If it was lower how would we know? Collective memory seems to be defined as "the shared pool of memories, knowledge and information of a social group that is s

If it was lower how would we know? Collective memory seems to be defined as "the shared pool of memories, knowledge and information of a social group that is significantly associated with the group's identity", and I don't really know what information is significant to the human identity. That number also seems to really depend on how we define "shared human memory" given that there's been something like 100 billion people on the planet over time and we don't remember the vast majority of their days, conversations, dreams, or poops.