Zeroing In on Mindfulness Facets: Similarities, Validity, and Dimensionality across Three Independent Measures

Integrating mindfulness into the extended process model of emotion regulation: The dual-mode model of mindful emotion regulation

Extensive research has been conducted regarding how people manage their emotions. Within this research, there has been growing attention toward the role of mindfulness in emotion regulation. While prior reviews have discussed mindfulness in the context of emotion regulation, they have not provided a thorough integration using the prevailing models of emotion regulation or mindfulness. The present review discusses the Extended Process Model of Emotion Regulation and Monitoring and Acceptance Theory of mindfulness in order to propose a novel integrated framework, the Dual-mode Model of Mindful Emotion Regulation (D-MER). This model proposes two "modes" of mindfulness: Implementation and facilitation. Implementation posits that mindfulness skills can be used as emotion regulation strategies through attentional deployment and cognitive change. Facilitation posits that mindfulness as a state or trait affects emotion generation and regulation through effects on cognitive processes and positive or negative valence systems. Further, the D-MER posits that mindfulness experience can improve the efficiency of mindfulness-based emotion regulation strategies (implementation) while effects of mindfulness on emotion regulation processes become increasingly trait-like and automatic over time (facilitation). Empirical and theoretical support for this model are discussed, specific hypotheses to guide further research are provided, and clinical implications are presented. Use of this model may identify mechanisms underlying the interaction between mindfulness and emotion regulation which can be used in ongoing affective and clinical research. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Validation of a Tamil Version of the Five Facet Mindfulness Questionnaire Using Rasch Analysis

Background

Various assessment tools that explore and assess mindfulness are available. Keeping in view both the origin of and the literature surrounding mindfulness assessment tools, this study aimed to evaluate the workability of one widely researched tool, the Five Facet Mindfulness Questionnaire (FFMQ), for establishing cross-cultural generalizability and utility in the Indian context.

Methods

We recruited 303 adults over 18 with proficiency in the Tamil language and no history of significant neurological trauma and/or psychiatric history. They completed a version of the 39-item FFMQ, which we had translated into Tamil (FFMQ-T). The psychometric properties of this scale were tested using the Partial-Credit model of Rasch analysis.

Results

Iterative Rasch analysis could not resolve consistent misfit of the Observe facet items. Using a subtest approach, a higher-order fit of the FFMQ-T could be achieved after the deletion of additional items from each of the remaining four facets. The resulting final model for the FFMQ-T questionnaire was a four-factor solution with 22 items.

Conclusions

This study concluded the usability of the new 22-item FFMQ-T. These results are not dissimilar to the other versions in similar populations, such as the Hindi version of the FFMQ. The ordinal-to-interval conversion tables provided here ensure that the FFMQ-T can be used with enhanced precision and parametric statistics.

The influence of socio-cognitive mindfulness and resilience on middle managers' stress and thriving during COVID-19: results from two studies

Purpose

The purpose of this study was to examine the influence of socio-cognitive mindfulness on resilience, stress and thriving among middle managers in higher education at two separate periods during the COVID-19 pandemic. In Study 1, the authors examined how socio-cognitive mindfulness predicted perceived stress and whether the relationship between mindfulness and perceived stress was mediated by resilience. In Study 2, the authors replicated the first study and further hypothesized that the link between mindfulness and thriving was also mediated by resilience.

Design/methodology/approach

The authors conducted cross-sectional correlational studies to test the hypotheses using data from 163 middle managers in higher education early in the pandemic in Study 1 and 204 middle managers a year later in Study 2.

Findings

Study 1 findings showed socio-cognitive mindfulness predicted perceived stress, and that resilience fully mediated this relationship. In Study 2, socio-cognitive mindfulness did not predict perceived stress, but it did predict thriving, and that relationship was fully mediated by resilience.

Originality/value

This research is the first to address how socio-cognitive mindfulness directly impacts perceived stress and thriving and its impact through building resilience. To date, few studies have focused on stress in higher education middle managers or addressed the importance of building socio-cognitive mindfulness and resilience to thrive amid ongoing challenges. Implications of the pandemic's influence on the results are also addressed.

