It is an unfortunate fact that in the heat of battle troops often don't respond as you, their commander, might want them to. Faced with terrifying supernatural foes their courage might fail, or they could simply be too dim to understand the orders they have been given. The hatred engendered by age-long feuds can overwhelm military discipline and leave troops overcome with bloodlust at the sight of their ancestral foes. Warriors can be so overwhelmed by berserk fury that they will charge into battle regardless of their orders.
As the army commander it is your duty to know about these things and take them into account in your plans. If you do not you may find that you are defeated before you even begin.
The Psychology rules represent these factors in the game and call upon the player to make occasional tests to determine whether his troops are affected by adverse psychology. Most psychology tests are made in the same way, so we'll describe the procedure first before we look at the individual psychological factors.