One recent study looked at women and their response to hearing a baby cry (I assume the researchers had a recording of a baby crying and didn't actually make a baby cry each time they ran the experiment). These women were also given puffs of oxytocin while being asked to intermittently squeeze a bar or relax their grip (Bakermans-Kranenburg et al 2012). It turns out their response to oxytocin differed by their relationship with their parents. Women who had not been disciplined harshly as children relaxed their grip when they heard the baby cry, presumably as preparation to comfort the baby in a gentle way. However, women who had been disciplined harshly as children did not relax their grip. This demonstrates that your experience with your parents shapes your oxytocin system. If the relationship contained harsh discipline then future oxytocin does not automatically create conditions for warm gentle interactions.
The second study I'm going to talk about looked at how oxytocin affects generosity (van Ijzendoorn et al 2011). The researchers gave women either oxytocin or placebo and had them fill out a questionnaire about how loving or withdrawn their parents had been. Participants were then paid for their time, and when they thought the study was over they were given an opportunity to donate to charity. Turns out that when women who had loving parents received oxytocin they donated significantly more to charity. In fact women who had withdrawn parents actually donated slightly less money to charity when receiving oxytocin, but this wasn't quite significant. So if you had a close relationship with your parents, then oxytocin increases feelings of generosity, but if you didn't have a close relationship with your parents, then you don't get the same benefit.
The final study I'm going to talk about actually shows that not only does having a bad relationship with your parents keep you from experiencing the benefits of oxytocin, but it can also make oxytocin have a negative effect. In this recent study the researchers gave a group of men a small puff of oxytocin and asked them to think about their mothers (Bartz et al 2010). Men who had positive, close relationships with their mothers remembered those relationships as even more positive. But for those who had difficult relationships with their mothers, they remembered them as even more negative and difficult. This is important because being close with other people is an essential part of happiness and well-being. If you had a difficult relationship with your parents, it may influence your ability to feel close with other people. And if you do start to feel close that boost in oxytocin can potentially fuel more negative thoughts.
All in all oxytocin is great news if you had a good relationship with your parents. But if you didn't have a great relationship with your parents then you don't get the same benefit from oxytocin, and that could have a negative impact on your romantic relationships. Now that might seem pretty sucky, because you can't change your childhood. But fortunately, long-term changes to the oxytocin system are possible, they may just require some sort of therapy or at least a willful intention to change yourself (e.g. with parenting). If you had a difficult relationship with your parents, your brain will have a tendency to react to romantic relationship in a particular way. Simply being aware of that response is a powerful thing, because self-awareness is the first step to true transformation.
