the stimulus from time of presentation to time of retrieval, rather that the failure is attributed to information not being encoded when the stimulus was present. It seems that inattentional blindness can be explained by both memory and perceptual failures because in experimental research participants may fail to report what was on display due to failures in encoded information (memory) or a failure in perceptually processed information (perception). Neuropsychological analogies There are similarities in the types of unconscious processing apparent in inattentional blindness and in neuropsychological syndromes such as visual neglect and extinction. The analogy between these phenomenon's seems to generate more questions as well as answers. These answers are fundamental for our understanding of the relationship between attention, stimulus coding and behavior. Visual neglect Research has shown that some aspects of the syndrome of unilateral visual neglect appear to be similar to normal subjects in a state of inattentional blindness. In neglect, patients with lesions to the parietal cortex fail to respond to and report stimuli presented on the side of space contralateral to damage. That is, they appear to be functionally blind to a range of stimuli. Since such lesions do not result in any sensory deficits, shortcomings have been explained in terms of a lack of attentional processing, for which the parietal cortex plays a large role. These phenomena draw strong parallels to one another, as in both cases stimuli are perceptible but unreported when unattended. Extinction In the phenomenon of extinction, patients can report the presence of a single stimulus presented on the affected side, but then fail to detect it when a second stimulus is presented simultaneously on the "good" (ipsilateral) side. Here the stimulus on the affected side seems to lose under conditions of attentional competition from stimuli in the ipsilesional field. The consequence of this competition is that the extinguished items may not be detected. Similar to studies of inattentional blindness, there is evidence of processing taking place in the neglected field. For example, there can be semantic priming from a stimulus presented in the neglected field, which affects responses to stimuli subsequently presented on the unimpaired side. Apparently in both neglect and inattentional blindness, there is some level processing of stimuli even when they are unattended. However one major difference between neuropsychological symptoms such as neglect and extinction, and inattentional blindness concerns the role of expectation. In inattentional blindness, subjects do not