Understanding reinforcement is the key to understanding how learning takes place. From a behaviorist’s perspective, each day is made up of a series of behaviors that are either reinforced or not reinforced. This is true for both animals and humans. The reinforcement that occurs, along with the strength and timing of that reinforcement, will determine whether the behaviors are likely to occur again.
Reinforcement occurs when a behavior, followed by a consequent stimulus, is strengthened, or becomes more likely to occur again.
A stimulus is any object or event that can be detected by the senses and that can affect a person’s or an animal’s behavior.
Stimuli (the plural of stimulus) can be sounds, food or drinks, smells, touches or visual signals.
In dog training, trainers are said to be providing reinforcement when they provide consequences that increase or maintain a behavior. Some examples of stimuli that affect behavior in dogs include verbal commands, encouraging noises, clickers or whistles, food treats, pats or snaps on a leash.
In operant conditioning, reinforcement can be categorized as either primary or secondary, or as either positive or negative. Let’s take a look at what these variables really mean.
Primary Reinforcement: Will Work for Food
Primary reinforcers are reinforcers that are related to biology. Examples of primary reinforcers include food, drink, some kinds of touch and sexual contact. When dogs are trained using treats, that is a primary reinforcer.
But primary reinforcers are more than food. For some breeds that are innately wired to be visual, visual stimuh seem to be primary reinforcers. Because of selective breeding over many centuries, many sporting dogs are very visually oriented. Some spaniels will look out a window and notice a leaf falling from a tree across the street. Owners of dogs with such finely tuned sensitivities often wonder why their dog isn’t paying attention in an outdoor obedience class. “I’m giving him treats,” they tell us, not understanding that for this dog, a treat just can’t compete with the field full of birds across the road.
A reinforcer is a stimulus that, when presented following a behavior, causes that behavior to be more likely to occur again in the future.
Secondary Reinforcement: "Good Boy!"
Secondary reinforcers are reinforcers that can be related to social conditions. In other words, they have a cultural context. Humans respond to secondary reinforcers such as praise, smiles, thumbs-up gestures and money. Dogs are social creatures, and many dogs also respond well to smiles, praise, attention, clapping, toys and pats. But, just as we have to learn that thumbs-up means “well done,” dogs have to learn that praise is something positive.
Verbal praise is the most commonly used secondary reinforcer. when a dog a young puppy, saying “good girl” to her has no meaning. It’s just a bunch of sounds. But when you say “good girl” and give her a piece of food or a pat, she learns to associate praise with good things. Praise has become a secondary reinforcer.
Secondary reinforcers become reinforcing by being paired with primary reinforcers.
Secondary reinforcers are also called conditioned reinforcers. This is because secondary reinforcers depend upon some conditioning taking place. For example, if a dog owner takes the leash out of a particular drawer just before taking her dog for a walk, taking the leash out of the drawer can become a conditioned reinforcer. If one day the dog is chewing on a shoe when she takes out the leash, chewing on a shoe may accidentally become reinforced; the dog may think that going for a walk is its reward for chewing on the shoe.
In place of verbal praise, some trainers use sounds as conditioned reinforcers that essentially mean “good job!” In marine mammal shows at places like Sea World, when the porpoise trainers blow a whistle to let the animal know it has performed correctly, the trainers are delivering conditioned reinforcement. Conditioned reinforcement is a way a trainer can offer reinforcement from a distance and when it is not handy to give food to the animal. Applause is another conditioned reinforcer, for both human performers and many competition dogs.
A conditioned reinforcer is a previously neutral stimulus that begins to function as a reinforcer after being paired a number of times with an established reinforcer.
Now We’re Clicking
Recently, the dog training community has seen an increase in the use of clicker training, which uses the clicker as a conditioned reinforcer. The clicker is a small metal and plastic device that makes a clicking sound. Clickers have been around for decades. Years ago they were called “crickets” and were sold as children’s toys.
When clickers are used as conditioned reinforcers, the dog is first given food alone as a primary reinforcer. Once the dog has clearly shown that it likes food, the pairing begins. The clicker is clicked; then the food is given. Because the clicking sound is associated with the delivery of food, the click alone begins to take on reinforcing properties. (You’ll find more information about clicker training in Chapter 14.)
Clicker training is one application of conditioned reinforcement. The clicker is a neutral stimulus that is followed by a primary reinforcer, and eventually becomes a conditioned reinforcer.
The clicker is a conditioned reinforcer because it started out as a neutral stimulus, meaning it had no meaning for the dog. But when it was paired with food, the dog eventually learned that a clicker also means “good job!”