“…Farah's (e.g., Farah, Monheit, & Wallace, 1991;Farah, O'Reilly, & Vecera, 1993;Wallace & Farah, 1992) studies help illustrate the proposed relationship between consciousness and the graded quality of representations. Farah et al (1991) studied patients with extinction, a disorder of spatial attention, who were presented pairs of stimuli (e.g., pictures of an apple and a comb), one of which was partially occluded, and were later asked to judge whether they matched or differed.…”