Vice President Kamala Harris has a strategy in her first presidential debate to smirk whenever former President Donald Trump is talking. Whether it works is to be determined, but it’s important to understand her thinking.

If you watch her on the split screen, Harris smirks and shakes her head regardless of what Trump is saying. Her headshakes and shocked googly eyes and muted-mic “not true” exclamations don’t correspond to her disagreements and her counterpoints. She is not actually reacting; she is simply making these faces because she knows she’s on camera.