Vividness is how clear or strong a mental image feels—whether you can "see," "hear," or "feel" it in your mind with a lot of detail and realism or only vaguely. Research tools like the VVIQ and Psi-Q ask you to rate vividness on scales (e.g. from "no image" to "as vivid as real perception"). The Imagination Index uses similar self-report items to derive your linear score and percentile score for each category. Higher vividness in a sense typically corresponds to hyperphantasia; very low or absent vividness to aphantasia.
What to do next
See where you fall on the imagination spectrum—take the free 12-minute assessment and get your Imagery Profile across all six senses.