Strasbourg and Tanganyika: Two Curious Cases of Cascades
In class we have discussed how information based cascades can lead to large amounts of people making identical decisions regardless of what their own experience tells them. While trusting in the crowd can be beneficial, it also has it’s dangers in the form of abundant misinformation; however, information cascades can also have some very physical impacts as well. Two very interesting and clear examples of this are the Dancing Plague of 1518 and the Tanganyika Laughter Epidemic (1962) both of which are rare occurrences of hysteria spread via a social network.
In 1518 in the town of Strasbourg a women by the name of Mrs. Troffea began to dance through the streets without stopping for four to six days. Within this time, roughly 34 others had joined her and the dancing only spread from there. In fact, the “plague” became so devastating that at it’s height, with over 400 dancers, approximately fifteen people died from exhaustion, heat, or dehydration per day. The most fascinating thing about this plague is that it seems to have had no cause. It was as if the compulsion to dance was contagious, spread and increased by the number of people joining in, and that precisely may have been the only catalyst needed to make dancing so contagious.
As the saying goes laughter is contagious, and in 1962 in the village of Tanganyika this was extraordinarily evident. In January three girls at a boarding school began to laugh uncontrollably, unable to stop for nearly sixteen hours after contracting symptoms. The compulsion quickly spread throughout the students – notably never affecting the teachers- and eventually becoming so distracting that the school had to be shut down by March. The laughter soon spread to nearby villages that the students lived in, inducing nearly 217 laughing attacks by May. Nearly two years and one-thousand infected individuals later, the epidemic died out, leaving many to speculate what the causes possibly could have been. The leading theory, by Purdue University Professor Charles Hempelmann, points to stress induced laughter due to Tanganyika recently winning independence. The theory relies upon the highly interconnected nature of the students and the boarding school, explaining why the laugher only spread among peers and family members.
These two “plagues” are particularly fascinating situations in which cascades have had power to the point of actually causing individuals to experience physical symptoms, and while rare, offer a unique opportunity to study how such cascades form and conclude. The importance of strongly connected networks to their pathogenesis is particularly worth noting, as it draws direct parallels to the in class material.
http://rltz.blogspot.com/2007/05/from-central-african-medical-journal.html
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2809%2960386-X/fulltext
really interesting!