Last night I went to a presentation about the evolution of altruism, given by my anthropology professor. She is a wonderful speaker and presented some key ideas that I hadn't heard in my previous anthro classes and readings.
Here are some of the notes I jotted down:
- Altruism is acting for the benefit of someone else at a cost to yourself.
- The two main theories to explain altruism found across primates societies are 1) kin selection, and 2) reciprocal altruism. Kin selection meaning we help our relatives to survive because it's indirectly helping our genes survive and get passed on. Reciprocal altruism meaning we help someone else so that they'll help us later. This requires some understanding of the future.
- Robin Dunbar (1992) found that group size correlates with neocortex size. Primates with smaller neocortexes live in smaller groups and primates with larger neocortexes live in larger groups. Based on this, Dunbar suggested that humans have the brain capacitiy to maintain about 150 core relationships at any given time...essentially that we can only care about 150 people at once. Interestingly, the average number of friends Facebook users have is 120; the average number of Christmas cards people send out is between 100-125.
- Homo sapiens who still live in hunter-gatherer societies do not live in groups of related individuals. Instead, individuals transfer between groups quite a lot. Since hominins have possibly been living in hunter-gatherer societies since the time of Homo erectus (about 1.8 million years ago), this suggests that we evolved the ability to be cooperative and altruistic in order to make friends more easily and to get along with all the new people we were meeting through these group transfers. So now, some cooperative behavior is simply embedded within our DNA, and therefore sometimes we express it through actions that don't benefit us at all. Other highly social mammals, like gorillas and dolphins, probably developed cooperative tendencies independently for the same reason.
- Primates, including humans, recognize as a sibling any individual that they grew up with. Spending a lot of time in close proximity to another individual throughout the development stages generally turns off a primate's sexual feelings for that individual, and the two do not breed. This proximity-prompted sibling-feeling happens even when the individuals are not genetic kin. [e.g. "I can't date him! We grew up together! We're like brother and sister."]
So while I'm chewing on these ideas, I'm feverishly working to collect all my measurements for my wisdom tooth project (see this post) before the next two lab sessions are over, so that I'll have time to re-do any faulty measurements and write a good analysis. If the results produce some coherent theory, I'll definitely want to take this project to ASU with me and see if I can revise it by increasing my sample size. And then I'd want to present or publish it. And this possibility makes me happy.
I also gave ASU the official notification that I'll be attending in the fall, and am planning a school visit toward the end of May, when this semester is over.
And in more news, I used part of my writing contest money to buy this book, one of the essentials for physical anthropologists:
How great is that?? I can't believe this will soon be my life. Of all the times I despaired, thinking my only option was to spend the rest of my life in a factory or trapped in some horrible retail/customer service job while reading Dilbert cartoons on my break.
Such despair was for naught!
Another path now lies before me.