Learning biases underlying individual differences in sensitivity to social rejection

The effect of social anxiety on threat acquisition and extinction: a systematic review and meta-analysis

Although exposure-based therapy has been found to be effective at alleviating symptoms of social anxiety disorder, it often does not lead to full remission, and relapse after treatment is common. Exposure therapy is based on theoretical principles of extinction of conditioned fear responses. However, there are inconsistencies in findings across experiments that have investigated the effect of social anxiety on threat conditioning and extinction processes. This systematic review and meta-analysis aimed to examine whether elevated levels of social anxiety are associated with abnormalities in threat conditioning and extinction processes. A second aim was to examine the sensitivity of various study designs and characteristics to detect social anxiety-related differences in threat conditioning and extinction. A systematic search was conducted, which identified twenty-three experiments for inclusion in the review. The findings did not demonstrate compelling evidence that high levels of social anxiety are associated with atypical threat conditioning or extinction. Further, when systematically examining the data, there was no convincing support that the use of a particular psychophysiological measure, subjective rating, or experimental parameter yields more consistent associations between social anxiety and conditioning processes during threat acquisition or extinction. Meta-analyses demonstrated that during threat extinction, the use of anxiety ratings as a dependent variable, socially relevant unconditioned stimuli, and a higher reinforcement schedule produced more detectable effects of social anxiety on compromised extinction processes compared to any other dependent variable (subjective or physiological) or experimental parameter. Overall, the results of this study suggest that social anxiety is not reliably related to deficits in conditioning and extinction processes in the context of laboratory-based Pavlovian conditioning paradigms.

Examining social reinforcement learning in social anxiety

BACKGROUND AND OBJECTIVES

Reinforcement learning biases have been empirically linked to anhedonia in depression and theoretically linked to social anhedonia in social anxiety disorder, but little work has directly assessed how socially anxious individuals learn from social reward and punishment.

METHODS

N = 157 individuals high and low in social anxiety symptoms completed a social probabilistic selection task that involved selecting between pairs of neutral faces with varying probabilities of changing to a happy or angry face. Computational modeling was performed to estimate learning rates. Accuracy in choosing the more rewarding face was also analyzed.

RESULTS

No significant group differences were found for learning rates. Contrary to hypotheses, participants high in social anxiety showed impaired punishment learning accuracy; they were more accurate at choosing the most rewarding face than they were at avoiding the most punishing face, and their punishment learning accuracy was lower than that of participants low in social anxiety. Secondary analyses found that high (vs. low) social anxiety participants were less accurate at selecting the more rewarding face on more (vs. less) punishing face pairs.

LIMITATIONS

Stimuli were static, White, facial images, which lack important social cues (e.g., movement, sound) and diversity, and participants were largely non-Hispanic, White undergraduates, whose social reinforcement learning may differ from individuals at different developmental stages and those holding more marginalized identities.

CONCLUSIONS

Socially anxious individuals may be less accurate at learning to avoid social punishment, which may maintain negative beliefs through an interpersonal stress generation process.

Angry and fearful compared to happy or neutral faces as conditional stimuli in human fear conditioning: A systematic review and meta-analysis

Some previous research has shown stronger acquisition and impaired extinction of fear conditioned to angry or fearful compared to happy or neutral face conditional stimuli (CS) - a difference attributed to biological 'preparedness'. A systematic review and meta-analysis of fear conditioning studies comparing face CSs of differing expressions identified thirty studies, eighteen of which were eligible for meta-analysis. Skin conductance responses were larger to angry or fearful faces compared to happy or neutral faces during habituation, acquisition and extinction. Significant differences in differential conditioning between angry, fearful, neutral, and happy face CSs were also found, but differences were more prominent between angry and neutral faces compared to angry/fearful and happy faces. This is likely due to lower arousal elicited by neutral compared to happy faces, which may be more salient as CSs. The findings suggest there are small to moderate differences in differential conditioning when angry or fearful compared to happy or neutral faces are used as CSs. These findings have implications for fear conditioning study design and the preparedness theory.

