A variety of approaches have been recently proposed to automatically infer users' personality from their user generated content in social media. Approaches differ in terms of the machine learning algorithms and the feature sets used, type of utilized footprint, and the social media environment used to collect the data. In this paper, we perform a comparative analysis of state-of-the-art computational personality recognition methods on a varied set of social media ground truth data from Facebook, Twitter and YouTube. We answer three questions: (1) Should personality prediction be treated as a multi-label prediction task (i.e., all personality traits of a given user are predicted at once), or should each trait be identified separately? (2) Which predictive features work well across different online environments? and (3) What is the decay in accuracy when porting models trained in one social media environment to another?

The Workshop on Computational Personality Recognition aims to define the state-of-the-art in the field and to provide tools for future standard evaluations in personality recognition tasks. In the WCPR14 we released two different datasets: one of Youtube Vlogs and one of Mobile Phone interactions. We structured the workshop in two tracks: an open shared task, where participants can do any kind of experiment, and a competition. We also distinguished two tasks: A) personality recognition from multimedia data, and B) personality recognition from text only. In this paper we discuss the results of the workshop. Categories and Subject Descriptors

In this paper, we address the issue of personality and interaction style recognition from profile pictures in Facebook. We recruited volunteers among Facebook users and collected a dataset of profile pictures, labeled with gold standard self-assessed personality and interaction style labels. Then, we exploited a bag-of-visualwords technique to extract features from pictures. Finally, different machine learning approaches were used to test the effectiveness of these features in predicting personality and interaction style traits. Our good results show that this task is very promising, because profile pictures convey a lot of information about a user and are directly connected to impression formation and identity management. Categories and Subject Descriptors [Emotional and Social Signals in Multimedia]:Novel methods for the classification and representation of interactive social and/or emotional signals General TermsFacebook profiling personality pictures algorithms

People spend considerable effort managing the impressions they give others. Social psychologists have shown that people manage these impressions differently depending upon their personality. Facebook and other social media provide a new forum for this fundamental process; hence, understanding people's behaviour on social media could provide interesting insights on their personality. In this paper we investigate automatic personality recognition from Facebook profile pictures. We analyze the effectiveness of four families of visual features and we discuss some human interpretable patterns that explain the personality traits of the individuals. For example, extroverts and agreeable individuals tend to have warm colored pictures and to exhibit many faces in their portraits, mirroring their inclination to socialize; while neurotic ones have a prevalence of pictures of indoor places. Then, we propose a classification approach to automatically recognize personality traits from these visual features. Finally, we compare the performance of our classification approach to the one obtained by human raters and we show that computer-based classifications are significantly more accurate than averaged human-based classifications for Extraversion and Neuroticism.

Abstract. Due to their large worldwide adoption, Social Network Sites (SNSs) have been widely used in many global events as an important source to spread news and information. While the searchability and persistence of this information make it ideal for sociological research, a quantitative approach is still challenging because of the size and complexity of the data. In this paper we provide a first analysis of Friendfeed, a well-known and feature-rich SNS. Research frameworkSocial Network Sites (SNSs) are undoubtedly one of the most interesting phenomena that bring together new technologies and social practices. They are going through an incredibly fast growth all over the world despite the fact many obstacles like the digital divide still exist. Despite this global success it would be hard to define a single global leader of the SNSs. Facebook, which counts more than 300 million single users mostly clustered in Europe and in the US, is surely a big player but QQ, with a high concentration of users in China, has an even larger user base. It seems that cultural diversity and local identity lead toward the choice of a specific SNS, while the shift toward the adoption of a SNS-model for online interpersonal communications seems to be global [1].Due to this large worldwide adoption, SNSs have been widely used in many global events as an important source to spread news and information. From the terroristic attack in Mumbai in 2008 to the so-called Twitter revolution in Iran in 2009 SNSs proved several times to be a reliable way to communicate and to spread information in a quick and relatively efficient way. Within this scenario the sociological analysis of SNS based communication is still largely based on a qualitative ethnographic approach aimed at investigating living practices and uses of the SNS [2,3,4]. This approach gave us the opportunity to gain an effective insight in SNS users' lives, motivations and communicative strategies but failed in giving us a general description of how SNSs work and deal, as complex entities, with the diffusion of information.

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In this article, we address the issue of how emotional stability affects social relationships in Twitter. In particular, we focus our study on users' communicative interactions, identified by the symbol "@." We collected a corpus of about 200,000 Twitter posts, and we annotated it with our personality recognition system. This system exploits linguistic features, such as punctuation and emoticons, and statistical features, such as follower count and retweeted posts. We tested the system on a data set annotated with personality models produced by human subjects and against a software for the analysis of Twitter data. Social network analysis shows that, whereas secure users have more mutual connections, neurotic users post more than secure ones and have the tendency to build longer chains of interacting users. Clustering coefficient analysis reveals that, whereas secure users tend to build stronger networks, neurotic users have difficulty in belonging to a stable community; hence, they seek for new contacts in online social networks.

In the Workshop on Computational Personality Recognition (Shared Task), we released two datasets, varying in size and genre, annotated with gold standard personality labels. This allowed participants to evaluate features and learning techniques, and even to compare the performances of their systems for personality recognition on a common benchmark. We had 8 participants to the task. In this paper we discuss the results and compare them to previous literature.