 To make our discussion concrete, consider Simons and Chabris’s (1999) famous “Selective Attention Test” on youtube (see the link in  Other Internet Resources).  When subjects were asked to count passes of basketballs—spoiler alert!—a fair number failed to notice a person in a gorilla suit who came into the scene. Given how hard it is to track the passes of basketballs, it is natural to assume that the non-noticers were attending only to the basketballs, and did not attend to the person in the gorilla suit. Now suppose that some of non-noticers still did experience a person in a gorilla suit in the scene, as a person in a gorilla suit. According to the Attention Needed view, their inattentive experience cannot provide them with justification to believe that someone’s there in a gorilla suit. According to the Attention Optional view, their inattentive experience might still provide them with justification to believe that someone’s there in a gorilla suit.