To make sentences, we sequence words one by one, as if those words were beads on a chain. So from the outside, sentences are linear, but underneath that linear sequence is a certain type of structure. That structure is hierarchical, meaning that words are combined into constituents, which are then combined again with other words into larger constituents, and so on. This can be seen, for example, in the ambiguity of a sentence like "the woman looks at the man with the binoculars". This sentence has two meanings, while none of the words is ambiguous. The ambiguity follows from the fact that "with the binoculars" can be linked to both "the man" and "saw the man". In the former, there is a man with binoculars being watched by a woman, and in the latter, the woman uses the binoculars to watch the man. To understand language, we need to construct a hierarchically organised structure from linear inputs. This thesis is about how we do that. To answer this question, Cas looked at both human behaviour and electrical brain activity in neurolinguistic experiments.
Cas Coopmans studied bachelor's in Psychology at Utrecht University and master's in Cognitive Neuroscience at Radboud University Nijmegen. After obtaining his master's, he started a PhD at the Max Planck Institute for Psycholinguistics in Nijmegen. For four years, Cas studied the role of hierarchical structure in processing written and spoken language. He is currently doing a post-doc at the Donders Centre for Cognitive Neuroimaging.