Abstract
Introduction
The sense of belonging is a fundamental human need for emotional security, developing interpersonal relationships, and mental health (Baumeister & Leary, 1995). Sometimes this need to belong can be threatened by others, which can be described as feeling ostracized (Williams, 1997). Youth (i.e., adolescents and emerging adults) may be at a higher risk for the negative consequences (e.g., negative emotions) when feeling ostracized than adults, though reactions to those threatening situations may differ per person. Youth with personality pathology may be especially vulnerable because of emotional distress, self-regulation problems, and interpersonal problems (Hopwood et al., 2013). Little is known about the emotional reactions of youth with personality pathology when the need to belong is threatened. The present study will investigate differences between youth diagnosed with personality pathology and youth from a community sample in emotional reaction to a specific negative social situation, namely, Cyberball.
Personality pathology and interpersonal theory
Personality pathology reflects “a process in which pathological temperament and toxic learning lead to internalizations that contribute to chronic and pervasive distortions and emotional dysregulation in interpersonal situations” (Pincus, 2005). It leads to impairments in self-functioning (e.g., emotional dysregulation) and interpersonal problems (e.g., conflicts and distrust). Often, personality pathology is seen as fundamentally interpersonal: Impairments in interpersonal functioning are pervasive and arise across different situations and various relationships (Hopwood et al., 2013; Wright et al., 2022). This interpersonal dysfunction is best described by the Contemporary Integrative Interpersonal Theory (CIIT; Pincus & Ansell, 2013). This theory starts with the assumption of Sullivan (1953) that expressions of personality and psychopathology occur within a situation where more than one person is present, also called “interpersonal situations.” These are situations involving a self and someone else, which can be actual people or mental representations of them. When the mental representation of an interpersonal situation does not match with the objective situation, a distortion originates (Pincus & Ansell, 2013). The severity of the distortion of the subjective interpretation of the interpersonal situation can be seen as the core of personality pathology (Hopwood et al., 2019; Pincus, 2011). These kinds of distortions are common in youth with personality pathology and often lead to a failure in achieving a feeling of security or self-esteem, and evoke difficulties in emotion regulation (Hopwood et al., 2013). In the present study, the CIIT will be used as the theoretical framework for understanding the emotional reactions youth experienced when they felt ostracized.
Need to belong and Cyberball
The need to belong is defined as a “pervasive drive to form and maintain at least a minimum quantity of lasting, positive, and significant interpersonal relationships” (Baumeister & Leary, 1995, p. 497). In other words, individuals generally show a strong desire for social acceptance and often have a strong aversion to social rejection (Leary, 2001). Although the need to belong is a fundamental human need, it can sometimes be threatened by others in a specific social situation, such as ostracism (Williams, 1997). Ostracism is described as “being ignored and excluded, often without excessive explanation or explicit negative attention” (Williams, 2007, p. 429). An experimental paradigm was developed by Williams et al. (2000) for measuring the effects of ostracism under standardized conditions. Several forms of this paradigm have been developed over the years, including Cyberball (Williams, 2007), which is a virtual ball-tossing game. Even though ostracism in Cyberball occurs in a “virtual world” on the computer and other players are not physically present, the ostracized players still experience more negative feelings after the game than before (Zadro et al., 2004). We will use this paradigm when investigating the differences in emotional reactions to threatening social situations.
