Chapter 7
It’s In Our Nature
It’s In Our Nature
Social Networks have recently become more visible with the
creation of so many online social networks, but they have always
existed and affected the way people live and interact!
You can watch social networks form on reality TV shows like
Survivor.
Photo by cbs.com
How Social Networks Form
The structure of a social network matches the needs of its community.
A burning house would
hopefully bring about a…
• cooperative
• supportive
• stable
social network structure
While an offensive football
team might form an…
• aggressive
• competitive
• changing
social network structure
Photos by Justin S. Campbell and Vlastula, Flickr
Cooperation
Cooperation and altruism are not evolutionarily practical.
Survival of the fittest, not the most helpful.
Evolutionary models of cooperation include for 4 types of people:
•Loners
•Cooperators
•Free-Riders
•Punishers
Photo by Dave Traynor, * Photos by Chris M *and Inkyhack, Flickr
Homo economicus
This tongue-in-cheek term means “Economic Man.”
It characterizes humans as selfish and rational.
If people where really like this, they would not share!
Homo dictyous (literally “network man”) better describes how
people really are.
Photo by kansasexplorer 3128, Flickr
The Ultimatatum Game
1. You are given $10 to split with another person.
2. If he or she accepts your split, you each get your part.
3. If he or she rejects your offer, you both get nothing.
Photo by YoavShapira, Flickr
Theoretically, you should accept any split
(something is better than nothing!).
But most offers under $2 are rejected.
The Ultimatum Game
The Ultimatum game only matches economic predictions (that
player 1 takes as much as possible and player 2 accepts anything)
within fairly isolated cultures.
Photo by wwarby, Flickr
The Dictator Game
A new game was created:
The Dictator Game
The Rules:
1. You have $10.
2. You make an offer to split it however you want
with another person.
3. They MUST accept.
4. You both get to keep the money.
In this game, you would expect player 1 to keep all
$10, but most of the time he gave player 2 some!
Photo by UnorthodoxY, Flickr
Networks Are in Our Genes
Nurture AND Nature are responsible for human sociability.
Twin studies show that genes influence our social networks
Photos by Oude School, Flickr
Networks Are in Our Genes
Genes account for 46% of
how popular you are!
Genes affect the probability
that two of your friends are
also friends with each
other.
Photos by djwudi, Flickr
Networks Are in Our Genes
Genes affect our emotions.
If you are predisposed by your genes to feel lonely, you might
become disconnected from your network.
Photos by peter.ca, Flickr
Networks Are in Our Genes
The ability to understand and work within social networks is even
programmed into our anatomy
The complexity of social networks could account for the large
size of the human brain.
Photos by EUSKALANATO, Flickr
Networks Are in Our Genes
Human brains are larger than monkey brains and human groups
are larger than monkey groups.
Monkeys groom each other one at a time, but humans can talk
To four people at once.
It seems the size of the brain
limits the size of the group.
Most natural human groups
are capped at about 150
People (Dunbar’s number).
Photos by thsutton, Flickr