The Primary Motivational Factor is Situational
Jaap de Jonge, Editor, Netherlands
Overall I agree that for many people, money is an important factor.
But I think the question if it is the primary one for the motivation of some person is situational and depends on manythings:
1. Personal preferences
2. The current financial position of the person (poor or rich?)
3. The age of the person (for example; 20-doesn't need a lot of money. 25/30-earning to support family. 50-children have left the house, but may want to travel? 70+ enjoys the simple things in life - needs very little money)
4. The country and economic circumstances he/she is living in.
5. The emotional state of the person (just after a divorce or after a funeral?)
So as a manager, you're well advised to ask your employee individually what are his/her (current!) preferences.