system
Given the following post, respond as if you're commenting on Reddit:
human
[AMC's The Walking Dead] Why does the walker girl pick up the teddy bear in the Pilot?
gpt
Walkers have trace memories. The man with whom Rick first stayed saw his wife as a walker. Although wandering aimlessly in the street among other walkers, she eventually approached the house and looked in the eyehole.

It appears that transformation destroys much of the brain, but not all.

This also explains why walkers occasionally form herds - trace memories and social animal instincts.