"Former" and "latter" are referring to the subject(s) of the previous sentence. For example, if I say "apples and oranges are fruit"... In this context, "the former" = apples, "the latter" = oranges. "The higher" implies that if the former (whatever it may be) IS higher, it will have the effect that the rest of the sentence describes. "the more developed" is doing the same thing, except with development instead of height. There should also be a comma between "are" and "the". I hope this makes sense. Don't worry too much about this, as I don't think a lot of native English speakers usually speak like in this sentence.