Social inertia is a term for the stability of dominance relationships despite changes in the intrinsic dominating abilities of opponents. In a standard test for social inertia, low-ranking birds in an established hierarchy receive implants with testosterone (treated) and high-ranking birds receive empty implants (untreated). Social inertia occurs when the treated birds remain subordinate to unt...

Ranking systems are central to many internet applications including, notably, Google’s PageRank algorithm for ranking web pages. Ranking systems are a special case of a social choice problem in which the set of agents and the set of outcomes coincide. In this paper we consider PageRank as a particular ranking system and we present two axiomatizations that allow PageRank to be studied from a soc...

Social networks have ensured the expanding disproportion between the face of WWW stored traditionally in search engine repositories and the actual ever changing face of Web. Exponential growth of web users and the ease with which they can upload contents on web highlights the need of content controls on material published on the web. As definition of search is changing, socially-enhanced intera...

The paper presents a framework for the selection and ranking of activities proposed to users in a social networking service, as for example Facebook’s “social events”. Our proposal takes into account the peculiarities of this application area, considering a variety of factors including the spatiotemporal relations between activities and between activities and users, and the social opinions weig...

User-Generated Content (UGC) on social media platforms and product search engines is changing the way consumers shop for goods online. However, current product search engines fail to effectively leverage information created across diverse social media platforms. Moreover, current ranking algorithms in these product search engines tend to induce consumers to focus on one single product character...

In social hierarchies, dominant individuals experience reproductive and health benefits, but the costs of social dominance remain a topic of debate. Prevailing hypotheses predict that higher-ranking males experience higher testosterone and glucocorticoid (stress hormone) levels than lower-ranking males when hierarchies are unstable but not otherwise. In this long-term study of rank-related stre...