Tyrell: [Offscreen]  Is this to be an empathy test?

[Tyrell appears at the other end of the room, walks towards the two]Tyrell: Capillary dilation of the so-called blush response…fluctuation of the pupil…involuntary dilation of the iris.Deckard: We call it Voight-Kampf for short.Rachael: Mr. Deckard, Dr. Eldon Tyrell.Tyrell: Demonstrate it. I want to see it work.Deckard: Where’s the subject?Tyrell: I want to see it work on a person. I want to see a negative before I provide you with a positive.Deckard: What’s that going to prove?Tyrell: [Smiling] Indulge me.Deckard: On you?Tyrell: [Nods at Rachael] Try her.