Intra-individual Stability Research Articles

Determination, intercorrelation and intraindividual stability of five steroids in hair, saliva and urine among chinese college students

Hair steroids and their ratios are believed to be reliable biomarkers reflecting the long-term exposure of circulating steroids. Hereinto, two underlying assumptions are that hair biomarkers have consistency with traditional biomarkers in saliva or urine, and good long-term intraindividual stability across a long time. However, these two assumptions have not been well verified for most of hair biomarkers except for hair cortisol. Thus, this study aimed to verify the two issues on eight hair biomarkers: cortisol, cortisone, dehydroepiandrosterone (DHEA), testosterone, progesterone, the ratios of cortisol to cortisone, DHEA and testosterone. The five steroids in hair, saliva and urine were measured with high performance chromatography tandem mass spectrometry. The results revealed that the hair biomarkers had significant correlations with the salivary biomarkers calculated by the mean area under curve (AUCg) in a matched time span (ps < 0.05) where the coefficients of correlations (r) were >0.3 (r = 0.322–0.616) except cortisone and progesterone (r = 0.177 and 0.212, respectively). It indicated that hair biomarkers had weak to moderate consistency with salivary ones. But only three biomarkers showed the consistency between hair and urine, such as testosterone (r = 0.352, p < 0.01), progesterone (r = 0.228, p < 0.05) and the ratio of cortisol to testosterone (r = 0.502, p < 0.01). Hair biomarkers showed no absolute stability, but moderate to high long-term relative stability across 12 months where interclass correlation coefficients ranged between 0.356 and 0.678 (ps < 0.01). These results implied that the eight biomarkers in hair could retrospectively reflect their cumulative exposure in vivo. Therefore, the hair biomarkers would be considerable reliable long-term biomarkers for psychological and physiological research.

Extending Evidence for Inter-Individual Differences in Social Comparison Orientation to Pay Fairness Evaluations.

This research extends the limited support for social comparison tendencies as an individual difference variable and a key moderator of pay fairness perceptions. Through three studies comprised of five data collections, the following adapts a measure of social comparison orientation to pay contexts and examines its association with heightened perceptions of distributive fairness in hypothetical and actual scenarios of pay equity, over-reward, and under-reward. In keeping with Gibbons and Buunk's construal, our targeted operationalization of social comparison orientation demonstrated inter-individual variation and intra-individual stability, providing corroboration of distinct individual predispositions towards social comparison. Our experimental findings further support this point in that socially relative pay information had a stronger impact on pay fairness evaluations among individuals predisposed to socially compare and a relatively weak impact on those that were not. This investigation is complementary but distinct from the prevalent focus on situational factors as drivers of social comparison. Further, examining this point in the context of pay is timely based on the recent level of public and managerial attention given to the fairness of relative pay differences.

Stability and change of values during the formative years: Latent state-trait analyses of adolescents in a seven-wave panel study.

Many researchers agree that a person's values are formed during the first two decades of one's life span. But little is known about the exact formation process and the typical development of values during youth. In this article, we investigate the question of intra-individual stability and changes in values during the so-called formative years. We used the dataset of a German panel study that took place in seven waves, from 2002 to 2008 (t1 -t7 ), which contained responses obtained from 2,957 boys and girls ages 13-19. The interviews were repeated yearly and were held mainly in classrooms. An analysis of stability and change over the observed time period was done using the framework of latent state-trait theory. The results showed a stable three-dimensional value structure, with strong growth in value stability that decreased slightly at the end of the adolescent period. The development of stability among youth seems to be dependent on the values themselves. These findings are consistent with the aging-stability hypothesis-that is, values become more and more stable parts of an individual's personality during the formative years. Moreover, our results would seem to substantiate hypotheses that assume value-specific courses of development and recurring periods of stability and change later in the life cycle.

Perceived stress and reference ranges of hair cortisol in healthy adolescents.

