Cro-Magnon, in first position, opens 1NT, 12-14 points, and you, Homo Sapiens, have:

Do you double for penalty? You have 16 points and Cro-Magnon, only 12-14; the question to ask is not: "Do you double?" but "Do you have a good lead?," and the answer is no. Therefore, you must pass, in tempo. A good tempo is very important because primitive people, I should say especially primitive people, have very good instincts.

If you hesitate, Cro-Magnon will feel something and be on guard. In addition, before opening 1NT, Cro-Magnon very shrewdly puts his index in his mouth and then points it towards the sky to register any variation in the air. If he feels a vibration from you, he will know.

But you have discovered his trick a long time ago (you are not Homo Sapiens for nothing) and you always sit downwind when you play against him. Cro-Magnon can only feel hesitations from your Woman Sapiens, who cannot hesitate because she is sitting in the 4th seat.

Cro-Magnon suspects that his trick is not working, but his limited intelligence cannot yet find the reason.

Cro's partner passes and your partner also. You lead a small spade!