Abstract: A complete and practical guide offering a concise overview of mentalization-based treatment (MBT) and its application in different situations and with different groups of patients to help improve the treatment of mental health disorders. Featuring an introduction to mentalizing and the evidence base to support it, followed by the principles of MBT and the basic clinical model in individual and group psychotherapy. Other chapters offer extensive clinical illustrations of the treatment of patients with depression, psychosis, trauma, eating disorders, and borderline, antisocial, narcissistic, and avoidant personality disorders. The final section outlines the application of mentalizing and MBT in different populations – children, adolescents, families, couples – and their use in different contexts – teams, schools, and care settings. Part of the Cambridge Guides to the Psychological Therapies series, offering all the latest scientifically rigorous and practical information on a range of key, evidence-based psychological interventions for clinicians.

Abstract: This article reviews the current status of research on the relationship between attachment and trauma in developmental psychopathology. Beginning with a review of the major issues and the state-of-the-art in relation to current thinking in the field of attachment about the impact of trauma and the inter-generational transmission of trauma, the review then considers recent neurobiological work on mentalizing and trauma and suggests areas of new development and implications for clinical practice.

Abstract: Background Inpatient psychosomatic rehabilitation is a key treatment for patients with mental health issues. However, knowledge about critical success factors for beneficial treatment outcomes is scarce. The aim of this study was to evaluate the association of mentalizing and epistemic trust with the improvement of psychological distress during rehabilitation. Methods In this naturalistic longitudinal observational study, patients completed routine assessments of psychological distress (BSI), health-related quality of life (HRQOL; WHODAS), mentalizing (MZQ), and epistemic trust (ETMCQ) before (T1) and after (T2) psychosomatic rehabilitation. Repeated measures ANOVA (rANOVAs) and structural equation models (SEMs) were calculated to investigate the association of mentalizing and epistemic trust with the improvement in psychological distress. Results A total sample of n = 249 patients were included in the study. Improvement in mentalizing was correlated with improvement in depression (r = 0.36), anxiety (r = 0.46), and somatization (r = 0.23), as well as improved cognition (r = 0.36), social functioning (r = 0.33), and social participation (r = 0.48; all p < 0.001). Mentalizing partially mediated changes in psychological distress between T1 and T2: the direct association decreased from β = 0.69 to β = 0.57 and the explained variance increased from 47 to 61%. Decreases in epistemic mistrust (β = 0.42, 0.18–0.28; p < 0.001) and epistemic credulity (β = 0.19, 0.29–0.38; p < 0.001) and increases in epistemic trust (β = 0.42, 0.18–0.28; p < 0.001) significantly predicted improved mentalizing. A good model fit was found (χ2 = 3.248, p = 0.66; CFI = 0.99; TLI = 0.99; RMSEA = 0.000). Conclusion Mentalizing was identified as a critical success factor in psychosomatic inpatient rehabilitation. A key component to increase mentalizing in this treatment context is the improvement of epistemic mistrust.

Abstract: In middle childhood, the first manifestations of mental health problems can emerge and become a precursor of mental health issues in adolescence. Given that weak parent-child attachment can contribute to this distress, it is possible that strengthening the attachment bond could reduce risk trajectory. Unfortunately, evidence-based attachment-focused interventions are lacking at this age. Attachment-based family therapy (ABFT) is a well-studied intervention for troubled adolescents and has the potential to be extended downward to children. However, ABFT for adolescents focuses on mentalization and trauma conversation strategies that may be developmentally advanced for children's capacities. Therefore, we modified the intervention strategies to be more developmentally sensitive to childhood. Middle childhood ABFT (MCABFT) builds on the theory that insecure attachment develops through a learning process that can be interrupted and reorganized to promote secure attachment development. MCABFT uses less conversation and more play and puts parents more at the center of the therapy compared with ABFT for adolescents. In this article, we describe MCABFT's theoretical and clinical model.

