Alexia Toskos Dils

Visual motion aftereffect from understanding motion language.

Do people spontaneously form visual mental images when understanding language, and if so, how truly visual are these representations? We test whether processing linguistic descriptions of motion produces sufficiently vivid mental images to cause direction-selective motion adaptation in the visual system (i.e., cause a motion aftereffect illusion). We tested for motion aftereffects (MAEs) following explicit motion imagery, and after processing literal or metaphorical motion language (without instructions to imagine). Intentionally imagining motion produced reliable MAEs. The aftereffect from processing motion language gained strength as people heard more and more of a story (participants heard motion stories in four installments, with a test after each). For the last two story installments, motion language produced reliable MAEs across participants. Individuals differed in how early in the story this effect appeared, and this difference was predicted by the strength of an individual’s MAE from imagining motion. Strong imagers (participants who showed the largest MAEs from imagining motion) were more likely to show an MAE in the course of understanding motion language than were weak imagers. The results demonstrate that processing language can spontaneously create sufficiently vivid mental images to produce direction-selective adaptation in the visual system. The timecourse of adaptation suggests that individuals may differ in how efficiently they recruit visual mechanisms in the service of language understanding. Further, the results reveal an intriguing link between the vividness of mental imagery and the nature of the processes and representations involved in language understanding.

Processing unrelated language can change what you see

When we hear a story, do we naturally imagine the visual scene being described? Do the representations derived in the course of normal language comprehension interact with visual perception broadly? For example, might understanding language change how we interpret visual scenes, even when the visual scenes are unrelated to the linguistic content? In our study, people interpreted an ambiguous image after they had (1) seen real visual motion either upward or downward (Experiment 1), (2) read a story describing physical motion (Experiment 2), or (3) read a story describing abstract motion (Experiment 3). The ambiguous figure could have been seen as a bird flying upward or a different bird flying downward, and the participants were simply asked to click on or draw a worm in the bird’s beak. People’s interpretations of the ambiguous figure were affected by viewing real motion and by reading literal stories describing physical motion, but not by the abstract motion stories. These findings suggest that processing linguistic descriptions of physical (but not abstract) motion can bias perceptual processing in a broad sense; in this case, reading about physical motion changed people’s interpretation of an unrelated ambiguous image.