Idiosyncratic Tower of Babel: Individual differences in word meaning representation increase along abstractness

Abstract

Humans primarily rely on language to communicate, based on a shared understanding of the basic building blocks of communication: words. However, words also have idiosyncratic aspects of meaning. Do we mean the same things when we use the same words? Classical philosophers disagreed on this point, speculating that words have more similar meanings across individuals if they are either more experiential (John Locke) or more abstract (Bertrand Russell). Here, we empirically characterize the individual variation pattern of 90 words using both behavioral and neuroimaging measures. We show that the magnitude of individual meaning disagreement is a function of how much language or sensory experience a word associates with, and this variation increases with abstractness of a word. Uncovering the cognitive and neural origins of word meaning disagreements across individuals has implications for potential mechanisms to modulate such disagreements.