Are toddlers scared of the dark? My 18 month old sleeps alone in his room. Should I be leaving the light on?

Leaving the light on is distracting and affects his day/night rhythm as we associate light with day and darkness with night. If your toddler is very afraid, try a night light instead of leaving the main light on. A night light glows softly and is not glaring. You can purchase cute ones off Qoo10, or get this one from Philips Avent. http://www.philips.com.sg/c-p/717653286/disney-sensor-night-light