Blindness reshapes mental time travel: From perceptual scenes to conceptual scaffolds

Abstract

How can humans remember and imagine without vision? Mental time travel, the ability to re-experience past events and envision future ones, is widely assumed to rely on visual imagery and the construction of mental scenes. Blindness provides a critical test of this assumption. Across behavioral interviews, language analyses, and multimodal neuroimaging in congenitally blind, late-blind, and sighted individuals, we show that blind individuals, even those blind from birth, mentally time travel as vividly as sighted people, but construct their inner worlds differently. Sighted participants relied on perceptual detail and activated classic scene-processing regions, whereas blind participants emphasized thoughts and emotions and recruited reorganized occipital cortex. Connectivity analyses revealed strengthened coupling between occipital and medial temporal regions, indicating adaptive reconfiguration of the episodic system. The brain does not require images to imagine: it flexibly builds internal experiences using the representational resources available. Summary ParagraphHow humans reconstruct events that are no longer available to the senses is a fundamental but unresolved question. Remembering the past and imagining the future, known as mental time travel, is a defining feature of human cognition, shaping identity and guiding decisions{superscript 1},{superscript 2}. Prevailing theories assume that such constructions depend on visual imagery, with the minds eye reconstructing events on a visuospatial stage3,. Blindness provides a critical test of this assumption. Across extensive behavioral interviews and multimodal neuroimaging, we find that mental time travel remains phenomenologically intact in blindness, but its scaffolding changes fundamentally. Sighted individuals rely on perceptual detail and activate regions specialized for visual scenes, whereas blind individuals, whether blind from birth or later in life, emphasize thoughts and emotions and reorganize occipital cortex for conceptual strategies,. These contrasting strategies map onto distinct neural signatures, revealing a dissociation between perceptual and conceptual routes to episodic simulation. Together, these findings reveal that the brains capacity to construct internal experience rests on conceptual scaffolding, not perceptual re-creation.