Abstract: Background Mentalizing and psychological mindedness are two key, partially overlapping facets of social cognition. While mentalizing refers to the ability to reflect on one’s own mental states and the mental states of others, psychological mindedness describes the ability for self-reflection and the inclination to communicate with others about one’s own mental states. Purpose This study examined the development of mentalizing and psychological mindedness throughout adolescence and into young adulthood, and the interplay between the two with gender and the Big Five Personality Traits. Methods 432 adolescents and young adults (ages 14–30) were recruited from two independent schools and two universities. Participants completed a set of self-report measures. Results A curvilinear trend in both mentalizing and psychological mindedness indicated a gradual development of these capacities with age, peaking in young adulthood. Across all age groups, females had consistently higher mentalizing scores than males. For females, scores only changed significantly between age bands 17–18 to 20+ (p<0.001), ES (d = 1.07, 95% CI [.1.52–.62]). However, for males, a significant change in scores appeared between two age bands of 14 to 15–16 (p<0.003), ES (d = .45, 95% CI [.82–.07]), and 17–18 to 20+ (p<0.001), ES (d = .6, 95% CI [.1.08–.1]). The change in psychological mindedness scores differed, and females did not have consistently higher scores than males. Females’ scores were only significantly higher for ages 14 (p<0.01), ES (d = .43, 95% CI [.82–.04]), and 15–16 (p<0.01), ES (d = .5, 95% CI [.87–.11]). As with the development of mentalizing abilities, female scores in psychological mindedness remained stable from 14 to 18 years of age, with a significant change between age bands 17–18 and 20+ (p<0.01), ES (d = 1.2, 95% CI [1.7–.67]). Contrastingly, for males significant change occurred between 15–16, 17–18 (p<0.01), ES (d = .65, 95% CI [1.1–.18]) and 20+ (p<0.01), ES (d = .84, 95% CI [1.5–.2]). A significant positive association was found between mentalizing and psychological mindedness and the personality traits of Agreeableness, Openness to Experience and Conscientiousness (p<0.0001). Psychological mindedness had a weaker positive correlation with Extraversion and Openness to Experience (p<0.05). Conclusions The discussion is focused on the interpretation of the findings in light of social cognition and brain development research.

Abstract: Abstract The neurocognitive bases of social cognition have been framed in terms of representing others’ actions through the mirror system and their mental states via the mentalizing network. Alongside representing another person’s actions or mental states, however, social cognitive processing is also shaped by their (mis)match with one’s own corresponding states. Here, we addressed the distinction between representing others’ states through the action observation or mentalizing networks (i.e. representational processing) and detecting the extent to which such states align with one’s own ones (i.e. relational processing, mediated by social conflict). We took a meta-analytic approach to unveil the neural bases of both relational and representational processing by focusing on previously reported brain activations from functional magnetic resonance imaging studies using false-belief and action observation tasks. Our findings suggest that relational processing for belief and action states involves, respectively, the left and right temporo-parietal junction, likely contributing to self-other differentiation. Moreover, distinct sectors of the posterior fronto-medial cortex support social conflict processing for belief and action, possibly through the inhibition of conflictual representations. These data might pave the way for further studies addressing social conflict as an important component of normal and pathological processing, and inform the design of rehabilitative treatments for social deficits.

Abstract: Abstract Over the past twenty years research interest has been focused on deepening the role of parental mentalizing. Nevertheless, few studies have specifically addressed the role played by fathers’ mentalizing. This systematic review aims to bridge this gap by offering an exploration of paternal mentalizing within attachment theory considering three different operationalizations: Reflective Functioning, Parental Insightfulness and Mind-Mindedness. Starting from this, the main goals of this systematic review are: (1) to show the effect of paternal mentalizing on child’s outcomes or paternal role within the family system, (2) to increase research exchange between different theoretical frameworks, enhancing the knowledge of the mentalization construct, (3) to explore under-researched areas and implications for research and clinical practice. PsycInfo, PsycArticle, Web Of Science, Scopus, Medline, PubMed and EMBASE were systematically searched for articles published until February 7, 2021. In total, 6311 studies were considered for the systematic review; of these, thirty-six met the inclusion criteria. The included studies were subsequently split on the basis of the specific mentalizing operationalization. Overall, the data showed significant associations between paternal mentalizing and both fathers’ parenting features and variables related to the paternal broader functioning within the family context. This systematic review also confirms the role of fathers’ mentalizing processes in relation to paternal features and child’s outcomes. In conclusion, further studies aimed at examining paternal mentalizing specific influences, exploring the causal pathways related to paternal mentalizing and investigating the relationship between different mentalizing dimensions and their diverse effects are recommended.

