See: "The pupillary light response as a physiological index of aphantasia, sensory and phenomenological imagery strength." https://www.ncbi.nlm.nih.gov/pmc/art

See: "The pupillary light response as a physiological index of aphantasia, sensory and phenomenological imagery strength." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9018072/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9018072/ This study had participants imagine a bright scene, which triggers a physiological pupil response similar to the response of actually walking out into the bright sun. Those who self-reported aphantasia had no physiological pupil response. Aphantasia is not a "false belief", and I assure you that those with aphantasia find it just as hard to understand mental visual imagery as you find it hard to understand a lack of mental visual imagery.