That's very interesting, since a larger amygdala is also associated with autism, you know, insensitivity to process other peoples emotions and faces:http://www.cnn.com/2009/HEALTH/05/04/autism.brain.amygdala/?iref=mpstoryview
And yet, larger amygdalas might be helpful for social bonding:
http://en.wikipedia.org/wiki/AmygdalaAmygdala volume correlates positively with both the size (the number of contacts a person has) and the complexity (the number of different groups to which a person belongs) of social networks. Individuals with larger amygdalae had larger and more complex social networks. It is hypothesized that a larger amygdala allows for greater emotional intelligence, enabling greater societal integration and cooperation with others.
A larger anterior cingulate is also associated with self-reflection, i.e. thinking about one's thinking process:
http://rewireyourbrainforlove.com/anterior-cingulate-cortex-6-seductive-reasons-why-bigger-is-better/One of the most important and exciting features of the ACC is that it is the part of the brain that is not only responsible for kids (and adults) being able to pay attention, but it also allows us to pay attention to attention – to think about what we’re thinking, to observe what we’re doing while we’re doing it. It’s taken me a long time to realize this is not a function that everybody’s brain is readily able to do, and certainly for most of us, not all the time. William James, the father of psychology, once said that “the education of attention would be an education par excellence.” He didn’t realize it, but he was essentially talking about building out the ACC! So that’s the first reason to help kids grow a Super-sized Anterior Cingulate … so they can learn to easily attend to what they’re attending to.