Reinforcement-Driven Spread of Innovations and Fads

We propose kinetic models for the spread of permanent innovations and transient fads by the mechanism of social reinforcement. Each individual can be in one of M+1 states of awareness 0,1,2,...,M, with state M corresponding to adopting an innovation. An individual with awareness k<M increases to k+1 by interacting with an adopter. Starting with a single adopter, the time for an initially unaware population of size N to adopt a permanent innovation grows as ln(N) for M=1, and as N^{1-1/M} for M>1. The fraction of the population that remains clueless about a transient fad after it has come and gone changes discontinuously as a function of the fad abandonment rate lambda for M>1. The fad dies out completely in a time that varies non-monotonically with lambda.Comment: 4 pages, 2 columns, 5 figures, revtex 4-1 format; revised version has been expanded and put into iop format, with one figure adde

Fads and Children: The Early Culture of Consumption

Fads have the ability to consume our attention and cause us to defy our better judgments. They have the power to pervade society with an intensity that rivals the infectiousness of an epidemic. Despite the influence of this phenomenon, there is no systematic assessment of the emergence of fads and their impacts on society. This thesis, “Fads and Children: The Early Culture of Consumption,” examines the effects of fads on children and families. This project begins by highlighting the fundamental characteristics of fads and how fads differ from traditional products. Since a discussion of the entire subject of fads would be overwhelming, this thesis focuses on fads as they pertain to a particular segment of the society. The children’s demographic was selected because of its potential as a dynamic market. This demographic is chosen also because of the increased susceptibility of children to fad activity. Children are known for their desire for the newest items and their perception of fads as the key to popularity and increased self worth. When compared to previous generations, children also possess greater spending power and purchasing influence. As a result of heightened competition and the potential benefits that can be generated from the children’s market, some marketers are prone to adopt potentially unethical approaches to reach children with their fad items. Although the methods of reaching children with fads and traditional products are the same, the impacts on children are dramatically different. Therefore, it is important to study how practices associated with marketing fads may influence children and the broader society. As a consequence of greater purchasing power on the part of children, more invasive marketing tactics, and the potential guilt and indulgence by parents, children are more inclined to exhibit feelings of narcissism, entitlement, and over-indulgence. Recommendations are included in this thesis in order to minimize the likelihood of these consequences

Dynamics of Confident Voting

We introduce the confident voter model, in which each voter can be in one of two opinions and can additionally have two levels of commitment to an opinion --- confident and unsure. Upon interacting with an agent of a different opinion, a confident voter becomes less committed, or unsure, but does not change opinion. However, an unsure agent changes opinion by interacting with an agent of a different opinion. In the mean-field limit, a population of size N is quickly driven to a mixed state and remains close to this state before consensus is eventually achieved in a time of the order of ln N. In two dimensions, the distribution of consensus times is characterized by two distinct times --- one that scales linearly with N and another that appears to scale as N^{3/2}. The longer time arises from configurations that fall into long-lived states that consist of two (or more) single-opinion stripes before consensus is reached. These stripe states arise from an effective surface tension between domains of different opinions.Comment: 13 pages, 8 figures, iop format. Version 2 has minor revisions in response to referee comments. For publication in JSTA

Social Influence and the Collective Dynamics of Opinion Formation

Social influence is the process by which individuals adapt their opinion, revise their beliefs, or change their behavior as a result of social interactions with other people. In our strongly interconnected society, social influence plays a prominent role in many self-organized phenomena such as herding in cultural markets, the spread of ideas and innovations, and the amplification of fears during epidemics. Yet, the mechanisms of opinion formation remain poorly understood, and existing physics-based models lack systematic empirical validation. Here, we report two controlled experiments showing how participants answering factual questions revise their initial judgments after being exposed to the opinion and confidence level of others. Based on the observation of 59 experimental subjects exposed to peer-opinion for 15 different items, we draw an influence map that describes the strength of peer influence during interactions. A simple process model derived from our observations demonstrates how opinions in a group of interacting people can converge or split over repeated interactions. In particular, we identify two major attractors of opinion: (i) the expert effect, induced by the presence of a highly confident individual in the group, and (ii) the majority effect, caused by the presence of a critical mass of laypeople sharing similar opinions. Additional simulations reveal the existence of a tipping point at which one attractor will dominate over the other, driving collective opinion in a given direction. These findings have implications for understanding the mechanisms of public opinion formation and managing conflicting situations in which self-confident and better informed minorities challenge the views of a large uninformed majority.Comment: Published Nov 05, 2013. Open access at: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.007843

An agent-based model of product competition: network structure and coexistence under different information regimes

The paper analyzes how the structure of interaction networks affects the diffusion patterns and market shares of different products in case of local network externalities and imperfect information. The diffusion of the different products/technologies in the market is modelled as the result of two (only partly) interrelated dynamics: i) the interaction between idiosyncratic individual thresholds and local network externalities; ii) the diffusion of the information about the product (via broadcast diffusion and word-of-mouth). The average clustering coefficient affects the overall outcome and the actual possibility that one product corners the market. Moreover, in case of small-world networks, despite the high clustering coefficient which increases the probability of an outcome with coexistence, the increase in the speed of diffusion impinges on the actual realization of such an outcome in case of sequential entry of the different technologies and/or imperfect information.Agent-based model, innovation diusion, network eects,social networks, small-world