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Is there any electrophysiological evidence for subliminal error processing?

Shalgi S, Deouell LY - Front Neurosci (2013)

Bottom Line: We found that error detection as reflected by the Ne is correlated with subjective awareness: when awareness (or more importantly lack thereof) is more strictly determined using the wagering paradigm, no Ne is elicited without awareness.This result effectively resolves the issue of why there are many conflicting findings regarding the Ne and error awareness.The average Ne amplitude appears to be influenced by individual criteria for error reporting and therefore, studies containing different mixtures of participants who are more confident of their own performance or less confident, or paradigms that either encourage or don't encourage reporting low confidence errors will show different results.

View Article: PubMed Central - PubMed

Affiliation: Department of Cognitive Science, The Hebrew University of Jerusalem Jerusalem, Israel.

ABSTRACT
The role of error awareness in executive control and modification of behavior is not fully understood. In line with many recent studies showing that conscious awareness is unnecessary for numerous high-level processes such as strategic adjustments and decision making, it was suggested that error detection can also take place unconsciously. The Error Negativity (Ne) component, long established as a robust error-related component that differentiates between correct responses and errors, was a fine candidate to test this notion: if an Ne is elicited also by errors which are not consciously detected, it would imply a subliminal process involved in error monitoring that does not necessarily lead to conscious awareness of the error. Indeed, for the past decade, the repeated finding of a similar Ne for errors which became aware and errors that did not achieve awareness, compared to the smaller negativity elicited by correct responses (Correct Response Negativity; CRN), has lent the Ne the prestigious status of an index of subliminal error processing. However, there were several notable exceptions to these findings. The study in the focus of this review (Shalgi and Deouell, 2012) sheds new light on both types of previous results. We found that error detection as reflected by the Ne is correlated with subjective awareness: when awareness (or more importantly lack thereof) is more strictly determined using the wagering paradigm, no Ne is elicited without awareness. This result effectively resolves the issue of why there are many conflicting findings regarding the Ne and error awareness. The average Ne amplitude appears to be influenced by individual criteria for error reporting and therefore, studies containing different mixtures of participants who are more confident of their own performance or less confident, or paradigms that either encourage or don't encourage reporting low confidence errors will show different results. Based on this evidence, it is no longer possible to unquestioningly uphold the notion that the amplitude of the Ne is unrelated to subjective awareness, and therefore, that errors are detected without conscious awareness.

No MeSH data available.


Related in: MedlinePlus

Metacognitive signal detection model of error reporting. (A) The correct and error signal probability distributions and the decision criteria for reporting an error (vertical dotted line). The distance between the peaks of the distributions is the metacognitive d' and defines the discriminability of an error from a correct response. In this example, the criterion is conservative, meaning that the subject will report only errors whose signal has very little overlap with the correct response signal. All other errors will be reported as “correct” as therefore, be classified as Unaware Errors. (B) The relationship between the metacognitive criterion and the subject's confidence, or betting scheme. The further the signal is from the criterion, the higher the confidence in the metacognitive decision, and the higher subjects will be willing to bet.
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Figure 2: Metacognitive signal detection model of error reporting. (A) The correct and error signal probability distributions and the decision criteria for reporting an error (vertical dotted line). The distance between the peaks of the distributions is the metacognitive d' and defines the discriminability of an error from a correct response. In this example, the criterion is conservative, meaning that the subject will report only errors whose signal has very little overlap with the correct response signal. All other errors will be reported as “correct” as therefore, be classified as Unaware Errors. (B) The relationship between the metacognitive criterion and the subject's confidence, or betting scheme. The further the signal is from the criterion, the higher the confidence in the metacognitive decision, and the higher subjects will be willing to bet.

Mentions: Under the framework of signal detection theory (SDT; Green and Swets, 1966), both the “signal” (in our case, the error signal) and the background “noise” are associated with neuronal activity patterns that have a probabilistic distribution, and these distributions may overlap. This overlap creates ambiguous situations, requiring the subjects to make a decision (in the present case, to indicate that an error was or wasn't made), even though the evidence is compatible with both options. SDT suggests that subjects set a threshold (criterion), and decide in favor of a “signal” only if the evidence exceeds this criterion. Under this framework, if subjects are conservative, they may refrain from declaring an error, even though there is a considerable evidence in favor of one (Figure 2A). Where does the wagering technique come into play within this scenario? Even if human subjects' overt responses are based on their personal criterion (which is presumed to be stable within an experiment), they nonetheless make individual responses with different degrees of confidence. The process of confidence judgment is still debated (Clarke, 1959; Kunimoto et al., 2001; Pleskac and Busemeyer, 2010; Maniscalco and Lau, 2012), and the specific arguments are beyond the scope of this review. However, consistent with models of SDT addressing metacognitive judgments such as error detection (Clarke, 1959; Maniscalco and Lau, 2012; Rahnev et al., 2012), it seems reasonable to assume that, for a given subject with a set discrimination criterion, decisions made with high confidence occur when ambiguity is minimal. That is, when the signal in a given trial is far from the decision criterion (Figure 2B), or when the discriminability between the error and no error condition is greater (larger metacognitive d')4. Note that here the confidence measured is about the secondary decision (also known as the “Type 2 decision,” see Galvin et al., 2003) about the error signal (“did I make and error or not”), and not about the initial decision about the stimulus (“Type 1 decision”). Thus, by examining only trials with high bets, one can limit the analysis to trials where the subjects were fully aware of the error, or, more importantly, truly had no awareness of the error.