Emotional reactions of youth with and without personality pathology following ostracism
In the present research, we will study the differences in emotional reaction after feeling ostracized between youth with and without personality pathology. Previous research has suggested that especially youth may be at an increased risk of experiencing negative emotions following ostracism (Buelow et al., 2015; Lawrence et al., 2011; Sebastian et al., 2010). To investigate how people respond to ostracism, Williams (2009) distinguishes three stages in the reactions to ostracism: (1) an immediate (or reflexive) stage, (2) a coping (or reflective) stage, and (3) a long-term (or resignation) stage. The present study focuses on the first two stages because it is neither feasible nor ethical in an experimental design to expose youth for a prolonged and repeated period to ostracism (Williams, 2009). The immediate stage is a direct reaction to ostracism and occurs like a reflex. This reflex is elicited by someone’s internal signals of ostracism and may cause social pain and negative affect. Negative affect (NA) is described as “a general dimension of subjective distress and unpleasurable engagement that subsumes a variety of aversive mood states, including anger, contempt, disgust, and guilt” (Watson & Clark, 1988, p. 1063). The coping stage is the phase in which more rational thoughts about the social threat come up, and coping with the negative feelings that are elicited takes place. Coping with the threats can be measured in terms of speed of emotional recovery (e.g., decrease in anger and sadness after an earlier increase; Williams, 2009). In other words, the emotional response after feeling ostracized can differ over time (i.e., immediate and coping stage), and the intensity of emotions during the stages can differ across individuals. Especially, individuals with and without personality pathology may respond differently immediate to ostracism and may recover differently. In line with the CIIT, these differences may occur because of distortions in the interpretation of the interpersonal situation of youth with personality pathology. Often, the interpretation results in negative feelings about the social situation (Hopwood et al., 2013). A systematic review by Reinhard and colleagues (2020) has described that individuals with mental disorders seem to show more negative emotions after feeling ostracized than individuals without mental disorders. Additionally, when specifically examining a specific form of personality pathology negative emotions after ostracism, simulated through the exclusion condition of the Cyberball paradigm, are reported significantly more by individuals with a Borderline Personality Disorder (BPD) than by individuals without this disorder (n = 25; Mage 25.0; Gutz et al., 2016). However, another study found an increase in negative emotions after playing Cyberball in the control group, which was not found in the group of individuals with BPD (n = 30; Mage = 28.8 years; Renneberg et al., 2012). The individuals with BPD reported more negative emotions than the control group at baseline (n = 30, age range: 15–24 years; Lawrence et al., 2011; Renneberg et al., 2012). The latter two studies show that, within a group of individuals with BPD, higher levels of negative affect (e.g., anger, sadness, and fear) were reported at baseline, but the increase in negative affect directly after feeling ostracized was similar for individuals with BPD and individuals in the control group. The recovery (coping stage) of negative affect after exclusion was similar between both groups (Lawrence et al., 2011). Moreover, individuals with BPD exceeded chronic depressive individuals in terms of their negative emotional reactions to social exclusion. Those individuals with BPD reported an increase in other-focused emotions (defined as anger, resentment, contempt, and boredom, whereas self-focused negative emotions are fear, sadness, and loneliness) after Cyberball, whereas the individuals with persistent depressive disorder and those in the control group did not (Seidl et al., 2020). Subsequently, a different online social rejection task (e.g., an online chat group) elicited specific negative emotions such as feelings of anger and hostility directly after being excluded among emerging adults with BPD pathology who believed they were rejected (Richmond et al., 2020). Taken together, existing literature shows differences in the emotional reactions to ostracism between individuals, mostly adults, with personality pathology compared to those without this pathology. The current study will add to the literature by studying the emotional reactions to ostracism of youth (not adults) with various personality disorders, instead of focusing only on the most common personality disorder—BPD compared to a community group. The comparison between youth with and without personality pathology is important for controlling for normal development. Investigating the emotional reactions to ostracism by youth with personality pathology may help to understand the development and persistence of interpersonal problems, as well as how to treat those problems. Youth with personality pathology have a tendency to hypermentalize—making assumptions about other’s mental states that go beyond observable behavior (Bateman & Fonagy, 2013)—in social situations. This can be seen as distortions of interpersonal situations as described in the CIIT (Pincus & Ansell, 2013). These distortions may be more visible after feeling ostracized and can be a focus in treatment of youth with personality pathology.
The present study
The aim of the present study is to investigate whether youth with personality pathology differ in their emotional reaction to ostracism compared to youth from a community sample. Considering the previous literature, we hypothesize the following: (1) Youth with personality pathology experience more negative affect in the immediate stage—directly after ostracism (exclusion version of Cyberball)—and (2) youth with personality pathology recover more slowly during the coping stage of ostracism (exclusion version of Cyberball), than youth without personality pathology (community group).
