Order does matter: the combined effects of classical conditioning and verbal suggestions on placebo hypoalgesia and nocebo hyperalgesia.

ABSTRACT: In most experimental studies in which verbal suggestion and classical conditioning are implemented together to induce placebo effects, the former precedes the latter. In naturally occurring situations, however, the information concerning pain does not always precede but often follows the pain experience. Moreover, this information is not always congruent with experience. This study investigates whether the chronology of verbal suggestion and conditioning, as well as their congruence, affects placebo hypoalgesia and nocebo hyperalgesia. The effects induced in 15 groups were compared. The participants in 8 experimental groups were presented with verbal suggestions that were either congruent or incongruent with classical conditioning. The verbal suggestions were provided either before or after conditioning. In 2 other experimental groups, placebo conditioning or nocebo conditioning was implemented without any verbal suggestion; in 2 groups, verbal suggestion of hypoalgesia or hyperalgesia without conditioning was applied. The control groups without any suggestions or conditioning were also included. Placebo hypoalgesia induced by congruent procedures was significantly stronger when the suggestion of hypoalgesia preceded rather than followed conditioning. The order of the congruent procedures did not affect the magnitude of nocebo hyperalgesia. In the groups in which incongruent procedures were implemented, placebo hypoalgesia or nocebo hyperalgesia was in line with the direction of the last-used procedure, regardless of whether it was conditioning or verbal suggestion. The results show that not the type of the procedure (verbal suggestion or conditioning), but the direction of the last-used procedure shapes pain-related expectancies and determines placebo effects.

Confidence in action: Differences between perceived accuracy of decision and motor response.

Each of our decisions is associated with a degree of confidence. This confidence can change once we have acted because we might start doubting our choice or even become convinced that we have made a mistake. In this study, we explore the relations between action and our confidence that our decision was correct or erroneous. Fifty-four volunteers took part in a perceptual decision task in which their decisions could either lead to action or not. At the end of each trial, participants rated their confidence that their decision was correct, or they reported that they had made an error. The main results showed that when given after a response, confidence ratings were higher and more strongly related to decision accuracy, and post-response reports of errors more often indicated actual errors. The results support the view that error awareness and confidence might be partially based on postaction processing.

Transcranial Magnetic Stimulation-Induced Motor Cortex Activity Influences Visual Awareness Judgments.

The influence of non-visual information on visual awareness judgments has recently gained substantial interest. Using single-pulse transcranial magnetic stimulation (TMS), we investigate the potential contribution of evidence from the motor system to judgment of visual awareness. We hypothesized that TMS-induced activity in the primary motor cortex (M1) would increase reported visual awareness as compared to the control condition. Additionally, we investigated whether TMS-induced motor-evoked potential (MEP) could measure accumulated evidence for stimulus perception. Following stimulus presentation and TMS, participants first rated their visual awareness verbally using the Perceptual Awareness Scale (PAS), after which they responded manually to a Gabor orientation identification task. Delivering TMS to M1 resulted in higher average awareness ratings as compared to the control condition, in both correct and incorrect identification task response trials, when the hand with which participants responded was contralateral to the stimulated hemisphere (TMS-response-congruent trials). This effect was accompanied by longer PAS response times (RTs), irrespective of the congruence between TMS and identification response. Moreover, longer identification RTs were observed in TMS-response-congruent trials in the M1 condition as compared to the control condition. Additionally, the amplitudes of MEPs were related to the awareness ratings when response congruence was taken into account. We argue that MEP can serve as an indirect measure of evidence accumulated for stimulus perception and that longer PAS RTs and higher amplitudes of MEPs in the M1 condition reflect integration of additional evidence with visual awareness judgment. In conclusion, we advocate that motor activity influences perceptual awareness judgments.

Visual awareness judgments are sensitive to accuracy feedback in stimulus discrimination tasks.

In this study we tested the hypothesis that perceptual awareness judgments are sensitive to accuracy feedback about the previous action. We used a perceptual discrimination task in which participants reported their stimulus awareness. We created two conditions: No-feedback and Feedback (discrimination accuracy feedback was provided at the end of each trial). The results showed that visual awareness judgments are related to the accuracy of current and previous responses. Participants reported lower stimulus awareness for incorrectly versus correctly discriminated stimuli in both conditions; they also reported lower stimulus awareness in trials preceded by incorrect discrimination responses, compared to trials preceded by correct discrimination responses. This difference was significantly stronger in the Feedback condition, in which we also observed post-error slowing for PAS ratings. We discuss the relation between visual awareness and the effects of performance monitoring and interpret the results in the context of current theories of consciousness.

