Metacognitive Feelings of Epistemic Gain are Central to the Understanding of Psychedelic-Induced Mystical-Type Experiences

Whereas declarative metacognition pertains to knowledge about one’s cognitive function, procedural metacognition concerns the actions one uses to optimize cognitive processes (Beran, 2012). In particular, the procedural facet of metacognition is divided into two functions: monitoring and control. Monitoring corresponds to awareness about what is going on in one’s cognitive system from an introspective point of view, for example, the extent to which one understands a scientific paper one is reading or whether it is necessary to go back and read it again for a better understanding. Control defines mental actions that can be undertaken and sustained, requiring proactive cognitive effort, such as shifting the inner focus of attention back from inner thoughts to one’s own breath during a mindfulness exercise (Braver, 2012). Crucially, this is not only a top-down regulation of cognition that starts from declarative conceptual strategies and scripts that one learns to apply in a given context (“in order to focus on my reading, I need to switch off my smartphone notifications”) – a bottom-up procedural non-conceptual regulation is also involved. As developed later in this work, this regulation process occurs first from non-conscious evaluation processes and then expresses itself by triggering metacognitive feelings at the level of the person’s awareness. In fact, previous research on primates shows that non-human animals can pursue informational goals and monitor their own success without being able to express their mental states semantically (Proust, 2019), showing that procedural metacognition is unrelated to language acquisition (Proust, 2010). In summary, feelings associated with cognitive processes related to reasoning are constitutive elements of conscious decision-making. Metacognitive processes unconsciously form these subjective feelings and consciously evaluate whether they are accurate or misleading. Investigating the monitoring and control functions of metacognition thus contributes to an understanding of the function and activity of meta-awareness (Koriat, 2007).

The difference between declarative and procedural aspects of metacognition is particularly relevant from a psychotherapeutic perspective and should thus be considered in the context of PAT. An overarching goal of psychotherapy is for patients to better understand themselves, acquiring new declarative concepts and fostering an improved understanding of their own cognitive functioning (Miller, 2016). It is indeed at the very core of patients’ motivation for undergoing psychotherapy that they acquire skills to face challenges with new ways of feeling, thinking, and behaving. In this sense, psychotherapy should support patients to enhance their ability to identify and be aware of “bad habits,” as well as to improve their emotional regulation and behavioral control under stressful or distressing situations. Crucially, such abilities are directly dependent on how we define them and declaratively assess them in the therapeutical context, but they must be learned from a pragmatic procedural perspective. This explains why cognitive behavioral therapy approaches integrate many techniques, bringing people to test their own emotional procedural competences and experiment with them (Borkovec et al., 2003), to rely on exposure to emotional avoidance (Foa et al., 2003), or to implement role-playing exercises (Bennett-Levy et al., 2009). In this context, PAT is able to provide a very intense subjective experience through an experiential exercise that is an inherent and central part of the clinical work (Zullino et al., 2025).

In this article, the term “metacognitive feelings” is used to account for feelings related to epistemic states and cognitive tasks (Goupil & Proust, 2023). These feelings are implicated in the modulation and manipulation of cognitions and are expressed as a function of the monitoring and control processes. Representative examples of such feelings include a tip-of-the-tongue (TOT) feeling, a feeling of curiosity, a feeling of confusion, a feeling of effort, a feeling of having learned, a feeling of being wrong, a feeling of having found, and an “Aha!”/ “Eureka!” feeling (Danek & Wiley, 2017), which have been considered metacognitive feelings of epistemic gain (Sooter et al., 2024). Such feelings, which have been the focus of extensive research in the last decades, are triggered during the learning process itself (Arango-Muñoz, 2019). From a cognitive science perspective, within a metacognition framework, reasoning is postulated as being essentially guided by metacognitive feelings (Proust, 2010). The procedural functions of monitoring and control play a pivotal role in cognitive actions, which are typically characterized by a tripartite structure: the conception of a hypothesis, the subsequent verification process, and the appraisal of the resulting outcomes (Goupil & Proust, 2023). At each stage in this sequence, metacognitive feelings play a noteworthy role, as they provide the individual with critical feedback that contributes to optimizing cognitive conscious and unconscious regulation. Figure 2 depicts a cognitive action through the steps of goal-related, process-related, and outcome-related metacognitive feelings, which is based on the framework proposed by Goupil and Proust (2023).

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According to Vervaeke and Ferraro (2013), when faced with a situation requiring a decision or problem-solving, individuals engage in a so-called cognitive action process. This process involves for the mind to creating a hypothesis on how to proceed to advance toward a solution, to monitor the advancement of the action, and to control it by persevering or bringing adjustments to the application of the deployed strategy. While monitoring the cognitive action, the individual experiments with all sorts of metacognitive feelings related to doubt, confidence, and sensations of “having found” or learned. During this process, individuals switch to different ways of manipulating the information, at times applying a potential strategy to attain their goal, and at other times “zooming out” to consider the result and evaluate a change in their strategy. These activities are metacognitive in nature and stem from both declarative knowledge and procedural activity of control and monitoring. It is noteworthy that a recent preregistered experiment showed that a person can feel that they are approaching the solution to an ill-defined insight problem, even without being aware of it (Laukkonen et al., 2021), which denotes the empirical possibility of measuring metacognitive feelings.

Numerous factors have been suggested as potential cues that trigger metacognitive feelings, including the recognition of the cue used to prompt memory recall, which gives a feeling of familiarity; the availability of relevant partial data about a requested memory target; and retrieval fluency, that is, the level of ease in accessing information (Reber & Greifeneder, 2017). Subjective confidence in the validity of recovered information is also considered to depend on how easily that information is recalled (Koriat, 2000). More recently, a study of “Aha!” moments and insight (Tulver et al., 2023) provided evidence on how to empirically assess and investigate outcome-related metacognitive feelings of knowing.

In addition, Dehaene et al. (2017) reported experimental findings related to the information-processing function of consciousness within the Global Neuronal Workspace theory of consciousness. In particular, for the self-monitoring aspect of consciousness (e.g., the meta-awareness procedural facet of metacognition), such findings concern the presence of metacognitive feelings related to a) subjective confidence of the accuracy of their inner reasoning, b) TOT feelings, c) subjective uncertainty regarding declarative knowledge, d) error detection, and e) social decision making.

Metacognitive feelings arising from the interplay between control and monitoring processes result in indices that influence controlled behavior. In line with this view, a causal link has been postulated between metacognitive monitoring and metacognitive control. More precisely, the self-regulation of behavior (control) is based on judgments about one’s own knowledge (monitoring) (Koriat, 2000).

Understanding metacognitive feelings thus requires consideration of the various steps of cognitive action and how they relate to monitoring and control processes. There are specific metacognitive feelings that stem from monitoring and control for every step of cognitive action (Proust, 2021). Metacognitive feelings exist as goal-related predictive feelings for the monitoring process as a feeling of familiarity and for the control process as TOT feelings. During cognitive action, individuals experiences metacognitive control feelings, such as feelings of frustration or effort in trying to retrieve something in memory. At the same time, metacognitive monitoring feelings are expressed as a function of the inference about the extent to which the individual is approaching their goal, such as feelings of incoherence, interest, or confusion. If the goal is not attained, another cycle is triggered with a new hypothesis to be tested as a cognitive action. In contrast, if the cognitive goal is attained, metacognitive control stops. At the same time, metacognitive monitoring feelings of having found are expressed as an “Aha!”/ “Eureka!” experience, pointing to the coherence and validity of the outcome obtained by the reasoning process and giving rise to a positive emotion of satisfaction. This feeling can be defined as a metacognitive feeling of epistemic gain (Sooter et al., 2024).

Metacognitive feelings hence possess a unique function in the differentiation between an overt, controlled manner of functioning and a covert, automatic one. They are inherently unconscious regarding their origin, yet are overt in both their experiential subjective aspects and outcomes. They serve within the meta-awareness process of the individual as a bridge that facilitates the shift from an unconscious, unregulated mode of operation to a conscious, regulated one, serving as the foundation for controlled action (Koriat, 2000) as pictured in Fig. 3.

