20,067 research outputs found
Social influence and position effects
A wide range of personal choices rely on the opinions or ratings of other individuals. This information has recently become a convenient way of simplifying the decision process. For instance, in online purchases of products and services, the possible choices or alternatives are often characterized by their position in a certain presentation order (or list) and their popularity, derived from an aggregate signal of the behavior of others. We have performed a laboratory experiment to quantify and compare popularity (or social influence) and position effects in a stylized setting of homogeneous preferences, with a small number of alternatives but considerable time constraints. Our design allows for the distinction between two phases in the decision process: (1) how agents search (i.e., not only which alternatives are analyzed but also in which order) and (2) how they ultimately choose. We find that in this process there are significant popularity and position effects. Position effects are stronger than social influence effects for predicting the searching behavior, however, social influence determines to a larger extent the actual choice. The reason is that social influence generates a double effect; it directly affects the final choice (independently on what alternative has been searched more thoroughly) and indirectly alters choice through the searching behavior which, in turn, is also affected by popularity. A novelty of our approach is that we account for personal traits and provide an individual analysis of sensitivity to both social influence and position effects. Surprisingly, we find that overconfident individuals are more influenceable, whereas other personal characteristics (e.g., gender and risk aversion) do not play a significant role in this context
Dynamical analysis for a scalar-tensor model with Gauss-Bonnet and non-minimal couplings
We study the autonomous system for a scalar-tensor model of dark energy with
Gauss-Bonnet and non-minimal couplings. The critical points describe important
stable asymptotic scenarios including quintessence, phantom and de Sitter
attractor solutions. Two functional forms for the coupling functions and the
scalar potential were considered: power-law and exponential functions of the
scalar field. For the exponential functions the existence of stable
quintessence, phantom or de Sitter solutions, allows an asymptotic behavior
where the effective Newtonian coupling becomes constant. The phantom solutions
could be realized without appealing to ghost degrees of freedom. Transient
inflationary and radiation dominated phases can also be described.Comment: 31 pages, 3 figures, to appear in EPJ
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