Global patterns of adoption spreading are induced by local adoption cascades initiated by multiple spontaneous adopters arriving at a constant rate, amplified by a large number of adoptions induced by social influence, and controlled by individuals who are immune to the actual adoption. This study, published in This study is based on an observation of payed service adoptions evolved over 8 years on the social network of Skype, which connects over 500 million people all around the world. This data was analysed by data analytics method, using mathematical modelling and statistical techniques. A behavioural threshold theory from sociology was used to categorise people by how vulnerable or immune they are to other people’s decisions.
"Our observations and model helps us to understand the underlying structural differences between emergent global patterns of adoption spreading. We explain why some cases of adoption processes, like online memes or information cascades, emerge rapidly and while others, like adoption of products or services, evolve with a moderate speed" explains Márton Karsai, assistant professor at Ecole Normale Supérieure de Lyon (France) with INRIA research chair, and AScI visiting researcher at the Department of Computer Science at Aalto University (Finland).
According to the study, people can be classified into three groups in a way they adopt new ideas :
- Innovators are spontaneous with their own ideas, and they have the necessary connections to effectively influence others.
- Socially-influenced individuals include both the vulnerables (getting easily influenced by other people) and the stables, who may be influenced but need stronger impact before getting convinced.
- In addition there is always an immune or unconcerned population who will never become adopters no matter what others do around them.
Márton Karsai , ( IXXI , ENS de Lyon). Márton Karsai and Riivo Kikas from the University of Tartu and STACC worked on the data analysis. Gerardo Ińiguez and Márton Karsai developed and analysed the threshold model. Professors Kimmo Kaski from the Department of Computer Science at Aalto University and János Kertész from Central European University supervised the study.
References: M. Karsai et al., Local cascades induced global contagion: How heterogeneous thresholds, exogenous effects, and unconcerned behaviour govern online adoption spreading.