My dog barks too much. What can I do to keep him quiet?

 There are eight ways, and eight ways only, to change undesired behaviour.
Karen Pryor in her ground breaking book, Don't Shoot The Dog describes the eight possible methods of changing undesired behaviour, both in humans and in dogs. There are four negative methods for STOPPING unacceptable behaviour & four positive methods to TEACH an alternative acceptable behaviour.
Method 1: Shoot the Animal  X
Method 2: Punishment  X
Method 3:  Negative reinforcement X
Method 4: Extinction ?

Method 1.
Shoot the Animal. Firing an employee, divorcing a spouse, selling a dog or having its vocal cords cut are all variations of the same method. If you make it impossible for the behaviour to happen in your presence the undesired behaviour, as far as you are concerned, is forever eliminated.
                    Even when used as a last resort surgically de-barking is ethically questionable. In some Australian States, & several countries overseas, it is illegal. Putting a dog to sleep is severe and very final. Either way, the unfortunate dog learns nothing.

Method 2.      Punishment. Hitting the dog, spraying it in the face with water, or giving it an electric shock may temporarily suppress on-going behaviour. However, again the dog learns nothing - other than to distrust people and be confused, fearful & sometimes defensively aggressive. When it re-offends the punishment is often escalated to the point of violence and abuse.

Method 3.      Negative reinforcement always includes a punisher and often has undesired side effects such as avoidance, resistance, and passivity. An example of negative reinforcement to stop barking is shining a torch at night into a barking dogs eyes at night (a punishment) & then turning it off when the dog stops barking.

Method 4.      Extinction. Bad behaviour that is totally ignored for long enough usually tends to disappear or extinguish, as in a dog that has developed a habit of begging for food at the dining room table. However, a dog that barks at the disappearing postman is self-rewarded. The behaviour will likely remain unless one of the four much more practical positive methods, below, of changing behaviour is used.

 Method 5.     Training an incompatible behaviour. A dog that has learned to sit instantly on request cant jump onto people. Similarly, being in a drop position is incompatible with barking.

 Method 6      Put the behaviour on cue. Using reward based training it is easy to teach a dog to bark on cue. In the absence of the command the dog sees no point to barking.

 Method 7.    Shape the absence of unwanted behaviours. If the absence of barking, or being quiet, is frequently rewarded the dog will enjoy being quiet. Saying the words Quiet or Shush while the dog is not barking, as information, will auto-train the words so that the words soon become a meaningful & instantly obeyed instruction to be silent.

 Method 8.      Change the motivation and the need to bark is eliminated. Dogs that bark excessively are usually lonely, frightened, or bored!

This method (#8) is the best, as well as the easiest, of all the methods to implement. All family members can use this method safely. 

        1. A dog that is adequately exercised sleeps well at night and doesn't bark aimlessly. 
        2. A dog that is allowed inside the house, with the rest of the family pack, is less stressed and has fewer behavioural problems than an outside dog.
        3. A dog that has lots of mental stimulation, such as challenging home-alone toys and well-stuffed Kongs, has no need to find its own amusement.
Notes on barking taken from talk by Dr Ian Dunbar, Veterinary Animal Behaviourist, at a Veterinarians and Trainers Conferenc, Dec 7, 8th and 9th 2002, Nara Seaworld Resort, Gold Coast, Queensland.
 Barking blows most peoples minds, most owners - and trainers (especially those who use punishment) - havent a clue what to do!
 What is training? 
  1. Getting behaviours we want by putting the behaviour on cue by saying the word
  2. Eliminate behaviours we dont want
 Five rules to follow:
  1. Reward the dog when it is doing something right (like being quiet).
[Most people, and many trainers, do the exact opposite they ignore a quiet dog and punish a barking dog, shouting at it or throwing things at it. The dog often thinks the owner is joining in the barking game and barks even more! ]
  1. Every barking spree is a training opportunity to reward cessation of barking. Reward instantly.
  2. Get rid of dogs food bowl altogether replace a bad habit with a good habit. [When the food is in Kongs and the dog is chewing it is lying down, not up barking. (It must have an established Kong habit first, so if not, go back to puppy training using short term and long term confinement methods to creating Kong habit, etc]
  1. Teach speak on cue, quiet/shush on cue
  2. Train at first in a BPS (best possible training scenario) and then move to WPS (Worst possible training scenario). Most people try and train their dogs at 3 a.m. when it is barking at a prowling cat not a BPS!
  3. Bomb proof the speak and shush commands in increasingly distracting situations so that your dog will perform, on cue, at any time in any place.
[In many animal shelters in USA the modern way to stopping barking is to use all or none reward training method, which quickly leads quickly to silent kennels. A person walks past a row of kennels, all dogs are instantly barking. He looks for a non-barking dog and rewards it. He then keeps walking up and down and rewarding only the non-barker. Other dogs will soon start to stop and look and be quiet.
       Next day the procedure is repeated and the kennels are quieter quicker. The same thing is done for several days. At the end of a 
       week the person has a dog at his side, as an extra distraction, and goes back to the beginning of teaching what is a new
For the home dog owner to teach speak Dunbar suggests:
 1.Request (speak)
 2. Lure (anything that makes the dog bark, usually the doorbell, or a game of tug of war, growling at the dog)
 3. Response (dog barks) 
 4.Reward (good boy)
To teach Shush, when dog is barking he suggests:
1. Request (shush!)
2.Lure (whispering, clapping hands, waggling food in front of dogs nose if sniffing it cant simultaneously bark).
3.Response = dog quietens and stops barking. 
4. Reward the dog with a 'to-die-for' piece of food
 Bomb proof the speak and shush commands in increasingly distracting situations so that your dog will perform, on cue, at any time in any place. 
Recommended websites:
This is part of the website of Brisbane's Dr Cam Day, Animal Behaviour Veterinarian. It contains excellent advice on appropriate and inappropriate methods to barking problems as well as many other common problem behaviours.