Abstract: Attachment-based interventions are important for improving parent-child outcomes. These interventions must be scaled and made available to under-resourced communities. An important part of scaling these interventions is delineating and reproducing high-quality training, including clinical training which often requires the completion of a supervised case. However, descriptions and guidelines for clinical training are frequently broad or not available in the literature. A detailed description of clinical training could lead to further research to improve the effectiveness and dissemination of evidence-based interventions. Mothering from the Inside Out (MIO) is an attachment-based parenting intervention effective at reducing substance use and depression, improving caregiving, and enhancing child attachment. It is now being brought from research to community settings. This paper outlines the didactic and clinical training components of MIO. We then present a qualitative case study of one community-based counselor participating in the clinical training of MIO and employ qualitative methods to describe the main themes that arose during the training. We aim to illustrate how the trainer assisted the counselor in implementing the core components of MIO, which included (a) refining the language used in MIO sessions, (b) making space to explore mental states, and (c) addressing trauma. We conclude by presenting the implications of these findings.

Abstract: Introduction Mentalization or reflective functioning (RF) is the capacity to interpret oneself or the others in terms of internal mental states. Its failures have been linked to several mental disorders and interventions improving RF have a therapeutic effect. Mentalizing capacity of the parents influences the children’s attachment. The Reflective Functioning Questionnaire (RFQ-8) is a widely used tool for the assessment of RF. No instrument is available to assess general RF in Spanish-speaking samples. The aim of this study is to develop a Spanish version of the RFQ-8 and to evaluate its reliability and validity in the general population and in individuals with personality disorders. Methods 602 non-clinical and 41 personality disordered participants completed a Spanish translation of the RFQ and a battery of self-reported questionnaires assessing several RF related constructs (alexithymia, perspective taking, identity diffusion and mindfulness), psychopathology (general and specific) and interpersonal problems. Temporal stability was tested in a non-clinical sub-sample of 113 participants. Results Exploratory and confirmatory factor analyses suggested a one-factor structure in the Spanish version of the RFQ-8. RFQ-8 understood as a single scale was tested, with low scorings reflecting genuine mentalizing, and high scorings uncertainty. The questionnaire showed good internal consistence in both samples and moderate temporal stability in non-clinical sample. RFQ correlated significantly with identity diffusion, alexithymia, and general psychopathology in both samples; and with mindfulness, perspective taking, and interpersonal problems in clinical sample. Mean values of the scale were significantly higher in the clinical group. Discussion This study provides evidence that the Spanish version of the RFQ-8, understood as a single scale, has an adequate reliability and validity assessing failures in reflective functioning (i.e., hypomentalization) in general population and personality disorders.

Abstract: Mothering from the Inside Out (MIO) is a mentalization-based parenting intervention developed to address challenges common among mothers experiencing substance use disorders (SUDs) and previously deemed effective when delivered by research clinicians. This randomized clinical trial was designed to test the efficacy of MIO when delivered by community-based addiction counselors in Connecticut, USA. Ninety-four mothers [M(SD)age = 31.01(4.01) years; 75.53% White] caring for a child 11-60 months of age were randomly assigned to participate in 12 sessions of either MIO or psychoeducation. Caregiving, psychiatric, and substance use outcomes were assessed repeatedly from baseline through 12-week follow-up. Mothers who participated in MIO showed decreased certainty about their child's mental states, and decreased depression; their children demonstrated increased clarity of cues. Participation in MIO was not associated with the same degree of improvement that was observed in prior trials where MIO was delivered by research clinicians. However, when delivered by community-based clinicians, MIO may be protective against a deterioration in caregiving over time often seen in mothers with addictions. The drop in efficacy of MIO in this trial raises questions about intervention-intervenor fit. Research should examine factors influencing MIO effectiveness to close the science-to-service gap common in the dissemination of empirically validated interventions.

Abstract: Autism has been previously linked to differences in social cognition and sensory processing (Simmons et al, 2009). A classical measure of low-level social cognition is the Frith-Happé animations task which measures perceived animacy and “mentalizing” ability (mentalizing is the attribution of thoughts and feelings to others) (Abel et al., 2000). We have adapted this classic psychological paradigm to Virtual Reality (VR) and evaluated its feasibility. 3D versions of the Frith-Happé animations were constructed using the software package Unity. The animations had the appearance of solid triangles of different sizes moving on a ground plane. Participants viewed these animations in our VR lab wearing a standard Head-Mounted Display. White et al.’s (2011) multiple choice scoring system was used to categorize animations based on the perceived interaction of 3D geometrical shapes. Questionnaires were used to assess autistic traits of the 33 participants (aged 18-45). Participants’ verbal feedback indicated that the increased level of immersion available in VR helped them appreciate the animacy more. Immersive VR has thus been found to be an appropriate tool for investigating animacy and mentalizing ability.

