Thanks to this Reddit submission for a three-term contingency example which highlights positive reinforcement.
Antecedent: Video to show and a person to show it to.
Behaviour: Play video
Consequence: person laughs (fake or not does not matter here as the person showing the video likely did not discriminate between a fake laugh and a genuine one)
In this case, laughing is a conditioned reinforcer. When a person’s displays of a video, telling of a joke or other performance is followed by laughing, it reinforces the showing/telling/performance; therefore, it is likely to happen again. Not only was this submitter subjected to more videos, but the person is also likely to show the same videos to other people.
It is easy to say, if it’s not funny, don’t laugh. But we all have that nervous laugh that is also under its own contingencies. Sometimes we laugh nervously to end an awkward situation or to avoid a more uncomfortable conversation if we were to speak the truth. This is an example of negative reinforcement where the behaviour of laughing worked to end an awkward, unpleasant or uncomfortable situation (the negative in this sense means to take something away). When finding ourselves in a similar situation we are likely to try this avoidance behaviour again (behaviour increases = reinforcement).