I was recently discussing bullying with an educator who specializes in anti-bullying action. This came about from my participation in the World Anti-Bullying Forum. He asked me some questions about the phrase – sticks and stones as it relates to bullying. I said, to me, it makes a good delta, but it’s not accurate to people’s lived experiences. Words really can hurt.
They then asked me to explain what I meant by deltas and by extension bridges. Since this is relevant to what I teach – behavioral techniques to stop bullying, I thought I would share my response here so you can understand how deltas and bridges are used to train behaviors.
What is Delta in behavior?
SΔ (S-Delta or Stimulus Delta) is behavior speak for a stimulus that signals that no reinforcers are available based on this stimulus.
This contrasts with a bridge, which is a stimulus that signals that a positive reinforcement is available based on this stimulus.
Animal trainers use deltas and bridges to actively communicate with our animals. So – say I asked a dolphin to do a jump, and instead it swam in a circle. I would issue a delta – basically a signal that says, that behavior is wrong, come back to station. No reward. There is no judgement on the term “wrong.” It’s just a signal that the behavior wasn’t right and won’t be rewarded nor will it be punished. It’s not good or bad. It’s just not correct. If I issue a bridge, I’m telling the animal – good job, you can come back and get a reward.
A delta is a signal that the behavior was wrong. A bridge is a signal that says the behavior was right. Trainers use both deltas and bridges when we train up behaviors.
To train up a delta, you have to positively reinforce the behavior you want in response to the delta. Same with a bridge. So with a dolphin, if I issue a delta, what I want them to do is stop what they are doing and come back to station. If they come back to station when I issue the delta, I thank them and positively reinforce the come back to station response to the delta.
In humans, we use “stop” as a delta all the time. And thank you and yes as bridges all the time. If a kid is doing something dangerous, we ask them to stop, and if you’ve trained up your delta well – the child will stop. If you haven’t, they won’t. If they do something right, we say – yes!!! And give them positive rewards. A delta does not signal a negative reinforcement is coming. It signals there is no reinforcement coming. A bridge signals a positive reinforcement is coming.
The important part is that both deltas and bridges are signals. Overt signals. A delta is not the removal of the reward, it’s the signal that says there will be no reward.
If I have a bully, I want to stop. I need to, ideally, interrupt the behavior and remove the reward for that behavior. Deltas are a great way to interrupt the behavior pattern the bully is expecting and remove the reward at the same time. So if a bully is calling me names and I say sticks and stones – that’s probably not the response they wanted. I’ve both interrupted the bully’s behavior pattern and not given them their reward for the unwanted behavior at the same time.
Silence isn’t a delta. A delta is a stimulus of some sort, usually mildly unpleasant enough that it gets the attention of the target of the delta and stops them and gives the trainer an opportunity to redirect.
In an animal training relationship, the delta is helpful to the animal because – a dolphin doesn’t speak English, so as I’m shaping behavior, and the animal is attempting to learn whatever behavior I’m trying to teach them, for instance, maybe a sideways summersault. It’s helpful for them to know, not that. Stop and come back. Humans tend to treat deltas as negatives, but they aren’t. They aren’t positive or negative, they are neutral. It’s just a stimulus that signals no reinforcement.
So – short answer, a delta is a stimulus that interrupts a behavior and removes the reward for the behavior. Or in laymen’s terms, you are signally that you will not be rewarding the unwanted behavior.