Sage Journals: Discover world-class research

Abstract

Nondual awareness (NDA), a unified, unchanging state of consciousness devoid of other phenomenal contents, can be achieved by various means such as contemplative practices. NDA seems to have a beneficial effect on well-being. This study aimed to validate a French version of the Nondual Awareness Dimensional Assessment-Trait (NADA-T) scale used to measure predisposition to NDA in the context of mindfulness meditation, during experiences with reduced phenomenal content, referring to a marked decrease in usual mental activity. To do this, 294 French-speaking students anonymously completed an online survey to allow us to examine the construct validity, internal consistency, and convergent and discriminant validity of the French version of the NADA-T. They also provided information about their meditation practice or other experiences that led them to experience this state of non-duality. The original structure, with one global factor (NDA) and two specific factors (self-transcendence and bliss), showed very good statistical indicators. In addition, the results showed good convergent and discriminant validity. Recommendations to address some of the study’s limitations included reformulating 2 items. However, although this preliminary French version of the NADA-T shows acceptable psychometric properties in a student population, further studies are needed to confirm the factor structure, test temporal stability, and extend these results to other populations.

Plain Language Summary

Measuring Nondual Awareness: Validating A French Version of The Assessment

Some people describe a unique state of consciousness in which they experience a profound sense of oneness with all that exists. This state, known as nondual awareness (NDA), often occurs during mindfulness meditation or other practices that calm the mind. Research suggests that experiencing NDA can improve well-being. The aim of this study was to create and validate a French version of the Nondual Awareness Dimensional Assessment-Trait (NADA-T), a questionnaire used to measure a person's tendency to experience non-dual awareness. The researchers translated the NADA-T questionnaire into French and tested it with a group of French-speaking students practising mindfulness meditation. The French version of the NADA-T closely matched the original English structure. The results showed that the questionnaire was reliable (consistent in its measures) and had good validity (it measured what it was supposed to measure). This study provides a validated tool for future research into NDA in French-speaking populations. Understanding NDA could help researchers explore its effects on well-being and mental health. This assessment could also be useful to mindfulness practitioners, psychologists and neuroscientists studying altered states of consciousness.

Keywords

nondual awareness consciousness mindfulness meditation non-ordinary states of consciousness

Introduction

Numerous scientific studies have sought to obtain a better understanding of what consciousness is, based exclusively on global states of wakefulness (referring to the different levels of consciousness such as sleep, dreams, etc.) and on phenomenal contents (referring to the sensory perceptions of our subjective experiences) (Josipovic, 2021). However, consciousness in general should not be considered to consist of these two elements alone but should also be considered to consist of consciousness itself, which is its founding and fundamental aspect and therefore prior to any specific state and content (Dunne, 2015; Josipovic, 2014, 2019; Josipovic and Baars, 2015; Rabjam, 2007). Consciousness-in-itself, otherwise known as nondual awareness (NDA), is described as a unified, unchanging type of consciousness devoid of other phenomenal contents (i.e., thoughts, perceptions, emotions and/or the usual sense of self and body, with no sense of space or even time) (Josipovic, 2019; Peters, 2013). Indeed, NDA is used to describe a state of consciousness characterized by minimal phenomenal experience, a consciousness empty of any mental content (a nonconceptual consciousness), other than the experience itself (Forman, 1998; Metzinger, 2018; Nikhilananda, 1987; Rabjam, 2001). However, NDA retains a quality of cognitive bliss (Dambrun & Ricard, 2012; Mills et al., 2020). Indeed, it is associated with emotionally positive nondual experiences in the context of mindfulness meditation (Dambrun, 2016; Hanley et al., 2017) but is also characterized by experiences in which there is a unification between subject and object, so that the existing boundaries between the self and world merge into a unified whole (Blackstone, 2015; Gyamtso, 1994; Krägeloh, 2018; Wright, 2017). Hence, these experiences of nonduality facilitate the emergence of a feeling of psychological as well as subjective well-being (Hanley & Garland, 2022; Hanley et al., 2018; Jones, 2023; Lynch & Troy, 2021).

NDA has been described as having two main dimensions (Bucke, 1901; Higgins, 2012). The first refers to self-transcendence, that is, the individual experience in which self-perception is “extended” in various ways. In self-transcendence, individuals report having a unitive experience, in which they are as if “absorbed” or “fused” into a unity with all things (otherwise known as “relational self-transcendence,” referring to the notion of ego dissolution and continuity with everything around them) and/or having an experience in which sensory representations of self and the world are only mental constructions (ontologically null and void of substance), thus not reflecting objective reality but rather an “illusory” reality (otherwise known as “annihilational self-transcendence”) (Dorjee, 2016; Kalupahana, 1987; Yaden et al., 2017). The second NDA dimension is bliss, referring to the idea that NDA is associated with an experience that elicits a strong positive emotional tone that is neither object- nor context-dependent and results in experiences of extreme joy, bliss or all-encompassing love (Hanley et al., 2018; Mills et al., 2020). Indeed, NDA leads individuals to experience the quiet contentment of being and feeling entirely complete within oneself, without the need to be other than who we are and without feeling lacking in any way (Deshmukh, 2022; Josipovic, 2014; Josipovic & Miskovic, 2020).

Based on this theoretical foundation and the selection of items from existing scales, a scale called the Nondual Awareness Dimensional Assessment-Trait (NADA-T) was specifically developed to reflect the two central and conceptually distinct dimensions of nondual consciousness. In fact, this design guided B-ESEM’s choice of a psychometric model, in order to test both a general factor of nondual awareness (NDA) and the two specific sub-dimensions (self-transcendence and bliss), while taking into account possible conceptual overlaps between certain items. It has thus been used and validated with various populations, including more general samples of adults online and in academic settings, as well as practitioners of mindfulness meditation and people who reported not practicing mindfulness meditation. The results confirmed the structural validity of the NADA-T and revealed the existence of two specific factors, as expected: self-transcendence and bliss (Hanley et al., 2018). To our knowledge, there is no adapted French version of the NADA-T. Such validation is necessary to develop scientific research on NDA and to explore it as a potential consequence of phenomenal content-reduction experiences occurring in the context of mindfulness meditation. Thus, we sought to assess the construct validity, internal consistencies, concurrent and discriminant validities of a French NADA-T scale. To do this, we asked French-speaking students to anonymously respond to an online survey.

