THE EFFECT OF ENGAGEMENT INTENSITY AND LEXICAL RICHNESS IN IDENTIFYING BOT ACCOUNTS ON TWITTER

The rise in the number of automated or bot accounts on Twitter engaging in manipulative behaviour is of great concern to studies using social media as a primary data source. Many strategies have been proposed and implemented, however, the sophistication and rate of deployment of bot accounts is increasing rapidly. This impedes and limits the capabilities of detecting bot strategies. Various features broadly related to account profiles, tweet content, network and temporal patterns have been utilised in detection systems. Tweet content has been proven instrumental in this process, but limited to the terms and entities occurring. Given a set of tweets with no obvious pattern, can we distinguish contents produced by social bots from those of humans? What constitutes engagement on Twitter and how can we measure the intensity of engagement among Twitter users? Can we distinguish between bot and human accounts based on engagement intensity? These are important questions whose answer will improve how detection systems operate to combat malicious activities by effectively distinguishing between human and social bot accounts on Twitter. This study attempts to answer these questions by analysing the engagement intensity and lexical richness of tweets produced by human and social bot accounts using large, diverse datasets. Our results show a clear margin between the two classes in terms of engagement intensity and lexical richness. We found that it is extremely rare for a social bot to engage meaningfully with other users and that lexical features significantly improve the performance of classifying both account types. These are important dimensions to explore toward improving the effectiveness of detection systems in combating the menace of social bot accounts on Twitter.