Oh, and with the help of the wikia, hold on a moment. All praise the all-knowing and almighty wikia! Anyways, there is a thing where if your intelligence is 3 or lower, you are treated like a retard. Duuuh, I guess you should look stuff up before complaining about it! http://fallout.wikia.com/wiki/Dean_Dewey
No need to be rude Mettaur. And besides, a single, incredibly obscure encounter at an easy to miss place, that doesn't have any quests tied to it is hardly a good comparison with the retard mode that the earlier games offered. I played this game pretty thoroughly and I had no idea of this being an option. You yourself admitted that you had to dig through the wiki archives to spot this.
I mean, playing a low intelligent character was a whole different experience. I'm always reminded of this hilarious moment from Fallout 2. One of the first settlements you got to has a village idiot named Torr. Torr needs help guarding the Brahmin but it's really hard to communicate with him since most of the words he can muster is his name, moo-moos and bugmen (what he calls radscorpions). However, if you happen to be dumb like him, you will actually have one of the most intelligent conversations you will find in the entire game.
It goes something like this:
Torr: Me Torr (I'm Torr. Can I help you with anything?)
You: You Torr (Hello, Torr. I do have a few questions for you.)
Torr: Me guard moo-moos from bugmen. (I guard our family's brahmin herd from ferocious nocturnal
attacks by bipedal, carapaced creatures that I call bugmen.)
You: Gugmen? (Bugmen? Well, that seems an appropriate appellation from your description. Tell me
more about that.)
Torr: Bugmen take moo-moos at night. Torr scared! Hep Torr? (Well, as I said, they are nocturnal in
their feeding habits. I sure could use some assistance in guarding the grahmin. Will you kill any
bugmen that you see near the brahmin?)
...and so on.
Torr also turns out to be one of the best guides in the town, telling you everything that you need to know about what's going around the place but this help is only available if you're "dumb enough" to understand him.