Method

Participants

No power analysis was performed in this study. However, in accordance with commonly accepted methodological recommendations for factor analyses, a number of participants between 5 and 10 per item is considered adequate (Costello and Osborne, 2005; Nunnally, 1967). Our final sample of 294 participants, after exclusion, more than meets this criterion, thus supporting the robustness of the analyses conducted. Participants were recruited from June 2023 to September 2023, and of the 650 participants who clicked on the link, 243 consented but did not complete the survey; 64 participants were excluded because they did not meet the inclusion criteria and 49 because they did not specify which practice/event had led to this experience of non-duality, which would have compromised the reliability and interpretability of the survey responses if they had been included in the analysis. Only data from respondents who completed the survey in its entirety were used in the analysis.

French Translation of the NADA-T

In order to obtain a consistent French translation of the NADA-T, we used the committee method (Vallerand, 1989). With the agreement of the original authors, the instructions and items were independently translated into French by two native French speakers with a good command of English (a clinical psychologist specializing in altered states of consciousness [GG] and a psychologist and physician also specializing in this field and in neuroscience [SK]). These two versions were then compared and discussed in committee (GG and SK) to arrive at a consensus version. The consensus version of the translated questionnaire was retranslated by AO, a French-speaking doctoral student in psychology and cognitive neuroscience who is fluent in English. The retranslation was then reviewed by the two translators who participated in the previous procedure (GG and SK). The French version was then discussed at a committee meeting (AO, GG, and SK) and, in the event of discrepancies, the changes to be made to the French wording were discussed by the committee, which always reached a consensus.

Measures

The NADA-T was the first standardized method of measuring disposition toward NDA that occurred during a modified state of consciousness such as mindfulness meditation. Participants were asked to think back to their experience and rate the extent to which they experienced the 13 items on a 5-point scale ranging from 1, never or very rarely to 5, very often or always. A total score is obtained by calculating the mean score of all items of the questionnaire, and two sub-scores are obtained by calculating the mean score of the items referring to different dimensions of NDA (i.e., self-transcendence and bliss). The French translation of the NADA-T used in this validation study is in Table 1.

Table 1.

Original and French Version of the Nondual Awareness Dimensional Assessment-Trait (NADA-T).

Item	Original label	French label
1	I have felt a sense of awe and wonder.	J’ai ressenti un sentiment de stupeur et d’émerveillement.
2	I have had an experience in which I felt myself to be absorbed as one with all things.	J’ai vécu une expérience au cours de laquelle je me suis senti(e) absorbé(e) par toutes les choses.
3	I have had an experience in which the boundaries of my self dissolved.	J’ai vécu une expérience dans laquelle les limites de mon moi se sont dissoutes.
4	I have experienced an all-embracing love.	J’ai fait l’expérience d’un amour englobant.
5	I have experienced a melting or merging with the others; I became others and they became me.	J’ai fait l’expérience d’une fusion avec les autres; je suis devenu(e) les autres et ils sont devenus moi.
6	I have had an experience in which my mind expanded into space.	J’ai eu une expérience dans laquelle mon esprit s’est fondu dans l’espace.
7	I have had an experience in which all things seemed to be unified into a single whole.	J’ai eu une expérience dans laquelle toutes les choses semblaient être unifiées en un seul tout.
8	I have been surrounded and filled with a blissful warmth or energy.	J’ai été entouré(e) et rempli(e) d’une chaleur ou d’une énergie de félicité.
9	I have experienced a feeling of oneness in which the boundaries between what is me and what is not me has dissolved.	J’ai éprouvé un sentiment d’unité dans lequel les limites entre ce qui est moi et ce qui ne l’est pas se sont dissoutes.
10	I have experienced a perfectly peaceful state.	J’ai connu un état de paix total.
11	It has seemed to me that my environment and I were one.	Il m’a semblé que mon environnement et moi ne faisions qu’un.
12	I have experienced all notion of self and identity dissolve away.	J’ai fait l’expérience de la disparition de toute notion de soi et d’identité.
13	I have experienced the insight that “all is One.”	J’ai fait l’expérience de l’intuition que “Tout est Un.”

To test the construct validity of the NADA-T, we used the following questionnaires: the MEQ (Barrett et al., 2015; MacLean et al., 2012), which measures different aspects of mystical experiences, and the STAI—Trait form (STAI-T), the general anxiety scale. To assess the mystical-type phenomena that can occur during modified states of consciousness experiences, participants additionally answered 27 questions from the MEQ (Barrett et al., 2015; MacLean et al., 2012) that correspond to three dimensions of mystical experience (i.e., mystical, positive mood and transcendence of time and space). Furthermore, within the mystical dimension, seven questions were related to the “unitive” experience, considered a fundamental characteristic of mystical experiences (Barrett et al., 2015; Hood, 1975; James, 1985; Stace, 1960). The instruction asks the participants to think back on the entirety of their experience and to rate the extent to which they experienced the 27 described phenomena on a 6-point scale (0, “none, not at all”; 1, “so slight cannot decide”; 2, “slight”; 3, “moderate”; 4, “strong [equivalent in degree to any previous strong experience or expectation of this description]”; and 5, “extreme [more than ever before in my life and stronger than 4]”). Three sub-scores are obtained by calculating the mean score of the items referring to the three selected different dimensions of the mystical experience. The inclusion of these 27 MEQ questions allowed us to measure the convergent validity of the NADA-T concept because the NDA concept is theoretically associated: unitive and mystical experiences, given that the self is widely distributed and deeply interdependent (i.e., the self extends to close relationships, physical objects, and ultimately to “all things”) and closely associated with self-transcendence (i.e., the self-extended to all things); positive mood, given the canonical characterization of NDA as blissful; and experiences of transcendence of space and time (e.g., “being in a world without spatial limitation”), referring to the fact that the usual boundaries of space can become blurred. The 3 items not included referred to the dimension of “ineffability” (i.e., measuring the difficulty in verbally describing the experience), as they were deemed less relevant in the strictly conceptual assessment of convergence, providing no direct information on the phenomenological content or cognitive aspects of the NDA.

The STAI-T is a popular self-reporting rating scale designed to measure a more general and long-standing quality of the “trait anxiety” (Spielberger, 1989). The STAI-T targets how respondents “generally feel.” It contains 10 items describing symptoms of anxiety (i.e., “I become tense and upset when I think about my current concerns”) and 10 items describing the absence of anxiety (i.e., “I feel fine”). Each item is scored on a 4-point Likert scale, ranging from 1, “almost never,” to 4, “almost always.” The minimum score is 20 and maximum score 80. Because the NADA-T contains subscales of bliss and is not supposed to assess how people generally feel, the STAI-T was used to assess discriminant validities of the French NADA-T.

