Human behavior depends on the ability to effectively introspect about our performance. For simple perceptual decisions, this introspective or metacognitive ability varies substantially across individuals and is correlated with the structure of focal areas in prefrontal cortex. This raises the possibility that the ability to introspect about different perceptual decisions might be mediated by a common cognitive process. To test this hypothesis, we examined whether inter-individual differences in metacognitive ability were correlated across two different perceptual tasks where individuals made judgments (...) about different and unrelated visual stimulus properties. We found that inter-individual differences were strongly correlated between the two tasks for metacognitive ability but not objective performance. Such stability of an individual’s metacognitive ability across different perceptual tasks indicates a general mechanism supporting metacognition independent of the specific task. (shrink)

How should we measure metacognitive sensitivity, i.e. the efficacy with which observers’ confidence ratings discriminate between their own correct and incorrect stimulus classifications? We argue that currently available methods are inadequate because they are influenced by factors such as response bias and type 1 sensitivity . Extending the signal detection theory approach of Galvin, Podd, Drga, and Whitmore , we propose a method of measuring type 2 sensitivity that is free from these confounds. We call our measure meta-d′, which reflects (...) how much information, in signal-to-noise units, is available for metacognition. Applying this novel method in a 2-interval forced choice visual task, we found that subjects’ metacognitive sensitivity was close to, but significantly below, optimality. We discuss the theoretical implications of these findings, as well as related computational issues of the method. We also provide free Matlab code for implementing the analysis. (shrink)

Wagering contingent on a previous decision, or post-decision wagering, has recently been proposed to measure conscious awareness. Whilst intuitively appealing, it remains unclear whether economic context interacts with subjective confidence and how such interactions might impact on the measurement of awareness. Here we propose a signal detection model which predicts that advantageous wagers placed on the identity of preceding stimuli are affected by loss aversion, despite stimulus visibility remaining constant. This pattern of predicted results was evident in a psychophysical task (...) where we independently manipulated perceptual and economic factors. Changes in wagering behaviour induced by changes in wager size were largely driven by changes in criterion, consistent with the model. However, for near-threshold stimuli, a reduction in wagering efficiency was also evident, consistent with an apparent but potentially illusory decrease in awareness of the stimulus. These findings challenge an assertion that post-decision wagering provides a direct index of subjective awareness. (shrink)

We explore three methods for measuring the conscious status of knowledge using the artificial grammar learning paradigm. We show wagering is no more sensitive to conscious knowledge than simple verbal confidence reports but is affected by risk aversion. When people wager rather than give verbal confidence they are less ready to indicate high confidence. We introduce a “no-loss gambling” method which is insensitive to risk aversion. We show that when people are just as ready to bet on a genuine random (...) process as their own classification decisions, their classifications are still above baseline, indicating knowledge participants are not aware of having. Our results have methodological implications for any study investigating whether people are aware of knowing. (shrink)