Thesis defense Nan van den Meerendonk (Donders Series 92)

July 3, 2012.

Promotors: Prof.dr. H. Kolk, Prof.dr. P. Indefrey; copromotors: dr. D.J. Chwilla, dr. S.-A. Rueschemeyer

States of indecision in the brain

Electrophysiological and hemodynamic reflection of monitoring in visual language perception

We generally take our ability to use language to express ourselves and to understand others for granted. Usually we understand what another person is saying or writing without any difficulty. Sometimes, however, this effortless understanding is interrupted and we might ask ourselves: ‘Did I hear/read that correctly?’. This happens for example when we encounter a spelling violation, or when a word is difficult to read because of a lack of visual information. In this thesis we investigated specifically these situations in visual language perception, where comprehension is temporarily hampered. Our studies show that a process of cognitive control called ‘monitoring’ is involved in preventing these situations to lead to actual misunderstandings. When there is a strong conflict between an expected and an observed linguistic element, or when a word is difficult to read because of a lack of bottom-up information, our brain reprocesses the input. This extra processing is reflected in a positive component in the EEG. And the area that is involved in guiding this reprocessing is Broca’s area.