Evidence for such negative pressure is inconclusive [1]. Such an effect may be more a result of socioeconomic status, not intelligence. As for a counter example of positive pressure on intelligence, I would expect the trait of humor [2], an attractive trait that is a by product of intelligence, to increase the probability of fertility.

1. http://en.wikipedia.org/wiki/Fertility_and_intelligence 2. Kaufman, Scott Barry, et al. "The role of creativity and humor in human mate selection." Mating intelligence: Sex, relationships, and the mind’s reproductive system (2008): 227-262.

Why are you assuming that the sheer number of first-round offspring generated is the only winning strategy for genes? It's a heck of a lot more complex than "who can pop the most babies the most quickly".

What about the multi-generational odds of survival and reproduction? What about surviving famines or predators? What about competition in sexual selection?

Idiocracy was an amusing movie, but it's underlying premise was never realistic.