In addition to genetics and environment a child’s behavior may be influenced by their temperament. It is not uncommon that children in the same family who have similar genetic make up and have grown up in the same family environment will exhibit different behavioral responses in the same situation. “Temperament is normally used as a collective term for a set of developing traits that (1) manifest in an organized fashion during early life, (2) are relatively stable during significant periods of life, (3) are relatively consistent across situations, (4) have characteristic neurophysiologic underpinnings, and (5) are partially heritable."5
In 1977, Thomas and Chess proposed three categories of temperament or children; easy temperament, difficult temperament and slow-to-warm-up temperament.
Easy temperament - biological regularity, quick adaptability to change, tendency to approach new situations versus withdraw, predominately positive mood of mild or moderate intensity.
Difficult temperament – biological irregularity, withdrawal tendencies to the new, slow adaptability to change.
Slow-to-warm-up temperament – This category is comprised of withdrawal tendencies to the new, slow adaptability to change, and frequent emotional reactions of low intensity. Such individuals are often labeled “shy.”6