Department of Cognition, Development and Educational Psychology, Universitat de Barcelona, Barcelona, Spain; Cognition and Brain Plasticity Unit [Bellvitge Biomedical Research Institute, IDIBELL], Barcelona, Spain.
Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga, Spain.
Neuroimage. 2019 Apr 1;189:192-201. doi: 10.1016/j.neuroimage.2019.01.005. Epub 2019 Jan 6.
According to prediction-based accounts of language comprehension, incoming contextual information is constantly used to guide the pre-activation of the most probable continuations to the unfolding sentences. However, there is still scarce evidence of the build-up of these predictions during sentence comprehension. Using event-related brain potentials, we investigated sustained processes associated to semantic prediction during online sentence comprehension. To address this, participants read sentences with varying levels of contextual constraint one word at a time. A 1000 ms interval preceded the final word, which could be congruent or incongruent. A slow sustained negativity developed gradually over the course of sentences, showing differences across conditions, with increasingly larger amplitudes for high than low levels of constraint. The effect was maximal in the interval preceding the closing word. This interval elicited a left-dominant slow negative potential with a graded amplitude modulation to contextual constraint, replicating previous results in speech comprehension. We argue that these slow potentials index the engagement of cognitive operations associated to semantic prediction. In addition, we replicated the finding of an earlier onset of the N400 effect (incongruent minus congruent) for high relative to low contextual constraint, suggesting facilitated processing for contextually-supported and highly expected words. Altogether, these results are consistent with prediction-based models of language comprehension and they also strengthen the value of investigating slow components as potential indices of mechanisms linked to language prediction.
根据基于预测的语言理解理论，输入的上下文信息会不断被用来指导展开句子的最可能的延续。然而，关于这些预测在句子理解过程中是如何逐渐建立的，目前仍缺乏证据。我们使用事件相关脑电位，研究了在线句子理解过程中与语义预测相关的持续过程。为了解决这个问题，参与者一个字一个字地阅读具有不同语境约束程度的句子。最后一个字之前有 1000 毫秒的间隔，可以是一致的，也可以是不一致的。在句子的过程中，逐渐发展出一种缓慢而持续的负向，在不同的条件下表现出差异，高约束水平的振幅比低约束水平的振幅更大。这种效应在最后一个字之前的间隔中达到最大值。这个间隔引发了一种以左侧为主的缓慢负向电位，其幅度随着语境约束的变化而逐渐变化，与言语理解中的先前结果相吻合。我们认为这些缓慢的电位反映了与语义预测相关的认知操作的参与。此外，我们复制了 N400 效应（不一致减去一致）在高语境约束条件下比低语境约束条件下更早出现的发现，这表明对于语境支持和高度预期的单词，处理过程更加顺利。总之，这些结果与语言理解的基于预测的模型一致，它们也进一步加强了研究缓慢成分作为与语言预测相关机制的潜在指标的价值。
