A study published in 2016 in a bulletin of Hiroshima University examined how speakers reach agreement in discussion. When native speakers of Japanese gave a negative response, they used demo or kedo, but, only once, and almost no other connecting words. They often delayed their responses instead. The study suggests that they delayed in order to prompt the other person to adjust their opinion.
In one example from the study, a native speaker softens a rejection with nanka, a filler, and a pause, and then proposes an alternative instead of stating the disagreement.