Methods
Participants
In total, 78 individuals were included in the current study, divided into two groups: 34 individuals (25 self-identified females, 74%; nine self-identified males, 36%) diagnosed with personality pathology and 44 community participants (32 self-identified females, 72%; 12 self-identified males, 38%). Participants with personality pathology were recruited from Reinier van Arkel, a mental health institute in the Netherlands. Exclusion criteria were acute psychotic symptoms, current substance abuse disorders, intellectual disabilities, and being younger than 16 years or older than 24 years. The mean age of youth with personality pathology was 21.1 years (SD = 1.59). In this study, we used the categorical system, section II of DSM-5, for measuring personality pathology (APA, 2013). All individuals with personality pathology met the general criteria for a specific personality disorder (PD) according to the DSM-5 (APA, 2013). More specifically, this group involved 16 individuals (47%) with an Avoidant PD, 12 individuals (35%) with a BPD, 2 individuals (6%) with an Obsessive-Compulsive PD, 1 individual (3%) with a Narcissistic PD, and 3 individuals (9%) with Other Specified PD. The most prevalent comorbid mental disorders in the current sample were Attention-Deficit/Hyperactivity Disorder (ADHD), Major Depressive Disorder (MDD), and Post-Traumatic Stress Disorder (PTSD).
The community participants were recruited from a secondary vocational education school in the Netherlands. The only exclusion criterion for this group was being younger than 16 years or older than 24 years. The mean age of this group was 18.6 years (SD = 1.44).
Procedure
The participants with personality pathology were informed by their therapist and were recruited at a later moment by the experimenter, whereas the students in the community group were recruited by their teachers. When individuals decided to participate, they signed an informed consent form and were invited for the experiment. At the experiment location, either a therapy-room at the mental health institute or a classroom at school, the experimenter explained the procedure to a group of participants.
The experiment began with participants completing a questionnaire on demographics and the PANAS (see description of measurements; Watson et al., 1988). Next, participants played Cyberball (Williams, 2007), followed by completing the PANAS once again within the immediate stage. Subsequently, they responded to three manipulation check items. Then, the participants were told to wait for 15 minutes and were offered something to drink. After 15 minutes, the participants were asked to fill in the PANAS again for the last time within the coping stage and were debriefed by the researcher. To the best of our knowledge, no golden standard for recovery time exists. We chose for 15 minutes because waiting too long might lead to homogeneous between-group results (Hartgerink et al., 2015).
Experimental procedure—Cyberball
Cyberball is an online ball-tossing game (Williams, 2007) where participants believe they are playing with two other participants. The procedure for administering Cyberball was based on previous research (Renneberg et al., 2012). Participants were led to believe they were logged in on the internet simultaneously with two other players and were told they take part in a virtual ball-tossing game to stimulate their mental visualization skills. In reality, the other players were pre-programmed computer players. The participant was represented by a hand, while the other players were shown as animated characters. Once the participant received the ball, they could decide to whom to throw the ball by clicking on one of the other figures with the computer mouse.
In the current study, two versions of this game were used. An inclusion version, where the participants received the ball equally compared to the two other players, and an exclusion version, where the participant received the ball four times at the beginning, after which the two other players excluded the participant and only threw the ball to each other. After 30 throws, both versions ended. Each participant played only one version of Cyberball (exclusion or inclusion), which was unknown for the participant but known to the experimenter.
Measures
Structural Clinical Interview for DSM-5 Personality Disorders
The Structural Clinical Interview for DSM-5 Personality Disorders (SCID-5-P; First et al., 2016) is a 119-item semi-structured diagnostic interview that measures personality pathology within the categorical system (section II of the DSM-5), resulting in a diagnosis of a specific personality disorder (PD; APA, 2013). Items were rated on a three-point scale, with “1” indicating not present, “2” indicating sub-threshold, and “3” indicating present (First et al., 2016). The Dutch language version of the SCID-5-P (Arntz et al., 2017) was used by two experienced interviewers with post-master education in clinical psychology. Previous Dutch research with the SCID-II (First et al., 2016) demonstrated that when interviewers were sufficiently trained, which is comparable with our study, test–retest reliabilities (kappa = .63) are adequate (Weertman et al., 2003; Zanarini et al., 2000).
All participants in the PD-group receive treatment, which encompasses various forms of therapy. For eight participants enrolled in the MBT-program, the SCID-5-P interview was not administered, as they had already received a diagnosis from a clinical professional/psychologist. All other participants with personality pathology were assessed using the SCID-5-P for a PD diagnosis.
