Tiancheng Hu


2024

pdf
Quantifying the Persona Effect in LLM Simulations
Tiancheng Hu | Nigel Collier
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Large language models (LLMs) have shown remarkable promise in simulating human language and behavior. This study investigates how integrating persona variables—demographic, social, and behavioral factors—impacts LLMs’ ability to simulate diverse perspectives. We find that persona variables account for <10% variance in annotations in existing subjective NLP datasets. Nonetheless, incorporating persona variables via prompting in LLMs provides modest but statistically significant improvements. Persona prompting is most effective in samples where many annotators disagree, but their disagreements are relatively minor. Notably, we find a linear relationship in our setting: the stronger the correlation between persona variables and human annotations, the more accurate the LLM predictions are using persona prompting. In a zero-shot setting, a powerful 70b model with persona prompting captures 81% of the annotation variance achievable by linear regression trained on ground truth annotations. However, for most subjective NLP datasets, where persona variables have limited explanatory power, the benefits of persona prompting are limited.

pdf
An Individualized News Affective Response Dataset
Tiancheng Hu | Nigel Collier
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 4: Student Research Workshop)

The rise of sensationalism in news reporting, driven by market saturation and online competition, has compromised news quality and trust. At the core of sensationalism is the evocation of affective responses in the readers. Current NLP approaches to emotion detection often overlook the subjective differences in groups and individuals, relying on aggregation techniques that can obscure nuanced reactions. We introduce a novel large-scale dataset capturing subjective affective responses to news headlines. The dataset includes Facebook post screenshots from popular UK media outlets and uses a comprehensive annotation scheme. Annotators report their affective responses, provide discrete emotion labels, assess relevance to current events, and indicate sharing likelihood. Additionally, we collect demographic, personality, and media consumption data. This ongoing dataset aims to enable more accurate models of affective response by considering individual and contextual factors. This work is ongoing and we highly appreciate any feedback.

2022

pdf
The Causal News Corpus: Annotating Causal Relations in Event Sentences from News
Fiona Anting Tan | Ali Hürriyetoğlu | Tommaso Caselli | Nelleke Oostdijk | Tadashi Nomoto | Hansi Hettiarachchi | Iqra Ameer | Onur Uca | Farhana Ferdousi Liza | Tiancheng Hu
Proceedings of the Thirteenth Language Resources and Evaluation Conference

Despite the importance of understanding causality, corpora addressing causal relations are limited. There is a discrepancy between existing annotation guidelines of event causality and conventional causality corpora that focus more on linguistics. Many guidelines restrict themselves to include only explicit relations or clause-based arguments. Therefore, we propose an annotation schema for event causality that addresses these concerns. We annotated 3,559 event sentences from protest event news with labels on whether it contains causal relations or not. Our corpus is known as the Causal News Corpus (CNC). A neural network built upon a state-of-the-art pre-trained language model performed well with 81.20% F1 score on test set, and 83.46% in 5-folds cross-validation. CNC is transferable across two external corpora: CausalTimeBank (CTB) and Penn Discourse Treebank (PDTB). Leveraging each of these external datasets for training, we achieved up to approximately 64% F1 on the CNC test set without additional fine-tuning. CNC also served as an effective training and pre-training dataset for the two external corpora. Lastly, we demonstrate the difficulty of our task to the layman in a crowd-sourced annotation exercise. Our annotated corpus is publicly available, providing a valuable resource for causal text mining researchers.

2021

pdf
Team “NoConflict” at CASE 2021 Task 1: Pretraining for Sentence-Level Protest Event Detection
Tiancheng Hu | Niklas Stoehr
Proceedings of the 4th Workshop on Challenges and Applications of Automated Extraction of Socio-political Events from Text (CASE 2021)

An ever-increasing amount of text, in the form of social media posts and news articles, gives rise to new challenges and opportunities for the automatic extraction of socio-political events. In this paper, we present our submission to the Shared Tasks on Socio-Political and Crisis Events Detection, Task 1, Multilingual Protest News Detection, Subtask 2, Event Sentence Classification, of CASE @ ACL-IJCNLP 2021. In our submission, we utilize the RoBERTa model with additional pretraining, and achieve the best F1 score of 0.8532 in event sentence classification in English and the second-best F1 score of 0.8700 in Portuguese via simple translation. We analyze the failure cases of our model. We also conduct an ablation study to show the effect of choosing the right pretrained language model, adding additional training data and data augmentation.

pdf
Discovering Black Lives Matter Events in the United States: Shared Task 3, CASE 2021
Salvatore Giorgi | Vanni Zavarella | Hristo Tanev | Nicolas Stefanovitch | Sy Hwang | Hansi Hettiarachchi | Tharindu Ranasinghe | Vivek Kalyan | Paul Tan | Shaun Tan | Martin Andrews | Tiancheng Hu | Niklas Stoehr | Francesco Ignazio Re | Daniel Vegh | Dennis Atzenhofer | Brenda Curtis | Ali Hürriyetoğlu
Proceedings of the 4th Workshop on Challenges and Applications of Automated Extraction of Socio-political Events from Text (CASE 2021)

Evaluating the state-of-the-art event detection systems on determining spatio-temporal distribution of the events on the ground is performed unfrequently. But, the ability to both (1) extract events “in the wild” from text and (2) properly evaluate event detection systems has potential to support a wide variety of tasks such as monitoring the activity of socio-political movements, examining media coverage and public support of these movements, and informing policy decisions. Therefore, we study performance of the best event detection systems on detecting Black Lives Matter (BLM) events from tweets and news articles. The murder of George Floyd, an unarmed Black man, at the hands of police officers received global attention throughout the second half of 2020. Protests against police violence emerged worldwide and the BLM movement, which was once mostly regulated to the United States, was now seeing activity globally. This shared task asks participants to identify BLM related events from large unstructured data sources, using systems pretrained to extract socio-political events from text. We evaluate several metrics, accessing each system’s ability to identify protest events both temporally and spatially. Results show that identifying daily protest counts is an easier task than classifying spatial and temporal protest trends simultaneously, with maximum performance of 0.745 and 0.210 (Pearson r), respectively. Additionally, all baselines and participant systems suffered from low recall, with a maximum recall of 5.08.