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How is it possible to “know that we know something while being unable to retrieve that information”? Certain metacognitive feelings have been shown to relate to a subjective feeling of knowing (Hewitt, 2011; Koriat, 2000; Maril et al., 2003; Metcalfe, 2000). One of the most common metacognitive feelings that can be experienced in daily life is called the TOT feeling, which was first described by William James (1890):

In this example, if instead the correct name is proposed, the correctness of the name creates an “Aha!”/“Eureka!” experience, a feeling related to discovering the correct solution, a feeling of “being right,” of “having found.” In that case, the control of cognition stops and leaves space for a positive emotional experience triggered by the successful completion of the task. In this regard, the TOT feeling constitutes a metacognition-related process that triggers the three components of cognitive action: setting a goal, controlling cognitive effort, and monitoring the outcome (Goupil & Proust, 2023) as depicted in Fig. 4.

The TOT feeling is thus the product of an incoherence between the subjective confidence of knowing the sought-after information and the current inability to actively retrieve it. The TOT feeling is postulated to emerge as a consequence of implicit/unconscious processing taking place in an active inference perspective (Friston et al., 2017a, 2017b), promoting the feeling that “there is something likely to be retrieved.” Feeling-of-knowing judgments often predict future retrieval success (Grimmer et al., 2022; Laukkonen et al., 2023) and are generally considered to be adaptive heuristics and intuitions: they stem from a rapid unconscious activity and generate an outcome that can be monitored and controlled for correctness. Individuals experiencing a TOT are able to perceive the emergence of the sought-after information via a meta-awareness state by judging its imminent retrieval (Grimmer et al., 2022; Koriat, 2000; Laukkonen et al., 2023). Identifying the correct semantic information marks the cessation of the thinking hunch: the metacognitive volitive effort of control stops as the goal of the cognitive action is attained. At the same time, an insight – an “Aha!”/ “Eureka!” feeling – emerges, tainted by a positive emotional state, signaling the accuracy of the found solution. As noted by Proust (2019), the phylogenetic conservation of this positive emotional valence is congruent with an evolutionary adaptative function of the “Aha!”/ “Eureka!” phenomenon. From a naturalistic evolutionary perspective, the agreeable feeling associated with the “Aha!”/ “Eureka!” experience serves to positively reinforce and ground the learning process when something important is understood, enabling a more adaptive relationship with the environment (Gopnik, 1998; Proust, 2010).

It has been suggested that TOT feelings might correspond to subjectively felt emotions promoted by an active inference calculation process going on beyond one’s own meta-awareness (Seth, 2013). Yet, having an “Aha!”/ “Eureka!” experience does not always reflect the correctness of the sought-after result, as it was shown that manipulation of past knowledge can elicit an “Aha!”/ “Eureka!” experience of insight regarding incorrect information (Laukkonen et al., 2023) (Fig. 4).

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In summary, when evaluating the likelihood of success of a cognitive activity (such as remembering or learning something), individuals rely on a set of unconscious probability distributions related to the expected results. Although it has been suggested that these forecasts are based on subconscious Bayesian calculations within a predictive inference model (Seth, 2013), at the subjective level, they lead to a conscious feeling connoted with specific positive or negative valence, intensity, and motivational pull (such as the TOT feeling, the feeling of cognitive effort, or the “Aha!”/ “Eureka!” experience; see Goupil & Proust, 2023).

Metaphors, analogies, and daily life examples are often used in the context of psychoeducational interventions to show patients how their behaviors, emotions, and thoughts work (Mathieson et al., 2016; Stott et al., 2010). The TOT feeling is a concrete, very common example of how metacognitive feelings work in daily life and how they are felt within the subjective perspective. It can be used by a therapist to help the patient understand the dynamic process of metacognitive feelings. This is particularly relevant for the ideas defended in the current paper, which suggest a connection between metacognitive feelings and psychedelic-induced mystical-type experiences.

Dysfunctional metacognitive processes play a key role in the onset, development, and maintenance of psychological disorders (Sun et al., 2017), including psychosis-related disorders and experiences (Cotter et al., 2017), anxiety disorders (Gkika et al., 2018; Wells, 2011), substance use and addictive behaviors (Hamonniere & Varescon, 2018), eating disorders (Palmieri et al., 2021), obsessive–compulsive disorder (Rees & Anderson, 2013), and mood disorders (Halvorsen et al., 2015).

One prominent concept that addresses dysfunctional metacognitive processes is the cognitive attentional syndrome (CAS), which can be viewed as a transdiagnostic mechanism underlying various forms of psychopathology (Fergus et al., 2013; Wells, 2011).

The CAS represents a perseverative thinking style in which one continually engages in dysfunctional and repetitive maladaptive coping strategies, including worrying and ruminating, while attempting to face adverse cognitions and emotions (Normann & Morina, 2018). Dysfunctional and inflexible metacognitive beliefs, such as believing that one cannot act on one’s thoughts or that worrying helps one to cope, influence the emergence of CAS (Normann & Morina, 2018; Wells, 2011). These processes can be identified and modified through metacognitive therapy (Wells, 2011). Metacognitive-oriented psychotherapeutic interventions also include raising awareness and developing more adaptive and flexible monitoring-control capacities by using detached mindfulness and attention training techniques (Murray et al., 2018; Philipp et al., 2020). Metacognitive therapy has shown its effectiveness in a wide range of psychological disorders, even more notably for anxiety and depression (for meta-analyses, see Normann & Morina, 2018; Rochat et al., 2018). Other psychotherapeutic interventions that directly target dysfunctional and maladaptive metacognitive processes include metacognitive training and metacognitively-oriented integrative psychotherapies (Philipp et al., 2020).

In addition, certain metacognitive processes are involved and indirectly targeted and fostered in various psychotherapeutic interventions, independently of the therapists’ theoretical approach. For example, decentering is a key metacognitive skill fostered in a wide range of psychotherapeutic approaches. Decentering corresponds to the capacity to look at one’s internal mental state from some distance and “stepping out” of what one is currently experiencing, thus promoting a shift in perspective (Safran & Segal, 1996). It allows for realizing that one’s thoughts are not immutable and do not define the self, which is known to positively affect mental health (Bernstein et al., 2015).

Moreover, one major objective of psychotherapy is to aid patients in fostering a new or modified understanding about themselves, thus gaining insight about their inner functioning and psychological problems (McAleavey & Castonguay, 2014). The word “insight” has, however, generated confusion in the literature because it has two different meanings, as shown in Fig. 5. On the one hand, insight can be related to the introspective ability to coherently assess aspects of one’s own subjective internal mental state. In this case, the term is used to evaluate the extent to which patients are aware of their own mental state and difficulties. This first meaning corresponds to the “capacity of insight,” as frequently used in psychodynamic therapeutic approaches (Moro et al., 2012). Such capacity has typically been found to be impaired in people with severe mental conditions such as schizophrenia (Baier, 2010). On the other hand, the word “insight” has been used to describe the “Aha!”/ “Eureka!” experience, in this case referring to a feeling and not to a competence. These two types of insight are likely to overlap when a person involved in introspection (using their “insight competence”) understands something that triggers an “Aha!”/ “Eureka!” experience (“insight feeling” followed by an introspective action). It is thus relevant to differentiate introspective phenomena, as they are not all accompanied by an “Aha!”/ “Eureka!” experience and vice versa. An introspective act can lead to the processing of something well known by the person and thus not likely to generate an “Aha!”/ “Eureka!” experience (e.g., “I have a problem with my alcohol consumption”). It is possible, however, to experience an “Aha!”/ “Eureka!” experience that is not related to one’s own internal subjective situation but rather to an external situation (e.g., “I finally understood this thing you are showing me!”; “here’s how to solve that riddle!”). By distinguishing the two meanings of the insight construct, it is possible to better understand the “Aha!”/ “Eureka!” experience as a metacognitive feeling of epistemic gain (Sooter et al., 2024).

