lamanhnguyen at SemEval-2026 Task 2: Uncovering Lexical Bias and Momentum Lag in Longitudinal Emotion Prediction using Multi-task DeBERTa
Paper · 2026 · Lam Anh Nguyen
Summary
This paper describes a system for SemEval-2026 Task 2, which asks participants to predict emotional Valence and Arousal from users' chronological diary entries. The task has three subtasks: current emotional state (Subtask 1), short-term change between entries (2a), and the user's long-run baseline (2b). The author treats all of them as multi-task regression with microsoft/deberta-v3-base, trained on the merged Subtask 1 and 2a training data. Two fine-tuned variants are combined in a 0.6/0.4 weighted ensemble. For the longitudinal subtasks, an Exponential Moving Average (EMA) filter with α = 0.1 smooths the raw predictions.
The system does well on point-in-time prediction, with the second-best Valence correlation. However, it yields negative correlations on both longitudinal subtasks. The error analysis traces part of this to a "Venting Effect": the model reads negative vocabulary as low valence, even when writers report feeling relieved after journaling. It also shows that EMA smoothing trades lower MAE for weaker Pearson r. These findings are a useful warning for anyone building emotion trackers over noisy, real-life text.
Key points
- Ensemble. The two DeBERTa-v3-base variants were V1 (4 epochs, LR 2e-5) and V3 (6 epochs, LR 1e-5). Weights were tuned by grid search, and ensembling cut validation MSE from 0.183 to 0.172.
- Subtask 1 results. Valence reached r = 0.687 (MAE 0.639) and Arousal reached r = 0.458 (MAE 0.395). This placed 2nd on Valence and 5th on the overall V&A average.
- Subtask 2 results. Correlations were negative. In 2a, Valence r was −0.273 and Arousal r was −0.275. In 2b, Valence r was −0.398 and Arousal r was −0.577, both significant at p < 0.01.
- Venting Effect. In the 5% of cases with the largest errors, about 56% contained strongly negative exhaustion-related words but had neutral or positive gold valence.
- Smoothing ablation (Subtask 2a, Valence). Without smoothing (α = 0.0), the model scored MAE 1.355 with r = 0.142. With α = 0.1, it scored MAE 1.322 with r = −0.273. The author attributes this to variance shrinkage and lag during abrupt mood shifts.
Fields, topics and concepts
📚 Shelves 5The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksPsychology · 1,552 worksExperimental and Cognitive Psychology · 870 worksSocial Psychology · 306 works
🧭 Topics 1Research subjects and languages the work is about.Sentiment & emotion · 972 works
Cite
Cite as Lam Anh Nguyen. 2026. lamanhnguyen at SemEval-2026 Task 2: Uncovering Lexical Bias and Momentum Lag in Longitudinal Emotion Prediction using Multi-task DeBERTa. Proceedings of the 20th International Workshop on Semantic Evaluation (2026).
@inproceedings{nguyen2026lamanhnguyen,
title = {{lamanhnguyen at SemEval-2026 Task 2: Uncovering Lexical Bias and Momentum Lag in Longitudinal Emotion Prediction using Multi-task DeBERTa}},
author = {Lam Anh Nguyen},
booktitle = {Proceedings of the 20th International Workshop on Semantic Evaluation (2026)},
year = {2026},
doi = {10.18653/v1/2026.semeval-1.91},
url = {https://doi.org/10.18653/v1/2026.semeval-1.91}
}References
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