The rise in popularity and ubiquity of Twitter has made sentiment analysis of tweets an important and well-covered area of research. However, the 140 character limit imposed on tweets makes it hard to use standard linguistic methods for sentiment classification. On the other hand, what tweets lack in structure they make up with sheer volume and rich metadata. This metadata includes geolocation, temporal and author information. We hypothesize that sentiment is dependent on all these contextual factors. Different locations, times and authors have different emotional valences. In this paper, we explored this hypothesis by utilizing distant supervision to collect millions of labelled tweets from different locations, times and authors. We used this data to analyse the variation of tweet sentiments across different authors, times and locations. Once we explored and understood the relationship between these variables and sentiment, we used a Bayesian approach to combine these variables with more standard linguistic features such as n-grams to create a Twitter sentiment classifier. This combined classifier outperforms the purely linguistic classifier, showing that integrating the rich contextual information available on Twitter into sentiment classification is a promising direction of research.
We conduct a detailed investigation of correlations between real-time expressions of individuals made across the United States and a wide range of emotional, geographic, demographic, and health characteristics. We do so by combining (1) a massive, geo-tagged data set comprising over 80 million words generated in 2011 on the social network service Twitter and (2) annually-surveyed characteristics of all 50 states and close to 400 urban populations. Among many results, we generate taxonomies of states and cities based on their similarities in word use; estimate the happiness levels of states and cities; correlate highly-resolved demographic characteristics with happiness levels; and connect word choice and message length with urban characteristics such as education levels and obesity rates. Our results show how social media may potentially be used to estimate real-time levels and changes in population-scale measures such as obesity rates. This paper uses the Experience Sampling Method data drawn from a national sample of American youth. It examines the proximal environmental factors as well as behaviors and habits that correlate to personal happiness. Momentary-level scores show that reported happiness varies significantly both by day of week and time of day. Furthermore, particular activities are associated with varying degrees of happiness. School activities rate below average scores in happiness, while social, active and passive leisure activities are above average. Particular companions also correlate to differing level of happiness. Being alone rates the lowest levels of happiness, while being with friend corresponds to the highest. Person-level averages of happiness suggest that both higher social class and age correlate with lower levels of happiness, while gender and race do not. Paradoxically, youth who spend more time in school and social activities are happier than those who spend less. Unexpectedly, students who spend more time pleasure reading report lower levels of happiness. Finally, feeling good about the self, excited, proud, sociable, active as well as being in the conditions for flow experience are the strongest predictors of trait happiness. Natural language is rich and varied, but also highly structured. The rules of grammar are a primary source of linguistic regularity, but there are many other factors that govern patterns of language use. Language models attempt to capture linguistic regularities, typically by modeling the statistics of word use, thereby folding in some aspects of grammar and style. Spoken language is an important and interesting subset of natural language that is temporally and spatially grounded. While time and space may directly contribute to a speaker’s choice of words, they may also serve as indicators for communicative intent or other contextual and situational factors. To investigate the value of spatial and temporal information, we build a series of language models using a large, naturalistic corpus of spatially and temporally coded speech collected from a home environment. We incorporate this extralinguistic information by building spatiotemporal word classifiers that are mixed with traditional unigram and bigram models. Our evaluation shows that both perplexity and word error rate can be significantly improved by incorporating this information in a simple framework. The underlying principles of this work could be applied in a wide range of scenarios in which temporal or spatial information is available. Index Terms: language modeling, multimodal, spatial, temporal, context  We perform a sentiment analysis of all tweets published on the microblogging platform Twitter in the second half of 2008. We use a psychometric instrument to extract six mood states (tension, depression, anger, vigor, fatigue, confusion) from the aggregated Twitter content and compute a six-dimensional mood vector for each day in the timeline. We compare our results to a record of popular events gathered from media and sources. We find that events in the social, political, cultural and economic sphere do have a significant, immediate and highly specific effect on the various dimensions of public mood. We speculate that large scale analyses of mood can provide a solid platform to model collective emotive trends in terms of their predictive value with regards to existing social as well as economic indicators. In this paper, we present a multimodal speech recognition system for real world scene description tasks. Given a visual scene, the system dynamically biases its language model based on the content of the visual scene and visual attention of the speaker. Visual attention is used to focus on likely objects within the scene. Given a spoken description the system then uses the visually biased language model to process the speech. The system uses head pose as a proxy for the visual attention of the speaker. Readily available standard computer vision algorithms are used to recognize the objects in the scene and automatic real time head pose estimation is done using depth data captured via a Microsoft Kinect. The system was evaluated on multiple participants. Overall, incorporating visual information into the speech recognizer greatly improved speech recognition accuracy. The rapidly decreasing cost of 3D sensing technologies such as the Kinect allows systems with similar underlying principles to be used for many speech recognition tasks where there is visual information.