Abstract: Children in foster care are psychologically vulnerable and show more social, developmental, and behavioral problems than those living with their family of origin. Many foster parents struggle to care for these children, some of whom have experienced severe adversity. Research and theory suggest that developing a strong and supportive foster parent-child relationship is essential for foster children to become more well-adjusted and experience a decrease in behavioral problems and emotional maladjustment. Mentalization-based therapy (MBT) for foster families aims at increasing the reflective functioning of the foster parents, thus promoting the development of more secure and less disorganized child attachment representations, which is subsequently proposed as a factor that reduces behavioral problems and emotional maladjustment in children and promotes their overall well-being.This is a prospective cluster-randomized controlled trial with two conditions: (1) the intervention group participating in MBT, and (2) the control group who receive usual care. Participants are 175 foster families with at least one foster child aged 4-17 years with emotional or behavioral problems. The intervention will be offered to foster families by 46 foster care consultants from 10 municipalities in Denmark. The foster care consultants will be randomized to MBT training (n = 23) or usual care (n = 23). The primary outcome is the psychosocial adjustment of the foster child measured by the Child Behavior Checklist (CBCL) as reported by foster parents. Secondary outcomes include child well-being, parental stress, parent mental health, parent reflective function and mind-mindedness, parent/child relations, child attachment representations, and placement breakdown. In order to explore implementation fidelity as well as practitioner experiences, we will administer questionnaires designed for this study and conduct qualitative research exploring the practice of the MBT therapists.This trial is the first experimental study of a family therapeutic intervention based on attachment theory for foster families within the Scandinavian context. This project will contribute with novel knowledge on attachment representations in foster children and the effects of an attachment-based intervention on essential outcomes for foster families and children. Trial registration ClinicalTrials.gov NCT05196724. Registered on January 19, 2022.

Abstract: Abstract Prior studies in Social Neuroeconomics have consistently reported activation in social cognition regions during interactive economic games, suggesting mentalizing during economic choice. Such mentalizing occurs during active participation in the game, as well as during passive observation of others’ interactions. We designed a novel version of the classic false-belief task (FBT) in which participants read vignettes about interactions between agents in the ultimatum and trust games and were subsequently asked to infer the agents’ beliefs. We compared activation patterns during the economic games FBT to those during the classic FBT using conjunction analyses. We find significant overlap in the left temporoparietal junction (TPJ) and dorsal medial prefrontal cortex, as well as the temporal pole (TP) during two task phases: belief formation and belief inference. Moreover, generalized Psychophysiological Interaction (gPPI) analyses show that during belief formation, the right TPJ is a target of both the left TPJ and the right TP seed regions, whereas during belief inferences all seed regions show interconnectivity with each other. These results indicate that across different task types and phases, mentalizing is associated with activation and connectivity across central nodes of the social cognition network. Importantly, this is the case for both the novel economic games and the classic FBTs.

Abstract: Abstract Background Borderline personality disorder (BPD) is characterized by impairments in emotion regulation, impulse control, and interpersonal and social functioning along with a deficit in emotional awareness and empathy. In this study, we investigated whether functional connectivity (FC) within the default mode network (DMN) is affected by 1-year psychodynamic psychotherapy in patients with BPD. Methods Nine BPD patients filled out the demography, Interpersonal Reactive Index (IRI), Toronto Alexithymia Scale 20 (TAS 20), the Alcohol, Smoking, and Substance Involvement Screening Test (ASSIST), and the Borderline Evaluation Severity over Time (BEST) questionnaire. The BPD group (9F) and the control group (9F) had a mean ± SD age of 28.2 ± 5.3 years and 30.4 ± 6.1 years, respectively. BPD subjects underwent longitudinal resting-state fMRI before psychodynamic psychotherapy and then every 4 months for a year after initiating psychotherapy. FC in DMN was characterized by calculating the nodal degree, a measure of centrality in the graph theory. Results The results indicated that patients with BPD present with aberrant DMN connectivity compared to healthy controls. Over a year of psychotherapy, the patients with BPD showed both FC changes (decreasing nodal degree in the dorsal anterior cingulate cortex and increasing in other cingulate cortex regions) and behavioral improvement in their symptoms and substance use. There was also a significant positive association between the decreased nodal degree in regions of the dorsal cingulate cortex and a decrease in the score of the TAS-20 indicating difficulty in identifying feelings after psychotherapy. Conclusion In BPD, there is altered FC within the DMN and disruption in self-processing and emotion regulation. Psychotherapy may modify the DMN connectivity and that modification is associated with positive changes in BPD emotional symptoms.

