Trobrianders tended to use magic in situations of great uncertainty (such as fishing in the open ocean) and not use magic in situations where they could rely on their own skill (such as fishing within the reef).

Trobrianders tended to use magic in situations of great uncertainty ((such as fishing within the reef) and not use magic in situations where they could rely on their own skill (such as fishing in the open ocean).

Trobrianders tended not to use magic in situations of great uncertainty (such as fishing in the open ocean) and to use magic in situations where they could rely on their own skill (such as fishing within the reef).

Trobrianders tended not to use magic in situations of great uncertainty (such as fishing within the reef) and to use magic in situations where they could rely on their own skill (such as fishing in the open ocean).