Survey Design and Completion

The French version of the NADA-T was used in an online survey entitled “Study on modified states of consciousness” to avoid explicitly revealing what was being evaluated in this survey (the experience of NDA) hosted on the Lime Survey platform (www.limesurvey.com). The link to the survey was posted on LinkedIn, intended for students. However, since participation is voluntary, this may introduce a selection bias, discussed in more detail in the “Limits and Recommendations” section. To take part in the survey, participants had to be at least 18 years and a student and have French as their mother tongue. The information letter and consent form were presented to participants after they had clicked on the link. With regard to data quality control, although no explicit attention checks (i.e., trick questions) were included in the survey, participants were informed that the maximum completion time would be 10 min, encouraging them to respond carefully. In addition, the sequential presentation of the three short questionnaires limited the likelihood of hasty responses. After giving consent, participants were invited to complete the survey.

After completing the NADA-T, Revised Mystical Experience Questionnaire (MEQ-30) and State-Trait Anxiety Inventory—State form (STAI-S) questionnaires (see Measures), participants were asked to answer a set of demographic questions about their age, sex, and level of education. They were also asked if they practiced mindfulness meditation and if so, for how long (<1 year, 1–5 years, 5–20 years, and >20 years; Thomas and Cohen, 2014) and how often (every day, at least once a week, at least once a month, at least once a year) and if they did not practice mindfulness meditation. They were also asked during which practice/event they had an experience of NDA (free choice to ensure that people did not answer randomly). For participants who experienced a modified state of consciousness as a result of an experience other than mindfulness meditation, responses were grouped according to the method of induction (occurring spontaneously, physically/physiologically induced, psychologically induced, pharmacologically induced or due to disorders or pathologies; Vaitl et al., 2005).

Procedure

All materials were assessed and approved by the ethics committee of the University and followed the principles of the Declaration of Helsinki. Data were collected anonymously. Participants were invited to give their informed consent on the survey introduction page, which presented information about the study and the consent form, then clicked on “next” to be directed to the questionnaire, where the questions were presented in a fixed order that was the same for all participants, ensuring consistency in administration.

Statistical Analysis

Statistical analyses were performed with Jamovi 2.3.24 and R 4.2.2 (R Core Team, 2018) and were performed in several steps. p < .05 was considered statistically significant. First, descriptive statistics were calculated for demographic information. Second, we assessed concurrent and discriminant validity. The convergent validity of our translation of the NADA-T was assessed by calculating Spearman’s correlation coefficients between scores for the three dimensions of the MEQ referring to the dimensions of mysticism, positive mood, and transcendence of time and space, as well as the 7 items measuring unitive experience, with scores for the NADA-T scale and its two component subscales, which are assumed to be positively correlated. Discriminant validity was assessed by calculating correlations between STAI-T general anxiety scores and NADA-T scores, for which we assumed that NDA experiences are significantly not correlated with anxiety. In addition, the Benjamini-Hochberg correction procedure was applied to adjust the p-values associated with the correlations, to control the false discovery rate.

Third, to validate the bifactorial structure of the NADA-T, we defined a model based on the results of the initial validation study by using Bifactor Exploratory Structural Equation Modeling (B-ESEM), after examining the normality of the data (using the Shapiro-Wilk normality test, separately for each item, to verify the need to adopt robust estimation methods). B-ESEM is an analytic approach that accounts for the likelihood that items “may be associated with more than one source of true score variance,” which is developed as an alternative to Confirmatory Factor Analysis (CFA) (Morin et al., 2016). B-ESEM avoids two primary sources of variance that the CFA does not account for by 1) allowing all observed variables to load on all latent variables and 2) partitioning the total covariance from all of the scale items into a global latent factor while allowing specific latent factors to explain the residual item covariance. Unlike CFA, it therefore allows simultaneous modeling of a hierarchical factor structure comprising a general factor (i.e., NDA) and specific factors (i.e., happiness and self-transcendence), while taking into account possible cross-loadings between items and non-targeted dimensions. The global factor and the two specific factors were specified as orthogonal by using the Weighted Least Squares Mean and Variance adjusted (WLSMV) Estimator adapted when the data do not follow a normal distribution, as in the original study, to ensure interpretability and consistency with the two-factor hypotheses. We also tested other models, namely, an Independent Clusters Model-CFA (ICM-CFA) with two factors, with items relating to the two NADA-T dimensions (self-transcendence and bliss) associated with two independent factors; an ESEM model allowing all 13 items to load onto the two factors/dimensions to introduce greater flexibility in the association of items with the latent dimensions; a bifactorial CFA model, with all items associated with the general factor (NDA) while retaining specific factors for the two NADA-T dimensions; and finally, a monofactorial CFA model with all items included in the same factor. For fit indices, we used the population-corrected robust Comparative Fit Index (CFI; Bentler, 1990), the Tucker-Lewis Index (TLI; Tucker & Lewis, 1973), the relative chi-square (Cmin/df), the root mean square error of approximation (RMSEA; Steiger, 1990), and the standardized root mean square residual (SRMR; Maydeu-Olivares et al., 2017).

Fourth, internal consistency of the French NADA-T total and subscale scores was assessed by the Cronbach alpha (α) (Cronbach, 1951) and McDonald’s total omega (ωtotal). A value >0.70 was considered good (Nunnally & Bernstein, 1994). Fifth, we examined the association between mindfulness meditation practice and NDA experiences measured by the NADA-T. To do this, we used a non-parametric t-test (Wilcoxon-Mann-Whitney test) for people who practice and do not practice mindfulness meditation, and nonparametric ANOVAs (Kruskal-Wallis test) to assess differences between multiple groups (i.e., based on “levels of expertise” [how long they have been practicing], frequency of practice, and induction method) in terms of scores on the general dimension of the NADA-T and its two specific dimensions (self-transcendence and bliss).

Results

Socio-Demographic Characteristics of Participants

The mean age of the participants was 23.218 years (SD = 3.473) and 74% were female. The estimated weighted average level of education was 15.928 years. The mean NADA-T total score was 2.231 (SD = 0.640). Overall, 35% of participants practiced mindfulness meditation: 3% daily, 19% at least once a week, 50% at least once a month, and 27% at least once a year. Also, 20% had been practicing for <1 year, 73% for >1 year, and 7% for >5 years. For other participants who did not practice mindfulness meditation, the modified state of consciousness recorded by the survey was induced pharmacologically in 4% of cases, physiologically in 12%, and psychologically in 40%; it occurred spontaneously in 44% of cases and pathologically in <1%. Thus, 103 people reported experiencing a state of NDA via their practice of mindfulness meditation and 191 people via other means, as described above.