Are mindful people less aggressive? The role of emotion regulation in the relations between mindfulness and aggression

Inducing mindfulness has shown a promising effect on reducing aggression in both clinical and nonclinical populations, possibly because mindfulness can improve emotion regulation. The present study examined the association between mindfulness and aggression through potential mediating effects of several emotion regulation strategies. University and community samples of U.S. adults completed questionnaires on mindfulness, emotion regulation strategies, and trait aggression. Results indicate that mindfulness was associated with rumination and expressive suppression, which mediated the mindfulness-aggression relationship. Most facets of mindfulness were unrelated to the use of reflection and cognitive reappraisal. The nonjudging of experience facet of mindfulness was negatively related to hostility through rumination and expressive suppression. In contrast, the observing mindfulness facet was positively related to verbal aggression and hostility; these relations were mediated by rumination and expressive suppression.

A meta-analytic investigation of the impact of curiosity-enhancing interventions

Curiosity is associated with a number of beneficial outcomes, such as greater life satisfaction, more work engagement and better academic performance. The connection between curiosity and beneficial outcomes supports the importance of examining whether it is possible to increase curiosity and to investigate what approaches may be effective in facilitating curiosity. This meta-analysis consolidated the effects of curiosity-enhancing interventions. Across 41 randomized controlled trials, with a total of 4,496 participants, interventions significantly increased curiosity. The weighted effect size was Hedges' g = 0.57 [0.44, 0.70]. These results indicated that interventions were effective across a variety of intervention principles used, with participants in various age groups, across various measures, and over different time periods. Interventions aiming to increase general curiosity showed larger effect sizes than interventions aiming to increase realm-specific curiosity. Interventions incorporating mystery or game playing had especially high effect sizes. Because higher levels of curiosity tend to be associated with various beneficial outcomes, the finding that across studies interventions are effective in increasing curiosity holds promise for future efforts to increase curiosity to bring about additional benefits.

Exploring the Optimal Factor Structure of the Five Facet Mindfulness Questionnaire: Associations Between Mindfulness Facets and Dimensions of Psychopathology

Recent studies of the Five Facet Mindfulness Questionnaire (FFMQ) and its condensed version (FFMQ-SF) fail to replicate the initially proposed five-factor structure in clinical samples. Failure to adequately understand the dimensionality of common mindfulness measures within clinical samples, therefore, represents an important gap in the current literature. The increasing popularity of mindfulness-based interventions warrants further investigation of differential associations between facets of mindfulness and different forms of psychopathology. We examined (a) the underlying structure of the FFMQ and FFMQ-SF, and (b) associations between FFMQ and FFMQ-SF facets and dimensions of psychopathology (i.e., internalizing and substance use disorders) in two large clinical samples (N = 2,779). Results from bass-ackwards analyses suggested similarly defensible five- and six-factor model solutions in terms of fit. The five-factor model was optimal when factoring in parsimony. Exploratory structural equation modeling revealed that all FFMQ facets with the exception of observe were negatively associated with the internalizing factor. Associations with substance use disorders were more complex. In both samples, five-factor FFMQ and FFMQ-SF models were determined to best represent these data. Whereas deficits in all FFMQ facets with the exception of observe correspond with lower internalizing psychopathology, a more nuanced association was observed with substance use disorders.

What do people mean when they talk about mindfulness?

Psychological theories cast mindfulness as a form of awareness in which accepting the presence of stressful thoughts and feelings facilitates engaged exploration and identification of adaptive responses. Critics of mindfulness' popularization suggest that lay people misconstrue acceptance as a passive endorsement of experience, undermining engaged problem-solving. To evaluate this criticism, we traced the contemporary semantic meaning of mindfulness in three of the most extensive linguistic corpora of English language and found that general public's depictions of mindfulness highlight engagement-related processes. We further analyzed the nomological network of mindfulness. While mindfulness theories suggest a general convergence of facets representing awareness and acceptance, in a meta-analysis (k = 145; N = 41,966) of the Five Facet Mindfulness Questionnaire only expert- and clinical samples reported convergence, whereas lay people showed absent or even antagonistic associations. Further, contrary to the synergistic model of awareness and acceptance contributing to greater engagement, empirical probes of two lay samples (N_total = 406) show that acceptance is either unrelated or inversely related to markers of engagement. To overcome resulting conceptual and methodological challenges, we highlight the need for a contextualized mindfulness framework whereby acceptance enables the process of engaging with life's challenges rather than avoiding them.

