It simulates a small group of experts making group decisions; whatever wouldn't be too cumbersome. If you have more than 6 players, you could consider splitting into smaller groups.
There is no minimum number. This could be a solo game. Either you (the player) could take on all the roles of a group of experts, or come up with some suspicions as to why the aliens wanted to interact with only one human and why that human was ... your character.
