Variations in Inner Language and Conceptual Thought Experience

Inner language is often assumed to include sensorimotor imagery, but is that necessary? How common are conceptual (non-linguistic) thoughts? Does low propensity to think in words indicate lowered ability to imagine language altogether? Here, we sought to characterize the variability in the format of thought by prompting participants (N=228) to (i) think about a given topic or (ii) imagine hearing language or speaking, and then report on their experiences. For thought prompts, a statistically non-trivial percentage of reports included non-sensorimotor inner language (17.5%) and concepts without a verbal or visual form (37.5%). While 74.6% of participants showed high propensity to experience inner language, 4.4% showed no propensity. For language imagery prompts, inner language ability was near-ubiquitous, with only 0.4% (N=1) reporting the absence of linguistic imagery. Overall, we highlight the variability in inner language and conceptual thought experiences, and dissociate the propensity vs. the ability to use language in thought.