Social Context and Rejection Expectations Modulate Neural and Behavioral Responses to Social Feedback

When meeting other people, some are optimistic and expect to be accepted by others, whereas others are pessimistic and expect mostly rejections. How social feedback is evaluated in situations that meet or do not meet these biases and how people differ in their response to rejection and acceptance depending on the social situation are unknown. In this study, participants experienced rejection and acceptance by peers in two different social contexts, one with high (negative context) and the other with low probability of rejection (positive context). We examined how the neural and behavioral responses to rejection are altered by this context and whether it depends on the individual's sensitivity to rejection. Behavioral results show that, on average, people maintain an optimistic bias even when mostly experiencing rejection. Importantly, personality differences in rejection sensitivity affected both prior expectations to be rejected in the paradigm and the extent to which expectations changed during the paradigm. The context also strongly modulated ERPs and theta responses to rejection and acceptance feedback. Specifically, valence effects on neural responses were enhanced in the negative context, suggesting a greater relevance to monitor social feedback in such a situation. Moreover, midfrontal theta predicted how expectations were changed in response to prediction errors, stressing a role for theta in learning from social feedback. Surprisingly, interindividual differences in rejection sensitivity did not affect neural responses to feedback. Our results stress the importance of considering the interaction between subjective expectations and the social context for behavioral and neural responses to social rejection.

Social anxiety, rejection sensitivity, and theory of mind decoding ability

OBJECTIVES

Recent initiatives have highlighted the importance of investigating clinically relevant variations in social processes that contribute to mental illness. Surprisingly little research has examined the associations between socially and clinically relevant transdiagnostic factors, such as social anxity (SA) and rejection sensitvity (RS), on theory of mind (ToM) decoding ability.

METHODS

The Reading the Mind in the Eyes Task and self-report measures of SA and RS were completed by 199 adult participants.

RESULTS

Linear regression analyses suggest a specific difficulty decoding positive emotion associated with SA and global decrements in ToM associated with RS that may reflect a negative interpretation bias.

CONCLUSIONS

These findings may have important implications for understanding how those with SA and RS perceive and navigate social interactions, which may contribute to the maintenance of symptoms and decreased psychosocial functioning.

Intolerance of uncertainty, and not social anxiety, is associated with compromised extinction of social threat

Extinction-resistant threat is regarded as a central hallmark of pathological anxiety. However, it remains relatively under-studied in social anxiety. Here we sought to determine whether self-reported trait social anxiety is associated with compromised threat extinction learning and retention. We tested this hypothesis within two separate, socially relevant conditioning studies. In the first experiment, a Selective Extinction Through Cognitive Evaluation (SECE) paradigm was used, which included a cognitive component during the extinction phase, while experiment 2 used a traditional threat extinction paradigm. Skin conductance responses and subjective ratings of anxiety (experiment 1 and 2) and expectancy (experiment 2) were collected across both experiments. The findings of both studies demonstrated no effect of social anxiety on extinction learning or retention. Instead, results from experiment 1 indicated that individual differences in Intolerance of Uncertainty (IU) were associated with the ability to use contextual cues to decrease a conditioned response during SECE. However, during extinction retention, high IU predicted greater generalisation across context cues. Findings of experiment 2 revealed that higher IU was associated with impaired extinction learning and retention. The results from both studies suggest that compromised threat extinction is likely to be a characteristic of high levels of IU and not social anxiety.

The Rejection Sensitivity Model as a Framework for Understanding Sexual Minority Mental Health

Sexual minorities are disproportionately affected by mental health problems (e.g., depression, anxiety, substance use disorders, suicidality). Minority stress theory and the psychological mediation framework have become the predominant conceptual models used to explain these disparities, and they have led to substantial advances in research on stigma-related stress and mental health. However, the field's reliance on these models has limited the extent to which other theories have been considered as potential frameworks for further advancing our understanding of sexual minority mental health. In this article, I discuss how the rejection sensitivity (RS) model can be used to complement and extend minority stress theory and the psychological mediation framework by: (1) emphasizing the role of perception in stigma-related experiences; (2) acknowledging the unique consequences of different anticipatory emotions; (3) describing additional mechanisms linking proximal minority stressors to mental health; and (4) further specifying the temporal order of these processes. I conclude by discussing the importance of attending to developmental processes in research on sexual orientation-related RS and describing important directions for future research.

