 Campion et al. (1983) raised an important alternative explanation: blindsight subjects in fact have severely degraded conscious vision but merely report on them with low confidence. In their reports, blindsight subjects feel like they are guessing about stimuli they can objectively discriminate. Campion et al. drew on signal detection theory, which emphasizes two determinants of detection behavior: perceptual sensitivity and response criterion. A subject’s ability to visually detect a signal will depend partly on how well her visual system extracts the signal from noise (sensitivity) but also on the criterion that is set as a threshold for response. Consider trying to detect something moving in the brush at twilight versus at noon. In the latter, the signal will be greatly separated from noise (the object will be easier to detect) while in the former, the signal will not be (the object will be harder to detect). Yet in either case, one might operate with a conservative response criterion, say because one is afraid to be wrong. Thus, even if the signal is detectable, one might still opt not to report on it given a conservative bias (criterion), say if one is in the twilight scenario and would be ridiculed for “false alarms”, i.e., claiming the object to be present when it is not.