Perceptual targeting acknowledges that the goal of room correction is NOT a perfectly flat measured response — it is a response that sounds natural to human ears. This accounts for: the ear's reduced sensitivity to bass at low volumes (leading to target curves with gentle bass boost), the precedence effect (early reflections under ~20ms are perceptually fused with the direct sound), and the fact that narrow-band corrections are often inaudible.
Room correction systems using perceptual targeting (Sonarworks, Dirac) apply smoothing to measurements and prioritize broad corrections over narrow surgical ones. A mathematically perfect correction of every peak and dip often sounds worse than a perceptually-informed one.