Social exclusion influences conditioned fear acquisition and generalization: A mediating effect from the medial prefrontal cortex

Fear acquisition and generalization play key roles in promoting the survival of mammals and contribute to anxiety disorders. While previous research has provided much evidence for the repercussions of social exclusion on mental health, how social exclusion affects fear acquisition and generalization has received scant attention. In our study, participants were divided into two groups according to two Cyberball paradigm conditions (exclusion/inclusion). Both groups underwent a Pavlovian conditioning paradigm, functional near-infrared spectroscopy (fNIRS), and skin conductance response (SCR) assessments. We aimed to determine the effects of social exclusion on fear acquisition and generalization and whether modulation of the medial prefrontal cortex (mPFC) mediates this relationship. Our results showed that socially excluded participants featured significantly higher and lower shock risk scores to safety stimuli (conditioned stimulus, CS-) and threatening stimuli (CS+), respectively, than did socially included subjects during fear acquisition. The exclusion group had increased skin conductance responses (SCRs) to CS and exhibited heightened shock risk and increased SCRs to generalized stimuli compared with the inclusion group. The fNIRS results demonstrated that the CS ​+ ​evoked larger oxy-Hb changes in the mPFC in the inclusion group than in the exclusion group during fear acquisition. Furthermore, the oxy-Hb of left mPFC of CS ​+ ​mediated the effect on the association between social exclusion and perceived risk of CS+ in the fear acquisition. Our results indicate that social exclusion impairs fear acquisition and generalization via the mediation of the mPFC and that social exclusion increases susceptibility to anxiety disorders through bias processing of fear discrimination in fear acquisition and generalization. By studying the role of social relationship in fear acquisition and generalization, our research provides new insights into the pathological mechanisms of anxiety disorder.

Intact Classical Fear Conditioning to Interpersonally Threatening Stimuli in Borderline Personality Disorder

Threat hypersensitivity is regarded as a central mechanism of deficient emotion regulation, a core feature of patients with borderline personality disorder (BPD). Here, we employed a classical fear-conditioning protocol in which interpersonally threatening, interpersonally non-threatening, and non-social (neutral) visual stimuli were predictive of an aversive auditory stimulus in a sample of 23 medication-free adult female patients with BPD and 21 age- and IQ-matched healthy women. The results did not confirm the hypothesized enhanced and prolonged conditioned skin conductance responses (SCR) and subjective stress and expectancy ratings to interpersonally threatening stimuli in patients with BPD compared to healthy women. Patients with BPD generally expected the aversive stimulus more often irrespective of stimulus category and conditioning. Furthermore, patients with BPD showed larger conditioned SCR to interpersonally non-threatening and neutral than interpersonally threatening stimuli, while interpersonally threatening stimuli elicited higher SCR compared to non-threatening or neutral stimuli in healthy controls. Together with previous studies, the results suggest no alterations in fear conditioning to generally aversive stimuli in BPD. Further studies using stimuli with BPD-specific topics, such as abandonment or rejection, and/or to investigate more interpersonal forms of learning, such as observational or instructed conditioning, are urgently needed to further elucidate the mechanisms involved in the etiology and maintenance of threat hypersensitivity in BPD.

Social anxiety and dynamic social reinforcement learning in a volatile environment

Adaptive social behavior requires learning probabilities of social reward and punishment, and updating these probabilities when they change. Given prior research on aberrant reinforcement learning in affective disorders, this study examines how social anxiety affects probabilistic social reinforcement learning and dynamic updating of learned probabilities in a volatile environment. N=222 online participants completed questionnaires and a computerized ball-catching game with changing probabilities of reward and punishment. Dynamic learning rates were estimated to assess the relative importance ascribed to new information in response to volatility. Mixed-effects regression was used to analyze throw patterns as a function of social anxiety symptoms. Higher social anxiety predicted fewer throws to the previously punishing avatar and different learning rates after certain role changes, suggesting that social anxiety may be characterized by difficulty updating learned social probabilities. Socially anxious individuals may miss the chance to learn that a once-punishing situation no longer poses a threat.

The link between rejection sensitivity and borderline personality disorder: A systematic review and meta-analysis

OBJECTIVE

People with Borderline Personality Disorder (BPD) may experience heightened rejection sensitivity (RS), a disposition developing from repeated childhood rejecting experiences. It is not known whether the full RS model accounts for the cognitive-affective experiences common in BPD. This systematic review extends upon previous reviews, firstly by assessing the link between childhood rejecting experiences and adult RS, and secondly by considering the link between BPD and RS in both non-clinical and clinical samples.

