Wiens' commentary makes two central claims: first, objective measures ignore and might therefore be incommensurate with the subjective nature of awareness; and second, objective measures are flawed because of the possibility that they do not exclusively measure explicit awareness.

Both 'subjective' and 'objective' tasks rely on observers' reports of conscious experience; neither ignores the subjective nature of awareness. Subjective thresholds are based on the report from each trial individually, whereas objective thresholds are based on cumulative experiences across many trials. Reported awareness on any given trial involves both subjects' explicit sensitivity to the target and their criterion to report it. If subjects adopt a conservative criterion, then on any given trial, they might not report a stimulus that was indeed consciously accessible. The goal of using an objective threshold is to avoid such errors on individual trials by showing that sensitivity to the target is absent; in the absence of sensitivity, decision criteria and confidence do not influence reports of awareness. In essence, the objective threshold is that level at which a stimulus is not reliably reportable rather than simply not reported.

Wiens states that we ?imply that methodological issues will disappear once imaging studies use objective measures? and then proceeds to note some challenges associated with measuring objective thresholds. That objective thresholds are challenging to obtain does not negate the reasons for using them, particularly when trying to show the existence of a distinct implicit processing mechanism. The objective approach is not a methodological panacea, but it is an improvement. Why not aim higher?

Wiens argues that objective approaches are flawed if the explicit task does not exclusively tap conscious processes. However, failure to meet this exclusiveness criterion only decreases the probability that evidence for implicit perception will be forthcoming ? the exclusivity critique does not apply to successful demonstrations of implicit perception using an objective threshold. By contrast, although subjective measures may be less likely to violate the exclusiveness criterion, they are also less likely to eliminate influences of conscious processing on performance, leading to erroneous reports of implicit perception. Given the goal of showing that processes are truly implicit, this failing seems more problematic.

More broadly, we did not propose abandoning subjective reports altogether ? we simply question their value in providing definitive evidence of implicit processing. We noted that many dissociations, such as blindsight, are theoretically and empirically interesting, offering ?fertile grounds for neuroimaging research?, regardless of whether they reflect a difference between explicit and implicit processes (Ref. 1, Box 4). Such dissociations, particularly when accompanied by qualitative differences in performance or neural activity, suggest the possibility of distinct processing mechanisms.

In summary, we maintain the view that neuroimaging provides an important new avenue for documenting qualitative differences between implicit and explicit processes if appropriately sensitive (objective) measures of conscious awareness are adopted. Subjective measures can be informative as well, even if they are ill-suited for dissociating explicit processes from purely implicit ones.