Ah love. Kind of fricked up when you think about it. You have a few nice meals with a person, let them sleepover and then BAM you are trapped to breed with this person with inferior genes because it will physically hurt to leave them. So what exactly is love? Plain and simple love can be created a laboratory. There are three types of love all relating back to evolution where finding a partner who will both protect us and our offspring was incredibly important to the survival of our species. Lusting love, i.e. a sex drive, was something that would get us out looking to find a partner. Romantic love to enable you to focus your energy on just one person at a time, conserving time and energy, rather than trying to juggle more partners. And attachment, the feeling of security you can feel with a long-term partner, which helps two people stay together long enough to raise kids as children need their parents for food and protection for a long time. All of this is caused by the strange chemicals in our heads, namely testosterone, oestrogen, dopamine, serotonin oxytocin, and vasopressin. Central dopamine pathways mediate partner preference behaviour, while and oxytocin mediate partner preference and attachment behaviours. Serotonin is responsible for the ability to find resources and food which leads to the release of endorphins which are associated with happiness. Being with someone who can provide these resources for potential children is vital for survival.