Welcome to Part 10 (and our final temperament trait) of my Baby Temperament and Sleep Series. If you are just joining us, you may want to start with Part 1, where I define baby temperament. This article will discuss your baby's mood as a baby temperament trait. In the next couple of weeks, I will give you a quiz to determine your child's temperament. Baby Temperament - Mood Your child's mood is generally how happy and smiley she is versus the child who is more serious in nature