Brown rice takes significantly longer to cook, so the rice cooker might not be programmed to do that.

Why would the rice cooker need to be programmed for it, though? For any given quantity of rice, the two variables during cooking is the amount of water and the power of the heating element[1].

It is known that brown rice requires a different ratio of water, but this is something that can be replicated with any method. Does the special brown rice setting change the heat output of the rice cooker?

[1]: Fancy rice cookers use non-constant power, or so I've heard. Not sure how much it influences the taste, though.

With the simplest rice cookers, there's no programming. When the water is gone, it is gone.

yep, i just add more water and the brown rice turns out fine. though i’m sure fancy 200 dollar zojirushi ones probably do it better, i’m happy with simplicity