BackgroundChronic stress during adolescence has usually been evaluated through subjective measures, leaving aside objective measures such as hair cortisol concentrations. Therefore, the aim of this study was to provide reference ranges for hair cortisol concentrations by sex and age and to study the relationship between subjective and objective measures of stress and temporal stability.MethodsThe participants were 170 adolescents aged between 12 and 14 years (mean = 12.78 years; standard deviation = 0.71 years; 52.40% girls) who completed the Perceived Stress Scale 4 and had their hair sampled.ResultsThe results revealed hair cortisol concentrations ranging from 0.07 pg/mg to 9.54 pg/mg. Subjective and objective measures of stress were not related, nor was there intraindividual stability of the hair cortisol concentrations. Girls had higher hair cortisol concentrations, and there were no age differences.ConclusionsThis research provides cortisol reference values for adolescents that will allow the early detection of chronic stress. Such detection methods make it possible to prevent problems arising from stress because we can act more quickly and the treatments will be more effective. The study suggests that there is no relationship between perceived and objective stress; while perceived stress remained stable, the levels of hair cortisol were increased at 6 months. Despite the interesting findings of the study, there are some limitations: the sample was not obtained through probabilistic sampling, the age range was narrow, and some demographic, anthropomorphic and clinical factors are missing, which make the generalization of results difficult.

Dentin hypersensitivity monitored by cold air quantitative sensory testing.

Quantification of dentin hypersensitivity (DH) is challenging and requires standardised, graded stimulation by natural-like stimuli. The present study aimed at identifying DH subjects and longitudinally monitoring their pain thresholds by cold air quantitative sensory testing (QST). Subject recruitment started with an online DH questionnaire. Respondents were screened by dental air stimulation. Sensitising and habituating subjects were excluded. A recently developed stimulation device was employed for cold air QST. Single tooth DH was verified by applying an equi-intense stimulus to a control tooth. Descriptive statistics were applied for subject characteristics. Mean values were calculated for the stimulation parameters temperature and air flow. Reliability of temperatures for detecting pain and for evoking moderate pain over multiple time points within a 3-week period was analysed by two-way random single- and average-measure intra-class correlation coefficients. A total of 353 persons completed the online DH questionnaire of which 117 were screened. Forty-four passed the screening, yet 15 were excluded for various reasons. Twenty-nine subjects were monitored by QST across 3weeks. Results revealed a high intra-individual stability of the temperature inducing moderate to strong pain intensity (MPI) (single-measure ICC of TMPI 0.83, P<0.001). Mean TMPI was -13.69°C, yet it highly varied among the 29 subjects (SD±10.04°C). Using a novel approach, namely dental QST based on cold air stimuli, we present evidence for temporally stable DH perceptions over a 3-week period. The method fulfils international guideline requirements and is recommendable for obtaining valid results when testing various interventions for DH management.

(169) Comparison of Temporal Stability of Conditioned Pain Modulation and Temporal Summation of Pain in Healthy Older and Younger Adults

The temporal stability (test-retest reliability) of temporal summation of pain (TS) and conditioned pain modulation (CPM) has yet to be established in healthy older adults. The current study intended to compare the temporal stability of TS and CPM in healthy older and younger adults, as well as investigate factors that might impact TS and CPM stability. In a test-retest study, 40 healthy older adults and 18 healthy younger adults completed two sessions of quantitative sensory testing within a 2-week period that included: 1) TS of heat pain, 2) TS of mechanical pain, 3) CPM with pressure pain thresholds (CPM-PPT) and suprathreshold heat pain (CPM-Heat) as test stimuli and a cold water bath as conditioning stimulus. During each session participants completed the pain catastrophizing scale and the State Trait Anxiety Scale – state version. The relative stability (Interclass correlation coefficients: ICCs) and intra-individual stability coefficients (ISC) were examined for each variable. Bivariate correlations examined the association of psychological variables and age with the ISCs of TS and CPM. Younger adults showed good to excellent stability for TS (ICC's: 0.64-0.89), except for mechanical TS on the hand (ICC: 0.34). Older adults showed moderate to good stability for TS (ICC's: 0.48-0.79). Stability of CPM-PPT was poor for younger and older adults, whereas stability of CPM-Heat was good for younger adults but poor for older adults. Correlational analyses indicated greater ISC's for CPM were associated with greater stability of the pre-test stimuli. State anxiety was significantly associated with stability of CPM-Heat and TS. These findings suggest that 1) TS and CPM may be more reliable in younger compared to older adults and 2) state anxiety is an important factor influencing the stability of CPM and TS in healthy adults. This study was funded by the IUPUI Developing Diverse Researchers with Investigative Experience Grant.

