Different types of love feel different. The love I have for my partner, my children, my parents, and even my dog are similar in some ways, but are very distinct in others. Thanks to fMRI images of the brains of people experiencing various types of love, scientists can now explain where the similarities and differences originate.

The topic isn't a new one in sexuality research circles. A Rutgers study comparing maternal and romantic love, which produced the image above, took place in 2004. The study showed that there are distinct parallels in brain activity between people experiencing the two types of love. A number of researchers turned to fMRI and other brain imaging techniques years earlier in hope of finding ways to identify the brain activity characteristic of sexual deviants like rapists and pedophiles, potentially to both reform them and prosecute them, as the case may be.

But the brain is complex. It's proven too difficult to tease out sexual criminals from the general population in a reliable way. However, a recent review paper that compares all known fMRI studies of brains in love has at least brought a few interesting aspects to light.

For one thing, love is complicated. Regardless of the type of love we're talking about, they all involve several distinct portions of the brain, including the higher-order portions typical of big brained creatures like humans. That suggests that love as we know it may not even be possible for creatures with less developed brains. Lizards and birds, it seems, are probably limited to friend-with-benefits sorts of relationships, rather than full blown love.

Not only can we love, but researchers have specifically studied three different types of love: romantic love between sexual partners, maternal love between a mother and child, and compassionate love for vulnerable strangers. All three types lead to increased blood flow, and pr...