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Previous research suggests that insight represents one of the general factors contributing to psychotherapeutic success, such as therapeutic alliance or non-conditional positive positioning, and is thus independent from the theoretical approach of the therapist (McAleavey & Castonguay, 2014; Wampold et al., 2007). Insight has also been positively associated with psychotherapeutic outcomes (for a meta-analysis, see Jennissen et al., 2018). This can be explained by the fact that understanding oneself helps to foster the sense of agency, as well as to open new perspectives for identifying and endorsing more adaptive and beneficial ways of thinking and acting (Jennissen et al., 2018).

Relevant to our purpose, the “Aha!”/ “Eureka!” experience has been linked to psychedelic-induced altered states of consciousness (Carhart-Harris & Friston, 2019; McGovern et al., 2024). In PAT, psychological insight or “Aha!”/ “Eureka!” experiences have been put forward as one of the main factors driving therapeutic benefits (Davis et al., 2020; Garcia-Romeu et al., 2020; Letheby, 2021; Tulver et al., 2023).

Having defined the functioning of metacognition as a monitoring and control mechanism, with metacognitive feelings being at the interplay of these two aspects, our aim is now to consider the extent to which this framework can be useful to understand altered states of consciousness.

The consideration of meditation, lucid dreaming, and ecstatic epilepsy is relevant for understanding how the procedural function of metacognition could inform the study of psychedelic-driven altered states of consciousness.

Mindfulness meditation-based techniques are now widely used in the context of psychotherapy (Davis & Hayes, 2011; Germer et al., 2005). It has been argued that mindfulness meditation can be understood from a metacognitive perspective (Jankowski & Holas, 2014). In fact, mindfulness meditation requires a great deal of activity in the procedural metacognitive control and monitoring processes, and it has been shown that this meditation affects metacognition (Jankowski & Holas, 2014) through specific mechanisms such as improving the inhibition of irrelevant stimuli (Sanger & Dorjee, 2016). During meditation, individuals constantly go through the cycle of monitoring their present meta-awareness and, after realizing that the focus of attention is lost, regain control of it to bring it back to the sought-after target, whether it be breath, a part of the body, or a loving-kindness mantra. This interplay between monitoring and control of one’s own stream of consciousness, which involves concentrating attention on something, is the basis of many breathing and meditation techniques.

This process follows a standard cognitive action model in which metacognitive feelings are heavily recruited. For example, while being present and monitoring their mind, someone can suddenly realize that their focus of attention has drifted away. This expresses itself as a metacognitive feeling of incoherence (“oh, something is wrong”), which makes the individual meta-aware about their ongoing activity (“I caught myself thinking about grocery but in fact I am meditating”) and the related need to bring their attention back to the target of the meditation (“while I meditate, I am supposed to keep my attention on my breath”). This in turn activates the control function of metacognition, creating a feeling of effort that is related to manipulating one’s attentional focus. Reallocating attentional focus makes the individual experience a metacognitive feeling of having attained the goal, which in turn expresses itself as a positive feeling of relaxation related to the completion of the cognitive action and gives space to the monitoring process once again. The extent to which psychoeducation interventions in metacognitive feelings could be proposed to help people progress in their meditation practice is outside the scope of this article.

It is interesting to note here a difference between two different kinds of cognitive actions: Attentional Agency (AA), defined as the ability to control one’s focus of attention, and Cognitive Agency (CA), as the ability to control goal/task-related, deliberate rational thought (Metzinger, 2015). AA and CA are both processes which underlie the feeling of being epistemic autonomous agents. As it is shown in Fig. 6, AA comes first, being the founding step for the system to get meta-aware of the cognitive operations going on, which in turns make possible to exert CA to deliberately engage in problem solving. This interplay of different functions shows the depth of involvement of metacognition in meditation.

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A lucid dream is a particular kind of phenomenon related to a state of consciousness in which a dreaming person becomes aware of being in a dream while being asleep. Metacognitive processes have been investigated to shed light on this particular phenomenon (Kahan & LaBerge, 1994; Kahan, 2001), which has a low random frequency of occurrence in the overall general population, but can also be learned and trained for. So-called lucid dreamers use techniques of metacognitive training to trigger meta-awareness in dreams and take control of their subjective experience while sleeping. This is achieved by training and developing behavioral strategies consisting in self-suggestions during daily waking time in ordinary conscious life and the contemplation of one’s own state of consciousness (Dresler et al., 2015) to develop a chronic specific self-monitoring behavioral script. For example, one of the most basic exercises is for the individual to count the fingers of their hand at random times and repeatedly during the day. This habit creates a script for a cognitive action that can automatically express itself during dreams. If it does, while dreaming, the person tries to count their fingers and is not able to. This incoherence triggers a metacognitive feeling of curiosity, driven to find an explanation for why fingers cannot be counted. A process-based feeling of incoherence is then felt, which in turn triggers an outcome-related metacognitive feeling, namely, an “Aha!”/ “Eureka!” experience, related to the realization of being in a dream as the reason for why the fingers cannot be counted. The end of the cognitive action (“why am I not able to count my fingers? Because I am in a dream.. Aha!”) leaves the space for a monitoring process within the dream, which in turns triggers meta-awareness. These elements are consistent with a predictive processing perspective of the mind (Sandved-Smith et al., 2021) and with experimental neuroimagery research that identified shared neural systems between lucid dreaming and metacognitive functions, in particular in the domain of thought monitoring (Filevich et al., 2015).

Ecstatic epilepsy is a rare form of focal epilepsy characterized by the subjective experience of an altered state of consciousness, which may precede the onset of a tonic–clonic seizure (Gschwind & Picard, 2016). As its name literally indicates, it consists of a mystical-type experience characterized by heightened well-being (serenity and bliss), a feeling of time dilatation, a feeling of enhanced self-awareness, a feeling of dissolution of boundaries between the self and surroundings (connectedness), and a noetic feeling of revelation of truth, coherence, and “understanding of the meaning of life” (Picard, 2023). This experience has been reliably reported by a specific group of patients having similar subjective accounts when describing the typical onset of their epileptic symptoms. Moreover, these experiences have been sometimes declared by them as having a transformative effect and cosmic, spiritual, or religious connotations (Picard & Craig, 2009). Thanks to the similar testimony of these patients, it has been possible to match their account with neuroimaging observation techniques, pinpointing the particular area where the focal epilepsy symptoms seem to originate, namely, the anterior insula. Most interestingly, this localization has been confirmed by electrical stimulation performed during a presurgical evaluation of pharmacoresistant epilepsy in a non-ecstatic epileptic case study report that evoked a mystical-type experience (Nencha et al., 2022). This case study showed that the patient, who had epilepsy but never experienced this particular set of symptoms before, felt and reported mystical-type subjective effects proper to the ecstatic epilepsy phenomenology, captured by the Mystical Experience Questionnaire (MEQ-30). This phenomenon was later integrated into a “surprise processing hypothesis” – based on the pivotal role played by the insula as a “comparator between predictions and real inputs” for multisensory integration and interoception (Picard & Friston, 2014), and in the processing of self-awareness and uncertainty (Picard, 2023). Within a predictive processing understanding, the computation of uncertainty between an internal model and external reality performed by the insula would be expressed as feelings of surprise, which could regulate learning, updating models and driving cognitive actions. These surprise feelings could be conceived as metacognitive feelings, resulting from the monitoring and control of cognitive actions within a predictive processing understanding of metacognition (Fernández Velasco & Loev, 2024; Foster & Keane, 2015). Moreover, insula activity has been linked to metacognition in various studies (Fleming & Dolan, 2012; Seth et al., 2012; Uddin et al., 2017).

