Optimism, Pessimism, and the Language between: Model Interpretability and Psycholinguistic Profiling

Stefana Arina Tabusca, Liviu P. Dinu


Abstract
This study explores how optimism and pessimism are expressed in social media by combining psycholinguistic profiling with model interpretability. Using the OPT dataset, we fine-tune a RoBERTa-based classifier and apply LIME to examine both the most confident and the most ambiguous predictions. We analyze the influential tokens driving these decisions and identify lexical patterns linked to affective intensity, certainty, and social orientation. A complementary LIWC-based analysis of ground truth labels reveals systematic differences in emotional tone and cognitive style. PCA projections further show that optimism and pessimism occupy overlapping yet distinguishable regions in psycholinguistic space. Our findings demonstrate the value of linguistic interpretability in understanding dispositional sentiment.
Anthology ID:
2025.ranlp-1.141
Volume:
Proceedings of the 15th International Conference on Recent Advances in Natural Language Processing - Natural Language Processing in the Generative AI Era
Month:
September
Year:
2025
Address:
Varna, Bulgaria
Editors:
Galia Angelova, Maria Kunilovskaya, Marie Escribe, Ruslan Mitkov
Venue:
RANLP
SIG:
Publisher:
INCOMA Ltd., Shoumen, Bulgaria
Note:
Pages:
1224–1231
Language:
URL:
https://aclanthology.org/2025.ranlp-1.141/
DOI:
Bibkey:
Cite (ACL):
Stefana Arina Tabusca and Liviu P. Dinu. 2025. Optimism, Pessimism, and the Language between: Model Interpretability and Psycholinguistic Profiling. In Proceedings of the 15th International Conference on Recent Advances in Natural Language Processing - Natural Language Processing in the Generative AI Era, pages 1224–1231, Varna, Bulgaria. INCOMA Ltd., Shoumen, Bulgaria.
Cite (Informal):
Optimism, Pessimism, and the Language between: Model Interpretability and Psycholinguistic Profiling (Tabusca & Dinu, RANLP 2025)
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PDF:
https://aclanthology.org/2025.ranlp-1.141.pdf