Final answer:
A first-then schedule is a visual tool that shows a sequence of two activities or events, with the first activity being a prerequisite for the second activity.
Step-by-step explanation:
A form of picture communication that is used to demonstrate a contingency is a first-then schedule. A first-then schedule is a visual tool that shows a sequence of two activities or events, with the first activity being a prerequisite for the second activity. This schedule helps individuals understand the order of tasks or events and can be particularly useful for individuals with autism or other developmental disabilities. For example, a first-then schedule can be used to show that a student must complete their homework (the first activity) before they can play video games (the second activity).