Primary Outcomes (explanation)
We will measure this outcome in three ways:
1) Observations. A research assistant observes and records participants' choices at the self-service cashier.
2) Self-report. At the end of the survey, participants complete a survey in which we embedded the following question:
"Please indicate what did you buy to drink at (name of the supermarket)?"
3) Individual purchase data from the supermarket. The supermarket will provide individual purchase data which we will be able to match with individual students via their student IDs recorded at the moment of purchase.