Questioning Awareness of Effect

<-NARRATOR:-> Now listen to part of a lecture in an education class.
<-MALE PROFESSOR:-> So, I used to teach a class of eight year olds. ... And one problem I sometimes had was getting the kids to raise their hands when they wanted to answer a question—
like lots of teachers, I had the rule that if a student wanted to answer a question,
they needed to raise their hand in the air and wait till I called their name, before speaking.
That gave all the students a chance to participate,
which helped everyone get more out of the discussion.
But some kids had trouble following the rule.
I remember there was one girl,
Sarah, who didn't raise her hand when she wanted to answer a question;
she would just call out the answer.
And this was frustrating for the other children who were waiting patiently with their hands raised.
So one day when Sarah called out,
I asked her if she knew that calling out was unfair to the other students.
I said to her,
[gently] "Sarah, do you realize that when you call out answers without raising your hand,
you're not being fair to the other students,
you're not giving them a chance to answer questions, too?"
And I didn't wait for her to answer, I just continued teaching the class.
And after that, anytime I asked the class a question,
Sarah didn't call out the answer;
she raised her hand along with everyone else.