In particular, the subjective feeling of the ecstatic epilepsy experience could be analyzed from the perspective of procedural-based, outcome-related metacognitive feelings of epistemic gain (Sooter et al., 2024). For example, consider the following subjective account of a patient with ecstatic epilepsy, who reported what a cognitive action of problem solving and its associated feeling of having found can look like in real-life situations (Ernst, 2005; subjective account reported with written consent from author):

“Indeed, one has (what is sometimes called) an ‘Aha!’ moment when we can suddenly explain several puzzling facts simultaneously with the same answer. Suppose I am puzzled when my car drives sluggishly and pulls to one side, and also seems to be getting poor gas mileage. If I also notice that my tire is slowly leaking air, then I will be very confident that the leak explains everything by making my earlier observations more coherent. The sense that I had when I was experiencing some of these seizures was not unlike a continuous series of ‘Aha!’ moments.”

Given what has been expressed so far, we hypothesize that the study of metacognition is relevant to the understanding of other types of altered states of consciousness such as those occurring in PAT. In the next sections, we examine the link between psychedelic-induced mystical-type experiences and metacognitive procedural processes, with a special focus on metacognitive feelings of epistemic gain.

In the context of cognitive science, noetic feelings can be conceptualized as a form of feelings of knowing within metacognitive processes, implicitly signaling mental constructs and their attributes to individuals (Beran, 2012; Dorsch, 2023; West & Conway-Smith, 2019). These feelings encompass bodily sensations and emotions that guide judgment and decision making across a multitude of contexts (Damasio et al., 1997; Kahneman, 1973; Proust & Fortier, 2018). Especially during problem solving, noetic feelings like the feelings of knowing and the “Aha!”/ “Eureka!” experience of sudden insight act as an embodied cue to guide people to their goals. These feelings allow for the assessment of new ideas, confronting them on the landscape of one’s own prior knowledge, facilitating adaptive actions and guiding the learning process (Laukkonen et al., 2023). In order to better characterize this feeling and to not indulge in the use of an ill-defined word, the “Aha!”/ “Eureka!” experience can be defined as a metacognitive feeling of epistemic gain, which means a metacognitive procedural-based, outcome-oriented feeling deriving from the sudden success of a cognitive action process.

In the context of psychedelic therapy research, noetic feelings refer to profound states of consciousness related to knowledge during which individuals may feel as though they are gaining direct insight or truth (Cole-Turner, 2021; Hewitt, 2011; Yaden, et al., 2017a). These feelings can be profound and life-changing, often described as mystical-type or spiritual experiences (Griffiths et al., 2006; Griffiths et al., 2008). Moreover, the noetic quality is used as a label to describe the insightfulness or spiritual characteristic of the psychedelic-induced altered state of consciousness, captured by the widely used Mystical Experience Questionnaire and the Altered State of Consciousness Questionnaire (Vollenweider & Smallridge, 2022). The noetic quality is also used as a label to indicate the extent to which an experience is felt as real (Yaden et al., 2017a).

When individuals report mystical-type experiences in the context of psychedelic-induced altered states of consciousness, other characteristics besides the noetic feeling are frequently reported: a sense of interconnectedness, transcendence of time and space, deeply felt positive mood, and a sense of being in touch with an ultimate reality or truth (Amada et al., 2020; McCulloch et al., 2022; Mosurinjohn et al., 2023). This subjective experience is associated with the use of psychedelic substances, but can also be induced by specific forms of meditation, bodily extenuation exercises, or breathing techniques (Timmermann et al., 2023). Such experiences are often described as having a quality of reality felt sometimes more real than reality itself, while also being difficult to justify or explain in rational terms. In the study of the factors involved in the effectiveness of PAT, the mystical-type experience has been found in different studies to be directly linked to a positive treatment outcome (Ko et al., 2022). In recent years, calls have emerged for better scientific understanding of these individuals’ subjective experiences in the context of PAT (Palitsky et al., 2023) in order to unveil the cognitive processes involved and tailor psychotherapeutic settings and practices accordingly.

In the Western context, the mystical-type experience was first studied by William James, who wrote about it in his book “The Varieties of Religious Experience” (1902). The author laid the basis for the scientific understanding of the phenomenon in terms of four main features defining this experience: ineffability, transiency, passivity, and noetic quality (Mosurinjohn et al., 2023). Concretely, James (1902) defined these experiences in the following terms:

William James understood the noetic quality to be a state related to feelings and to knowledge. He defined the noetic quality of mystical-type experiences as states of knowledge and insight into the revelation of some truth that cannot be expressed in words and which carries a sense of authority. His definition establishes a parallel between mystical-type experiences and a particular kind of feeling related to knowledge, which can be seen as a metacognitive feeling of epistemic gain, like the “Aha!”/ “Eureka!” experience.

James (1902) also pointed out that the noetic quality does not necessarily lead to new concepts or insights, but rather offers a deeper understanding of already known ideas, describing this as a feeling of having “been here before.” Crucially, recent neuroscientific research on the effects of psychedelics showed that these substances affect cognitive flexibility and feeling-of-knowing experiences (Doss et al., 2020). In particular, the episodic autobiographical memory literature has been linked with the study of the noetic feeling caused by familiarity driven by semantic priming and fluency (McGovern et al., 2024). Fluency has been specifically studied as a form of metacognitive feeling because of the ease of processing and the related concepts of truth and beauty (Schwarz, 2018). Neuroscience is laying the groundwork to understand the brain correlates of these states that are thought to be important to consider for therapeutic intervention (Krystal et al., 2023). Notably, the feeling of familiarity is only one of the metacognitive feelings related to knowledge processing. This points to the fact that there is a panel of feelings and processes that are yet to be studied within the empirical analysis of the mystical-type experience from a cognitive science perspective.

For example, self-transcendence, an emotion studied within the effects of ego dissolution and oceanic boundlessness, is an aspect of the mystical-type experience that psychedelic substances can induce, and it is a factor widely investigated to account for this state, especially in the context of psychotherapy (Jungaberle et al., 2018; Yaden et al., 2017a, 2017b). Affective regulation researchers have recently gained interest in understanding the underlying taxonomy of self-transcendent states as defined from a subjective folk perspective. When analyzing the different aspects of the phenomenology of self-transcendence, researchers have identified two majorly implicated dimensions that can distinguish non-self-transcendent and self-transcendent emotions on an empirical basis. In particular, the two broad families of self-transcendent emotions are divided into social emotions, concerning engagement in prosocial behavior, and epistemic emotions, which are associated with interest, surprise, mental challenge, and the motivation to engage with and learn new things (Abatista & Cova, 2023), facets that could arguably be related as expressions of a metacognitive feeling of epistemic gain.

In summary, noetic feelings reported subjectively during a psychedelic-induced mystical-type experience could be better defined, from a naturalistic perspective, as intense subjective experiences of a metacognitive feeling of epistemic gain: the feeling of knowing and having understood, also conceptualized as an “Aha!”/ “Eureka!” experience, sparked by the procedural-based, outcome-related functioning of the monitoring facet of metacognition.

The RElaxed Beliefs Under pSychedelics (REBUS) model (Carhart-Harris & Friston, 2019) is a neuroscientific framework used to understand the effects of psychedelic substances in the brain and psyche. The main objective of this model is to account for the brain-mind process as a predictive processing engine that projects a model of the world and looks for inconsistencies to trigger a learning action and better adapt to the demands of the external environment. Within this learning action, grounding it with the free energy principle developed by Friston (Friston, 2009, 2010), the model posits insight as a key phenomenon in psychedelic therapy, and defines it as follows: a) novelty seeking, explorative search, curious behavior; b) unconscious abductive reasoning processes conducting to “Aha!”/ “Eureka!” experiences. First, metacognitive feelings can be conceived from a predictive process perspective as feelings arising to meta-awareness from the implicit calculations of the brain while performing a cognitive action (Fernández Velasco & Loev, 2024). Second, metacognitive feelings are relevant for understanding the insight process from a subjective perspective because curiosity can be thought of as a metacognitive feeling process (Goupil & Proust, 2023) and, as explained earlier, an “Aha!”/ “Eureka!” experience can be defined as a procedural outcome-related metacognitive feeling of epistemic gain (Sooter et al., 2024; Proust, 2010).