Positive and negative affect schedule
The level of experienced negative emotions was measured by the Positive and Negative Affect Schedule (PANAS; Watson et al., 1988), which includes 10 items for the Positive Affect scale and 10 items for the Negative Affect (NA) scale: afraid, scared, nervous, jittery, irritable, hostile, guilty, ashamed, upset, and distressed. In this study, only the NA scale of the Dutch language version of the PANAS was used (Engelen et al., 2006). The items were rated on a five-point rating scale (1 = “very little,” 5 = “very much”). The scales proved to be a reliable and valid measurement of the underlying dimensions (Watson & Clark, 1991). Cronbach’s alpha for NA was .87 (Watson et al., 1988).
Manipulation check
Three manipulation check items for inclusion/exclusion were administered. The check items were as follows: (1) “Assuming that the ball should be thrown to each person equally (33% if three people), what percentage of the throws was directed to you?” (open answer), (2) “I was ignored,” and (3) “I was excluded.” The last two questions had answer options on a five-point scale ranging from 1 = “not at all” to 5 = “very much so.”
Statistical analyses
A post hoc power-analysis, performed with G-power, reveals a power of .99. This is based on a sample size of 78 with three measurement moments, and four groups (k = 4), with a medium effect size (f = 0.25) and an α of .05. This indicates that the sample is large enough to perform the analysis with adequate power.
All analyses were performed in IBM SPSS Statistics (version 26.0). The significance level was .05 for all analyses. We first performed a manipulation check to assess whether the experimental condition (exclusion version of Cyberball) was successfully induced. The percentage of perceived ball throws, level of ignorance, and level of exclusion were compared between the inclusion and exclusion groups by using independent samples T-tests. Additionally, descriptive statistics were calculated for all different study variables.
For the main analyses, we performed a Repeated Measures 2 (between) × 2 (between) × 3 (within) Mixed-model ANOVA. The within factor was the three measurement moments of NA described as time. Two between factors were included in the analyses:
1. Participant group—PD or community group and 2. Cyberball version—inclusion or exclusion. Finally, a three-way interaction effect with time as the third factor was analyzed. Significant main effects were analyzed with Bonferroni-corrected pairwise comparisons.
Ethics statement
This study was ethically approved by the institutional scientific review board from Reinier van Arkel (nr MH/CW01808). All participants signed an informed consent form.
Results
Preliminary analyses and descriptive statistics
Descriptive statistics of negative affect within the four different groups.
Note. Total N = 78.
Manipulation check
T-tests were performed to investigate whether there was a significant difference between the groups playing the inclusion versus the exclusion version of Cyberball. The results demonstrated that youth playing the exclusion version felt significantly more ignored (M = 3.89, SD = 1.11, t(76) = −7.88, p < .001, Cohen’s d = −1.81), more excluded (M = 4.02, SD = 1.15, t (76) = −8.00, p < .001, Cohen’s d = −1.84), and they estimated fewer ball throws measured in percentages (M = 11.5%, SD = 5.52, t (44.3) = 8.47, p < .001, Cohen’s d = 2.55). Thus, it can be concluded that there were significant differences between the players of the two versions; the exclusion version was conducted successfully and elicited a perception of feeling excluded.
Differences between youth with and without personality pathology in experiencing NA after feeling ostracized
To investigate whether there was a difference in level of NA among youth across time and between various groups, a Repeated Measures ANOVA with 2 × 2 × 3 design was performed. The sphericity assumption was not met (Mauchly’s sphericity test, p = .006); therefore, results using the Greenhouse–Geisser corrections (the degrees of freedom were adjusted) were interpreted. Results indicated a main effect of Time (F (1.77, 130.68) = 37.29, p < .001, η p 2 = .34), which means that there is a difference in NA over time. Results showed a decrease of NA over time without taking the different groups into account. Also, an interaction effect of Time x Group (F (1.77, 130.68) = 10.42, p < .001, η p 2 = .12) was found, which means that there was a difference in NA at different time points between the PD and community group. The pairwise comparison revealed that the PD-group reported higher levels of NA at all three measurement moments (without considering the Cyberball version). No other statistically significant differences were observed. Results did not indicate an interaction effect of Time x Cyberball condition (F (1.77, 130.68) = 0.46, p = .632, η p 2 = .006) and no 3-way interaction of Time x Group x Cyberball condition (F (1.77, 130.68) = 0.40, p = .645, η p 2 = .005).
