Modality effects and individual differences in language processing

Project 1 - Word recognition: the effect of modality and written language experience

In this project we investigate whether university students differ in their efficiency with which they recognize written, spoken, or audiovisually presented words varying in the degree to which they are known by the general population. 

We found that participants recognized spoken, written and audiovisual words equally efficiently, regardless of how common or uncommon the words were. We also investigated whether word recognition was influenced by individual differences in experience with written materials. 

Our study indicated that written language experience influenced word recognition: people who read in general more tended to recognize more uncommon words. It is likely that people who read a lot tend to encounter many uncommon words in books, and therefore know more of these uncommon words than people who tend to read less.

Project 2 - The effect of modality and written language experience on word recognition: a diverse sample

Based on the key result from the previous project, that already in a homogeneous group of university students word recognition was influenced by individual differences in their exposure to print,  we sought to explore this finding in more detail, by studying a more diverse group of students: both university as well as vocational (MBO) students were tested.

The study showed that recognition accuracy was equal for words presented in the written and spoken modality. However, people could recognize written words faster than spoken words, and this effect was larger for words people knew very well.

With regard to written language experience, experienced readers were found to recognize more difficult words in particular. Also, these people were faster at recognizing easy words than people who don't read as much.

Project 3 - The influence of written language experience on language abilities

People tend to vary a lot in their language abilities. The question is how these differences between people come about. One theory proposes that one's exposure to language influences the level of their language skills. That is, people who are more exposed to language, tend to have more efficient language processing skills such as production and comprehension.  Written language is known to be more information-dense and to contain more intricate linguistic structures and more uncommon words than spoken language. Therefore, people who have been more exposed to written language specifically have better language skills. In this project this is precisely what we investigate: does one's exposure to written language affect their language processing skills when accounting for the influence of their general cognitive skills? In our study we adopted a latent variable approach and measured the constructs of written language ability using reading, spelling and vocabulary tasks and a questionnaire one people's knowledge of authors. The language skills word production and word comprehension were also measured with a multitude of different tasks. 

Our study indicates that that written language exposure contributes to people's language processing skills even after we account the differences in their general cognitive ability. This suggest that exposure to writing has a strong influence on people's language abilities and that it even transfers its influence to language ability in the spoken modality.

Project 4 - A systematic review on the effect of written language experience on written and spoken word recognition

In the previous project, we found that written language experience contributes to people's language processing skills even after we account the influence of their general cognitive ability. Participants who tend to read a lot, show more efficient language processing. In this project, we emarked on a literature review to uncover why and how literacy experience has such a large effect on efficient word-level language processing. In a comprehensive review, we looked at 49 studies that compared word recognition efficiency in groups of people that differed in their level of literacy experience. Low literate adults were compared to high literate adults, adults were compared to children, and children of different age groups were compared to each other. The review focused especially on determining at what type of representations (syntax, phonology, orthography, semantic) and at which level of representation (word-level, syllable or morpheme level, sub-lexical level (letter/sounds). 

The literature described that as people become more experienced with written language, their word-level representations become more precisely defined. This is the case at all levels of representation. Moreover, written language experience seems to improve language processing in both the written and spoken modality.