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arXiv 2602.04081cs.CL
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抽象诱导语言和语音模型的脑对齐

Abstraction Induces the Brain Alignment of Language and Speech Models

The University of Texas at Austin, USA(德克萨斯大学奥斯汀分校);Zuckerman Mind Brain Behavior Institute, Columbia University, USA(祖克曼心智-大脑-行为研究所,哥伦比亚大学)

Emily Cheng, Aditya R. Vaidya, Richard Antonello

AI总结:

研究发现语言和语音模型通过共享的意义抽象与大脑对齐,中间层的高内在维度和语义内容增强了大脑预测性。

摘要:

研究反复表明,从大型语言模型和语音音频模型中提取的中间隐藏状态可以预测对自然语言刺激的测量脑反应。然而,关于使这种高预测性能得以实现的表示属性却知之甚少。为什么是中间层而不是输出层最有效于这种独特且高度通用的转移任务?我们提供证据表明,语音和语言模型与大脑之间的对应关系源于共享的意义抽象,而不是它们的下个词预测属性。特别是,模型在其中间层构建更高阶的语言特征,这些特征由层间内在维度的峰值所提示,这是特征复杂性的度量。我们证明了一层的内在维度强烈预测其解释fMRI和ECoG信号的能力;内在维度与大脑预测性之间的关系出现在模型预训练过程中;对模型进行微调以更好地预测大脑因果性会增加表示的内在维度和语义内容。结果表明,语义丰富性、高内在维度和大脑预测性相互映射,而模型与大脑相似性的关键驱动力是输入的丰富意义抽象,其中语言建模是一个足够复杂(但可能不是唯一的)任务,需要这种抽象。

英文摘要:

Research has repeatedly demonstrated that intermediate hidden states extracted from large language models and speech audio models predict measured brain response to natural language stimuli. Yet, very little is known about the representation properties that enable this high prediction performance. Why is it the intermediate layers, and not the output layers, that are most effective for this unique and highly general transfer task? We give evidence that the correspondence between speech and language models and the brain derives from shared meaning abstraction and not their next-word prediction properties. In particular, models construct higher-order linguistic features in their middle layers, cued by a peak in the layerwise intrinsic dimension, a measure of feature complexity. We show that a layer's intrinsic dimension strongly predicts how well it explains fMRI and ECoG signals; that the relation between intrinsic dimension and brain predictivity arises over model pre-training; and finetuning models to better predict the brain causally increases both representations' intrinsic dimension and their semantic content. Results suggest that semantic richness, high intrinsic dimension, and brain predictivity mirror each other, and that the key driver of model-brain similarity is rich meaning abstraction of the inputs, where language modeling is a task complex enough (but perhaps not the only) to require it.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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