Idioms in the ageing brain: The effects of age-related cognitive decline on the processing and comprehension of idioms, funded by a NWO PhDs in the Humanities grant.

Ageing and Language
My research focuses on the link between cognitive ageing and the processing of language. The general cognitive abilities that are affected by ageing are also involved in language processing skills. Therefore, an interesting question is how cognitive ageing correlates with elderly adults’ language processing abilities. In this way, language can be used as a tool to study cognitive decline in elderly adults.
In my project I investigate how the age-related cognitive decline correlates with elderly adults’ ability to process and comprehend ambiguous language. Ambiguities are an interesting linguistic phenomenon to study, because the majority of the language that we encounter on a daily basis is actually ambiguous. For instance, the simple utterance “He walked towards the bank” already contains two ambiguities: it is unclear 1) to which male character ‘he’ is referring 2) whether the speaker is talking about a ‘bank’ as a financial institution or the slope alongside a river. The fact that ambiguities are omnipresent in our everyday vocabulary makes them highly interesting to study within the scope of cognitive ageing and more generally, the ageing of society.

In this project, the linguistic tool that is used to create ambiguity are idiomatic expressions. Idioms are short figurative expressions, such as the Dutch tegen de lamp lopen or de kop in het zand steken. The meaning of idioms is ambiguous. For example, tegen de lamp lopen literally means ‘to bump into a lamp’, but figuratively ‘to get caught’. Neuro-imaging research shows that when processing idiomatic compared to literal expressions people recruit additional areas in the frontal part of the brain, which is involved in higher-order cognitive, or executive functioning. As executive functions are subject to age-related cognitive decline, the question is how elderly adults process and comprehend idiomatic expressions. By investigating this research question, my project will not only provide insight in language processing in old age, but more generally also in the relation between general cognitive functions and language processing abilities.

Event-related potentials & eye-tracking
To study the relation between age-related cognitive decline and language processing abilities, I use event-related potentials (ERPs) and eye-tracking. The ERP technique measures people’s electrophysiological brain activation pattern while reading or listening to sentences. Based on the latency and amplitude of the different ERP components, we can draw inferences about the processes involved in the incremental processing of language. An advantage of using online research techniques in addition to behavioral methods is that the temporal precision of the ERP and eye-tracking methodology allows us to get insight in the processes that take place while people are processing language, instead of only reflecting the end result of the process. Moreover, as electrophysiological brain activation patterns, as well as eye movements are uncontrolled responses, these measures can increase our understanding of natural language processing.