Intra-individual stability of NREM sleep quantitative EEG measures in obstructive sleep apnea.

Electroencephalography is collected routinely during clinical polysomnography, but is often utilised to simply determine sleep time to calculate apnea-hypopnea indices. Quantitative analysis of these data (quantitative electroencephalogram) may provide trait-like information to predict patient vulnerability to sleepiness. Measurements of trait-like characteristics need to have high test-retest reliability. We aimed to investigate the intra-individual stability of slow-wave (delta power) and spindle frequency (sigma power) activity during non-rapid eye movement sleep in patients with obstructive sleep apnea. We recorded sleep electroencephalograms during two overnight polysomnographic recordings in 61 patients with obstructive sleep apnea (median days between studies 47, inter-quartile range 53). Electroencephalograms recorded at C3-M2 derivation were quantitatively analysed using power spectral analysis following artefact removal. Relative delta (0.5-4.5 Hz) and sigma (12-15 Hz) power during non-rapid eye movement sleep were calculated. Intra-class correlation coefficients and Bland-Altman plots were used to assess agreement between nights. Intra-class correlation coefficients demonstrated good-to-excellent agreement in the delta and sigma frequencies between nights (intra-class correlation coefficients: 0.84, 0.89, respectively). Bland-Altman analysis of delta power showed a mean difference close to zero (-0.4, 95% limits of agreement -9.4, 8.7) and no heteroscedasticity with increasing power. Sigma power demonstrated heteroscedasticity, with reduced stability as sigma power increased. The mean difference of sigma power between nights was close to zero (0.1, 95% limits -1.6, 1.8). We have demonstrated the stability of slow-wave and spindle frequency electroencephalograms during non-rapid eye movement sleep within patients with obstructive sleep apnea. The electroencephalogram profile during non-rapid eye movement sleep may be a useful biomarker for predicting vulnerability to daytime impairment in obstructive sleep apnea and responsiveness to treatment.

She Always Steps in the Same River: Similarity Among Long-Term Partners in Their Demographic, Physical, and Personality Characteristics.

In mate choice, individuals consider a wide pool of potential partners. It has been found that people have certain preferences, but intraindividual stability of mate choice over time remains little explored. We tested individual consistency of mate choice with respect to a number of demographic, physical, and personality characteristics. Only mothers were recruited for this study, because we wanted to find out not only whether women choose long-term partners with certain characteristics but also whether the father of their child(ren) differs from their other long-term (ex-)partners. Women (N = 537) of 19–45 years of age indicated the demographic, physical (by using image stimuli), and personality characteristics of all of their long-term partners (partners per respondent: mean = 2.98, SD = 1.32). Then we compared the average difference between an individual’s long-term partners with the expected average difference using a permutation test. We also evaluated differences between partners who had children with the participants (fathers) and other long-term partners (non-fathers) using permutation tests and mixed-effect models. Our results revealed that women choose long-term partners consistently with respect to all types of characteristics. Although effect sizes for the individual characteristics were rather weak, maximal cumulative effect size for all characteristics together was high, which suggests that relatively low effect sizes were caused by high variability with low correlations between characteristics, and not by inconsistent mate choice. Furthermore, we found that despite some differences between partners, fathers of participants’ child(ren) do fit their ‘type’. These results suggest that mate choice may be guided by relatively stable but to some degree flexible preferences, which makes mate choice cognitively less demanding and less time-consuming. Further longitudinal studies are needed to confirm this conclusion.

HeadNet: An End-to-End Adaptive Relational Network for Head Detection

Head detection plays an important role in localizing and identifying persons from visual data. Most existing methods treat head detection as a specific form of object detection. Head detection is nontrivial due to the considerable difficulty in building the local and global information under conditions of unconstrained pose and orientation. To address these issues, this paper presents an effective adaptive relational network to capture context information, which is greatly helpful to suppress missed detection. We show that the fundamental contextual properties, such as the global shape priors from different heads and the local adjacent relationship between the head and shoulders, can be systematically quantified by visual operators. Specifically, we propose a two-step search algorithm to quantify the global intergroup conflict with adaptive scale, pose and viewpoint. Meanwhile, a structured feature module is introduced to capture the local relation of intraindividual stability. Finally, the global priors and local relation are integrated seamlessly into a single-stage head detector that is end-to-end trainable. An extensive ablation analysis demonstrates the effectiveness of our approach. We achieve state-of-the-art results on two challenging datasets, i.e., HollywoodHeads and Brainwash.