Confounding in Studies on Metacognition: A Preliminary Causal Analysis Framework.

By definition, metacognitive processes may monitor or regulate various stages of first-order processing. By combining causal analysis with hypotheses expressed by other authors we derive the theoretical and methodological consequences of this special relation between metacognition and the underlying processes. In particular, we prove that because multiple processing stages may be monitored or regulated and because metacognition may form latent feedback loops, (1) without strong additional causal assumptions, typical measures of metacognitive monitoring or regulation are confounded; (2) without strong additional causal assumptions, typical methods of controlling for first-order task performance (i.e., calibration, staircase, including first-order task performance in a regression analysis, or analyzing correct and incorrect trials separately) not only do not deconfound measures of metacognition but may even introduce bias; (3) that the first two problems cannot be solved by using simple models of decision-making derived from Signal Detection Theory. We conclude the paper by advocating robust methods of discovering properties of latent mechanisms.

The bhsdtr package: a general-purpose method of Bayesian inference for signal detection theory models.

We describe a novel method of Bayesian inference for hierarchical or non-hierarchical equal variance normal signal detection theory models with one or more criteria. The method is implemented as an open-source R package that uses the state-of-the-art Stan platform for sampling from posterior distributions. Our method can accommodate binary responses as well as additional ratings and an arbitrary number of nested or crossed random grouping factors. The SDT parameters can be regressed on additional predictors within the same model via intermediate unconstrained parameters, and the model can be extended by using automatically generated human-readable Stan code as a template. In the paper, we explain how our method improves on other similar available methods, give an overview of the package, demonstrate its use by providing a real-study data analysis walk-through, and show that the model successfully recovers known parameter values when fitted to simulated data. We also demonstrate that ignoring a hierarchical data structure may lead to severely biased estimates when fitting signal detection theory models.

In search of the optimal measure of awareness: Discrete or continuous?

Studies of perceptual awareness require sensitive measures reflecting subjective judgments of visibility. Two scales have been proposed for this purpose: the Continuous Scale (CS) and the Perceptual Awareness Scale (PAS). Here we compare the scales in the context of the Gabor patch orientation discrimination task and propose a Continuous Perceptual Awareness Scale (C-PAS) that aims to combine their advantages. The results of the study shown no differences in sensitivity between the scales. However, we observed differences between the scales in awareness ratings frequencies and accuracy associated with the lowest ratings. We concluded that visibility ratings are often biased, and thus, the scale sensitivity may not be optimal. Furthermore, based on the additional analyses, we argued that there is an advantage of using C-PAS over CS. The scale allows to use an additional variability of judgment within PAS categories and thus it may enable more fine-grained measurement of visibility at near-threshold conditions.

Motor response influences perceptual awareness judgements.

What is the relation between perceptual awareness and action? In this study we tested the hypothesis that motor response influences perceptual awareness judgements. We used a perceptual discrimination task in which presentation of the stimulus was immediately followed by a cue requiring a motor response that was irrelevant to the task but could be the same, opposite, or neutral to the correct response to the stimulus. After responding to the cue, participants rated their stimulus awareness using the Perceptual Awareness Scale, and then carried out their discrimination response. Participants reported a higher level of stimulus awareness after carrying out responses that were either congruent or incongruent with the response required by the stimulus, compared to the neutral condition. The results suggest that the motor response overlapping with a potential response to the stimulus provides information about the outcome of decision process and increases the reported awareness of stimuli.

Responses improve the accuracy of confidence judgements in memory tasks.

How do we assess what we remember? Previous work on metacognition suggests that confidence judgments are more accurate when given after than before a response to a perceptual task. Here we present two experiments that investigate the influence of decision and response on metacognitive accuracy in a memory task so as to establish what kind of information people use to assess their memory content. Participants were asked to remember lists of words and then to decide which of two target words had previously been presented. In both experiments, participants rated their confidence either after or before the response. However, the experiments differed in the amount of information provided for confidence rating. In Experiment 1, before confidence rating, participants were either presented with both target words and asked to decide between them, or they were only presented with a cue (first letter of the subsequent target words). In Experiment 2, participants were always presented with a target word before confidence rating. The results of both experiments showed that although task accuracy correlated with confidence ratings in both conditions, this relationship was weaker when confidence was assessed before response to a memory task. We argue that metacognitive judgments are influenced by processing information that is not available at the time of primary response. We discuss the implications for theories of confidence and metacognition. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Post-Decision Wagering Affects Metacognitive Awareness of Emotional Stimuli: An Event Related Potential Study.

