ABC'S: ANIMAL BEHAVIOR CONCERNS & SOLUTIONS
A Question & Answer Forum For Animal Professionals
Copyright © By Diana Guerrero

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Welcome to the ABC's! Animal Behavior Concerns & Solutions is an animal behavior column written by animal behaviorist and animal trainer, Diana L. Guerrero. This section is dedicated to animal training techniques for all animals and pets, and topics related to operant conditioning and reinforcement. Topics related to operant conditioning discussed here are the bridge aka the secondary reinforcer in this four part topic. For pet training please visit the pet section, see our pet behavior booklets in the shop, or visit our teleseminar section.

Overview of the Bridge Part One of Four

QUESTION
American Zoo. Could you give an overview of the use of the bridge and maybe some resources related to it?

ANSWER
Questions on this topic will be discussed in the next couple of columns.

The bridge is used as a signal to let an animal know that they are on the right track or performing correctly. Like any other behavior, the association has to be trained in order to have any significance to an animal.

The role of the bridge is to create a link between the behavior and the reinforcer. This "IOU" signals the animal that reinforcement is coming and so becomes reinforcing itself. So a bridge is also a secondary reinforcer. Think of it as a "bridge" between the correct activity/behavior and the primary reinforcer. Many trainers will refer to the use of the bridge is as an event marker, since it marks the moment of success.

The bridge is used as a signal to convey good progress or successful completion of a behavior or chain of behaviors. The intermediate bridge signals that the animal is on the right track, while the terminal bridge signals that the animal has successfully completed a behavior.

The most familiar bridging tools in the zoo world are clickers, whistles, lights, specific tones or words, or specific actions or movements. Used efficiently, the bridge allows you to quickly communicate without having to bother with primary reinforcement at the exact moment of success.

The bridge is initially trained through consistent application and presentation with food (or primary reinforcement). So, if you use a clicker, pair it with the presentation of the food. Each time the animal gets a tidbit; the click is given at exactly the same time.

In the beginning, one click equals one reward. This is what is known as continuous reinforcement. As you become more adept at training you will move away from this rewarding schedule into an intermittent or variable reinforcement schedules. Then as you get more sophisticated you may then get into other types of schedules. *

Changing your reinforcement schedule is what makes training even more interesting to both the animal and trainer. Each trainer and facility will have different views on how to approach training and bridging applications. This is what makes training a science and an art. Sometimes you do things from an intuitive level and that is what makes each trainer vary in their approaches. Everyone has a different opinion, so just keep that in mind as I address some of your more specific questions.

Is there a minimum response level to the bridge that we should see before using it in the training program?

Yes. Outlining criteria for this is difficult since I actually use more of a subjective evaluation. The animal has to recognize the association between the bridge and the primary reinforcement. You will have to train that before you can begin to use the bridge in a training program.

Usually after several presentations of pairing the bridge with the presentation of reinforcement, you will see the animal "light up." This might occur as a more alert response, a twinkle in the eye, or shift in attention or posture. The association between the tone and the food is established. Some animals take longer to establish this association but once it is understood, the bridge can begin to be used in training applications.

In the past I have just sounded the bridge and rewarded at the same time. Experience often gives you an eye for catching what the animal understands or is missing. However, for an observer learning the process I will sometimes work out a way to get a clear indication that the animal "gets" the concept.

For example, I might say the name of the animal and when the animal voluntarily gives me eye contact I will bridge and reinforce. After a few times if I bridge without using a name and the animal then looks at me, this gives me an indicator that the animal has an association between the bridge and the behavior and the reward. For those species reluctant to give eye contact this can be a challenge, but you get the idea through the illustration.

To test this concept with your animal, train the bridge then once you think the association is established consider moving slightly, and then sound your bridge to check the animal's response. If the animal responds accordingly that is a gauge for you.

In some cases many trainers prefer to introduce a target at this stage. They will touch the animal with the target while sounding the bridge. After a while they will slightly edge the target away and wait until the animal moves slightly to touch it. Bridging on contact usually clarifies the concept for the animal. The next attempt usually results in a faster response signaling to you, the trainer, that the association is understood.

What types of bridging stimuli have trainers used that work well?

Just about anything. Keep in mind that various tools have come into popularity for different reasons. Tools that can be used by all and that remain consistent between trainers help with maintaining consistency. Other tools are preferred because they can travel through water clearly or can keep your hands free. Here is a short list but you are only limited to your imagination: clickers, dog or police whistles, lights, vibration, specific tones, certain words, particular actions, or particular movements.

*NOTE: Most of you will probably encounter horrific amounts of acronyms like CRF, FI, FR, VI, VR, RIR, VRRV, to mention just a few. These are topics for other columns. Keep in mind; acronyms do not always translate well across industries. Use professional courtesy with others by stating or writing what you mean and giving the acronym after. These explanations are appreciated by everyone not just neophyte trainers! Return to Article

Continue to Part Two of Bridging Overview

Are you a reader with a question? Be sure to submit it--and good luck in all your training endeavors!

About the columnist: Since 1978 Diana L. Guerrero has worked professionally with both wild and domestic animals. Guerrero has been affiliated with and certified by a variety of animal programs in the USA and Europe. Based in California, she writes, consults, and leads safaris. Information on her animal career programs, training courses, and her books, What Animals Can Teach Us about Spirituality (SkyLight Paths, 2003), Blessing of the Animals (Sterling, 2007), Help! My Pet is Driving Me Crazy (Guerrero Ink, 2007), Animal Disaster Preparedness for Pet Owners & Pet Professionals (Guerrero Ink, 2007) are available through this web site. Questions for ABC's should be submitted to Diana directly through the ABC's zoo questionnaire on this web site, or contact her now.