Initial Validation of the Mindful Presence Scale: The Issue of the Construal Level of Scale Items

Our research has two main aims. It undertakes the validation of a six-item trait mindfulness scale called Mindful Presence Scale (MPS), which measures central aspects of mindfulness. For the first time in mindfulness literature, the construal level of scale items is also examined. Four questionnaire-based online studies were conducted. Study 1 drew three samples (n n = 391, n p = 215, and n b = 235) from the students at the University of Debrecen. It examined the factor structure, reliability, and internal consistency of the three differently worded scale versions. The positively worded scale version (MPSp) yielded a stable two-factor structure and demonstrated the best psychometric properties. Study 2 performed a confirmatory factor analysis on a sample drawn from public employees across the country (n cfa = 420). The two-factor solution in Study 1 was confirmed. χ2 tests were not significant, and fit indices were excellent. There was no significant difference between the high-level construal subscale (Fhlc) and the low-level construal subscale (Fllc) in terms of factorial stability. Participant of Study 3 were students who did not take part in Study 1. The sample (n inv = 250) was tested for measurement invariance across gender. The scaled results supported strong/threshold invariance. Study 4 tested concurrent validity with 10 concurrent instruments. A sample of secondary school teachers (n con = 128) was tested by examining Spearman's rank order correlations. There was a significant difference in how the Fhlc and Fllc subscales predicted scores of some of the concurrent instruments. Further research is warranted into how the construal level of mindfulness scale items affects the recollection of the mindful experience. Overall, MPSp proved to be a valid short mindfulness measure.

Decentering, Acceptance, and Non-Attachment: Challenging the Question "Is It Me?"

Among mindfulness measures the three constructs acceptance, decentering, and non-attachment are psychometrically closely related, despite their apparent semantic differences. These three facets present robust psychometric features and can be considered core themes in most "third wave" clinical models. The aim of the present study was to explore the apparently different content domains (acceptance, decentering, and non-attachment) by administering various psychometric scales in a large sample of 608 volunteers. Resilience and depression were also assessed. Exploratory and confirmatory factor analyses performed in two randomly selected subsamples showed a bifactor approximation. The explained common variance suggested a unidimensional nature for the general factor, with good psychometric properties, which we named "Delusion of Me" (DoM). This construct is also strongly correlated with resilience and depression, and appears to be a solid latent general construct closely related to the concept of "ego." DoM emerges as a potentially transdiagnostic construct with influence on well-being and clinical indexes such as resilience and depression. Further studies should analyze the potential utility of this new construct at a therapeutic level.

Self-critical perfectionism and lower mindfulness and self-compassion predict anxious and depressive symptoms over two years

This study of 124 community adults examined whether perfectionism interacts with mindfulness and self-compassion to predict anxiety and depressive symptoms over two years. Participants completed measures of self-critical (SC) and personal standards (PS) higher-order dimensions of perfectionism at Time 1; mindfulness and self-compassion domains and facets at Time 2 one year later; and general distress (i.e., shared between depression and anxiety), anxious arousal, and anhedonic depressive symptoms at Time 1, Time 2, and Time 3 two years after baseline. In contrast to PS, SC perfectionism was associated with lower mindfulness and self-compassion domains and facets. Hierarchical regression analyses of moderator effects demonstrated that individuals with higher Time 1 SC perfectionism and lower Time 2 domain mindfulness or self-compassion had higher Time 3 general distress symptoms than others, adjusting for the effects of Time 1 and Time 2 symptoms. SC perfectionism also interacted with specific facets of mindfulness (i.e., observing, nonreactivity) and self-compassion (i.e., self-kindness, mindfulness, over-identification) to predict Time 3 general distress and/or anxious arousal symptoms. These findings highlight the importance of fostering mindfulness and self-compassion to reduce vulnerability to anxious and depressive symptoms in individuals with higher SC perfectionism.

Network Analysis of Mindfulness Facets, Affect, Compassion, and Distress

Objectives

Mindfulness, positive affect, and compassion may protect against psychological distress but there is lack of understanding about the ways in which these factors are linked to mental health. Network analysis is a statistical method used to investigate complex associations among constructs in a single network and is particularly suitable for this purpose. The aim of this study was to explore how mindfulness facets, affect, and compassion were linked to psychological distress using network analysis.