Discussion
This study examined, using an experimental design, whether there are differences in emotional reactions after feeling ostracized between youth with and without personality pathology. We hypothesized that youth with personality pathology would experience more NA after feeling ostracized during the immediate stage and would recover more slowly in the coping stage than the community group. Our results demonstrate that youth with a PD experience significantly higher scores of NA at all three measurement moments than the individuals in the community group. Although the manipulation check indicated that the exclusion was performed successfully, there were no significant differences found in NA scores between the inclusion and exclusion condition over all three measurement moments. Moreover, contradictory to our hypothesis, we did not find an increase in NA scores during the immediate stage within the PD-group nor in the community group. The current findings do not indicate a significantly slower recovery during the coping stage of NA for youth with a PD after feeling ostracized compared to youth from a community sample. Similarly, the reverse was not found; NA did not decrease significantly more within the PD group. Together, this indicates that no differences in the recovery of NA were found between both groups.
Consistent with prior research, youth with personality pathology tended to report higher levels of NA than their counterparts from a community sample, even before playing Cyberball. While previous studies have also observed elevated NA scores within specific patient groups, such as those with BPD or chronic depression (Jobst et al., 2014; Lawrence et al., 2011; Renneberg et al., 2012), this study contributes new insights by examining a more diverse sample of youth with various PDs. The higher levels of NA scores among youth with personality pathology, even before playing Cyberball, may be attributed to their predisposition to rejection sensitivity, a common trait among individuals with severe emotional disorders. This sensitivity often leads to an exaggerated emotional response following perceived rejection signals (Downey & Feldman, 1996). Moreover, this heightened sensitivity may result in biased interpretations of social situations, distorting the interpersonal dynamics, as outlined in the CIIT (Pincus & Ansell, 2013). Such distortions may contribute to a self-fulfilling prophecy, a phenomenon frequently studied in individuals with BPD but potentially applicable to those with avoidant PDs as well, given their similar hypersensitivity to social exclusion (Poggi et al., 2019). With 82% of our clinical sample comprising youth diagnosed with either BPD or avoidant PD, this pattern may elucidate why individuals with personality pathology exhibited higher levels of NA across all conditions.
Furthermore, we did not find a difference in NA scores between the inclusion and exclusion versions of Cyberball. However, earlier research did find differences with higher scores on NA within the exclusion group (Reinhard et al., 2020; Seidl et al., 2020). Our results may be related to the composition of the inclusion and exclusion groups. Within those groups, youth with and without personality pathology are combined, and analyses are performed. The difference in NA scores between youth with and without personality pathology is considerably high in our sample, which may result in regression to the mean for the NA scores within the inclusion and exclusion groups, leading to no differences in NA when those groups are compared.
Contradictory to our hypothesis, in the present study, youth did not report an increase in NA after playing the Cyberball experiment. Previous research found a significant increase in NA in both a control group (Renneberg et al., 2012) and a group of individuals with BPD (Lawrence et al., 2011) during the immediate phase (i.e., after Cyberball). Our finding may be the result of using the overall score for NA, in contrast to earlier studies. More specifically, after exclusion, both adults from a community group and adults with BPD showed a significant increase in anger, whereas a decrease in sadness was found (Renneberg et al., 2012). The same pattern was found for youth with a BPD: being excluded by Cyberball increased feelings of anger, rejection, surprise, and suspicion (Lawrence et al., 2011). We used a mean score of the 10 negative emotions because the PANAS is developed this way. Our sample was too small to analyze the data for the 10 emotions separately. Therefore, we have not been able to determine whether the same pattern would have been found within our group of youth if we had the possibility to divide our total score into separate negative emotions. Another explanation for this finding may be that the current experience of social exclusion, simulated within Cyberball, is a situation of mild interpersonal stress for youth with personality pathology compared to their life experiences of abandonment or abuse in interpersonal relationships. This form of social exclusion (Cyberball) may not have been sufficiently salient to elicit a more extreme emotional response in this group. Youth with personality pathology dealing with mild interpersonal stress might be capable of regulating their emotional reactions to mild stressful situations, and they may be less sensitive for rejection during such moments of mild stress. This pattern of NA scores did not differ between the group of individuals with personality pathology and the community group. This finding was in line with findings of Lawrence and colleagues (2011). They explain that youth with and without personality pathology regulate their negative emotional responses in similar ways in situations of mild interpersonal stress (Lawrence et al., 2011). For the PD-group, this finding of no increase in NA scores after feeling ostracized might also be caused by a ceiling effect of negative emotions. The negative emotions of youth with personality pathology were already reasonably high at baseline, which prevented a further increase in the NA scores after feeling ostracized. Finally, the decrease in NA immediately after Cyberball may also result from anticipatory stress among youth. The knowledge of dealing with a stressful situation can already increase levels of stress or NA (Kalokerinos et al., 2023). Playing the Cyberball game may be seen as a form of distraction, resulting in a decrease of anticipatory stress as well as the levels of NA. However, future research may include items about anticipatory stress. Additionally, a more sophisticated form of measuring ostracism instead of Cyberball may be used, which is not experienced as distraction of anticipatory stress but as a form more close to a real-life experience of exclusion.
