Researchers have figured out what to say - and not to say - on a first date

What distinguishes a good first date from a bad one? It's pretty much all on display in the famous double date scene from When Harry Met Sally. Sally and her terrible date firmly disagree about important topics. Harry and his terrible date are politely disinterested in each other. Then comes the moment where both of their terrible dates click - with each other.

"Nobody has ever quoted me back to me before," Sally's date says to Harry's date in admiration.

First dates are a staple of romantic comedy. They are also the focus of a 55-page study from researchers at Stanford University and the University of California, Santa Barbara, that looks at what people say on successful dates and not-so-successful dates.

To carry out their study, the researchers ran free speed dating events for (heterosexual) grad students in which they recorded what the everyone said. After the date, the grad students reported how well they "clicked" with their partners for roughly 1,000 four-minute conversations.

The researchers found that physical and character traits, like men's height and shared hobbies, actually had a larger influence on whether couples said they clicked than what they said to each other.

But with each additional minute the couple spent together, things like height and shared hobbies became less important and the flow of their conversation became more important.

The data showed that women felt more connected when men were actively engaged in the conversation and focused on them. Women were more likely to feel connected:

• when men "mimicked their laughter" (meaning they laughed right after the woman laughed, not made fun of their laugh),

• "interrupted them" (also not what it sounds like - asked questions to show they were paying attention),

• demonstrated their appreciation by saying positive or flattering things,

• and used the word "you."

Men reported feeling less connected when women did what the researchers called "hedging" - saying things like "kind of," "sort of," and "maybe."

In contrast, the men said they felt a spark when women talked about themselves, using words like "I," "me," "myself." (In fact, the researchers suggest that it may be a bad sign for a man's date if the woman is asking a lot of questions about the man. "We found that questions were used by women to keep a lagging conversation going," they wrote.)

The researchers looked not just at what people said but also how they said it. They found that men and women in the study actually altered the pitch of their voice when on a good first date - basically, taking on a more "masculine" or "feminine" voice when speaking to someone they were interested in.

So what does all this mean?

As Priceonomics' Rose Cima, who recently wrote about this 2013 study, points out, one funny thing about this research is there is an obvious mismatch between the behavior of men and women. Women report feeling a connection when men interrupt them to show that they're paying attention and say nice things that indicate that they appreciate them. However, men who report feeling connected to women don't actually do these things at a statistically significant level. (Tip to men: Try these things.)

There were two things that men and women had in common, however. First, both men and women are less likely to report a connection when a woman uses uncertain words like "kinda," "sorta," and "maybe." Second, both men and women were more likely to report a connection if the woman talked about herself.

Taken together, these two findings suggest an uneven relationship between men and women: That whether a couple "clicks" is mostly determined by whether the woman is interested in the man, and not vice versa. At least in this study, these behaviors seem to be an accurate sign of a woman's interest, and men picked up on those signals.

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