Methods

The sample (n = 400) included equal numbers from general and student populations who completed measures of five mindfulness facets, compassion, positive and negative affect, depression, anxiety, and stress. Network analysis was used to explore the direct associations between these variables.

Results

Compassion was directly related to positive affect, which in turn was strongly and inversely related to depression and positively related to the observing and describing facets of mindfulness. The non-judgment facet of mindfulness was strongly and inversely related to negative affect, anxiety, and depression, while non-reactivity and acting with awareness were inversely associated with stress and anxiety, respectively. Strong associations were found between all distress variables.

Conclusions

The present network analysis highlights the strong link between compassion and positive affect and suggests that observing and describing the world through the lens of compassion may enhance resilience to depression. Taking a non-judging and non-reacting stance toward internal experience while acting with awareness may protect against psychological distress. Applicability of these findings can be examined in experimental studies aiming to prevent distress and enhance psychological well-being.

Testing the Intermediary Role of Perceived Stress in the Relationship between Mindfulness and Burnout Subtypes in a Large Sample of Spanish University Students

The burnout syndrome is the consequence of chronic stress that overwhelms an individual’s resources to cope with occupational or academic demands. Frenetic, under-challenged, and worn-out are different burnout subtypes. Mindfulness has been recognized to reduce stress, comprising five facets (observing, describing, acting with awareness, non-judging of inner experience, and non-reactivity to inner experience). This cross-sectional study aimed to assess the relationship between mindfulness facets, perceived stress, and burnout subtypes in a sample of 1233 students of Education, Nursing, and Psychology degrees from different universities of Valencia (Spain). Structural Equation Modelling (SEM) was computed showing an adequate fit (Chi-square, CFI, TLI, RMSEA, and SRMR). Four mindfulness facets (all but observing) significantly correlated with general second-order mindfulness. Unexpected results were found: Acting with awareness facet was positively associated with frenetic subtype, while the non-reacting facet was positively associated with frenetic and under-challenged subtype. Ultimately, mindfulness facets negatively predicted the perceived stress levels, which in turn, predicted burnout. However, mindfulness plays different roles in the early stages of burnout syndrome (i.e., frenetic and under-challenged).

Mindful Eating, General Mindful Awareness, and Acceptance as Predictors of Weight Loss

Objectives

The goal of the present study was to determine whether baseline mindful eating, general mindful awareness, or acceptance was most strongly associated with short- and long-term weight loss in a lifestyle modification program.

Methods

Data were from 178 participants (baseline BMI=40.9±5.9 kg/m², age=44.2±11.2 years; 87.6% female; 71.3% black) who enrolled in a two-phase trial. All participants attended an initial 14-week lifestyle modification program that included a meal replacement diet. Participants who had lost ≥5% of initial weight (N=137) were then randomized to 52 weeks of lifestyle modification with lorcaserin or placebo. Linear mixed models examined whether mindful eating (Mindful Eating Questionnaire) and general mindful awareness and acceptance (Philadelphia Mindfulness Scale) predicted short-term weight loss at week 14 in the full sample and long-term weight loss at the end of the trial in the subsample of randomized participants.

Results

In the full sample, higher baseline acceptance predicted greater short-term weight losses (p=.004). At week 14, individuals low in acceptance (-1SD) lost an average of 8.7 kg (SE=0.6) compared to 11.2 kg (SE=0.6) among those high in acceptance (+1SD). In the subsample of participants who successfully lost weight in phase 1, the independent effect of acceptance on total losses at the end of the trial did not reach statistical significance (p=.058). Neither mindful eating nor general mindful awareness independently predicted weight loss at either time point.

Conclusions

Acceptance was a stronger predictor than either general or eating-specific awareness of weight loss with lifestyle modification.

Validation of the Philadelphia Mindfulness Scale on experienced meditators and nonmeditators

OBJECTIVE

The Philadelphia Mindfulness Scale's (PHLMS) psychometric properties, theoretical assumptions, convergent validity, and relationships to symptom, happiness and social desirability measures were investigated in novel samples.

METHODS

Internet-recruited general public samples of experienced meditators (n = 67, 21 male, 46 female, average age 50) and nonmeditators (n = 61, 28 male, 32 female, and 1 transgender; average age 41.9) were used.

