for target details not contained in the retinal image cannot truly be said to have been recognized. Perceptual learning has also been invoked in possible adaptation of normal observers to the inevitable image degradation by their ocu-lar aberrations (Artal et al., 2004). Recent advances in adaptive op-tics techniques have enabled their cancellation with consequent improvement in visual acuity. Careful probing has revealed little if any perceptual adaptation to this long-standing image degrada-tion (Rossi et al., 2007; Rossi & Roorda, 2010). The topic of percep-tual learning with subsequent improvement in an observer’s