The method of conditioned suppression described in this unit involves training a thirsty mouse to make steady contact with a waterspout in order to receive a slow, but steady trickle of water and then pairing a sound with mild electric shock delivered through the spout. The mouse quickly learns to avoid the shock by breaking contact with the spout whenever it detects the sound. This suppression of drinking is then used to indicate that the animal detected the sound. Because it is a cognitively simple procedure, conditioned suppression can be used to determine the ability of brain-damaged and genetically altered as well as normal animals to detect and discriminate sounds.