Limitations
Despite the current study using a robust experimental paradigm for ostracism (i.e., Cyberball), including both inclusion and exclusion versions of Cyberball, and investigating both a clinical and community sample in order to differentiate between groups, there are some limitations. First, we used self-reporting measures, and people with personality pathology tend to have a bias towards self-report, which may impact the results. Physiological measures, such as skin conductance response measurement, might have provided better insights into the unconscious emotional response to social exclusion. Also, the PANAS only measured self-focused emotions and not other-focused emotions like contempt or resentment. Consequently, we were unable to assess other-focused emotions. Future research may investigate both forms of emotions to differentiate reactions to ostracism. A third limitation concerns the manipulation task used in this study. We did not find an increase in NA after Cyberball, which may indicate that the ostracism was not experienced strongly enough to report higher levels of NA after the experiment. The Cyberball paradigm is well established (Williams, 2007); however, the question arises whether this paradigm still elicits feelings of exclusion strong enough for the current generation of youth, who are growing up with modern social media. This may explain the decrease in NA instead of an increase. Virtual Reality (VR) might be more applicable for simulating real-life settings (Kassner et al., 2012). Preliminary results show a positive effect of using VR as an experimental design for ostracism on eliciting different emotional responses (Kassner et al., 2012; Kothgassner et al., 2021; Stallmann et al., 2023). In addition to VR, other more modern forms of ostracism tasks are currently being developed in the form of “chatroom” paradigms (comparable to WhatsApp) which measure the effects of ostracism during online communication (Filipkowski et al., 2022; Latina et al., 2023; Schneider et al., 2017). Fourth, although all youth with personality pathology met the general criteria for personality pathology, the group of participants was heterogeneous. The categorical system (section II of DSM-5; APA, 2013) was used to measure personality pathology because it is still the most commonly used system among therapists in the clinical field. However, we were unable to analyze the data for the various subgroups of youth with specific PDs due to power issues. Future research may investigate youth with personality pathology based on the Alternative Model of Personality Disorders (AMPD) described in DSM-5 section III. The AMPD describes personality pathology according to impairments in self and interpersonal functioning (criterion A) and the presence of five maladaptive personality domains (criterion B; APA, 2013). This model considers impairments in functioning and high levels of maladaptive traits necessary for the PD diagnosis. This way of conceptualizing personality pathology results in a dimensional description of participants rather than a description based on subgroups. Future research might focus on dimensional approach in measuring personality pathology, using the level of personality functioning as the core of personality pathology, instead of relying on the categorical system. New directions could investigate whether interpersonal dysfunctioning may moderate the scores on NA after experiencing ostracism.
Conclusion
In conclusion, the present study focused on differences in emotional reaction after exclusion or “ostracized” in youth with personality pathology compared to a community sample. Youth with personality pathology already experienced significantly higher levels of NA than youth from a community sample even before engaging in a negative social situation. These negative social situations, where the sense of belonging is threatened by others, did not induce higher levels of NA in either group. Additionally, recovery from the negative social situation did not occur more slowly for individuals with personality pathology compared to the community sample. Therefore, the same pattern of experiencing NA levels after a negative social situation was found for youth with and without personality pathology, with the only exception being that individuals with personality pathology already report higher levels of NA.
Footnotes
Author contributions
DH, PH, and OL conceptualized the study; DH conducted and supervised data collection; DH analyzed the data and drafted the manuscript; HS and PH provided supervision and feedback on the manuscript. OL and RS critically reviewed the manuscript.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
Ethical statement
Data availability statement
The dataset used and analyzed during the current study is available from the corresponding author on reasonable request.
Appendix
Author Biographies