Concerning PAT, the authors propose standard practice to help patients better go through an altered state of consciousness triggered by psychedelic intake: trust, let go, be open (Carhart-Harris & Friston, 2019). Carhart-Harris and Friston describe the insight-related processes as being more effective if the executive function is suspended. It is thus relevant to study these processes through the prism of metacognition, that is, considering the monitoring of cognition, which is postulated to have a role in making the person more able to trust and be open to the psychedelic-induced subjective experience and the resulting metacognitive feelings.

The False Insights and Beliefs Under Psychedelics (FIBUS) model (McGovern et al., 2024) is an integrated neurocognitive theory which explores the impact of psychedelics in engendering false and maladaptive insights. In this theory insight moments or “Aha!”/ “Eureka!” experiences are considered a special type of problem-solving process involving the sudden restructuration of a problem accompanied by satisfaction, surprise, noetic quality and confidence. In this framework the “Aha!”/ “Eureka!” experience is considered an heuristic which can guide the person in epistemic decision making (Laukkonen et al., 2023). This framework shows that not all the “Aha!”/ “Eureka!” experiences under psychedelics involves an actual epistemic gain and thus can potentially lead to the creation of false beliefs. These are referred to as “metacognitive illusions” and are considered stemming from the metacognitive process underlying the function of the mind during epistemic decision-making and the selection of ideas (McGovern et al., 2024). Hence, a heuristic view of the insight feeling (Laukkonen et al., 2023) could benefit from a metacognitive integrated understanding of the “Aha!”/ “Eureka!” experience. In particular, the metacognitive feeling of epistemic gain specific definition is suited to make the difference between the declarative processes related to problem solving, which heuristics are part of as conceptual strategies, and the procedural processes, which are related to attentional and cognitive agency (Metzinger, 2015) but are non-conceptual abilities. This would help better define the effect of insights in PAT because it practically defines the functioning of this particular aspect of cognitive phenomenology (Bayne & Montague, 2011), giving a descriptive framework for patients to understand it. This would consequently, as it is hoped by the FIBUS model, improve an optimal integration of “Aha!”/ “Eureka!” experiences in therapy.

Capitalizing on the conceptual framework developed in the previous sections, we can now consider the direct link between metacognitive feelings and the use of psychedelics. From a subjective phenomenological perspective, there are similarities between the introspective feelings reported during psychedelic-induced mystical-type experiences and metacognitive feelings reported in cognitive actions. Specifically, psychedelic intake has the potential to evoke metacognitive procedural, performance-based, outcome-related feelings of “Aha!”/ “Eureka!” experiences, which we consider as metacognitive feelings of epistemic gain. The next sections present the arguments to support this assumption.

One of the hallmarks of the mystical-type experience induced by psychedelics is the feeling of reaching a new reality that is being revealed, or a new truth that one has learned; a sensation of interconnectedness; the experience of having discovered and understood something important (eureka!). A rational naturalistic way to make sense of these widespread and common subjective accounts is to consider that, in daily life, people often already experience such feelings, although of smaller magnitude (Griffiths et al., 2008). In fact, whenever a person’s mind triggers a cognitive action related to the discovery of something that is hypothesized as being reachable and useful (cognitive affordance), the cognitive process possibly culminates in a feeling of having learned or having understood, an “Aha!”/ “Eureka!” experience coupled with a release of tension and a sense of satisfaction. Conceiving these feelings as a natural expression of one’s cognitive inferential activity under the threshold of meta-awareness is coherent from a neurobiological perspective, according to the active inference functioning of the brain (Friston et al., 2017a, 2017b), and is likely to be informative about the functioning of the mind (Dehaene et al., 2017; Thagard, 2014). In this sense, and because of its neurological hyperconnectivity effect (Carhart-Harris & Friston, 2019), psychedelic intake could act as an amplifier for these kinds of feelings: the expression of metacognitive feelings of epistemic gain would not be related to a specific cognitive action outcome but would simply be felt as a result of the massive binding happening between neural populations (Thagard, 2014; Thagard & Stewart, 2011) and potentially projected into any possible representation or target of attention. This would provoke an important effort from the declarative processes to make sense of such powerful “Aha!”/ “Eureka!” feelings that are evoked out-of-nowhere (outside of a cognitive action sequence scenario), thereby creating the massive availability of new potential representations, giving the impression that all things are interconnected and potentially engendering a profound problem-solving semantic reconfiguration. In addition, some declarative representations already present in memory could finally “make sense,” as they would be invested with an abundant feeling of epistemic gain evoked by the substance intake, giving the individual the impression that they finally really understood with their “gut,” meaning through an embodied procedural process, something that they already knew for a long time with their “head,” meaning within a declarative perspective.

Psychedelic intake creates a massive disruption of cognitive superior executive functions of the brain (Carhart-Harris & Friston, 2019; Nichols, 2016; Sayalı & Barrett, 2023). This is congruent with positing that there is no need for a structured cognitive action process in order for a psychedelic to induce an amplified metacognitive procedural, performance-based, outcome-related feeling of epistemic gain. In turn, this amplified “Aha!”/ “Eureka!” experience could also lead to the alteration of the feeling of time, affecting the function of coming back to the present moment that is felt when a cognitive action process is normally resolved. This can give rise to the subjective feeling of being in an eternal present moment that transcends time. In fact, from an interoceptive perspective (Craig, 2009), the passage of subjective time is related to the salience of the ongoing experience. In this way, the powerful salience of a prolonged “Aha!”/ “Eureka!” experience would increase the number of global emotional moments incorporated, thus dilating the perceived subjective time.

Additionally, considering the positive valence of the emotion related to the “Aha!”/ “Eureka!” experience (Gopnik, 1998), it can be argued that the enhancement of this metacognitive feeling of epistemic gain is at the origin of the strong positive ecstatic emotions and bliss feelings that are associated with the mystical-type experience observed in psychedelic-induced alterations of the state of consciousness.

Overall, as depicted in Fig. 7, a parallel can be drawn between the noetic feeling within the mystical-type experience induced by psychedelics and the “Aha!”/ “Eureka!” experience happening within the process of a cognitive action, which can be defined as metacognitive feeling of epistemic gain.

Afbeelding vergroten

Psychedelic-induced mystical-type experiences have been studied regarding their impact on and potential benefits in PAT (Garcia-Romeu et al., 2015; Griffiths et al., 2006, 2008, 2016; Ko et al., 2022) Mystical-type experiences are deemed central to the psychedelic-induced altered states of consciousness subjective experience (Passie & Scharfetter, 2018; Barrett & Griffiths, 2017; Richards, 2008), and they have been proposed to be a significant factor contributing to the sustained positive effects of psychedelic therapy in volunteers not affected by mental conditions (Griffiths et al., 2006; McCulloch et al., 2022). A recent systematic review of clinical studies found that mystical experience was a significant predictor of better clinical outcomes in diverse mental disorders (Ko et al., 2022). Twelve clinical studies were included in the systematic review and nine of the 12 studies independently stressed correlations between the intensity of the mystical experience scores and the reduction of symptoms in a range of mental disorders, including cancer-related anxiety and mood disorders (Griffiths et al., 2016; Ross et al., 2016); treatment-resistant depression (Carhart-Harris et al., 2018; Roseman et al., 2018); and substance use disorders, notably alcohol use disorder (Bogenschutz et al., 2015; Rothberg et al., 2021), tobacco use disorder (Garcia-Romeu et al., 2015; Johnson et al., 2017), and cocaine use disorder (Dakwar et al., 2018). Mystical experience scores were also associated with a reduction in symptoms at follow-up 6 months after the session in six of 12 studies (Bogenschutz et al., 2015; Carhart-Harris et al., 2018; Garcia-Romeu et al., 2015; Griffiths et al., 2016; Johnson et al., 2017; Ross et al., 2016).

