On the other hand, if I tell him that a certain undesirable thing will happen if he follows a course I have forbidden, that thing invariably happens.
I have made it to their interest to do what I want done.

For example, the best all-round man on a long sledge journey got more than the others.

A record was always kept of the game secured by each Eskimo, and the best hunter got a special prize.

Thus I kept them interested in their work.

The man who killed the musk ox with the finest set of horns and the man who killed the deer with the most magnificent antlers were specially rewarded.