Sleep problems during infancy are associated with behavior and emotional problems, poor language development , parental distress and mood disturbances, and overweight and obese children. The investigators proposed that children who receive the light, activity, and sleep training (LAST) intervention program in this study will have less parent report of problem sleep behaviors and longer duration of nighttime sleep compared to children with no intervention provided.

Sleep problems are reported in 71.65% of our nation's infants and toddlers, and the prevalence is much higher than the 20-30% reported in Western countries. The investigators' preliminary findings also show that approximately 53-55% of parents of children between 6 and 12 months of age consider their child sleep a problem with about 4% not knowing whether their child sleep is a problem. Sleep development during infancy is characterized by increasing day-night differences in sleep-wakefulness such as longer bouts of sleep and fewer awakenings at night, and is driven by neurobiological maturation and environmental interactions. By 3 months of age, nearly 58% of infants can sleep continuously between 24:00-05:00 hours. When infants do not sleep through the night by 17 months of age, they are less likely to be able to do so at 29 months of age and beyond. Without proper intervention, sleep problems during infancy can persist to toddler and preschool age. Various interventions have been developed and tested in Western and Asian Countries to address the sleep problems in infants and young children, but none are in Taiwan.

Inclusion Criteria:

• Healthy singleton infant born at gestational age >= 37 weeks

Exclusion Criteria:

• Infants born before 37 weeks gestation
• Infants born with a congenital abnormality or a genetic disorder
• Parents with insufficient Chinese