Beyond symptom reduction, psychedelic-induced mystical-type experiences also seem to increase general well-being and life satisfaction and to induce positive changes in attitudes and behavior in healthy participants (for a narrative review of the literature, see Kangaslampi, 2023). In fact, a study conducted with hallucinogen-naïve adults who reported regular participation in religious or spiritual activities showed that these experiences were described as being among the top five most meaningful and transformative events of their lives (Griffiths et al., 2006; Griffiths et al., 2008). Some authors have proposed that the reason that mystical experiences are therapeutic is that they allow the person to embrace a more meaningful and purposeful perspective of life (Van Elk & Yaden, 2022). More specifically, Davis et al. (2020) suggest that the impact of mystical experience on the reduction of depression and anxiety might be mediated by increased psychological flexibility.

It has nevertheless been argued that the mystical-type experience is not essential for psychotherapeutic outcomes in PAT (Calder et al., 2024; Gasser et al., 2015; Schmid et al., 2021). Not only is the mystical-type experience not always present during a psychedelic-induced experience, but other mechanisms are involved in PAT, such as ego dissolution and emotional breakthroughs, which have been argued to play a pivotal role in therapeutical success (Davis et al., 2020; Kangaslampi, 2020; Roseman et al., 2019).

Finally, the multidimensionality of the mystical-type experience construct is an obstacle to its precise definition, conceptualization, and assessment, complicating its operationalization and study through experimental research design (Van Elk & Yaden, 2022). Furthermore, an ongoing debate surrounds the notion that the subjective effects of psychedelics play a role in their effect on symptom reduction. Essentially, what has to be elucidated is whether these subjective effects are the mere epiphenomenal byproduct of neural mechanisms or whether they play a causal role in the clinical outcomes observed in PAT (Olson, 2022; Yaden et al., 2024).

As various factors are involved in therapeutic work and success (Wampold, 2015), the upshot is that caution is warranted before assigning too much importance to the psychedelic-induced mystical-type experience. This is particularly important to dampen a potential “miracle-like hyped expectation” of PAT, to help patients focus their effort on the therapeutic preparation and integration work surrounding the psychedelic substance (Aicher & Gasser, 2024; Seragnoli et al., 2024), and to avoid a feeling of failure when the psychedelic-induced experience is not profound enough.

Whether psychedelic-induced mystical-type experiences are or are not beneficial for clinical outcomes in the context of PAT, they must be taken into account and integrated within the therapy, given their potential impact on clinically and psychologically relevant meta-cognitive processes. Moreover, taking them into account is likely to highlight specific phenomena and processes unique to PAT, which might be absent in other forms of psychotherapy.

As previously seen, consciousness can be operationalized as metacognitive processes of monitoring and control which results in metacognitive feelings and in potentially triggering meta-awareness. Psychedelic intake is apt to induce a change in the monitoring and control function of consciousness, in particular causing a disruption in the control function, with evidence for this being observed both from a neurological and a cognitive perspective (Gattuso et al., 2023; Vollenweider & Preller, 2020). Regarding the monitoring aspect, it is defined as the capacity for a person to be in touch with the present moment and with the ongoing functioning of their mind. In fact, this is a widespread suggestion used to explain to patients what to do during the psychedelic therapy intake session: the patient is invited to let go of control and be present to what is happening, subjectively following the natural neurocognitive effect of the psychedelic intake (Carhart-Harris et al., 2014). In addition, the patient is invited not to resist what is happening in the present or to try to find solutions or to reason and rationalize around it, but rather to accept and embody (to feel) whatever is happening within their introspection (Watts & Luoma, 2020). Because control is abandoned, monitoring is what is left and this can in turn generate an extremely positive feeling as a (felt-like) perennial state of being in the present moment and having solved all cognitive actions, hence having no further need to provide cognitive effort.

People undergoing psychotherapy are generally confronted with declarative knowledge experienced about their own functioning (Miller, 2016). An often-reported effect of psychedelic intake is that psychedelics tend to promote a feeling of “having finally understood” what one already knew related to elements consciously accessible (e.g., autobiographical or episodic memories) but not connected with each other (Carhart-Harris & Friston, 2019).

As an analogy, the case of split-brain research can be used (Gazzaniga, 2005). In these experiments, patients who underwent surgery that severed their corpus callosum and thereby lost the neural connection between the two hemispheres, had to make sense of what one hand had done by using the opposite “blinded” hemisphere. When they had to make sense of why they had done something, their declarative mind completely and unconsciously generated an explanation to account for what had already happened. We can hypothesize about the effects of psychotherapy in the same way, that after having felt such a powerful metacognitive feeling of epistemic gain, the declarative function could be pushed to come up with a good enough reason for why that feeling occurred. Given the intensity of this amplified “Aha!”/ “Eureka!” experience, the mind could stretch its imaginative capacity for conjuring novel original representations, drawing them from prior available knowledge. Accordingly, the potential efficacy of PAT could be explained by the fact that cognitive restructuration operates on the declarative process because of the powerful affective states induced by psychedelics, in particular at the level of the role of the feelings of epistemic gain and meaning in the human brain-mind-narrative system, in which metacognitive feelings are an integral part. This hypothesized powerful learning process could also explain why people deem these experiences among the most meaningful of their lives, feeling a before-after transformative effect (Griffiths et al., 2006).

Another aspect to be considered is the capacity to create behavioral scripts that influence meta-awareness. Similar to what is observed in lucid dreams (Dresler et al., 2015; Filevich et al., 2015; Kahan & LaBerge, 1994; Kahan, 2001), it is conceivable that psychedelics increase the frequency of triggering a moment of monitoring and meta-awareness in the daily waking non-sleep state of consciousness. People can be trained on metacognitive-informed behavioral scripts, such as a more mindful attitude acquired in meditation practice, to enhance their agency and cognitive flexibility in their daily lives, more frequently expressing the capacity to take control over their attentional focus and act according to their values (Metzinger, 2013). This technique can be an important integration tool for PAT and could be improved with informed psychoeducation related to daily felt metacognitive feelings. This hypothesis could explain, from a cognitive process perspective, the fact that people can experience long-lasting increases in trait mindfulness after psilocybin intake (Singer et al., 2024; Søndergaard et al., 2022), this being directly correlated with the intensity of the felt mystical-type psychedelic-induced subjective experience. A potential explanation for this finding might be that the deeply felt metacognitive feeling of epistemic gain induced by psychedelic intake sensitizes the feelings related to control and monitoring of cognition, increasing meta-awareness of them on a daily basis by reducing the threshold for experiencing them (Berit et al., 2024). A more frequent and intense increase in metacognitive feeling of epistemic gain could in turn raise the frequency of meta-awareness being triggered, bringing the person back to the present moment at the completion of a cognitive action (Søndergaard et al., 2022).

A specific aspect of being prepared for a PAT session involves defining the so-called intention of the session (Aicher et al., 2024; Seragnoli, et al., 2024). Intention can be defined as a specific goal or desire that guides an individual's therapeutic process during the psychedelic experience. The patient and the therapist collaborate to establish a clear and defined intention in the preparatory sessions prior to the substance consumption session. This intention can consist of a sentence or some keywords that the patient is often allowed to bring as written words during the substance session. This method is widely used in PAT and is conceived as being useful to help people navigate their experience, facilitate post-session integration, and give a better understanding of the subjective experience. From a cognitive science naturalistic perspective, a hypothesis can be made that this procedure consists at its core of a priming process that is applied to the alteration of the state of consciousness during the dosing session (Dupuis, 2021). Crucially, from the metacognitive feeling framework laid out here, a coherent hypothesis is that the intention is invested by metacognitive feeling of epistemic gain evoked by psychedelic intake, making it even more meaningful and having as strong and durable an effect as the intensity of the “Aha!”/ “Eureka!” experience occurring in the session. To summarize, the patient should be able to consider the intention during psychedelic-altered states of consciousness, to be able to pour a powerful attribution of metacognitive feeling of epistemic gain on it, in order to obtain a consequent directly proportional cognitive declarative restructuring (Hartogsohn, 2018). The capacity to prepare patients to exploit this effect has yet to be studied and could be part of a metacognitive epistemic feeling-based psychoeducation intervention as preparation for patients in PAT.

