Department of Linguistics, New York University, New York, NY 10003
New York University Abu Dhabi Institute, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, United Arab Emirate.
eNeuro. 2021 Jan 14;8(1). doi: 10.1523/ENEURO.0290-20.2020. Print 2021 Jan-Feb.
A hallmark of human thought is the ability to think about not just the actual world but also about alternative ways the world could be. One way to study this contrast is through language. Language has grammatical devices for expressing possibilities and necessities, such as the words or With these devices, called "modal expressions," we can study the actual versus possible contrast in a highly controlled way. While factual utterances such as "There is a monster under my bed" update the here-and-now of a discourse model, a modal version of this sentence, "There might be a monster under my bed," displaces from the here-and-now and merely postulates a possibility. We used magnetoencephalography (MEG) to test whether the processes of discourse updating and modal displacement dissociate in the brain. Factual and modal utterances were embedded in short narratives, and across two experiments, factual expressions increased the measured activity over modal expressions. However, the localization of the increase appeared to depend on perspective: signal localizing in right temporoparietal areas increased when updating the representation of someone else's beliefs, while frontal medial areas seem sensitive to updating one's own beliefs. The presence of modal displacement did not elevate MEG signal strength in any of our analyses. In sum, this study identifies potential neural signatures of the process by which facts get added to our mental representation of the world.
人类思维的一个特点是，不仅能够思考现实世界，还能够思考世界的其他可能存在方式。研究这种对比的一种方法是通过语言。语言有表达可能性和必然性的语法手段，例如“或者”和“可能”。通过这些被称为“模态表达式”的手段，我们可以以高度受控的方式研究实际与可能之间的对比。虽然像“我的床底下有一个怪物”这样的事实陈述更新了话语模型的此时此地，但这个句子的模态版本“我的床底下可能有一个怪物”则将此时此地从话语中置换出来，只是假设了一种可能性。我们使用脑磁图（MEG）来测试大脑中话语更新和模态置换是否分离。事实和模态陈述被嵌入在短叙事中，在两个实验中，事实陈述比模态陈述增加了测量到的活动。然而，增加的定位似乎取决于视角：当更新别人的信念的表示时，信号定位在右颞顶区域增加，而额内侧区域似乎对更新自己的信念敏感。在我们的任何分析中，模态置换的出现都没有提高 MEG 信号强度。总之，这项研究确定了事实被添加到我们对世界的心理表征的过程中的潜在神经特征。
