_http://www.spring.org.uk/2014/04/are-people-born-nice-or-nasty.php
A recent study finds that at least part of people’s ‘niceness’ is in their genes.
The research from the University at Buffalo and the University of California, Irvine, published in Psychological Science, tested the genes of 711 people (Poulin et al., 2012). ...
The study’s lead author, Michel Poulin, explained the results:
“The study found that these genes combined with people’s perceptions of the world as a more or less threatening place to predict generosity.
Specifically, study participants who found the world threatening were less likely to help others — unless they had versions of the receptor genes that are generally associated with niceness.”
[The nice genes] …allow you to overcome feelings of the world being threatening and help other people in spite of those fears.” ...
In this study, ‘nice’ people were able to get over their fears to volunteer their time.