METHOD

Two research questions were devised, and searches based on predetermined criteria were conducted using PsycNET, PubMed, SCOPUS, and Web of Science. Data were extracted by one researcher and 20% was inter-rated, with high levels of agreement. Forty-three papers were systematically reviewed, and 31 included in meta-analysis and meta-regression.

RESULTS

Studies assessing the link between childhood rejection and RS are limited; however, emotional abuse and neglect appears linked with RS. Pooled effect sizes suggest RS is linked with BPD (r = .326), with strong effect sizes when comparing clinical and control samples (r = .655). Qualitative synthesis suggests this may be mediated by executive control, although further research is required. The small number of studies considering the full RS model with regard to BPD suggests the interaction between emotional abuse and neglect affects rejection sensitivity; however, outcomes are inconsistent.

CONCLUSIONS

Childhood rejection, particularly emotional abuse and neglect, appears to be linked to rejection sensitivity, and rejection sensitivity is linked to BPD. However, this may not be linear. Implications for clinical practice and research are discussed.

PRACTITIONER POINTS

Rejection sensitivity is consistently linked with BPD, in clinical and non-clinical samples. Supporting mentalization or improved theory of mind may offer a therapeutic target for this disposition. Considering the causes and effects of rejection sensitivity may offer a non-blaming explanation of interpersonal difficulties in BPD and could be utilized as part of formulation and the therapeutic relationship. However, the possible interaction between emotional abuse and neglect and rejection sensitivity suggests rejection sensitivity is not always apparent for people with BPD. Idiosyncratic formulation should consider this. The literature included in the review is limited to Western populations with a high proportion of females, which may limit generalizability. Measures of rejection sensitivity included in the review were restricted to self-report, which may be subject to bias. Furthermore, measures of childhood rejection were retrospective in nature due to the exclusion of child samples. Further research should consider longitudinal and observational study designs.

Modulation of brain response to peer rejection by rejection sensitivity: An exploratory study

A number of studies have explored how rejection sensitivity (RS) affects the neural and physiological responses to stimuli with implicit rejection clues. Peer rejection during social interaction conveys explicit rejection feedback. The current event-related potentials (ERP) study using Chatroom task aimed to test to what extent RS modulated individuals' psychological and neural response to explicit rejection feedback. The subjective ratings mainly demonstrated that RS modulated ostracism distress and negative mood following rejection feedback. The ERP results showed that compared with low RS individuals, both the parietal P3 and left frontal LPP responses towards rejection feedback were enhanced in high RS individuals, indicating that high RS individuals exhibit attentional bias, intense anger experience and lower emotion regulation towards rejection suggested by their neural responses. The current study provides a new insight into neural correlates of RS in the high ecological experimental context.

Links between rejection sensitivity and biobehavioral response to laboratory stress in youth

Although rejection sensitivity has been shown to predict altered psychological and relational well-being, a surprising dearth of research has examined physiological effects of this individual difference measure during childhood and adolescence. In the present research, we investigated the relationship between rejection sensitivity, negative affect, and sympathetic nervous system (SNS) response to laboratory performance stressors among youth. Thirty-two normally developing youth completed a modified version of the Trier Social Stress Task. Self-report measures of negative affect and salivary alpha amylase were collected over the course of the stress session. Controlling for gender, rejection sensitivity was related to greater negative affect and blunted alpha amylase reactivity. These data are the first to demonstrate that rejection sensitivity is associated with altered physiological stress response among youth. These findings also identify a plausible psychobiological mechanism that could provide new insight into why rejection sensitivity is a vulnerability factor for suboptimal academic performance in childhood and adolescence.

Evidence that disrupted orienting to evaluative social feedback undermines error correction in rejection sensitive women

For individuals high in Rejection Sensitivity (RS), a learned orientation to anxiously expect rejection from valued others, negative feedback from social sources may disrupt engagement with learning opportunities, impeding recovery from mistakes. One context in which this disruption may be particularly pronounced is among women high in RS following evaluation by a male in authority. To investigate this prediction, 40 college students (50% female) answered general knowledge questions followed by immediate performance feedback and the correct answer while we recorded event-related potentials. Error correction was measured with a subsequent surprise retest. Performance feedback was either nonsocial (asterisk/tone) or social (male professor's face/voice). Attention and learning were indexed respectively by the anterior frontal P3a (attentional orienting) and a set of negative-going waveforms over left inferior-posterior regions associated with successful encoding. For women, but not men, higher RS scores predicted poorer error correction in the social condition. A path analysis suggested that, for women, high RS disrupted attentional orienting to the social-evaluative performance feedback, which affected subsequent memory for the correct answer by reducing engagement with learning opportunities. These results suggest a mechanism for how social feedback may impede learning among women who are high in RS.

