text: Yo, temperament, it's all about behavior and emotion,
  Differences between individuals, from infancy to devotion.
  It's observed early on, in the childhood stage,
  Affects behavior in many contexts, over years, it's engaged.
  
  Now let's talk about a classification, it's real tight,
  Avoiding the unfamiliar, withdrawing from sight,
  People, objects, unexpected events, they make you pause,
  Behavioral inhibition, inhibited temperament, it's the cause.
  
  IT, they call it, it's in your genes, heritable for sure,
  Measured in different species, it's a trait to explore.
  In humans, peep the first year of life, watch it unfold,
  Direct observations, reports from caregivers, teachers, they hold.
  
  Later on, we can use similar methods, no doubt,
  Questionnaires, self-reports, to figure IT out,
  Current or retrospective levels, it's all in the mix,
  Understanding temperament, it's a fascinating fix.