The Invalsi Benchmark: measuring Language Models Mathematical and Language understanding in Italian

While Italian is by all metrics a high resource language, currently, there are isn't a Language Model pre-trained exclusively in this language. This results in a lower number of available benchmarks to evaluate the performance of language models in Italian. This work presents two new benchmarks to evaluate the models performance on mathematical understanding and language understanding in Italian. These benchmarks are based on real tests that are undertaken by students of age between 11 and 18 within the Italian school system and have therefore been validated by several experts in didactics and pedagogy. To validate this dataset we evaluate the performance of 9 language models that are the best performing when writing in Italian, including our own fine-tuned models. We show that this is a challenging benchmark where current language models are bound by 60\% accuracy. We believe that the release of this dataset paves the way for improving future models mathematical and language understanding in Italian.

M4GT-Bench: Evaluation Benchmark for Black-Box Machine-Generated Text Detection

The advent of Large Language Models (LLMs) has brought an unprecedented surge in machine-generated text (MGT) across diverse channels. This raises legitimate concerns about its potential misuse and societal implications. The need to identify and differentiate such content from genuine human-generated text is critical in combating disinformation, preserving the integrity of education and scientific fields, and maintaining trust in communication. In this work, we address this problem by introducing a new benchmark involving multilingual, multi-domain and multi-generator for MGT detection -- M4GT-Bench. It is collected for three task formulations: (1) mono-lingual and multi-lingual binary MGT detection; (2) multi-way detection identifies which particular model generates the text; and (3) human-machine mixed text detection, where a word boundary delimiting MGT from human-written content should be determined. Human evaluation for Task 2 shows less than random guess performance, demonstrating the challenges to distinguish unique LLMs. Promising results always occur when training and test data distribute within the same domain or generators.

Outliers Dimensions that Disrupt Transformers Are Driven by Frequency

Transformer-based language models are known to display anisotropic behavior: the token embeddings are not homogeneously spread in space, but rather accumulate along certain directions. A related recent finding is the outlier phenomenon: the parameters in the final element of Transformer layers that consistently have unusual magnitude in the same dimension across the model, and significantly degrade its performance if disabled. We replicate the evidence for the outlier phenomenon and we link it to the geometry of the embedding space. Our main finding is that in both BERT and RoBERTa the token frequency, known to contribute to anisotropicity, also contributes to the outlier phenomenon. In its turn, the outlier phenomenon contributes to the "vertical" self-attention pattern that enables the model to focus on the special tokens. We also find that, surprisingly, the outlier effect on the model performance varies by layer, and that variance is also related to the correlation between outlier magnitude and encoded token frequency.