The present research investigated metacognitive awareness of emotional stimuli and its psychophysiological correlates. We used a backward masking task presenting participants with fearful or neutral faces. We asked participants for face discrimination and then probed their metacognitive awareness with confidence rating (CR) and post-decision wagering (PDW) scales. We also analysed psychophysiological correlates of awareness with event-related potential (ERP) components: P1, N170, early posterior negativity (EPN), and P3. We have not observed any differences between PDW and CR conditions in the emotion identification task. However, the "aware" ratings were associated with increased accuracy performance. This effect was more pronounced in PDW, especially for fearful faces, suggesting that emotional stimuli awareness may be enhanced by monetary incentives. EEG analysis showed larger N170, EPN and P3 amplitudes in aware compared to unaware trials. It also appeared that both EPN and P3 ERP components were more pronounced in the PDW condition, especially when emotional faces were presented. Taken together, our ERP findings suggest that metacognitive awareness of emotional stimuli depends on the effectiveness of both early and late visual information processing. Our study also indicates that awareness of emotional stimuli can be enhanced by the motivation induced by wagering.

But I Was So Sure! Metacognitive Judgments Are Less Accurate Given Prospectively than Retrospectively.

Prospective and retrospective metacognitive judgments have been studied extensively in the field of memory; however, their accuracy has not been systematically compared. Such a comparison is important for studying how metacognitive judgments are formed. Here, we present the results of an experiment aiming to investigate the relation between performance in an anagram task and the accuracy of prospective and retrospective confidence judgments. Participants worked on anagrams and were then asked to respond whether a presented word was the solution. They also rated their confidence, either before or after the response and either before or after seeing the suggested solution. The results showed that although response accuracy always correlated with confidence, this relationship was weaker when metacognitive judgements were given before the response. We discuss the theoretical and methodological implications of this finding for studies on metacognition and consciousness.

Does level of processing affect the transition from unconscious to conscious perception?

Recently, Windey, Gevers, and Cleeremans (2013) proposed a level of processing (LoP) hypothesis claiming that the transition from unconscious to conscious perception is influenced by the level of processing imposed by task requirements. Here, we carried out two experiments to test the LoP hypothesis. In both, participants were asked to classify briefly presented pairs of letters as same or different, based either on the letters' physical features (a low-level task), or on a semantic rule (a high-level task). Stimulus awareness was measured by means of the four-point Perceptual Awareness Scale (PAS). The results showed that low or moderate stimulus visibility was reported more frequently in the low-level task than in the high-level task, suggesting that the transition from unconscious to conscious perception is more gradual in the former than in the latter. Therefore, although alternative interpretations remain possible, the results of the present study fully support the LoP hypothesis.

[Attentional bias training in reducing symptoms of anxiety]. / Trening tendencyjnosci uwagi w redukcji objawów lekowych.

Anxiety is related to attentional bias, i.e. a tendency to pay attention to threatening stimuli. This occurs both in individuals suffering from anxiety disorders, and in healthy individuals with elevated levels of trait anxiety. This article is an analysis of a research paradigm, used to modify attentional bias (CBM-A Cognitive Bias Modification - Attention). A growing number of studies indicate that with the help of computer methods such as a modified version of the dot-probe task we can train individuals to direct attention away from threatening stimuli, which in turn reduces symptoms of anxiety. This effect was observed in adults, adolescents and children suffering from social phobia, generalised anxiety disorder and subclinical symptoms of obsessive-compulsive disorder. Effectiveness of this method constitutes the evidence for attentional bias being among the causes of anxiety disorders. The article also analyses the still not completely clear mechanisms of CBM-A and limitations of this method.

The efficacy of determinants of attention bias training in mental disorders.