Is there any electrophysiological evidence for subliminal error processing?

Shalgi S, Deouell LY - Front Neurosci (2013)

Metacognitive signal detection model of error reporting. (A) The correct and error signal probability distributions and the decision criteria for reporting an error (vertical dotted line). The distance between the peaks of the distributions is the metacognitive d' and defines the discriminability of an error from a correct response. In this example, the criterion is conservative, meaning that the subject will report only errors whose signal has very little overlap with the correct response signal. All other errors will be reported as “correct” as therefore, be classified as Unaware Errors. (B) The relationship between the metacognitive criterion and the subject's confidence, or betting scheme. The further the signal is from the criterion, the higher the confidence in the metacognitive decision, and the higher subjects will be willing to bet.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3756425&req=5

Figure 2: Metacognitive signal detection model of error reporting. (A) The correct and error signal probability distributions and the decision criteria for reporting an error (vertical dotted line). The distance between the peaks of the distributions is the metacognitive d' and defines the discriminability of an error from a correct response. In this example, the criterion is conservative, meaning that the subject will report only errors whose signal has very little overlap with the correct response signal. All other errors will be reported as “correct” as therefore, be classified as Unaware Errors. (B) The relationship between the metacognitive criterion and the subject's confidence, or betting scheme. The further the signal is from the criterion, the higher the confidence in the metacognitive decision, and the higher subjects will be willing to bet.
Mentions: Under the framework of signal detection theory (SDT; Green and Swets, 1966), both the “signal” (in our case, the error signal) and the background “noise” are associated with neuronal activity patterns that have a probabilistic distribution, and these distributions may overlap. This overlap creates ambiguous situations, requiring the subjects to make a decision (in the present case, to indicate that an error was or wasn't made), even though the evidence is compatible with both options. SDT suggests that subjects set a threshold (criterion), and decide in favor of a “signal” only if the evidence exceeds this criterion. Under this framework, if subjects are conservative, they may refrain from declaring an error, even though there is a considerable evidence in favor of one (Figure 2A). Where does the wagering technique come into play within this scenario? Even if human subjects' overt responses are based on their personal criterion (which is presumed to be stable within an experiment), they nonetheless make individual responses with different degrees of confidence. The process of confidence judgment is still debated (Clarke, 1959; Kunimoto et al., 2001; Pleskac and Busemeyer, 2010; Maniscalco and Lau, 2012), and the specific arguments are beyond the scope of this review. However, consistent with models of SDT addressing metacognitive judgments such as error detection (Clarke, 1959; Maniscalco and Lau, 2012; Rahnev et al., 2012), it seems reasonable to assume that, for a given subject with a set discrimination criterion, decisions made with high confidence occur when ambiguity is minimal. That is, when the signal in a given trial is far from the decision criterion (Figure 2B), or when the discriminability between the error and no error condition is greater (larger metacognitive d')4. Note that here the confidence measured is about the secondary decision (also known as the “Type 2 decision,” see Galvin et al., 2003) about the error signal (“did I make and error or not”), and not about the initial decision about the stimulus (“Type 1 decision”). Thus, by examining only trials with high bets, one can limit the analysis to trials where the subjects were fully aware of the error, or, more importantly, truly had no awareness of the error.

Bottom Line: We found that error detection as reflected by the Ne is correlated with subjective awareness: when awareness (or more importantly lack thereof) is more strictly determined using the wagering paradigm, no Ne is elicited without awareness.This result effectively resolves the issue of why there are many conflicting findings regarding the Ne and error awareness.The average Ne amplitude appears to be influenced by individual criteria for error reporting and therefore, studies containing different mixtures of participants who are more confident of their own performance or less confident, or paradigms that either encourage or don't encourage reporting low confidence errors will show different results.

View Article: PubMed Central - PubMed

Affiliation: Department of Cognitive Science, The Hebrew University of Jerusalem Jerusalem, Israel.

ABSTRACT
The role of error awareness in executive control and modification of behavior is not fully understood. In line with many recent studies showing that conscious awareness is unnecessary for numerous high-level processes such as strategic adjustments and decision making, it was suggested that error detection can also take place unconsciously. The Error Negativity (Ne) component, long established as a robust error-related component that differentiates between correct responses and errors, was a fine candidate to test this notion: if an Ne is elicited also by errors which are not consciously detected, it would imply a subliminal process involved in error monitoring that does not necessarily lead to conscious awareness of the error. Indeed, for the past decade, the repeated finding of a similar Ne for errors which became aware and errors that did not achieve awareness, compared to the smaller negativity elicited by correct responses (Correct Response Negativity; CRN), has lent the Ne the prestigious status of an index of subliminal error processing. However, there were several notable exceptions to these findings. The study in the focus of this review (Shalgi and Deouell, 2012) sheds new light on both types of previous results. We found that error detection as reflected by the Ne is correlated with subjective awareness: when awareness (or more importantly lack thereof) is more strictly determined using the wagering paradigm, no Ne is elicited without awareness. This result effectively resolves the issue of why there are many conflicting findings regarding the Ne and error awareness. The average Ne amplitude appears to be influenced by individual criteria for error reporting and therefore, studies containing different mixtures of participants who are more confident of their own performance or less confident, or paradigms that either encourage or don't encourage reporting low confidence errors will show different results. Based on this evidence, it is no longer possible to unquestioningly uphold the notion that the amplitude of the Ne is unrelated to subjective awareness, and therefore, that errors are detected without conscious awareness.

No MeSH data available.


Related in: MedlinePlus