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Ted Talk: The Hidden Influence of Social Networks



Nicholas Christakis reveals how certain traits and characteristics of a person can spread through a social network, rather quickly and easily. They examined many aspects of daily life, such as voting, obesity, smoking and drinking, and found that people with similar habits tended to cluster together over time. Studies of obesity show that when you have less degrees of separation between you and the obese person, there is a higher probability that you are also overweight. Christakis theorizes that this phenomenon is not the spread of behavior but instead the spread of a norm or idea that alters your behavior.


Emotional contagion was studied in a similar manner as it is observed that happy and unhappy people tend to be clustered together within social networks. Another tendency was for the unhappy people to be located at the edges and for the happy people to be in the center. These observations led to new theories on the causes and effects of the structure of a social network. He has predicted that a main cause for our role in a network is due to the genes we were born with. For example, people are either naturally extroverted or naturally introverted. It becomes obvious that this one trait will lead to differences in the number of friends that one obtains and the interconnectivity of these friends. Eventually these “different structural locations [will] have different implications for your life”, shaping how you interact with others within the web of humanity.


This Ted Talk deeply relates to the basic ideas of population and structural effects in networks. The study of obesity exemplified the outbreak of a “social contagion”, demonstrating how people naturally align their behavior with immediate neighbors, forming social patterns and norms.


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October 2016