A huge man, shapeless of face [like a child], with large, pale eyes, with wide, sloping shoulder; and he walked heavily, dragging his feet a little, the way a bear drags his paws.

Despite his size, Lennie is subservient to George, and thinks as a child.  For instance, George has to scold him about drinking so much water as Lennie submerges his entire head into the lake.  Then, he

dabbled his big paw in the water and wiggled his fingers so the water arose in little splashes...

As the two men camp out, waiting for the next day, George scolds Lennie as though he were a child, cautioning him not to drink too much water, instructing him about how to behave the next day on the job, telling Lennie that he holds his work card so Lennie will not lose it.  Then, George notices that Lennie, like a small boy, has something in his hand.  Again, he must scold Lennie, reminding him of the trouble that he got into at the other place.  Lennie gigles as he recalls.  As he lies quietly for a time, Lennie then asks Georges questions, just as a child would, such as why are they not going to the ranch today and what are they going to eat.  The "parent" George espies something in Lennie's hand.

George tells Lennie to throw away the mouse: 'I wasn't doin' nothing bad with it, George, Jus' strokin' it.'  When George alludes to Aunt Clara, Lennie looks at George sadly. for his mother-figure is now dead.  He asks George to tell him about their friendship and their "dream"; this tale is like a night-time story for Lennie, and he is lulled into comfort.  Before they bed down, George instructs Lennie about what to do if they get into "trouble," having Lennie repeat such phrases as "Hide in the bush."  Lennie falls asleep as he listens to George tell him about the rabbits they will have and the ranch they will own. Dependent upon George for thinking for him as well as for his income, Lennie is absolutely lost without George, for George is like a father-figure to him.