Convergent and Discriminant Validities

The NADA-T score was moderately (i.e., effect size between 0.5 and 0.8) and positively correlated with scores for the MEQ mystical and unitive experience dimensions (rs = 0.720, p < .001, 95% CI [0.660, 0.771]; rs = 0.739, p < .001, 95% CI [0.682, 0.787]) as well as scores for the other two MEQ dimensions tested, positive mood and transcendence of space and time (rs = 0.547, p < .001, 95% CI [0.462, 0.623]; rs = 0.555, p < .00, 95% CI [0.470, 0.629]). These significant positive correlations confirmed the convergent validity of our scale. The NADA-T score was very weakly (i.e., effect size less than 0.2) and non-significantly correlated with the general anxiety score (STAI-T) (rs = 0.018, p = 0.759, 95% CI [−0.097, 0.132]), which suggests that these two scales do not assess the same concepts and confirms the discriminant validity of our scale. Nor was the general anxiety score correlated with scores for the mystical, unitive experience, and transcendence of space and time dimensions of the MEQ (rs = −0.076, p = 0.229, 95% CI [−0.189, 0.039]; rs = −0.047, p = 0.448, 95% CI [−0.160, 0.068]; rs = 0.061 p = 0.331, 95% CI [−0.054, 0.174], respectively). However, the general anxiety score was weakly (i.e., effect size between 0.2 and 0.5) but negatively correlated with the score for the MEQ positive mood dimension (rs = −0.265, p < .001, 95% CI [−0.368, −0.155]).

The score for the NADA-T self-transcendence dimension was moderately and positively correlated with scores for the mystical, unitive experience, and space and time transcendence dimensions of the MEQ (rs = 0.682, p < .001, 95% CI [0.616, 0.739]; rs = 0.723, p < .001, 95% CI [0.654, 0.774]; rs = 0.605, p < .001, 95% CI [0.527, 0.673], respectively) and weakly with the score for the positive mood dimension (rs = 0.409, p < .001, 95% CI [0.309, 0.500]) but very weakly with the general anxiety score (rs = 0.122, p = 0.046, 95% CI [0.008, 0.233]). The score for the NADA-T bliss dimension was moderately and positively correlated with scores for the mystical, unitive experience, and positive mood dimensions of the MEQ (rs = 0.587, p < .001, 95% CI [0.507, 0.657]; rs = 0.544, p < .001, 95% CI [0.458, 0.620]; rs = 0.664, p < .001, 95% CI [0.595, 0.723], respectively). It was weakly but positively correlated with the MEQ transcendence of space and time dimension (rs = 0.286, p < .001, 95% CI [0.177, 0.387]) and weakly but negatively with the general anxiety score (rs = −0.204, p = 0.001, 95% CI [−0.312, −0.092]).

Construct Validity: Factorial Analyses

The Shapiro-Wilk normality test results indicated that all items showed significant deviations from normal distribution, with p-values significantly below the 0.05 threshold. For our B-ESEM model, we used a robust estimator, the WLSMV Estimator, specially adapted for data not following a normal distribution. The B-ESEM model best fit the data, as seen from the fit indices, which indicate that the bifactorial structure of the NADA-T was better than that for the other four models tested (see Table 2). Indeed, after calculating the relative chi-square (χ²/df), which is less sensitive to sample size than the raw chi-square, the estimated relative chi-square of our model was 2.385, indicating acceptable fit. Similarly, values for the CFI (=1) and TLI (=1) indices were >0.90, indicating excellent model fit. The RMSEA value was between 0.05 and 0.08 (0.069), indicating an acceptable model fit. Finally, the SRMR value was <0.08 (=0.038), also indicating very good fit. Therefore, the bifactorial structure of the French NADA-T is accepted, with indices close to those of the original study.

Table 2.

Fit Indices of All Models Tested for the French Nondual Awareness Dimensional Assessment-Trait (NADA-T).

Model	χ²	p	df	CFI	TLI	RMSEA	SRMR
Uni CFA	375.191	<.001	65.000	0.960	0.952	0.128	0.091
ICM-CFA	317.093	<.001	64.000	0.969	0.962	0.116	0.080
ESEM	145.758	<.001	55.000	0.992	0.989	0.075	0.054
Bifactor CFA	164.797	<.001	52.000	0.993	0.989	0.086	0.053
Bifactor ESEM	102.539	<.001	43.000	1.000	1.000	0.069	0.038

Note. χ² = chi-squared test; df = degrees of freedom; CFI = Comparative Fit Index; TLI = Tucker-Lewis Index; RMSEA = root mean square error of approximation; SRMR = standardized root mean square residual; CFA = confirmatory factor analysis; ICM-CFA = Independent Clusters Model-CFA; ESEM = Exploratory Structural Equation Modeling.

The B-ESEM results showed that the NADA-T consistently captured a global dimension of the NDA as well as two specific dimensions (self-transcendence and bliss) and that these two specific dimensions also explained significant amounts of the covariance of items not fully covered by the global factor (see Figure 1 for heatmap of factor loadings). As the factor loadings of the “self-transcendence” factor were all negative despite the positive wording of the items, they were multiplied by −1 with the factor scores to facilitate interpretation, without affecting the structure and fit indices of the model. Only 1 item made a small contribution to the overall factor and was lower than the loadings in the two specific factors “J’ai vécu une expérience au cours de laquelle je me suis senti(e) absorbé(e) par toutes les choses,” with a standardized factor loading of 0.509 on the “self-transcendence” dimension and 0.38 on the “bliss” dimension. All other items had a significant low to high load on the global NDA factor (standardized factor loadings ranging from 0.254 to 0.811). For the self-transcendence dimension, all items associated with this dimension had significant low to strong standardized loadings (ranging from 0.264 to 0.671), except for the item “Il m’a semblé que mon environnement et moi ne faisions qu’un,” which loaded significantly and strongly on the global NDA factor (standardized factor loading 0.811) and a significant weak impact on the bliss dimension (standardized factor loading of 0.237). For the bliss dimension, all items loaded significantly and low to strongly (from 0.264 to 0.571). However, the item “J’ai été entouré(e) et rempli(e) d’une chaleur ou d’une énergie de félicité,” loaded significantly and strongly on the global NDA factor (standardized factor loading 0.558).

Figure 1.