Abstract: INTRODUCTION Mentalizing incapacity is increasingly identified as a common factor in psychopathology. The Mentalization Scale (MentS) is a cost-effective measure built upon the dimensional model of mentalizing. We aimed to evaluate the psychometric properties of the Iranian version of MentS. METHODS Two samples of community-based adults (N1 = 450, N2 = 445) completed different batteries of self-report measures. In addition to MentS, participants completed measures of reflective functioning and attachment insecurities in the first sample and a measure of emotion dysregulation in the second sample. RESULTS Due to the conflicting results of confirmatory and exploratory factor analyses, an item-parceling approach was applied, which replicated the original three-factor structure of MentS, yielding Self-Related Mentalization, Other-Related Mentalization, and Motivation to Mentalize. The reliability and convergent validity of MentS were supported in both samples. CONCLUSION Our findings provided preliminary evidence for using the Iranian version of MentS in nonclinical populations as a reliable and valid measure.

Abstract: This review outlines the literature concerning the impact of adverse childhood experiences (ACEs) on parenting, focusing on how childhood trauma in parents might impede the development of adaptive parental mentalizing skills. Non-adaptive parental mentalizing may lead to non-mentalizing cycles between parents and children, which can put the child's mental health at risk. When parents who have endured ACEs have to cope with their children's mental health problems, they may have to deal with a double dose of parental stress related to their own traumatic history and their children's emotional difficulties. This heightened parental stress may further shake the parents' mentalizing skills. In line with this special issue's topic, we propose the promoting and restoring of parental mentalizing as a treatment goal for parents who have endured ACEs and whose children face mental health difficulties. We review the empirical and clinical evidence regarding the benefits of effective parental mentalizing and the availability of techniques to enhance it. We argue that working therapeutically and focusing on supporting and advancing parental mentalizing is an effective and feasible treatment goal with parents who endured ACEs. We demonstrate how we use these interventions through fictional vignettes from our therapeutic work and offer recommendations for clinical work with parents with traumatic histories.

Abstract: Anorexia nervosa (AN) usually emerges in adolescence when important changes occur in cognitive, emotional, and social processes. Mentalizing, alexithymia, and impulsiveness represent key dimensions for the understanding and interpretation of psychological difficulties in AN. The outbreak of the COVID-19 pandemic has impacted adolescents with AN, showing a worsening of the disease. The main aims of the present paper are (1) to compare adolescents with AN before and during the COVID-19 pandemic and (2) to explore the relationship between mentalizing, alexithymia, impulsiveness, and psychological difficulties related to eating disorders in adolescents with AN during the COVID-19 pandemic. One hundred and ninety-six AN female adolescents (N = 94 before COVID-19; N = 102 during COVID-19) participated in this study. The results show that adolescents with AN during the COVID-19 pandemic had a more impaired functioning profile than the before COVID-19 group. Mentalizing, alexithymia, and impulsiveness had a predictive role on psychological difficulties related to eating disorders in adolescents with AN during the COVID-19 pandemic. In conclusion, our data reveal that the COVID-19 pandemic has likely represented a stress condition that affects mental health; worsening the severity of adolescents with AN clinical condition. Lastly, predictive patterns suggest the existence of a link between difficulties in the ability to face the problems of the present time using effective strategies and the severity of psychological symptoms.