Music is commonly used to regulate affective states in daily life (Saarikallio et al., 2013). It has a central role in PAT and is used to accompany, modulate, and amplify the subjective processes unfolding in the psychedelic experience (Bonny & Pahnke, 1972; Kaelen et al., 2018; O’Callaghan et al., 2020; Seragnoli et al., 2024). Because metacognition is a core skill for understanding music and is actively engaged while an individual listens to music (Hallam, 2001), metacognitive feelings may also be implicated in music processing. In particular, when music is played in the background, it can enhance or impair processing fluency, thereby affecting metacognitive feelings of fluency (Schwarz, 2010). Research also indicates that the positive effect of processing fluency can be eliminated when participants attribute their positive affective responses to an external influence, such as background music (Schwarz, 2018). This means that music can evoke metacognitive feelings that can foster confrontation and reduce avoidance-related processes occurring in therapy.

Moreover, from a metacognitive procedural perspective, it is relevant to consider the role of metacognitive feelings of epistemic gain related to music. One of the pleasures derived from listening to music is to feel how the music unfolds. On the one hand, to know that a particular sound or playing of an instrument is about to happen creates an expectation and an “Aha!”/ “Eureka!” experience when it does happen, which explains in part why the appreciation of a song can increase the more one listens to it. This process reflects a cognitive action model, involving goal-related, process-related, and outcome-related metacognitive feelings (Schwarz, 2018). On the other hand, listening to unknown music can lead to feelings of surprise and trigger cognitive actions and “Aha!”/ “Eureka!” feelings related to the gradual discovery of a newfound melodic pattern (Fernández Velasco & Loev, 2024). Metacognitive feelings of epistemic gain can be modulated differently by familiar versus unfamiliar music, potentially amplifying or reducing them, thus influencing the opportunity for new experiences in PAT (Kaelen et al., 2018).

The use of music in PAT is generally calibrated in terms of the phases of the substance’s effect (pre-peak, peak, come down) (Jerotic et al., 2024). To what extent the impact of music on metacognitive feelings depends on the specific session’s phase remains an empirical question to be studied.

Psychedelic experiences commonly entail the recollection and reliving of autobiographical memories, particularly those that carry strong emotional significance, whether positive or negative (Seragnoli et al., 2024). These memories are often those that were deliberately avoided or forgotten before the psychedelic intake (Healy, 2021). According to the Self-Memory System (Conway, 2005) and the self-model theory of subjectivity (Metzinger, 2003), it may be that the intake of psychedelics facilitates new and spontaneous associations between some elements of the long-term self (consisting of a basis of autobiographical knowledge and a conceptual self) and episodic memories, thereby contributing to greater autobiographical reasoning, which may result in or be induced by the psychedelic effect on metacognitive feeling of epistemic gain.

One issue of PAT is the recalling of forgotten past autobiographical memories, which is most important when they concern traumatic events (Oehen & Gasser, 2022). A common problem for patients is that, most often for memories related to childhood abuses, people have no possibility to verify whether what they have recalled has actually happened. The intense alteration of the state of consciousness caused by psychedelics can in fact amplify negative emotions and intensify the subjective perceived psychological pain. Coupling this with the hallucinogenic property of these substances, it can be coherently argued that these memories are not real and instead just a vivid symbolization of attachment neglect and past emotional distress. Using this naturalistic framework, it can be understood why it is so difficult to discern the autobiographical truth in a psychedelic substance-induced subjective experience: the metacognitive feeling of epistemic gain could be at the very foundation of these processes in diverse ways. Feeling the “reality,” the truth and the “Aha!”/ “Eureka!” experience of having finally understood and having found a new memory within one’s own autobiography, could be elicited by a real discovery of memories and facts driven by the increased flexibility due to the substance effects, or, conversely, just by a false metacognitive feeling of epistemic gain attribution to a product of the hallucinatory symbolization (Dupuis, 2021). Given this framework, the therapeutic approach to this problem would be for the therapist to always come back to the question not of the truthfulness of the event itself, which most of the time cannot be confirmed or denied by the subjective psychedelic experience, but of the meaning and the feelings associated with it, which in turn are clear and real for the patient, giving space and recognition to the patient’s own pain and dignity.

The involvement of metacognitive feelings of epistemic gain can also be studied in relation to actual re-experiencing of traumatic memory during PAT. The aversive affective nature of the traumatic memory which push for recollection avoidance could be counterbalanced from a positive feeling associated to a metacognitive feeling of epistemic gain. Indeed, while remembering and understanding again a trauma-related content which triggers pain and negative feelings, someone can still experience amplified positive feeling through the learning process which they are going through during the substance session and which could have been prompted in the setting of the intention. In this case, it is possible to better navigate a painful memory by having at the same time an amplified positive feeling related to a different understanding of the situation and its consequences. Relatedly, metaphors used to explain the capacity of the person to confront one’s own traumatic memory like the helioscope effect (Calder & Hasler, 2023) could indeed be used to understand the underlying cognitive processes at play.

With the increasing demand for PAT internationally, the question of whether PAT therapists should have personal experience with psychedelics has emerged as a significant point of contention in this field (Aicher & Gasser, 2024; Golafshani et al., 2024; Jacobs et al., 2024). PAT is a psychotherapy that uses a specific pharmacological tool to modify the standard waking state of consciousness in the individual as an opportunity to amplify psychotherapeutic processes. This alteration of the state of consciousness is useful for therapeutic purposes and can be compared with other therapies such as mindfulness-based cognitive therapy (MBCT) and hypnotherapy in which self-experience is part of the therapists’ training. Proponents of self-experience argue that personal exposure to psychedelics enables therapists to develop a deeper understanding of the unique phenomenology associated with these substances (Guss et al., 2020). Opponents of self-experience argue that personal use of psychedelics is unnecessary and may even be harmful in the context of therapy (Emmerich & Humphries, 2023). Moreover, it was also argued that considering self-experience as necessary in the context of PAT contributes and perpetuates ableism in medicine by excluding professionals who would not be able to consume a psychedelic substance because of their susceptibility and/or medical history profile (Golafshani et al., 2024). It has, for example, been suggested that because of the intensity and the potential change in beliefs associated with psychedelic intake, self-experience could promote cognitive distortions or dysfunctional beliefs (e.g., paranormal beliefs) around the principles and factors of the therapeutic process of PAT, giving rise to questionable ethical practices for therapists and research in this field (Wahbeh et al., 2022a). Hence, the study of metacognitive feeling of epistemic gain can be important to consider both for the opportunities and the risks associated with self-experience for therapists.

On the one hand, using this naturalistic framework could help therapists better understand these subjective feelings in order to support the integration process of their patients. A broader argument can be considered that applies to the debate about the phenomenology of the daily subjective experience (Nagel, 1974) and the extent of understanding that a therapist can have of a patient’s mind, which goes far beyond the noetic debate, opening up the neurophenomenology approach (Sandved-Smith et al., 2021; Timmermann et al., 2023, 2022). William James described the ineffability of the mystical-type experience as follows:

On the other hand, powerful psychedelic-induced mystical-type experiences lived by therapists could represent a risk ranging from creating cognitive bias and distorted expectations to the process of PAT (Forstmann & Sagioglou, 2021; Kious et al., 2022; Thorens et al., 2023) to unethical practices tainted by the exaltation of narcissistic traits or sectarianism, which can be extensively found in the history of this discipline, by therapists who believed that they had finally found the tenets of the “real and true psychotherapy.” A naturalistic metacognitive-based understanding of the metacognitive feelings of epistemic gain within mystical-type experiences potentially caused by psychedelic substance intake could help therapists better integrate their own subjective experience, if they go through self-administration of a psychedelic in a supervised psychotherapeutic training.