Linking Individual Learning Styles to Approach-Avoidance Motivational Traits and Computational Aspects of Reinforcement Learning

Learning how to gain rewards (approach learning) and avoid punishments (avoidance learning) is fundamental for everyday life. While individual differences in approach and avoidance learning styles have been related to genetics and aging, the contribution of personality factors, such as traits, remains undetermined. Moreover, little is known about the computational mechanisms mediating differences in learning styles. Here, we used a probabilistic selection task with positive and negative feedbacks, in combination with computational modelling, to show that individuals displaying better approach (vs. avoidance) learning scored higher on measures of approach (vs. avoidance) trait motivation, but, paradoxically, also displayed reduced learning speed following positive (vs. negative) outcomes. These data suggest that learning different types of information depend on associated reward values and internal motivational drives, possibly determined by personality traits.

The left hemisphere learns what is right: Hemispatial reward learning depends on reinforcement learning processes in the contralateral hemisphere

Orienting biases refer to consistent, trait-like direction of attention or locomotion toward one side of space. Recent studies suggest that such hemispatial biases may determine how well people memorize information presented in the left or right hemifield. Moreover, lesion studies indicate that learning rewarded stimuli in one hemispace depends on the integrity of the contralateral striatum. However, the exact neural and computational mechanisms underlying the influence of individual orienting biases on reward learning remain unclear. Because reward-based behavioural adaptation depends on the dopaminergic system and prediction error (PE) encoding in the ventral striatum, we hypothesized that hemispheric asymmetries in dopamine (DA) function may determine individual spatial biases in reward learning. To test this prediction, we acquired fMRI in 33 healthy human participants while they performed a lateralized reward task. Learning differences between hemispaces were assessed by presenting stimuli, assigned to different reward probabilities, to the left or right of central fixation, i.e. presented in the left or right visual hemifield. Hemispheric differences in DA function were estimated through differential fMRI responses to positive vs. negative feedback in the left vs. right ventral striatum, and a computational approach was used to identify the neural correlates of PEs. Our results show that spatial biases favoring reward learning in the right (vs. left) hemifield were associated with increased reward responses in the left hemisphere and relatively better neural encoding of PEs for stimuli presented in the right (vs. left) hemifield. These findings demonstrate that trait-like spatial biases implicate hemisphere-specific learning mechanisms, with individual differences between hemispheres contributing to reinforcing spatial biases.

Trait rejection sensitivity is associated with vigilance and defensive response rather than detection of social rejection cues

Prior studies suggest that psychological difficulties arise from higher trait Rejection Sensitivity (RS)-heightened vigilance and differential detection of social rejection cues and defensive response to. On the other hand, from an evolutionary perspective, rapid and efficient detection of social rejection cues can be considered beneficial. We conducted a survey and an electrophysiological experiment to reconcile this seeming contradiction. We compared the effects of RS and Rejection Detection Capability (RDC) on perceived interpersonal experiences (Study 1) and on neurocognitive processes in response to cues of social rejection (disgusted faces; Study 2). We found that RS and RDC were not significantly related, although RS was positively related to perceived social rejection experiences and RDC was positively related to perceived social inclusion experiences. Event-related brain potentials (ERPs) revealed that higher RS was related to cognitive avoidance (i.e., P1) and heightened motivated attention (i.e., late positive potential: LPP), but not to facial expression encoding (i.e., N170) toward disgusted faces. On the other hand, higher RDC was related to heightened N170 amplitude, but not to P1 and LPP amplitudes. These findings imply that sensitivity to rejection is apparently distinct from the ability to detect social rejection cues and instead reflects intense vigilance and defensive response to those cues. We discussed an alternative explanation of the relationship between RS and RDC from a signal detection perspective.