Abstract: Little work has examined longitudinal associations between parental reflective functioning (PRF) and mind-mindedness (MM), limiting the understanding of separate or bidirectional trajectories of these related but distinct forms of mentalization. We examined cross-lagged associations between PRF, assessed via interview, and MM, coded from play interactions, over 12 months among 90 parents (86% female; 57% White, 43% Black) of infants (Mage = 10.56 months, SD = 8.20) who were participating in The Michigan Model of Infant Mental Health Home Visiting. Data were collected at study enrollment Time 1 (T1) and at 6-month Time 2 (T2) and 12-month Time 3 (T3) postenrollment. Mind-minded comments were coded as appropriate, reflecting accurate interpretation of mental states or nonattuned, characterizing inaccurate interpretations. PRF and appropriate MM each remained stable over time. PRF at the T1 positively predicted appropriate MM at T2. No other cross-lagged associations between PRF and appropriate MM were significant. Concurrent correlations between appropriate MM and PRF were significant only at T3. Nonattuned MM showed stability from T1 to T2 but nonattuned MM at the T2 did not predict nonattuned MM at T3. Greater PRF at T1 predicted less nonattuned MM at T2. No other cross-lagged associations between PRF and nonattuned MM were significant. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Abstract: Attributing motives to others is a crucial aspect of mentalizing, which is disturbed by prejudice and is also affected by common psychiatric disorders. Thus it is important to understand in depth the neuro-computational functions underpinning mentalizing and social reward. We hypothesized that people quickly infer whether other’s motives are likely beneficial or detrimental, then refine their judgment. Such ‘Classify-refine’, active inference models of mentalizing motives might improve on traditional models, and hence allow testing the hypothesis that serotonergic antidepressant drugs improve function partly by inducing more benign views of others. In a week-long, placebo vs. Citalopram study using an iterated dictator task, ‘Classify-refine’ models accounted for behaviour better than traditional models. Citalopram did not lead to more magnanimous attributions of motives, but we found evidence that it may help refine attributions about others’ motives through learning. With respect to social differences, model comparison clearly indicated that ethnicity-dependent, in-task biases played no role in attributing motives for the large majority of participants. This is a very encouraging result which further research should seek to replicate, and, if replicated, celebrate. Lower subjective socio-economic status was associated with lower attributions of harm intent to others. We discuss how classify-refine social cognition may be highly adaptive. Future research should examine the role of Serotonergic antidepressants in clinical studies over longer time spans. Significance Statement We developed computational models to study how, in social situations, first impressions count a lot, but people also gradually refine their views to do justice to others. In our study, such ‘classify-refine’ models clearly outperformed the ones based on simpler learning. Modeling analyses indicated that refining one’s views was facilitated by serotonergic antidepressants. We expected that those who perceived themselves as socially disadvantaged, and those interacting with people of color, would tend to attribute less benign motives to others. However in our low income, highly educated, young sample, we found evidence against both these biases. Further studies are needed to test how far these encouraging neuropharmacological and psychosocial findings apply to other populations.

Abstract: ABSTRACT This study examined the relationship between childhood trauma, dissociation, and mentalization. Childhood trauma has been understood to affect both dissociation and mentalization, but it is unclear how these processes interact amidst the presence of childhood trauma. Specifically, the study sought to determine whether hypermentalization or hypomentalization would mediate the relationship between childhood trauma and dissociation. Mentalization describes the ability to understand the mental states of both the self and others, and suboptimal mentalization occurs when an individual experiences hypermentalizing, understood as a high level of certainty about mental states, or hypomentalizing, understood as a high level of uncertainty about mental states. 100 participants completed self-report measures assessing their experiences of childhood trauma using the Early Trauma Inventory Short Form Revised, dissociation using the Dissociative Experiences Scale II, and mentalization capacities using the Reflective Functioning Questionnaire. A series of mediation analyses were conducted, and it was found that neither hypermentalization or hypomentalization mediated the relationship between childhood trauma and dissociation. However, additional analyses revealed that dissociation mediated the relationship between childhood trauma and hypermentalization. The implications of the findings are explored and discussed within the context of the current literature, and the relationship between dissociation and mentalization is considered.

Abstract: Abstract Natural language processing (NLP) is central to the communication with machines and among ourselves, and NLP research field has long sought to produce human‐quality language. Identification of informative criteria for measuring NLP‐produced language quality will support development of ever‐better NLP tools. The authors hypothesize that mentalizing network neural activity may be used to distinguish NLP‐produced language from human‐produced language, even for cases where human judges cannot subjectively distinguish the language source. Using the social chatbots Google Meena in English and Microsoft XiaoIce in Chinese to generate NLP‐produced language, behavioral tests which reveal that variance of personality perceived from chatbot chats is larger than for human chats are conducted, suggesting that chatbot language usage patterns are not stable. Using an identity rating task with functional magnetic resonance imaging, neuroimaging analyses which reveal distinct patterns of brain activity in the mentalizing network including the DMPFC and rTPJ in response to chatbot versus human chats that cannot be distinguished subjectively are conducted. This study illustrates a promising empirical basis for measuring the quality of NLP‐produced language: adding a judge's implicit perception as an additional criterion.