The positive evidence bias in perceptual confidence is not post-decisional

Abstract

Confidence in a perceptual decision is a subjective estimate of the accuracy of one's choice. As such, confidence is thought to be an important computation for a variety of cognitive and perceptual processes, and it features heavily in theorizing about conscious access to perceptual states. Recent experiments have revealed a "positive evidence bias" (PEB) in the computations underlying confidence reports. A PEB occurs when confidence, unlike objective choice, overweights the evidence for the chosen option, relative to evidence against the chosen option.Accordingly, in a perceptual task, appropriate stimulus conditions can be arranged that produce selective changes in confidence reports but no changes in accuracy. Although the PEB is generally assumed to reflect the observer's perceptual and/or decision processes, postdecisional accounts have not been ruled out. We therefore asked whether the PEB persisted under novel conditions that eliminated two possible post-decisional accounts: 1) post-decision evidence accumulation that contributes to a confidence report solicited after the perceptual choice, and 2) a memory bias that emerges in the delay between the stimulus offset and the confidence report. We found that even when the stimulus remained on the screen until observers responded, and when observers reported their choice and confidence simultaneously, the PEB still emerged. Signal detection-based modeling also showed that the PEB was not associated with changes to metacognitive efficiency, but rather to confidence criteria. We conclude that once-plausible post-decisional accounts of the PEB do not explain the bias, bolstering the idea that it is perceptual or decisional in nature.

Spontaneous alpha-band amplitude predicts subjective visibility but not discrimination accuracy during high-level perception

“…The phenomenon of blindsight is a prime example of a much more profound dissociation brought about through lesions of visual cortex (Cowey & Stoerig, 1991), however our results suggest that even in neurologically intact individuals, an observer's subjective visibility of a stimulus can be modulated independently of their ability to accurately discriminate its identity. Indeed, there is a growing body of psychophysical work pointing to the separability of subjective and objective visual reports (Koizumi et al, 2015;Lau & Passingham, 2006;Maniscalco et al, 2016;Odegaard et al, 2018;Rahnev et al, 2011;Samaha et al, 2016Samaha et al, , 2019Samaha & Denison, 2020;Zylberberg et al, 2012Zylberberg et al, , 2014. In all of these cases (though perhaps less so in neurological blindsight), there is a question as to which metric, the objective or subjective, better tracks observers' conscious experience.…”

SalemGarcia_2021

“…Our model of confidence biased by the value of the chosen option suggests a post-decisional mechanism, as choice itself affects confidence. Yet, a recent preprint suggests post-decisional mechanisms are not necessary to cause the response-congruent bias in a perceptual task (Samaha and Denison, 2020). Further research leveraging reinforcement learning and sequential sampling models in conjunction (Fontanesi et al, 2019b(Fontanesi et al, , 2019a may help quantify the extent to which our results can be explained by deliberational process.…”

“…Whether in the learning or in the transfer phase, this bias in the construction of confidence towards the value of the chosen option is reminiscent of a positive evidence bias observed in perceptual decisions, whereby people seem to inform their confidence reports only by sensory evidence in favor of their choices (Maniscalco et al, 2016;Peters et al, 2017;Samaha and Denison, 2020;Zylberberg et al, 2012). This simplification of confidence computationsometimes referred to as a heuristiccould be ecologically efficient, providing a mechanism that is computationally inexpensive and easily generalizable to scenarios with more than two options (Maniscalco et al, 2016).…”

Defending subjective inflation: An inference to the best explanation

“…But this is not to say that subjective measures are simply "better than nothing." In addition to their face validity for assessing phenomenology, recent work explains the utility and relevance of using confidence ratings in paradigms where performance is matched to probe conscious awareness of phenomenological content (Morales, Odegaard, and Maniscalco 2019) , and at least some perceptual findings using confidence and visibility judgments cannot be accounted for by post-decisional cognitive/memory biases (Samaha and Denison 2020) . Researchers can also analyze visibility and confidence judgments within the framework of 1 Finding a double dissociation between a measurement indicator I and a phenomenon P does not imply that, in general, I is not a good indicator of P .…”