A trigger is a stimulus that elicits a response or behavior. In behavior design, a trigger is a specific cue or prompt that is designed to remind a person to engage in a desired behavior. Triggers can be external, such as a reminder on a smartphone, or internal, such as a feeling of hunger or thirst. The goal of using triggers in behavior design is to make the desired behavior more automatic and habitual. For example, a person might be prompted to floss their teeth every night by placing their toothbrush next to their bed as a reminder. Over time, the behavior of flossing can become more automatic and no longer require the external trigger.