Heatmap of factor loadings from the bifactor exploratory structural equation modeling for the overall dimension and specific dimensions of the NADA-T.

Internal Consistency

Internal consistency indices were good (>.70) for the NADA-T global NDA dimension (α = .851, ωt = .858) and self-transcendence dimension (α = .851, ωt = .856) but were acceptable but questionable (α = .643, ωt = .651) for the bliss dimension. To further examine the internal consistency of the bliss dimension, a detailed analysis of the correlations between the items and the total was carried out. All items showed corrected item-total correlations ranging from 0.457 to 0.621 (i.e., above the recommended threshold of 0.30), indicating acceptable internal consistency. Moreover, deleting an item didn’t improve the reliability of the dimension. Scores for the two specific dimensions were strongly and positively correlated (r = 0.494, p < .001).

Association Between the NADA-T and Mindfulness Meditation Practice

We found no significant differences between students practicing and not practicing mindfulness meditation in scores for the NADA-T global NDA dimension (W = 9483, p = .611, r = −0.036), self-transcendence dimension (W = 9741.5, p = .892, r = −0.010), and bliss dimension (W = 9037, p = .248, r = −0.081). In addition, in order to explore more closely the effects of meditation practice on non-dual consciousness, participants practicing mindfulness meditation were divided into several groups based on their responses to questions about their “level of expertise” and frequency of their practice (see Method section). Participants who reported no mindfulness practice were grouped together, as in the previous analysis, in a “non-meditating” group. Kruskal-Wallis analyses did not reveal any significant differences between the groups for the two analyses conducted.

We therefore wanted to determine whether there were significant differences depending on the method used to induce NDA. However, as we only had one participant in the “pathologically induced” category, we decided to include this participant in a new category called “other” along with participants who reported a pharmacologically induced NDA state. The Kruskal-Wallis test revealed no significant differences between the groups in scores on the global NDA dimension, χ²(4) = 6.467, p = .167, ε² = 0.022, self-transcendence dimension, χ²(4) = 6.024, p = .197, ε² = 0.021, and bliss dimension, χ²(4) = 9.142, p = .058, ε² = 0.031. To examine this marginally significant trend for the bliss dimension score in more detail, we carried out post-hoc comparisons using the Dwass, Steel, Critchlow and Fligner (DSCF) method. However, none of the pairwise comparisons reached significance, suggesting no sufficiently pronounced differences between the groups.

Discussion

Results Summary and Interpretations

The aim of this study was to provide preliminary evidence of the construct validity, reliability and concurrent and discriminant validity of our French version of the NADA-T to provide a psychometrically sound instrument for assessing experiences of NDA in French. The French version of the NADA-T had the same structure as the original English version (Hanley et al., 2018), with two NDA-specific factors, representing the dimensions of self-transcendence and bliss, which are two interdependent elements of a global NDA concept. The bifactorial structure obtained from the NADA-T thus confirms the complexity of the NDA, which is characterized both as a comprehensive integrative experience and by specific differentiable components. These models are increasingly used to represent and analyze complex constructs (Bornovalova et al., 2020; Markon, 2019), allowing for a better structural understanding of psychometric scales by distinguishing between the variance shared between items (global factor) and that specific to sub-dimensions (specific factors; Chen et al., 2011). Thus, our results support the idea that non-dual consciousness can be modeled as a construct that is both unified (i.e., marked by higher loadings on the global factor than on the specific factors) and differentiated, as this does not invalidate the relevance of the sub-dimensions.

However, 1 item, “J’ai vécu une expérience au cours de laquelle je me suis senti(e) absorbé(e) par toutes les choses,” contributed little to the overall factor and was lower than the loadings in the two specific factors, which seems to be a problem specific to this item rather than to the overall structure of the model, given the good quality indices of the B-ESEM model. Indeed, this item loaded significantly and predominantly on the specific dimension of self-transcendence, which is conceptually and theoretically expected, as well as significantly on the specific dimension of bliss, which should not be the case. As a result, we propose a slight modification of the wording of the item, “J’ai vécu une expérience au cours de laquelle je me suis senti(e) absorbé(e) comme faisant un avec toute chose,” so that it is more specific to the dimension of self-transcendence, as do the other items in this dimension, avoiding any ambiguity or conceptual overlap, and contributing more to the overall NDA factor.

Moreover, the item “Il m’a semblé que mon environnement et moi ne faisions qu’un” saturated predominantly and strongly on the global NDA dimension, with low saturation on the bliss dimension rather than on the specific dimension of self-transcendence. This finding could be explained by the item reflecting a more general trend in the concept of NDA rather than being limited to the transcendental aspect. Indeed, this item loaded preferentially on the global NDA factor in the original study, for all three samples tested (including the university sample), which reinforces the idea that it captures a more general than specific experience of connection (Hanley et al., 2018). Therefore, we propose a slight modification of the wording of the item, “Il m’a semblé qu’il n’y avait plus de distinction entre mon environnement et moi,” to make it more specific to the dimension of self-transcendence, avoiding any ambiguity or conceptual overlap with the dimension of bliss, as the expression “ne faisions qu’un” can suggest a pleasant feeling of fusion close to bliss. By rephrasing it, the emphasis is then placed more on the cognitive perception of unity.

Furthermore, it is important to emphasize that the need to reformulate these 2 items also raises questions about the possible influence of linguistic or cultural nuances in the interpretation of items relating to the in the NDA. Indeed, several studies highlight the need for numerous adjustments in reformulations to ensure construct validity (Peña-Gayo et al., 2018), as concepts such as “self-transcendence” and “bliss” can be understood differently across cultures (Choi et al., 2022; Rudaz et al., 2020). In addition, internal consistency for the total NADA-T score was very good, as was the score for the self-transcendence dimension, because the Cronbach α was >.70 (Nunnally & Bernstein, 1994). The internal consistency index for the bliss dimension score was acceptable but could be explained by the moderate significant correlations between the scores for the 4 items in this dimension: even if we removed an item (e.g., the item “J’ai été entouré(e) et rempli(e) d’une chaleur ou d’une énergie de félicité,” loading significantly and strongly on the global NDA factor), there would be even fewer items to capture the shared variance, thus further reducing the dimension’s internal consistency. Furthermore, although all the items in the specific bliss dimension are related to interoceptive awareness (i.e., the ability to become aware of the body’s physiological state and the evaluative interpretations that flow from this; Mehling et al., 2012), this item seems more related to the aspect of “bodily listening” rather than to the interoceptive elements of emotional awareness as for the other items (“J’ai ressenti un sentiment de stupeur et d’émerveillement,”“J’ai fait l’expérience d’un amour englobant,” and “J’ai connu un état de paix total”). Indeed, for this item, the focus is more on the evaluation of pleasant bodily cues rather than the recognition and/or more general experience of specific bliss-related emotions. Thus, this item has access to both internal body sensations and external aspects of subjective experience as compared with the other items.