Common oxytocin receptor gene variant interacts with rejection sensitivity to influence cortisol reactivity during negative evaluation

The study tested the hypothesis that variation in the oxytocin receptor gene (OXTR rs53576) and self-report of rejection sensitivity are associated with adrenocortical reactivity to social stress. Participants (N=94; 36.17% male; Mage=20.18yrs; 62.8% Caucasian) completed a writing task on a salient problem in society, provided self-report via questionnaire of rejection sensitivity, and were then informed that a committee of peers would evaluate their written comments. Participants received either scripted praise or criticism as a way to induce social evaluative threat. Saliva was collected before and after the stress task and assayed for cortisol. Results revealed that cortisol levels increased in participants with moderate levels of social rejection sensitivity-inferred by rs53576 genotype and reported rejection sensitivity-while cortisol levels decreased in participants with high and low levels of social rejection sensitivity. Our findings suggest a curvilinear relationship between social rejection sensitivity and cortisol reactivity in the context of social rejection, warranting further consideration in future studies.

Learning to fear depends on emotion and gaze interaction: The role of self-relevance in fear learning

Emotional learning is an adaptive function, however its psychological determinants are unclear. Here, we propose a new theoretical framework based on appraisal theories of emotion, which holds that emotional learning is modulated by a process of relevance detection. Testing the model, we predicted faster, larger acquisition and greater resistance to extinction of the conditioned response (CR) to self-relevant stimuli relative to stimuli with less relevance. We manipulated self-relevance through emotion and gaze direction of synthetic dynamic facial expressions during differential aversive conditioning. Results provided mixed evidence for our hypotheses. Critically, we revealed faster acquisition of the CR to angry faces with direct compared with averted gaze and greater resistance to extinction to fearful faces with averted relative to direct gaze. We conclude that the relevance detection hypothesis offers an appropriate theoretical framework allowing to (re)interpret existing evidence, incorporate our results, and propose a new research perspective in the study of emotional learning.

Rejection sensitivity and symptom severity in patients with borderline personality disorder: effects of childhood maltreatment and self-esteem

BACKGROUND

Interpersonal dysfunction in Borderline Personality Disorder (BPD) is characterized by an 'anxious preoccupation with real or imagined abandonment' (DSM-5). This symptom description bears a close resemblance to that of rejection sensitivity, a cognitive affective disposition that affects perceptions, emotions and behavior in the context of social rejection. The present study investigates the level of rejection sensitivity in acute and remitted BPD patients and its relation to BPD symptom severity, childhood maltreatment, and self-esteem.

METHODS

Data were obtained from 167 female subjects: 77 with acute BPD, 15 with remitted BPD, and 75 healthy controls who were matched with the patients for age and education. The instruments used for assessment were the Rejection Sensitivity Questionnaire, the short version of the Borderline Symptom List, the Childhood Trauma Questionnaire, and the Rosenberg Self-Esteem Scale.

RESULTS

Both acute and remitted BPD patients had higher scores on the Rejection Sensitivity Questionnaire than did healthy controls. Lower self-esteem was found to be positively correlated with both increased BPD symptom severity and higher rejection sensitivity, and mediated the relation between the two. History of childhood maltreatment did not correlate with rejection sensitivity, BPD symptom severity, or self-esteem.

CONCLUSIONS

Our findings support the hypothesis that rejection sensitivity is an important component in BPD, even for remitted BPD patients. Level of self-esteem appears to be a relevant factor in the relationship between rejection sensitivity and BPD symptom severity. Therapeutic interventions for BPD would do well to target rejection sensitivity.

Laughter as a social rejection cue: gelotophobia and transient cardiac responses to other persons' laughter and insult

Other persons' laughter, normally perceived as a signal that persons are friendly and inviting others to approach, can also be perceived as a cue of social rejection. In this study, prerecorded laughter was placed in a realistic and personally relevant context, and participants' responses were related to gelotophobia, a trait predisposing to perceiving laughter as a cue of social rejection. Individuals with gelotophobia showed marked heart rate deceleration in response to the laughter stimulus, possibly indicating a "freezing-like" response. Moreover, cardiac responses to anger provocation by overtly insulting statements indicated heightened aggressive anger in response to cumulated social threat. The study adds to recent research showing specific cardiac responses to social rejection and to the literature on social rejection sensitivity by demonstrating the value of using well interpretable physiological measures in this research context.