with the night sky so polluted as in "if the tarantula nebula was as close to earth as m42 is it would fill the night sky and be so bright it would cast a shadow",
planet inhabitants would take much much longer to even look up with conscious curiosity.
so I think I'd say: the darker (and less interesting) the night sky is the faster intellectual evolution regarding astronomy and space travel will develop.
now, that's a new criteria for searching for extraterrestrial life forms to go visit. we wouldn't want to scare them if they are assumably completely ignorant