Regarding convergent validity, the NADA-T total score was significantly and positively correlated with scores for the four MEQ dimensions tested (mystical, unitive experience, positive mood, transcendence of space and time), thus confirming our initial hypotheses. In addition, scores for the two specific NADA-T dimensions (self-transcendence and bliss dimensions) were significantly and positively correlated with scores for the three of the four MEQ dimensions tested. These results indicate the convergent validity of our French NADA-T.

The results showed no significant association between the general anxiety score and the NADA-T total score, which agrees with the confirmation of the discriminant validity of our French scale. This assertion is further strengthened by the weak negative correlation between scores for the bliss dimension and general anxiety (and also a weak negative correlation between scores for the MEQ positive mood dimension and general anxiety). Scores for the self-transcendence dimension and general anxiety were very weakly but positively correlated: although very weakly associated, they do not assess the same concepts. This observation could be explained by self-transcendence playing a role in anxiety management by helping to harness the adaptive aspects of anxiety (i.e., in stressful situations, people with anxiety may adopt a self-transcending orientation by seeking to connect to something greater, such as others; Flotman, 2021). Nevertheless, this very weak positive association remains to be considered in future research.

We examined a possible association between involvement or not in a mindfulness meditation practice and NDA, as was done in the original study. NADA-T total, self-transcendence, and bliss scores were not higher for mindfulness meditation practitioners than non-practitioners, even when “levels of expertise” (i.e., how long they have been practicing) and frequency of practice were taken into account. These results could be explained by people not practicing mindfulness meditation reporting having NDA experiences (not knowing that it was the concept of NDA that we were evaluating in the study but rather modified consciousness experiences; see Survey design and completion) as a result of other NDA induction methods. These other induction methods include the use of psychedelics, which contributes to the deconstruction of the self-model (i.e., the perception of the self as a separate fixed being) and thus frees attention from the constraints of the ego to connect to wider contexts (Kähönen, 2023; Letheby, 2017, 2021). However, these results should be considered with caution, as the sample consisted mainly of students and it would be useful to take other variables into account, such as the duration of the practices.

Practical Implications

This validation study of the French version of the NADA-T provides a valuable tool for both researchers (i.e., to explore phenomena related to non-dual consciousness in various contexts in a more rigorous and systematic manner) and healthcare professionals (i.e., to evaluate the effects of modified states of consciousness in a therapeutic setting). Researchers can use this measurement tool in experiments involving modified states of consciousness induced by mindfulness meditation, psychedelics, or other methods. Healthcare professionals can use it in therapeutic protocols to accurately assess the psychological and emotional effects of these practices on patients’ mental health and psychological adjustment.

Limitations and Recommendations

This study has a number of limitations. First, it involved a retrospective survey because we asked participants about NDA experiences that had occurred in the past. As a result, they may not have remembered precisely what they perceived or felt at the time of the experience, even if they were able to say that it was different from what they usually experienced. However, given that access to this non-dual state of consciousness is not systematically achieved in practice, we recommend that future studies assess the confidence of the memory (e.g., “To what extent does your memory of this non-dual state of consciousness seem clear, rich, and precise to you?”) using a 10-point Likert-type visual analog scale.

Also, our sample was both predominantly female and students but also predominantly irregular mindfulness meditation practitioners, thereby preventing us from truly assessing whether mindfulness meditation practice is associated with the likelihood of experiencing NDA as compared with other methods (i.e., described above). As a result, future research should include a more heterogeneous sample in terms of sex and age and a more homogeneous sample in terms of practice. In addition, given that participants who responded to the online survey were recruited on a voluntary basis, no clear sampling method was used, which limits the representativeness of the sample. Furthermore, due to the anonymous and voluntary nature of the study, no data was collected on non-respondents’ refusal or withdrawal from participation, limiting the assessment of any possible non-response bias. At last, we recommend that future studies adopt the proposed modification to item 2 “J’ai vécu une expérience au cours de laquelle je me suis senti(e) absorbé(e) comme faisant un avec toute chose ” (originally, “J’ai vécu une expérience au cours de laquelle je me suis senti(e) absorbé(e) par toutes les choses”) and item 11 “Il m’a semblé qu'il n’y avait plus de distinction entre mon environnement et moi” (originally, “Il m’a semblé que mon environnement et moi ne faisions qu’un”), to further capture the concept of self-transcendence.

Conclusions

In conclusion, this study presents a preliminary French version of the NADA-T administered to a sample of French students who reported experiencing NDA after practicing mindfulness meditation or another induction method (i.e., occurring spontaneously, physically/physiologically induced, psychologically induced, pharmacologically or pathologically induced). Our French version demonstrated good validity and reliability and can be used as a two-dimensional measure of the NDA experience, confirming the factorial structure of the original English version of the NADA-T. However, we suggest modifying the wording of two of the items (i.e., item 2 and item 11) associated with the specific dimension of self-transcendence for future studies.

Supplemental Material

sj-docx-1-sgo-10.1177_21582440251403827 – Supplemental material for Validation of a French Version of the Nondual Awareness Dimensional Assessment-Trait

Supplemental material, sj-docx-1-sgo-10.1177_21582440251403827 for Validation of a French Version of the Nondual Awareness Dimensional Assessment-Trait by Andréa Oddos, Guy Gimenez and Stéphanie Khalfa in SAGE Open

Footnotes

Acknowledgements

We particularly like to thank Adam W. Hanley, Yoshio Nakamura, and Eric L. Garland who allowed us to translate and validate their scale in French. We are grateful for the two anonymous reviewers for their review of this first version of the manuscript. Also, we thank all the students for their participation.

ORCID iD

Andréa Oddos

Ethical Considerations

All materials were assessed and approved by the ethics committee of the University of Aix-Marseille (2023-06-15-004) and followed the principles of the Declaration of Helsinki. Data were collected anonymously. Participants were invited to give their informed consent on the survey introduction page, which presented information about the study and the consent form, then clicked on “next” to be directed to the questionnaire.