RESULTS

Meditators scored higher than nonmeditators on both PHLMS Acceptance, t(126) = 2.77, p < .01, d = 0.49, and Awareness t(126) = 4.18, p < .01, d = 0.74. Higher PHLMS Acceptance subscale scores were associated with decreased scores on all symptom measures in nonmeditators, but only in select measures among meditators. Generally, PHLMS Awareness subscale scores were not related to symptoms. Awareness interacted with meditator status on outcome measures.

CONCLUSIONS

PHLMS may be used in the general public and experienced meditator populations. Mindfulness facets become intercorrelated in experienced meditators.

The relationship between trait mindfulness and affective symptoms: A meta-analysis of the Five Facet Mindfulness Questionnaire (FFMQ)

Trait mindfulness appears to be related to lower levels of negative affective symptoms, but it remains uncertain which facets of mindfulness are most important in this relationship. Accordingly, the present meta-analysis examined studies reporting correlations between affective symptoms and trait mindfulness as assessed by the Five Facet Mindfulness Questionnaire. A comprehensive search yielded 148 eligible studies, comprising 157 distinct samples and 44,075 participants. The weighted mean correlation for affective symptoms and overall trait mindfulness was r = -0.53. Among mindfulness facets, Nonjudge (r = -0.48) and Act with Awareness (r = -0.47) demonstrated the largest correlations, followed by Nonreact (r = -0.33) and Describe (r = -0.29). Observe was not significantly correlated with affective symptoms. No significant differences in the strength of correlations were found between anxiety, depression and posttraumatic stress disorder (PTSD) symptoms, though symptoms of generalized anxiety disorder exhibited a weaker negative relationship with the Describe facet compared to PTSD symptoms. Describe also showed a stronger relationship with affective symptoms in Eastern samples compared to Western samples, whereas Western samples had a stronger relationship with Nonjudge. These results provide insight into the nature of the association between trait mindfulness and negative affect.

Less Binge Eating and Loss of Control over Eating Are Associated with Greater Levels of Mindfulness: Identifying Patterns in Postmenopausal Women with Obesity

Obesity is a public health concern resulting in widespread personal, social, and economic burden. Many individuals with obesity report feeling unable to stop eating or to control their food intake (i.e., a loss of control over eating) despite their best efforts. Experiencing loss of control over eating predicts further eating pathology and is a key feature of binge eating. Mindfulness (i.e., awareness and acceptance of current thoughts, feelings, sensations, and surrounding events) has emerged as a potential strategy to treat such eating disorder behaviors, but it is not known whether there is merit in investigating this strategy to address binge eating in postmenopausal women with obesity. Thus, this study aimed to examine the relationships between binge eating and mindfulness in postmenopausal women with obesity seeking weight loss treatment. Participants (n = 101) were assessed with the Eating Disorder Examination Questionnaire, the Loss of Control over Eating Scale, the Five-Facet Mindfulness Questionnaire, and the Langer Mindfulness Scale. Participants´ overall scores on both mindfulness scales were significantly and negatively correlated with binge eating frequency or the severity of loss of control over eating. Moreover, participants who reported fewer binge eating episodes were significantly more mindful than those who reported greater frequencies of binge eating episodes within the past 28 days. These findings suggest a merit in investigating the use of mindfulness-based therapies to treat binge eating in postmenopausal women with obesity.

Does mindfulness training modulate the influence of spatial attention on the processing of intracutaneous electrical stimuli?

Mindfulness based stress reduction (MBSR) training has been proposed to improve attentional skills by modulating thalamo-cortical loops that affect the sensitivity of relevant cortical areas like the somatosensory cortex. This modulation may be reflected in the electroencephalographic (EEG) alpha rhythm, and could affect the processing of subsequently applied intracutaneous electrical stimuli. Participants took part in an MBSR training and participated in two EEG sessions. EEG was measured in variants of an endogenous orienting paradigm in which attention had to be directed to the left or right forearm. After the orienting interval, the electrical stimulus was applied, equally likely on the attended or the unattended forearm. One group of participants took part in the EEG session before and after the training, while the other group took part after the training, and another time, eight weeks later. The influence of the MBSR training and spatial attention were examined with behavioral measures, lateralized alpha power within the orienting interval, and with event-related potentials (ERPs) evoked by the electrical stimuli. Self-reported mindfulness was clearly affected by the training, but no influence was found on other behavioral measures. Alpha power was clearly lateralized due to spatial attention and several ERP components (N130, N180, P340) were modulated by spatial attention but no support was found for an influence of the MBSR training. Finally, analyses revealed that individual differences in training time modulated some of the observed effects, but no support was found for an influence on attentional orienting.

