Dr. Stella Chess and her husband Dr. Alexander Thomas spearheaded the classic New York Longitudinal study in the early 1950s to track hundreds of children over a 30-year period to understand the tendencies that babies are born with and how they influence their lives, and from that research they developed the 9 Temperamental Traits.[i]

The traits are:

1. Activity Level: how active is your child most of the time?
2. Distractibility: how easily do outside influences distract your child?
3. Intensity: how much intensity does your child have in her responses?
4. Regularity: does your child vary in her eating or sleeping patterns?
5. Sensory Threshold: how sensitive is your child to physical sensations?
6. Approach/Withdrawal: how does your child respond to strangers?
7. Adaptability: how easily does your child adapt to changes in his day?
8. Persistence: how long will your child work to solve something that is hard?
9. Mood: is your child a glass half empty or half full kind of person?

5 Chess, Dr. Stella, and Dr. Alexander Thomas. TEMPERAMENT: Theory and Practice. Psychology Press, 1996.