My experience with Japanese people (I used to work in a Japanese company and attended a lot of meetings in Japanese) listening to someone else in meetings is a lot of "Aaaa, sou sou sou sou. Sou desu. Wakarimashita. Hai. Wakarimashita. Mmmm. Mmm Mmm. Sou desu." I eventually did some of it myself. Seems like a lot of aizuchi to me :P