The trainability of cats has always been put to question, mostly because of the constant comparison between them and their canine counterparts. In actuality, cats are quite intelligent and can develop better behavior or even be trained to operate simple mechanisms. The reason for this is that cats are self-sufficient whether they are trained or not. It's part of their instinct.
Another reason for the belief that cats cannot be trained is the case of aggressive cats. There are several categories that aggressive cats may fall into depending on how they exhibit their aggression. These categories are play aggression, defensive aggression, misdirected aggression and territorial status aggression. The way to handle a situation with an aggressive cat is to determine what aggression the cat is exhibiting.
A cat that is play aggressive would not make any sound while a truly hostile cat will growl as it advances. No negative stimulus needs to be put into play when a cat is in play aggression. Usually, aggressive cats in play aggression are over stimulated by the play their owner bestows on them and treats the owner just like another cat thus causing scratches or bits. But if a cat begins scratching or biting with no previous indication of violent behavior, the cat needs to be brought to a veterinarian because the cat may be exhibiting aggression due to pain from a medical problem.
Over stimulation is a big No No with cats. Once they are over stimulated, they can lash out with their teeth and claws. It is important for owners to know the tolerance level of their pets to know what activities to stay away from. Cats can also be in defensive aggression if they feel cornered or encounter something that disturbs them. In the case of disturbance, it does not usually mean something traumatizing but just something that they have not adjusted to yet.
Misdirected aggression is when a cat is disturbed by something that is different from the target of its supposed attack. The best way to get rid of this type of aggression is to take away the cause of the cat's hostility.
Very few cats exhibit territorial aggression toward people. Usually, cats vie for position amongst each other with the general idea that the provider of the food is not someone to be messed with or attacked. Breeds like the Siamese or Burmese are two that exhibit this aggression. Territorial aggression is often dealt with by professionals who can assess the behavior, identify the triggers and work at modifying them.
Owners should not hit cats to stop aggression because the cat does not understand this correction thus making it fearful or more defensive than before. For a successful try at getting rid of aggression, taking the cat to a professional is always a good idea.