The AT&T U-Verse gateways don't look around to see how congested the bands are and instead default. You have to manually change the channel. Luckily for me, none of my neighbours seem to have this figured this out, leaving me the opportunity to set my APs on different channels with less interference.
reply to AggieDan I live in an apartment by my college, all of my neighbors except for 1 are on channel 11. I have no complaints though, as it leaves me 1 free non-overlapping channel, and 1 lightly used channel.