Thought-Action Fusion in Individuals with a History of Recurrent Depression and Suicidal Depression: Findings from a Community Sample

Although suicidal ideation is one of the most consistent symptoms across recurrent episodes of depression, the mechanisms underpinning its maintenance are poorly understood. In order to develop effective treatments for suicidally depressed patients, understanding what maintains suicidal distress is critical. We hypothesised that Thought–Action Fusion (TAF), i.e., to assume that having a thought has real world consequences, originally described in Obsessive–Compulsive Disorder, might be a bias in recurrently suicidally depressed people. To assess this, we revised the original TAF scale, and assessed TAF in three samples: healthy controls, recurrently depressed individuals with no history of suicidality (D-NS) and individuals with a history of recurrent suicidal depression (D-S). Exploratory and confirmatory factor analyses indicated a three-factor solution of TAF: (1) TAF for uncontrollable events, (2) self-suicidal TAF for suicidal acts related to oneself, and (3) TAF for positive controllable events. Compared to healthy controls, the D-NS group reported significantly higher total TAF, TAF uncontrollable, and TAF self-suicidal subscales, whilst positive controllable TAF was lower compared to healthy controls. Both D-S and D-NS samples reported higher TAF for suicidal thought compared to healthy controls, i.e., believing that having suicidal thoughts means they will act on them, however in the context of low mood this became more pronounced for the D-S group. These findings suggest that targeting TAF both in suicidal and non-suicidal depression has merit.

The mindful personality: A meta-analysis from a cybernetic perspective

Dispositional mindfulness (DM), or the tendency to attend to present moment experience, may have important implications for the structure of human personality. However, relationships between DM and the Big Five Model of Personality (BF) have not been definitively established. Therefore, the purpose of this meta-analysis was to extend previous investigations of the relationship between DM and the BF, utilizing a larger sample of studies, attending to relational inconsistencies potentially associated with alternative methods of operationalizing DM, conducting the first meta-analysis of the DM subdomains in relation to the BF, and situating the results in a cybernetic model. Results indicate that neuroticism evidenced the strongest, negative relationship with DM and conscientiousness evidenced the strongest, positive relationship with DM, suggesting the mindful personality may be characterized principally by emotional stability and conscientious self-regulation - potentially reflective of an inclination towards the personality metatrait stability. Measurement differences were also observed, with the mindful personality arrived at through the FFMQ differing to some extent from the mindful personality emerging from the MAAS. Broadly, the mindful personality associated with the FFMQ appears to reflect greater personality complexity, with the FFMQ evidencing associations with all five personality factors while the MAAS appears primarily linked with only three personality factors (Neuroticism, Conscientiousness and Agreeableness). Examination of the relationships between the BF and DM at the facet level also suggest unique patterns of association between the DM facets and each of the personality factors.

Dispositional Mindfulness and Psychological Health: a Systematic Review

Interest in the influence of dispositional mindfulness (DM) on psychological health has been gathering pace over recent years. Despite this, a systematic review of this topic has not been conducted. A systematic review can benefit the field by identifying the terminology and measures used by researchers and by highlighting methodological weaknesses and empirical gaps. We systematically reviewed non-interventional, quantitative papers on DM and psychological health in non-clinical samples published in English up to June 2016, following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. A literature search was conducted using PsycINFO, PubMED, Medline and Embase, and 93 papers met the inclusion criteria. Within these, three main themes emerged, depicting the relationship between DM and psychological health: (1) DM appears to be inversely related to psychopathological symptoms such as depressive symptoms, (2) DM is positively linked to adaptive cognitive processes such as less rumination and pain catastrophizing and (3) DM appears to be associated with better emotional processing and regulation. These themes informed the creation of a taxonomy. We conclude that research has consistently shown a positive relationship between DM and psychological health. Suggestions for future research and conceptual and methodological limitations within the field are discussed.