Predicting high variability in imageability ratings across age groups and its influence on visual word recognition

Imageability, an important word characteristic in the psycholinguistic literature, is typically assessed by asking participants to estimate the ease with which a word can evoke a mental image. Our aim was to explore inter-rater disagreement in normative imageability ratings. We examined the predictors of variability around average imageability ratings for young, middle-aged and older adults (Study 1) and assessed its impact on visual word recognition performance in young adults (Study 2). Analyses of French age-related imageability ratings (Ballot et al., Behavior Research Methods, 54, 196-215, 2022) revealed that inter-rater disagreement around the average imageability value was critically high for most words within the imageability norms, thus questioning the construct validity of the average rating for the most variable items. Variability in ratings changed between age groups (18-25, 26-40, 41-59, and over 60 years) and was associated with words that are longer, less frequent, learnt later in life and less emotional (Study 1). To examine the consequences of elevated standard deviations around the average imageability rating on visual word recognition, we entered this factor in a hierarchical regression alongside classic lexico-semantic predictors. The effect of word-imageability on young adults' lexical decision times (Ferrand et al., Behavior Research Methods, 50, 1285-1307, 2018) remained significant after accounting for inter-rater disagreement in imageability ratings, even when considering the least consensual words (Study 2). We conclude that imageability ratings reliably predict visual word recognition performance in young adults for large datasets, but might require caution for smaller ones. Given imageability rating differences across adulthood, further research investigating age-related differences in language processing is necessary.