Changes in Self-awareness Induced by Psychoactive Substances: an Experimental Study With Psilocybin.

The Multidimensional Assessment of Interoceptive Awareness (MAIA) is a 32-item self-report questionnaire designed to measure multidimensional interoceptive body awareness across eight distinct subscales: Noticing, Not-Distracting, Not-Worrying, Attention Regulation, Emotional Awareness, Self-Regulation, Body Listening, and Trusting. Respondents rate items on a 6-point Likert scale ranging from 0 ("never") to 5 ("always"). Subscale scores are calculated as the average of their respective items, with higher scores reflecting greater interoceptive awareness and adaptive body focus. The instrument evaluates how individuals perceive, process, and regulate internal bodily sensations. The total cumulative raw score across all items ranges from 0 to 160. Higher average scores reflect a greater and more mindful degree of interoceptive awareness. More information at https://doi.org/10.1371/journal.pone.0048230

The Emotion Regulation Questionnaire (ERQ) is a 10-item self-report scale designed to assess individual differences in two widely used emotion regulation strategies: Cognitive Reappraisal (6 items) and Expressive Suppression (4 items). Respondents rate statements on a 7-point Likert scale ranging from 1 ("strongly disagree") to 7 ("strongly agree"). Subscale scores are calculated by averaging the items corresponding to each strategy, with higher scores reflecting a greater, more habitual reliance on that specific emotional regulation strategy. More information at: https://pubmed.ncbi.nlm.nih.gov/12916575/

The TAS is a 20-item, self-administered questionnaire that measures difficulty in identifying and describing emotions (alexithymia) across three subscales: Difficulty Identifying Feelings (DIF, 7 items), Difficulty Describing Feelings (DDF, 5 items), and Externally-Oriented Thinking (EOT, 8 items). Respondents rate items on a 5-point Likert scale ranging from 1 ("strongly disagree") to 5 ("strongly agree"), with five items negatively keyed. Total scores are calculated by summing item responses, with higher overall and subscale scores indicating greater difficulty with emotional processing, awareness, and expression. The instrument evaluates individual deficits in recognizing, articulating, and reflecting on emotional states. More information at: https://doi.org/10.1016/0022-3999(94)90005-1

The 10-item Ruminative Response Scale (RRS-10) is a brief self-report questionnaire designed to assess repetitive, depressive rumination without confounding items related to depressive symptoms. It evaluates two distinct subscales with 5 items each: Brooding (a passive, maladaptive focus on unachieved standards) and Reflection (a purposeful, adaptive engagement in cognitive problem-solving). Respondents rate statements on a 4-point Likert scale ranging from 1 ("almost never") to 4 ("almost always"). Subscale and total scores are calculated by summing or averaging the respective item responses, with higher scores reflecting a greater frequency of ruminative thought patterns. More information at: doi.org/10.1007/978-3-030-77644-2_84-1

Self-report questionnaire designed to measure ego-dissolution-the temporary breakdown or loss of a distinct sense of self and personal identity. Uses an 8-item scale rated on a visual analog scale (VAS) from 0 to 100. 0 means "No, not more than usual" and 100 means "Yes, I experienced this completely/entirely". Total Score is calculated as the mean of all eight items, yielding an overall score from 0 to 100 that represents the strength of the experience. More information at: https://pubmed.ncbi.nlm.nih.gov/27378878/

Self-report questionnaire used to measure subjective experiences during non-ordinary states of consciousness. It evaluates three core dimensions: Oceanic Boundlessness, Dread of Ego Dissolution, and Visionary Restructuralization. It contains 66 items rated on a continuous line or numerical scale (0 to 100), from "No, not more than usual" (0) to "Yes, much more than usual" (100). Higher scores mean a greater intensity of subjective changes during an experience for each dimension. More information at: https://doi.org/10.1371/journal.pone.0012412

In this task, participants silently count their felt heartbeats within randomized time windows of 25 to 50 seconds, without manually checking their pulse. Actual heartbeats are measured with an electrocardiogram (ECG). Participants are also asked how confident they feel about their estimates. These responses are then used to quantify metacognitive interoceptive awareness by correlating confidence with actual performance accuracy. More information can be found at: http://dx.doi.org/10.1016/j.biopsycho.2014.11.004

This task measures explicit sense of agency (SoA) through a retrospective judgment of self-authorship, where participants rate their perceived control over a sensory event triggered by their action, and implicit SoA via "intentional binding," which assesses the compression of subjective temporal intervals between a voluntary motor action and its sensory effect. The task derives two primary scores: an explicit Agency Rating Score obtained from a 9-point Likert scale (ranging from 1 for "not at all" to 9 for "extremely strongly"), and an implicit Intentional Binding Score calculated as an estimation ratio of subjective interval durations between baseline (passive) and active tasks. More details can be found at: https://doi.org/10.1016/j.concog.2018.11.005.

The Spontaneous Sensations Task is a standard behavioral method for evaluating body awareness by measuring sensations in the absence of external triggers. Participants rest one hand palm-up on a white fabric and focus their direct gaze on it for 10 seconds. Immediately after, they must report any detected sensations on a standardized hand map, specifying their location, extent, intensity (1-10 scale), confidence level, and sensory descriptors. More details can be found at: https://doi.org/10.1080/08990220.2021.1914018

The online self-referential encoding paradigm assesses memory enhancement driven by self-related concepts. The task evaluates how information is systematically processed and retained when encoded in relation to the self versus structural or semantic controls. During the encoding phase, participants answer specific questions about single-trait adjectives (e.g., "Does this word describe yourself?"). The task measures memory performance through an incidental free-recall activity or a recognition format administered after a short filler task. More information can be found at: https://doi.org/10.1371/journal.pone.0176611

To assess the prospective contribution of action selection to the sense of agency, participants perform the Eriksen flanker task, in which they respond to a central target letter flanked by supraliminal stimuli that are congruent, neutral, or incongruent. Correct responses trigger the appearance of a colored circle after a variable delay, and participants judge their level of control over the color. The protocol evaluates how conflict in action selection affects agency ratings, more specifically, whether dysfluency reduces the perceived sense of control. More information ca be found at: http://dx.doi.org/10.1016/j.actpsy.2016.03.003

This task measures the integration of visual and proprioceptive information regarding hand location using a mirror along the midsagittal plane. Participants perform reaching movements to a target with their unseen hand behind the mirror under different conditions of exposure to the mirror-reflected hand. The task evaluates how spatial congruence between visual and real hand positions affects reach accuracy, as visual conflicts can significantly bias reaching movements. The goal is to determine how multisensory conflict affects the visual recalibration of proprioception. More information can be found at: doi.org/10.1007/s00221-005-2389-4