Author Contributions

AO, GG, and SK designed the study. AO implemented the questionnaire, collected the data, analyzed the data statistically, interpreted the results and wrote the report. GG and SK contributed to the critical revision of the interpretation of the results and the drafting of the work. All authors have approved the final version of this manuscript for publication and have agreed to be responsible for all aspects of the work, ensuring that issues relating to the accuracy or integrity of any part of the work are appropriately considered and resolved.

Funding

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: AO is funded by the Laboratoire de Psychologie Clinique, de Psychopathologie et de Psychanalyse, and the Centre de Recherche en Psychologie et Neurosciences of Aix-Marseille-Université, France.

Declaration of Conflicting Interests

The authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Data Availability Statement

Data sharing not applicable to this article as no datasets were generated or analyzed during the current study.

Supplemental Material

Supplemental material for this article is available online.

References

Barrett

F. S.

Johnson

M. W.

Griffiths

R. R.

(2015). Validation of the revised Mystical Experience Questionnaire in experimental sessions with psilocybin. Journal of Psychopharmacology, 29, 1182–1190. https://doi.org/10.1177/0269881115609019

Bentler

P. M.

(1990). Comparative fit indexes in structural models. Psychological Bulletin, 107(2), 238–246. https://doi.org/10.1037/0033-2909.107.2.238

Blackstone

(2015). Intersubjectivity and nonduality in the psychotherapeutic relationship. The Journal of Transpersonal Psychology, 38(1), 25–40.

Bornovalova

M. A.

Choate

A. M.

Fatimah

Petersen

K. J.

Wiernik

B. M.

(2020). Appropriate use of bifactor analysis in psychopathology research: Appreciating benefits and limitations. Biological Psychiatry, 88(1), 18–27. https://doi.org/10.1016/j.biopsych.2020.01.013

Bucke

R. M.

(1901). Cosmic consciousness: A study in the evolution of the human Mind.

Chen

F. F.

Hayes

Carver

C. S.

Laurenceau

Zhang

(2011). Modeling general and specific variance in multifaceted constructs: A comparison of the bifactor model to other approaches. Journal of Personality, 80(1), 219–251. https://doi.org/10.1111/j.1467-6494.2011.00739.x

Choi

S. H.

McClintock

C. H.

Lau

Miller

(2022). The impact of perceived relationship to ancestors on the association between self-transcendence and psychopathology: A cross-cultural examination. Transcultural Psychiatry, 62(4), 461–477. https://doi.org/10.1177/13634615211049072

Costello

A. B.

Osborne

J. W.

(2005). Exploratory Factor Analysis: Four recommendations for getting the most from your analysis. Practical Assessment, Research, and Evaluation, 10(7), 1–9.

Dambrun

(2016). When the dissolution of perceived body boundaries elicits happiness: The effect of selflessness induced by a body scan meditation. Consciousness and Cognition, 46, 89–98. https://doi.org/10.1016/j.concog.2016.09.013

10.

Dambrun

Ricard

(2012). La transcendance de soi et le bonheur: Une mise à l’épreuve du modèle du bonheur basé sur le soi centré-décentré. Les Cahiers Internationaux de Psychologie Sociale, 93(1), 89–102. https://doi.org/10.3917/cips.093.0089

11.

Deshmukh

V. D.

(2022). Consciousness, awareness, and presence. International Journal of Yoga, 15(2), 144–149. https://doi.org/10.4103/ijoy.ijoy_77_22

12.

Dorjee

(2016). Defining contemplative science: The metacognitive self-regulatory capacity of the mind, context of meditation practice and modes of existential awareness. Frontiers in Psychology, 7, 1788. https://doi.org/10.3389/fpsyg.2016.01788

13.

Dunne

J. D.

(2015). Buddhist styles of mindfulness: A heuristic approach. In: Ostafin

Robinson

Meier

(Eds.), Handbook of mindfulness and self-regulation. Springer.

14.

Flotman

(2021). Work as meaningful and menacing phenomenon for South African middle managers during the COVID-19 pandemic: The role of self-transcendence in cultivating meaning and wellbeing. Frontiers in Psychology, 12, 650060. https://doi.org/10.3389/fpsyg.2021.650060

15.

Forman

R. K. C.

(1998). Innate capacity. Oxford University Press.

16.

Gyamtso

K. T.

(1994). Progressive stages of meditation on emptiness. Longchen Foundation.

17.

Hanley

A. W.

Baker

A. K.

Garland

E. L.

(2017). Self-interest may Not be entirely in the interest of the self: Association between selflessness, dispositional mindfulness and psychological well-being. Personality and Individual Differences, 117, 166–171.

18.

Hanley

A. W.

Garland

E. L.

(2022). Self-transcendence predicts better pre- and postoperative outcomes in two randomized clinical trials of brief mindfulness-based interventions. Mindfulness, 13, 1532–1543. https://doi.org/10.1007/s12671-022-01896-6

19.

Hanley

A. W.

Nakamura

Garland

E. L.

(2018). The Nondual Awareness Dimensional Assessment (NADA): New tools to assess nondual traits and states of consciousness occurring within and beyond the context of meditation. Psychological Assessment, 30(12), 1625–1639. https://doi.org/10.1037/pas0000615

20.

Higgins

(2012). An Introduction to the Tibetan Dzogchen (Great Perfection) philosophy of mind. Religion Compass, 6(10), 441–450. https://doi.org/10.1111/rec3.12004

21.

Hood

(1975). The construction and preliminary validation of a measure of reported mystical experience. Journal for the Scientific Study of Religion, 14, 29–41. https://doi.org/10.2307/1384454

22.

James

(1985). The Varieties of Religious Experience. Harvard University Press (Original work published in 1902).

23.

Jones

(2022). Mindfulness and nondual well-being – What is the evidence that we can stay happy? Review of General Psychology, 27(2), 103–120. https://doi.org/10.1177/10892680221093013

24.

Josipovic

(2014). Neural correlates of nondual awareness in meditation. Annals of the New York Academy of Sciences, 1307(1), 9–18.

25.

Josipovic

(2019). Nondual awareness: Consciousness-as-such as non-representational reflexivity. Progress in Brain Research, 244, 273–298. https://doi.org/10.1016/bs.pbr.2018.10.021

26.

Josipovic

(2021). Implicit–explicit gradient of nondual awareness or consciousness as such. Neuroscience of Consciousness, 2021(2), niab031. https://doi.org/10.1093/nc/niab031

27.

Josipovic

Baars

B. J.

(2015). Editorial: What can Neuroscience Learn from Contemplative Practices? Frontiers In Psychology, 6, 1731. https://doi.org/10.3389/fpsyg.2015.01731

28.

