No, just one villager, then the whole tribe elevates in some understanding, ability to heal I guess. I usually take one villager at a time to each of 6 plants, watch to see if if says they "Improved" (check the job on their details, medicine I think). If they just don't "get it" at all afte 2 hits then I release them to other jobs and try another. Usually at least one will respond and improve in that and respond to the rest of the plants and get points. If so, I make them tribe doctor. Altho I think once he or she responds to each plant, then all the rest have the healing ability if you drag them to a sick one. Usually the one you made doc will go to the sick on their own. When nothing much else to do, like I've got everybody working on tech points, I still take that villager around repeating the plants which gives him more points each time it says "Improved" Otherwise they only get points for healing, this get him closer to getting master doctor.