Fluency is defined as a metacognitive feeling that affects learning and knowledge acquisition (Proust, 2021; Reber & Greifeneder, 2017). Fluency as a feeling is the familiarity with which information is perceived and the ease with which it is processed. The feeling of fluency is routinely reassessed by a learner during information processing. In particular, fluency is felt when a new fact is well anchored to pre-existing facts, it is congruent with them, and it permits many new apparently anchored and coherent associations among pre-existing facts (Rajaram & Geraci, 2000). This process follows the dynamic of concept learning, which is the acquisition of a pattern-based internal model of the world. The formation of concepts offers an advantage in terms of the quantity of information at one’s disposal to predict future events more efficiently (Goldstone et al., 2018). In contrast, the feeling of fluency is disrupted or absent if a new fact is incoherent in the context of prior knowledge. Considering this, fluency has been studied in the context of beauty and aesthetic appreciation, given the subjective affective nature of these assessments (Schwarz, 2018).

To minimize cognitive effort to reach an epistemic goal, the system uses cues related to feelings of fluency to quickly form logical reasoning and beliefs in order to orient itself coherently in the semantic space. The cognitive system is normally efficient at managing the massive amounts of information being processed at any given time, flexibly shifting the investment of limited working memory capacity. This is the origin of routinely used reasoning shortcuts, also referred to as cognitive biases or heuristics. In this sense, the “Aha!”/ “Eureka!” experience can be considered to be a heuristic that guides decision-making processes (Laukkonen et al., 2023), showing how a person can intuitively orient themselves to reach an epistemic objective.

From an individual perspective, the metacognitive feeling of epistemic gain supports the feeling of fluency, thereby increasing the possible amount of treated information (Wolk et al., 2004). In turn, this can explain why psychedelic-induced metacognitive feelings of epistemic gain could affect the processing of suggestibility related to the therapeutic intention primed prior to the therapy session, as previously described. Suggestibility, the tendency to comply with suggestions from others, has been studied as a factor potentially involved in PAT efficacy (Hartogsohn, 2016). In their study, Szigeti et al. (2024) found that the suggestibility trait (defined as the tendency to act or accept suggestions based on the input of others) of participants was predictive of psilocybin efficacy but not of escitalopram. A possible hypothesis put forward by Szigeti et al. (2024) is that “[…] high suggestibility could imply elevated attunement to acute insights, and influence from therapy personnel […]” (p. 1722). Consistent with our hypothesis, future research could test whether metacognitive feelings of epistemic gain mediate the relationship between individual differences in suggestibility and the effect of psychedelics.

Psychedelics have been studied as tools for belief transmission in the context of ritual and religious use (Dupuis, 2021) and have been historically used in traditional ceremonies (Kettner et al., 2021). Unfortunately, psychedelics have also been associated with dangerous sectarian practices (Paglia, 2003; Richardson, 1979; Tramacchi, 2000). From a group perspective, the impact of metacognitive feelings of epistemic gain in perceived fluency could in part explain psychedelic-induced cognitive influences in cult collective contexts (e.g., sectarianism) (Marinacci, 2023), particularly during socially mediated processes of epistemic formation imposed by an authoritative persuasive figure (e.g., guruism) (Sperber, 2010). A metacognitive-informed understanding of the way in which beliefs are transmitted in social contexts, whether religious, cultural, or sectarian, can be a key element for a truly interdisciplinary understanding of the use of psychedelics and their culturally mediated mechanisms (Fortier, 2018).

Integrating the effects of metacognitive feelings of epistemic gain with information processing in social interactions can thus improve our understanding of the impact of cultural values and narratives operating in the variety of settings used for psychedelic substance intake, while at the same time keeping a neurocognitive model that underlines these processes (Nardou et al., 2023).

The hallucinatory quality of psychedelic-induced altered states of consciousness can induce a very wide range of personal explanatory narratives to make sense of what is experienced. Among these, one can include metaphysical beliefs about the nature of reality, encountering God or entities, or even unverifiable facts about childhood trauma. These new narratives can have powerful impact on one’s world-view and mental health, sometimes beneficial, but sometimes also damaging or delusional, ranging from pseudo-science to parapsychology (Wahbeh et al., 2022a). This problem is commonly known in the psychedelic research field as “spiritual bypassing” or “woo-woo” effects (Carhart-Harris & Friston, 2019). The powerful metacognitive feeling of epistemic gain triggered by psychedelics can induce the person to adopt dogmatic beliefs or have the impression to finally understand the “ultimate Reality.” This could be explained because of the bursts of a too-intense metacognitive feeling of epistemic gain, which could induce the person to try to make sense of it with an important enough matching semantic representational object (Clément, 2003).

It could be possible to implement forms of psychoeducation in PAT with the goal of giving patients a naturalistic framework about how to recognize and interpret mystical-type experiences stemming from psychedelic intake, comparing the metacognitive feeling of epistemic gain to those same feelings being experienced in daily life activities. One important aspect to be highlighted in such psychoeducation is the bodily sensations of these feelings, corresponding to a sense of positive affect, satisfaction, and release from cognitive frustration. This type of psychoeducation would be important during the post-experience integration sessions to mediate the new beliefs and cognitive restructuring that the patients went through. Instead of focusing on the veracity of visions or ideas about absolute truths (e.g., God) that have been felt as “revealed” in the context of the psychedelic-induced experience, the therapist could let the patient focus on the revelation “Aha!”/ “Eureka!” experience itself. Where else in daily life does the patient usually feel this kind of feeling of meaning and bliss? When performing what kind of activities? The patient could thus be supported in realizing when this feeling is evoked in daily life by the contact with something important, good, coherent or useful to one’s own personal appreciation and taste for life (e.g., spiritual practice, playful activities, sport, creative expression, work-related tasks, learning activities). This approach is a naturalistically grounded way to be able to make sense of and accompany people in integrating mystical-type and spiritual experiences that can result from PAT sessions, which is an important issue in this type of psychotherapy (Dupuis, 2021; Sjöstedt-Hughes, 2023). It also highlights the importance of affording an intense subjective meaningful experience, also called “portentousness” (Krystal et al., 2023), which is an integral part of PAT, the intensity of which is related to the establishment of cognitive behavioral learning acquisition.

These peak experiences can help recalibrate the predictive processing active inference function of the metacognitive system, which is dysregulated in various psychopathologies, making it more able to express coherent subjectively felt insights (Carhart-Harris & Friston, 2019). Psychedelics can in fact reopen the social reward learning critical period (Nardou et al., 2023). From this perspective, the regulation of the metacognitive feeling of epistemic gain could also be impacted because of the social cognition aspects of the interactive nature of the different phases of PAT: therapeutic preparation and intention setting; suggestibility; traumatic memory recall. In this way, the reopening of the social reward learning critical period could reflect for the person an improvement in the regulation of socially induced metacognitive feelings of epistemic gain.

The extent to which extra-pharmacological factors, such as the PAT set and setting, can be used to increase the probability of affording an intense metacognitive feeling of epistemic gain experience could be specifically studied. Moreover, in people coming back to their day-to-day life activities after having done a PAT session, integration tools could be developed to better support the patient to recognize mentally and/or bodily such short daily moments of “Aha!”/ “Eureka!”.

Moreover, the ongoing integration work for the patient could also be invested by this framework by letting the patient learn how to better recognize this metacognitive feeling of epistemic gain in daily life and then discuss it in the ongoing therapy. In this sense, this approach could be particularly fruitful because it operationalizes a clear aspect of the subjective experience, that can be taken as a concrete principle to ground mindfulness-like skill training for daily life purposes. A metacognitive epistemic feeling oriented psychotherapeutic intervention, inscribed in a PAT cognitive behavioral informed therapy, would consist of helping the patient focus on finding, training, and amplifying the metacognitive feeling of epistemic gain in day-to-day life. The extent to which various practices could be integrated in such an approach would be important to understand (Vervaeke & Ferraro, 2013)