Josipovic

Miskovic

(2020). Nondual awareness and minimal phenomenal experience. Frontiers in Psychology, 11, 2087. https://doi.org/10.3389/fpsyg.2020.02087

29.

Kähönen

(2023). Psychedelic unselfing: Self-transcendence and change of values in psychedelic experiences. Frontiers in Psychology, 14, 1104627. https://doi.org/10.3389/fpsyg.2023.1104627

30.

Kalupahana

D. J.

(1987). The principles of Buddhist psychology. http://ci.nii.ac.jp/ncid/BA1942943X

31.

Krägeloh

(2018). Phenomenological research fails to capture the experience of nondual awareness. Mindfulness, 10(2), 15–25. https://doi.org/10.1007/s12671-018-0995-z

32.

Letheby

(2017). Naturalizing psychedelic spirituality. Zygon, 523, 623–642.

33.

Letheby

(2021). Philosophy of psychedelics. Oxford University Press.

34.

Lynch

J. M.

Troy

A. S.

(2021). The role of nonduality in the relationship between flow states and well-being. Mindfulness, 12(7), 1639–1652. https://doi.org/10.1007/s12671-021-01627-3

35.

Markon

K. E.

(2019). Bifactor and hierarchical models: Specification, inference, and interpretation. Annual Review of Clinical Psychology, 15(1), 51–69. https://doi.org/10.1146/annurev-clinpsy-050718-095522

36.

MacLean

K. A.

Leoutsakos

J. M. S.

Johnson

M. W.

Griffiths

R. R.

(2012). Factor analysis of the mystical experience questionnaire: A study of experiences occasioned by the hallucinogen psilocybin. Journal for the Scientific Study of Religion, 51(4), 721–737. https://doi.org/10.1111/j.1468-5906.2012.01685.x

37.

Maydeu-Olivares

Fairchild

A. J.

Hall

A. G.

(2017). Goodness of fit in item factor analysis: Effect of the number of response alternatives. Structural Equation Modeling, 24, 495–505.

38.

Mehling

W. E.

Price

Daubenmier

J. J.

Acree

Bartmess

Stewart

(2012). The multidimensional assessment of interoceptive awareness (MAIA). PLoS ONE, 7(11), e48230. https://doi.org/10.1371/journal.pone.0048230

39.

Metzinger

(2018). A minimal phenomenal experience. MindRxiv Papers. https://doi.org/10.31231/osf.io/5wyg7

40.

Mills

P. J.

Barsotti

T. J.

Blackstone

Chopra

Josipovic

(2020). Nondual awareness and the whole person. Global Advances in Health and Medicine, 9, 2164956120914600. https://doi.org/10.1177/2164956120914600

41.

Morin

A. J. S.

Arens

A. K.

Marsh

H. W.

(2016). A bifactor exploratory structural equation modeling framework for the identification of distinct sources of construct-relevant psychometric multidimensionality. Structural Equation Modeling, 23(1), 116–139. https://doi.org/10.1080/10705511.2014.961800

42.

Nikhilananda

(1987). Atmabodha of Shankaracharya. Sri Ramakrishna Math.

43.

Nunnally

J. C.

(1967). Psychometric Theory. McGraw-Hill.

44.

Nunnally

J. C.

Bernstein

I. H.

(1994). The assessment of reliability. Psychometric Theory, 3, 248–292.

45.

Peña-Gayo

González-Chordá

V. M.

Cervera-Gasch

Á.

Mena-Tudela

(2018). Cross-cultural adaptation and validation of Pamela Reed’s Self-Transcendence Scale for the Spanish context. Revista Latino-Americana de Enfermagem, 26, e3058. https://doi.org/10.1590/1518-8345.2750.3058

46.

Peters

(2013). Theories of consciousness as reflexivity. The Philosophical Forum, 44(4), 341–372. https://doi.org/10.1111/phil.12018

47.

R Core Team. (2018). R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing.

48.

Rabjam

(2001). The precious treasury of the basic space of phenomena. https://openlibrary.org/books/OL12144666M/The_Precious_Treasury_of_the_Basic_Space_of_Phenomena

49.

Rabjam

(2007). The precious treasury of philosophical systems: A treatise elucidating the meaning of the entire range of spiritual approaches. https://www.amazon.com/Precious-Treasury-Philosophical-Systems-Elucidating/dp/1881847446

50.

Rudaz

Ledermann

May

R. W.

Fincham

F. D.

(2020). A brief scale to measure caring for bliss: Conceptualization, initial development, and validation. Mindfulness, 11, 615–626. https://doi.org/10.1007/s12671-019-01267-8

51.

Stace

W. T.

(1960). Mysticism and Philosophy. St. Martin’s Press.

52.

Steiger

J. H.

(1990). Structural model evaluation and modification: An interval estimation approach. Multivariate Behavioral Research, 25, 173–180.

53.

Spielberger

C. D.

(1989). State-Trait Anxiety Inventory: Bibliography (2nd ed.). Consulting Psychologists Press.

54.

Thomas

J. W.

Cohen

(2014). A methodological review of meditation research. Frontiers in Psychiatry, 5, 74. https://doi.org/10.3389/fpsyt.2014.00074

55.

Tucker

Lewis

(1973). A reliability coefficient for maximum likelihood factor analysis. Psychometrika, 38, 1–10. https://doi.org/10.1007/BF02291170

56.

Vaitl

Birbaumer

Gruzelier

Jamieson

G. A.

Kotchoubey

Kübler

Lehmann

Miltner

W. H. R.

Ott

Pütz

Sammer

Strauch

Strehl

Wackermann

Weiss

(2005). Psychobiology of Altered States of Consciousness. Psychological Bulletin, 131(1), 98–127. https://doi.org/10.1037/0033-2909.131.1.98

57.

Vallerand

R. J.

(1989). Vers une méthodologie de validation trans-culturelle de questionnaires psychologiques: Implications pour la recherche en langue française. Canadian Psychology, 30(4), 662–680. https://doi.org/10.1037/h0079856

58.

Wright

(2017). Why Buddhism is true: the science and philosophy of meditation and enlightenment. Simon & Schuster.

59.

Yaden

D. B.

Haidt

Hood

R. W.

Vago

D. R.

Newberg

A. B.

(2017). The varieties of self-transcendent experience. Review of General Psychology, 21(2), 143–160.

Supplementary Material

Please find the following supplemental material available below.

For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.

For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.

0.00 MB

0.02 MB