Reddit's human content wins amid the AI flood For Ines Tan there's one particular site she turns to again and again for advice - and that's Reddit. Tan, who works in communications, regularly jumps on the site for skincare advice, to view reactions to shows she watches, such as The Traitors, and for help planning her upcoming wedding in May. It's a very empathetic place, she says of Reddit. For my wedding, I've found help emotionally, logistically and inspiration-wise. Tan believes people are consulting the online discussion platform more as they're craving human interaction in the world of increasing AI slop.

Reddit is being touted as an antidote to AI-generated content. Reddit is being touted as an antidote to AI-generated content. Platform is now Britain's fourth most visited social media site as users seek out human-generated content Reddit, the online discussion platform, has overtaken TikTok as Britain's fourth most visited social media service, as search algorithms and gen Z have dramatically transformed its prominence. The platform has undergone huge growth over the last two years, with an 88% increase in the proportion of UK internet users it reaches. Three in five Brits online now encounter the site, up from a third in 2023, according to Ofcom .

Reddit is considered one of the most human spaces left on the internet, but mods and users are overwhelmed with slop posts in the most popular subreddits. A Reddit post about a bride who demands a wedding guest wear a specific, unflattering shade is sure to provoke rage, let alone one about a bridesmaid or mother of the groom who wants to wear white. A scenario where a parent asks someone on an airplane to switch seats so they can sit next to their young child is likely to invoke the same rush of anger. But those posts may trigger a Reddit moderator's annoyance for a different reason--they are common themes within a growing genre of AI -generated, fake posts. These are examples that spring to mind for Cassie, one of dozens of moderators for r/AmItheAsshole .

Recently powerful Large Language Models (LLMs) have become easily accessible to hundreds of millions of users world-wide.

Large language models (LLMs) have shown great potential in flagging harmful content in online communities. Yet, existing approaches for moderation require a separate model for every community and are opaque in their decision-making, limiting real-world adoption. We introduce Mixture of Moderation Experts (MoMoE), a modular, cross-community framework that adds post-hoc explanations to scalable content moderation. MoMoE orchestrates four operators -- Allocate, Predict, Aggregate, Explain -- and is instantiated as seven community-specialized experts (MoMoE-Community) and five norm-violation experts (MoMoE-NormVio). On 30 unseen subreddits, the best variants obtain Micro-F1 scores of 0.72 and 0.67, respectively, matching or surpassing strong fine-tuned baselines while consistently producing concise and reliable explanations. Although community-specialized experts deliver the highest peak accuracy, norm-violation experts provide steadier performance across domains. These findings show that MoMoE yields scalable, transparent moderation without needing per-community fine-tuning. More broadly, they suggest that lightweight, explainable expert ensembles can guide future NLP and HCI research on trustworthy human-AI governance of online communities.

Accurately estimating how users respond to moderation interventions is paramount for developing effective and user-centred moderation strategies. However, this requires a clear understanding of which user characteristics are associated with different behavioural responses, which is the goal of this work. We investigate the informativeness of 753 socio-behavioural, linguistic, relational, and psychological features, in predicting the behavioural changes of 16.8K users affected by a major moderation intervention on Reddit. To reach this goal, we frame the problem in terms of "quantification", a task well-suited to estimating shifts in aggregate user behaviour. We then apply a greedy feature selection strategy with the double goal of (i) identifying the features that are most predictive of changes in user activity, toxicity, and participation diversity, and (ii) estimating their importance. Our results allow identifying a small set of features that are consistently informative across all tasks, and determining that many others are either task-specific or of limited utility altogether. We also find that predictive performance varies according to the task, with changes in activity and toxicity being easier to estimate than changes in diversity. Overall, our results pave the way for the development of accurate systems that predict user reactions to moderation interventions. Furthermore, our findings highlight the complexity of post-moderation user behaviour, and indicate that effective moderation should be tailored not only to user traits but also to the specific objective of the intervention.

Here, we test this hypothesis using novel machine learning methods to create a bottom-up, atheoretical model of personality from the same trait-descriptive adjective list that led to the dominant, contemporary model of personality (the Big Five). We then compare the descriptive utility of this machine learning method (resulting in lexical clusters) by comparing it to the established Big Five personality model in how well these describe conversations online (on Reddit forums). Our analysis of 1 million online comments shows that the Big Five model provides a much more powerful and interpretable description of these communities and the differences between them. Specifically, the dimensions of Agreeableness, Conscientiousness, and Neuroticism effectively distinguish Reddit communities. In contrast, our lexical clusters do not provide meaningful distinctions and fail to describe the spread. Validation against the International Personality Item Pool confirmed the Big Five model's superior psychometric coherence, and our machine learning methods notably failed to recover the trait of Extraversion. These results affirm the robustness of the Big Five, while also showing that the semantic structure of personality is likely depending on social context. Our findings suggest that while machine learning can help with understanding and explaining human behavior, especially by checking ecological validity of existing theories, machine learning methods may not be able to replace established psychological theories.

Generative large language models (LLMs) have become central to everyday life, producing human-like text across diverse domains. A growing body of research investigates whether these models also exhibit personality- and demographic-like characteristics in their language. In this work, we introduce a novel, data-driven methodology for assessing LLM personality without relying on self-report questionnaires, applying instead automatic personality and gender classifiers to model replies on open-ended questions collected from Reddit. Comparing six widely used models to human-authored responses, we find that LLMs systematically express higher Agreeableness and lower Neuroticism, reflecting cooperative and stable conversational tendencies. Gendered language patterns in model text broadly resemble those of human writers, though with reduced variation, echoing prior findings on automated agents. We contribute a new dataset of human and model responses, along with large-scale comparative analyses, shedding new light on the topic of personality and demographic patterns of generative AI.

Music serves as a powerful reflection of individual identity, often aligning with deeper psychological traits. Prior research has established correlations between musical preferences and personality, while separate studies have demonstrated that personality is detectable through linguistic analysis. Our study bridges these two research domains by investigating whether individuals' musical preferences leave traces in their spontaneous language through the lens of the Big Five personality traits (Openness, Conscientiousness, Extroversion, Agreeableness, and Neuroticism). Using a carefully curated dataset of over 500,000 text samples from nearly 5,000 authors with reliably identified musical preferences, we build advanced models to assess personality characteristics. Our results reveal significant personality differences across fans of five musical genres. We release resources for future research at the intersection of computational linguistics, music psychology and personality analysis.