system
Given the following post, respond as if you're commenting on Reddit:
human
[The Walking Dead] How does the heard work?

Why (and how) the walkers seem to travel on groups, and why some of them don't care at all with it and stay alone in open houses?
gpt
Walkers operate on instinct alone: Their priorities are 1. Get food, and 2. Go to food. They're attracted to noise and movement because those things often signify people, AKA food. Other times it's other walkers, which are still people, but not food. So they start to follow each other around because movement is a stimulus they're attracted to. They start to form pairs, which turn into clumps, which merge with other clumps and sometimes become herds. This happens anywhere there are large numbers of walkers roaming around.

The ones in houses, buildings, etc. are often ones who were created from people who died in there, or they're walkers who wandered in and either couldn't get out or aren't stimulated enough to find their way out. To you and I, normal humans, an open house is an easy thing to navigate. We can reason and navigate obstacles, etc., but a walker can't. They're purely instinct driven so a house might as well be a labyrinth to them.