This paper focuses on a method of attention bias training, considering in particular its efficacy and usability in several mental disorders. The results of current meta-analyses and selected experiments indicate possible efficacy of training in case of some anxiety disorders (generalised anxiety disorder and social phobia), particularly in young individuals. Its efficacy in other previously tested disorders such as depression and addictions seems questionable. We analysed moderators of training efficacy considered in previous studies: subjects' age, type of training task, type and location of emotional stimuli, duration of training, awareness of test objective and place of testing (research laboratory or subjects' homes). It seems that greater efficacy of attention bias can be achieved by conducting longer trainings, located in a laboratory, rather than in-house, and using verbal rather than visual stimuli. It is not clear whether participants should be informed of the training objective or whether arranging stimuli vertically is more efficient than horizontally.

Different subjective awareness measures demonstrate the influence of visual identification on perceptual awareness ratings.

We compare four subjective awareness measures in the context of a visual identification task and investigate quantitative differences in terms of scale use and correlation with task performance. We also analyse the effect of identification task decisions on subsequent subjective reports. Results show that awareness ratings strongly predict accuracy for all scale types, although the type of awareness measure may influence the reported level of perceptual awareness. Surprisingly, the overall relationship between awareness ratings and performance was weaker when participants rated their awareness before providing identification responses. Furthermore, the Perceptual Awareness Scale was most exhaustive only when used after the identification task, whereas confidence ratings were most exhaustive when used before the identification task. We conclude that the type of subjective measure applied may influence the reports on visual awareness. We also propose that identification task decisions may affect subsequent awareness ratings.

Are attentional bias and memory bias for negative words causally related?

BACKGROUND AND OBJECTIVES: In cognitive theories of depression, processing biases are assumed to be partly responsible for the onset and maintenance of mood disorders. Despite a wealth of studies examining the relation between depression and individual biases (at the level of attention, interpretation, and memory), little is known about relationships between different biases. The purpose of the present study was to assess if attentional bias is causally related to memory bias. METHODS: 71 participants were randomly assigned to a control (n = 37) or attentional training group (n = 34). The attentional manipulation was followed by an explicit, intentional memory task during which novel neutral, negative, and positive words were presented. RESULTS: It was found that individuals with elevated depression score trained to orient away from negative words did not display a memory bias for negative words (adjectives) whereas similar individuals displayed this memory bias in the control condition. LIMITATION: Generalization of the findings is limited because of the short study time frame and specific nature of the memory task. CONCLUSIONS: These results indicate that altering attentional bias can influence elaborative processing of emotional material and that this bias could be one of the causes of mood congruent memory in depression.

Subjective measures of consciousness in artificial grammar learning task.

Consciousness can be measured in various ways, but different measures often yield different conclusions about the extent to which awareness relates to performance. Here, we compare five different subjective measures of awareness in the context of an artificial grammar learning task. Participants (N=217) expressed their subjective awareness of rules using one of five different scales: confidence ratings (CRs), post-decision wagering (PDW), feeling of warmth (FOW), rule awareness (RAS), and continuous scale (SDS). All scales were equally sensitive to conscious knowledge. PDW, however, was affected by risk aversion, and both RAS and SDS applied different minimal criteria for rule awareness. CR seems to capture the largest range of consciousness, but failed to indicate unconscious knowledge with the guessing criterion. We close by discussing the theoretical implications of scale sensitivity and propose that CR's unique features enable (in conjunction with RAS and FOW) a finer assessment of subjective states of awareness.

[Cognitive vulnerability to depression]. / Poznawcza podatnosc na depresje.

This concise review of cognitive vulnerability to depression contains the discussion of several fundamental theoretical, methodological and empirical issues related to this important subject. The main aim was to describe in some detail the construct itself and to critically evaluate the hypotheses concerning the causal relation between specific processes, structures and cognitive contents and the probability of suffering from affective disorders. Some of the most important empirical findings obtained from research on cognitive vulnerability to depression was carefully analysed. The types of designs included in the analysis ranged from research done with remitted patients, longitudinal studies and behavioural risk design type studies. The most important methodological problems were enumerated and briefly described. On the basis of those analyses it was concluded that at least several cognitive vulnerability factors can indeed significantly increase the probability of depression. At the same time the empirical findings do not seem to support the assumed causal relation unequivocally, mainly because of the methodological shortcomings of the typical designs addressing the vulnerability issue. Appreciation of cognitive vulnerability factors can lead to improvements in affective disorders therapy and in the prophylactic interventions aimed at persons showing symptoms of cognitive schemata, structures or content known to increase the risk of depression.