Vocabulary knowledge and non-verbal IQ predict successful comprehension of ambiguous sentences

We aim to identify and explain neuro-cognitive sources of variability in spoken language comprehension success, focusing here on the challenge of semantic ambiguity (e.g. BALL has multiple meanings) and the role of language-specific function (e.g. quality of lexico-semantic representations) and/or domain-general function (e.g. executive processes). In an online study, we measured listeners’ (n=71, 19-59 years) comprehension of sentences containing ambiguity in a Meaning Definitions Task. Listeners also completed six standardized tests – the Mill Hill Vocabulary Test, the Spot the Word Task, and the four-part Cattell 2a Culture Fair Test, which loaded (in a PCA) on to two components reflecting vocabulary knowledge and non-verbal IQ. Correlational analyses showed an increase in age was associated with increased vocabulary-knowledge but decreased non-verbal IQ, in line with previous research (Hartshorne & Germine, 2015). Multiple linear regression showed that comprehension success was predicted by both vocabulary knowledge and non-verbal IQ, but not by age.