Kevin Winter / GettyAngelina Jolie and Brad Pitt.

If you listen to the psychology research, falling in love isn't a matter of destiny — it's a mixture of biology, upbringing, and context. 

But that doesn't make it any less mysterious. 

Since your partner plays a significant role in your long-term health, happiness, and career prospects, we've scoured the studies and collected some of the reasons two people click.