We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

Random graphs

We are in the midst of a technological revolution whereby, for the first time, researchers can link daily word use to a broad array of real-world behaviors. This article reviews several computerized text analysis methods and describes how Linguistic Inquiry and Word Count (LIWC) was created and validated. LIWC is a transparent text analysis program that counts words in psychologically meaningful categories. Empirical results using LIWC demonstrate its ability to detect meaning in a wide variety of experimental settings, including to show attentional focus, emotionality, social relationships, thinking styles, and individual differences.

/pdf/the-psychological-meaning-of-words-liwc-and-computerized-4sd1bn03dk.pdf

The psychological meaning of words: LIWC and computerized text analysis methods

The inherent nature of social media content poses serious challenges to practical applications of sentiment analysis. We present VADER, a simple rule-based model for general sentiment analysis, and compare its effectiveness to eleven typical state-of-practice benchmarks including LIWC, ANEW, the General Inquirer, SentiWordNet, and machine learning oriented techniques relying on Naive Bayes, Maximum Entropy, and Support Vector Machine (SVM) algorithms. Using a combination of qualitative and quantitative methods, we first construct and empirically validate a gold-standard list of lexical features (along with their associated sentiment intensity measures) which are specifically attuned to sentiment in microblog-like contexts. We then combine these lexical features with consideration for five general rules that embody grammatical and syntactical conventions for expressing and emphasizing sentiment intensity. Interestingly, using our parsimonious rule-based model to assess the sentiment of tweets, we find that VADER outperforms individual human raters (F1 Classification Accuracy = 0.96 and 0.84, respectively), and generalizes more favorably across contexts than any of our benchmarks.

/pdf/vader-a-parsimonious-rule-based-model-for-sentiment-analysis-47uwj744t2.pdf

VADER: A Parsimonious Rule-based Model for Sentiment Analysis of Social Media Text

The COVID-19 pandemic represents a massive global health crisis. Because the crisis requires large-scale behaviour change and places significant psychological burdens on individuals, insights from the social and behavioural sciences can be used to help align human behaviour with the recommendations of epidemiologists and public health experts. Here we discuss evidence from a selection of research topics relevant to pandemics, including work on navigating threats, social and cultural influences on behaviour, science communication, moral decision-making, leadership, and stress and coping. In each section, we note the nature and quality of prior research, including uncertainty and unsettled issues. We identify several insights for effective response to the COVID-19 pandemic and highlight important gaps researchers should move quickly to fill in the coming weeks and months.

/pdf/using-social-and-behavioural-science-to-support-covid-19-25vr5kyvxt.pdf

Using social and behavioural science to support COVID-19 pandemic response.

Emotional states can be transferred to others via emotional contagion, leading people to experience the same emotions without their awareness. Emotional contagion is well established in laboratory experiments, with people transferring positive and negative emotions to others. Data from a large real-world social network, collected over a 20-y period suggests that longer-lasting moods (e.g., depression, happiness) can be transferred through networks [Fowler JH, Christakis NA (2008) BMJ 337:a2338], although the results are controversial. In an experiment with people who use Facebook, we test whether emotional contagion occurs outside of in-person interaction between individuals by reducing the amount of emotional content in the News Feed. When positive expressions were reduced, people produced fewer positive posts and more negative posts; when negative expressions were reduced, the opposite pattern occurred. These results indicate that emotions expressed by others on Facebook influence our own emotions, constituting experimental evidence for massive-scale contagion via social networks. This work also suggests that, in contrast to prevailing assumptions, in-person interaction and nonverbal cues are not strictly necessary for emotional contagion, and that the observation of others' positive experiences constitutes a positive experience for people.

/pdf/experimental-evidence-of-massive-scale-emotional-contagion-3ncbihzoj3.pdf

Experimental evidence of massive-scale emotional contagion through social networks

Online social networks are everywhere. They must be influencing the way society is developing, but hard evidence is scarce. For instance, the relative effectiveness of online friendships and face-to-face friendships as drivers of social change is not known. In what may be the largest experiment ever conducted with human subjects, James Fowler and colleagues randomly assigned messages to 61 million Facebook users on Election Day in the United States in 2010, and tracked their behaviour both online and offline, using publicly available records. The results show that the messages influenced the political communication, information-seeking and voting behaviour of millions of people. Social messages had more impact than informational messages and 'weak ties' were much less likely than 'strong ties' to spread behaviour via the social network. Thus online mobilization works primarily through strong-tie networks that may exist offline but have an online representation.

https://jasonjones.ninja/papers/massive_turnout.pdf

A 61-million-person experiment in social influence and political mobilization

Happiness and other emotions spread between people in direct contact, but it is unclear whether massive online social networks also contribute to this spread. Here, we elaborate a novel method for measuring the contagion of emotional expression. With data from millions of Facebook users, we show that rainfall directly influences the emotional content of their status messages, and it also affects the status messages of friends in other cities who are not experiencing rainfall. For every one person affected directly, rainfall alters the emotional expression of about one to two other people, suggesting that online social networks may magnify the intensity of global emotional synchrony.

/pdf/detecting-emotional-contagion-in-massive-social-networks-5612xnl0zz.pdf

Detecting Emotional Contagion in Massive Social Networks

This article considers tools to support remote gesture in video systems being used to complete collaborative physical tasks-tasks in which two or more individuals work together manipulating three-dimensional objects in the real world. We first discuss the process of conversational grounding during collaborative physical tasks, particularly the role of two types of gestures in the grounding process: pointing gestures, which are used to refer to task objects and locations, and representational gestures, which are used to represent the form of task objects and the nature of actions to be used with those objects. We then consider ways in which both pointing and representational gestures can be instantiated in systems for remote collaboration on physical tasks. We present the results of two studies that use a "surrogate" approach to remote gesture, in which images are intended to express the meaning of gestures through visible embodiments, rather than direct views of the hands. In Study 1, we compare performance with a cursor-based pointing device that allows remote partners to point to objects in a video feed of the work area to performance side-by-side or with the video system alone. In Study 2, we compare performance with two variations of a pen-based drawing tool that allows for both pointing and representational gestures to performance with video alone. The results suggest that simple surrogate gesture tools can be used to convey gestures from remote sites, but that the tools need to be able to convey representational as well as pointing gestures to be effective. The results further suggest that an automatic erasure function, in which drawings disappear a few seconds after they were created, is more beneficial for collaboration than tools requiring manual erasure. We conclude with a discussion of the theoretical and practical implications of the results, as well as several areas for future research.

/pdf/gestures-over-video-streams-to-support-remote-collaboration-4mygngrvz2.pdf

Gestures over video streams to support remote collaboration on physical tasks

I analyze the use of emotion words for approximately 100 million Facebook users since September of 2007. "Gross national happiness" is operationalized as a standardized difference between the use of positive and negative words, aggregated across days, and present a graph of this metric. I begin to validate this metric by showing that positive and negative word use in status updates covaries with self-reported satisfaction with life (convergent validity), and also note that the graph shows peaks and valleys on days that are culturally and emotionally significant (face validity). I discuss the development and computation of this metric, argue that this metric and graph serves as a representation of the overall emotional health of the nation, and discuss the importance of tracking such metrics.

/pdf/an-unobtrusive-behavioral-model-of-gross-national-happiness-22wtem9ebz.pdf

Adam D. I. Kramer

Papers

Experimental evidence of massive-scale emotional contagion through social networks

A 61-million-person experiment in social influence and political mobilization

Detecting Emotional Contagion in Massive Social Networks

Gestures over video streams to support remote collaboration on physical tasks

An unobtrusive behavioral model of "gross national happiness"