Upon hearing about an MIT invention that can supposedly read emotions, Sheldon decides to test it. Leonard meets Penny's brother and Raj asks his ex-girlfriends for dating advice.
- Fallback Marriage Pact: When Raj worries that he'll never find love in "The Emotion Detection Automation", Howard jokingly says that if he and Bernadette ever broke up, Raj could marry him. When Raj asks why he would marry Howard instead of Bernadette after said break-up scenario, Howard responds that Stuart already claimed that option.
- Gone Horribly Right: Sheldon gets an emotion detecting machine to be able to tell what people actually feel. Unfortunately, that means he learns exactly how bad he makes people feel.
- One Steve Limit: Played with. Raj gathers his ex-girlfriends, which includes two Emilys. He calls one Redheaded Emily, but then realizes the other Emily also has red hair, so he calls her Redheaded Emily Junior.
- Romantic Runner-Up: Raj discovers that all his exes found better relationships after they broke up with him.