Ignorance as a Commitment Device.

In a strategic environment, when a player's information acquisition is observable to others, it may strictly decrease the player's resulting equilibrium payoff even if information acquisition itself is costless. This phenomenon has previously been known by a number of examples. This paper shows that such a phenomenon can indeed arise under a broad class of conditions, not being confined to carefully selected specific examples. Excess information is almost always hurtful. This finding implies that public provision of information can strictly hurt the set of economic agents to be informed. To protect the interest of a certain economic group, it is almost always desirable to impose appropriate limitations on the official disclosure of information to the group.