What is an example of a positive reinforcer?

A positive reinforcer is something that increases the likelihood of a desired behavior being repeated in the future when presented following that behavior. In the context of dog training, providing food after a desired behavior exemplifies this principle exceptionally well. When a dog performs a behavior that the trainer wants to encourage, such as sitting on command, giving food as a reward reinforces that behavior. This means the dog is more likely to sit again in the future in anticipation of receiving a reward, thereby establishing a positive association with the behavior.

The other options provided do not fit the definition of a positive reinforcer. For instance, taking away a toy represents a form of negative reinforcement or punishment, aiming at decreasing undesired behavior rather than reinforcing a desired one. Ignoring unwanted behavior may discourage that behavior over time, but it does not actively reinforce a desired behavior through a reward. Delaying a reward can lead to confusion or frustration, and may not effectively reinforce the desired behavior consistently in the way that immediate positive reinforcement does.