Curiosity is one of the most underrated phenomena in the world. It's ironic that people aren't more curious about curiosity. It's a powerful thing.
For example, if you ever wondered if someone is attracted to you, the answer lies in curiosity. If someone asks personal questions about your past, your plans, your likes and dislikes, that is an unambiguous sign of attraction. If someone tries to steer you into the bedroom without some conspicuous data gathering, that is a sign of simple horniness.
The friend variety of attraction is milder than the lover type. You can be friends with someone for years without remembering the names of his or her siblings. But if you love someone, you automatically develop a voracious appetite for information about that person.
When someone you are not attracted to talks a lot about his or her own life, you get bored to death. When someone you are attracted to talks a lot, you might find that person to be full of life, and fascinating. Attraction and curiosity are inseparable.
Let's say you're interviewing for a job. You wonder if the interviewer is attracted to you as a potential employee or just going through the motions. Look for the curiosity trail. If his questions are all of the typical variety, he's probably just moving through the steps. If you sense some questions that veer off the normal path, such as asking where you like to golf, you almost certainly have something more.
If you're trying to sell something, it is useful to judge how much the other party really wants your product. Look for curiosity. If the potential buyer says nice generic things about a product, it's not as good an indicator as if he asks a series of questions, especially if the questions include some that don't seem important to the decision. In poker terms, questions about relatively unimportant aspects of a product are the buyer's tell.
A good book conspicuously manipulates your curiosity. The writer develops a character that you are attracted to, and then creates a series of situations in which it is not obvious how things will turn out. The Harry Potter books written by J.K. Rowling are a sensational example of that simple formula. Harry is young, and kind, and cute with his glasses and mop of hair. And he's an orphan. In our culture, Harry comes as close as you can get to the sort of person that almost anyone would like. That's the first part of the formula. Then Rowling ends each chapter with a tease of danger to come, making you wait a chapter or more to find out how things will turn out for Harry. Rowling became a billionaire by manipulating the connection between attraction and curiosity.
Movie studios know how important it is to feature likeable stars in their movies. It compensates for bad writing, bad directing, and bad everything else. If you are attracted to the lead actor, your curiosity is activated. It doesn't take a lot of movie magic to make you interested in what will happen to Sandra Bullock. As soon as she appears on screen you start getting curious about her because she's so likeable.
Curiosity is rarely faked simply because people aren't generally aware that it is such a reliable indicator of attraction. Once you learn to recognize the connection between attraction and curiosity, it's like having a mild form of ESP.