A seven-day, six-participant experiment designed to form the habit of applying sunscreen.

1. The Sunscreen Challenge Seven days. Six people. Five bottles of sunscreen. Four surprises. Alan Viverettehabits.stanford.edu

2. Premise Sunscreen is an important tool in the fight against skin cancer. Unfortunately, it’s also oily and smelly. If it’s possible to get six people to start wearing sunscreen as a habit in only seven days, anything is possible.

3. The Setup Five self-selected participants each received a travel-sized bottle of 30SPF sunscreen. A sixth participantused his own bottle of sunscreen. All participants were instructed to put the sunscreen near something they use every morning, like a toothbrush.

4. FF, Materials Science In dresser drawer with toothpaste. MA, Japanese In backpack with daily medications. JB, Electrical Eng. On bathroom counter with toothpaste. NH, Symbolic Systems (no response to location survey) RM, Public Policy In basket with shower supplies. JK, Biology (no response to location survey)

5. Daily Check-in Each day, participants received an email form asking whether they had put on sunscreen. Occasionally, participants were tagged in a Facebook image to reward compliance.

7. Findings Four important take-aways and three future directions.

8. Attaching sunscreen to an existing morning routine (medications, moisturizer) gave near-perfect results 1

9. Email surveys served as triggers – early or late, sunscreen was usually applied right after opening the email 2

10. Free sunscreen resulted in higher compliance rates than personally owned sunscreen 3

11. Little correlation shown between actual need (based on weather) and compliance rates 4

12. Future directions Include a daily UV index to increase motivation when appropriate Send emails early to provide timely behavior triggers Pair participants for check-in, thereby making check-in a responsibility rather than a formality

13. In conclusion While none of the participants continued to apply sunscreen daily after the Challenge ended, several continued to use their free bottles on sunny days. In short, nothing is impossible.