Why is this important to study?

Light is the strongest environmental signal to the internal biological clock of humans. Although the biological response to light as been investigated in adults, very little is known about how light influences the biological clock of young children. The primary goal of this study is to understand how light can delay the timing of the biological clock of preschool-age children.

Who should get involved?

We are interested in healthy children with no sleep problems who will be ages 3-4 between May 2018 and August 2018. A parent must be available for at-home assessments.

How can my child qualify for the study? 

In a brief telephone interview, we ask you questions about your child’s sleep and developmental/health history, family schedules, and parental health history. We also ask you to complete questionnaires that help us determine if your child is a good fit for the study.

What will my child be doing in the study?

This study lasts about 10 days.  It begins with an orientation session at your home where we provide you with information about what your child and you will be asked to complete during the study. These tasks will include:

Training Visits

We make brief visits to your home during the first week of the study to slowly introduce the procedures used to measure melatonin in saliva.

Sleep Schedules

Your child is given a strict bedtime and rise time schedule, which includes daytime naps (if your child is still napping) and nighttime sleep periods. Your child will follow this sleep schedule for 1 week. This is a very important part of the study!

Activity Monitoring

Your child wears a small watch-like wrist monitor for the duration of the study. This monitor records movement and lets us keep track of your child’s sleep patterns throughout the study.

Sleep Diary

 You are asked to complete a brief sleep diary and telephone the lab each day to report your child’s bedtimes and rise times.

Biological Rhythms Assessment

On the last three evenings your child gives saliva samples by “mouthing” a dry cotton roll for about 1-minute. Saliva samples allow us to measure levels of melatonin, a hormone related to the body’s biological “clock.”  On one of these three evenings your child will be exposed to bright light before bedtime.


Because this study requires time and effort, your family will receive a cash reward at the end of the study when all assessments are complete. Your child is also frequently rewarded with small “gifts.”  If you must withdraw from the study before completion, you will receive partial compensation.

Thinking your child will never do these things? 

Think again! Our research team is experienced in working with young children and making our study activities fun, rewarding, and interactive. “Sleep fairies” use games, books, and other play activities to introduce your child to the study procedures and to develop rapport with your child.


Fill out the short screening form by clicking here

This screening form will ask a few questions regarding your family and child’s health history and sleep patterns.  This information will help us determine if your child qualifies for the study. Once you have completed this screening form, a study coordinator from our lab will contact you to schedule a phone conversation. 

Want more information? 

Call 303-492-4584 for email sleepdev@colorado.edu