The backtest modification in piglet behavior test

The aim of presented study was to evaluate behavioral reaction to modified backtest in set of 25 piglets. The backtest was performed without holding or touching tested piglet. The backtest was repeated three times at the ages 3, 4 and 5 weeks and latency attempt to turn, number of attempts and duration test to turn were recorded. All backtest parameters were influenced by modification. Latency was shorter than in classical backtest, 7.48 s in 1st test, 6.69 s in 2nd test and 3.45 s in 3rd test on average. Number of attempts showed very low variability, most piglets did turn at first attempt (60% in 1st test, 76% in 2nd test and 84% in 3rd test). Duration correlated with latency and was shorter than in classical backtest as well. The consistency of behavior in repeated tests (Spearman rank correlation) was from 0.463 to 0.704 (P<0.05) and the repeatability (R) was higher than 0.7. High levels of consistency as well as repeatability indicate intra-individual stability of reaction and behavior to modified backtest in piglets.

IL23R-Protective Coding Variant Promotes Beneficial Bacteria and Diversity in the Ileal Microbiome in Healthy Individuals Without Inflammatory Bowel Disease.

This study aimed to characterize the mucosa-associated microbiota in ileal Crohn's disease [CD] patients and in healthy controls in terms of host genotype and inflammation status. The mucosa-associated microbiotas of intestinal pinch biopsies from 15 ileal CD patients with mild and moderate disease and from 58 healthy controls were analysed based on 16S ribosomal sequencing to determine microbial profile differences between [1] IL23R, NOD2 and ATG16L1 genotypes in healthy subjects, [2] ileal CD patients and control subjects, and [3] inflamed and non-inflamed mucosal tissue in CD patients. The protective variant of the IL23R gene [rs11209026] significantly impacted the microbial composition in the ileum of healthy subjects and was associated with an increased abundance of phylotypes within the family Christensenellaceae as well as increases in diversity and richness. Comparative analysis of healthy and non-inflamed CD microbiome samples indicated a notable decrease in the abundance of Faecalibacterium prausnitzii as well as Shannon diversity and richness. Inflamed and non-inflamed ileal samples of CD subjects had high intra-individual stability and inter-individual variability, but no significant alterations in diversity, richness or taxa were identified. Calprotectin correlated positively with the abundance of Proteobacteria and negatively with diversity in the samples from healthy subjects. The observation of low diversity and low abundance of beneficial bacteria in healthy control subjects carrying the IL23R [rs11209026] wild-type GG genotype indicates that the gut microbiome is influenced by host genetics and is altered prior to disease diagnosis. Faecal calprotectin may be a potential non-invasive screening tool for dysbiosis in subjects without disorders of intestinal inflammation.

Psychomotor agitation in subjects hospitalized for an acute exacerbation of Schizophrenia

The aims of this study were to establish the prevalence of moderate and severe psychomotor agitation in patients hospitalized for an active phase of schizophrenia, the associations between psychomotor agitation and patients’ demographic and clinical variables, the intra-individual stability of the agitated/non-agitated dichotomy in independent psychotic breakdowns. The study was performed on a database relative to 630 inpatients hospitalized with a diagnosis of schizophrenia. Psychomotor agitation was measured with the Positive and Negative Syndrome Scale – Excited Component (PANSS-EC). Prevalence of moderate and severe psychomotor agitation was 40.5% and 23.7%, respectively. Non-agitated patients were older, with longer illness history and duration of untreated psychosis, were more frequently on antipsychotic medication, had lower incidence of recent use of substances, and functioned better before the index hospitalization than moderately and/or severely agitated patients. Non-agitated patients had lower scores for total PANSS and Emsley's positive and anxiety dimensions. Compared with the severely agitated group, non-agitated and moderately agitated patients scored more in Emsley's depression dimension. Poor functioning before index hospital admission, higher scores for negative subscale and Emsley's positive dimension and use of substances exerted an effect on risk of psychomotor agitation.

Short-term stability of different drinking patterns over the course of four weeks among adults. A latent transition analysis

ObjectiveThe purpose of the present study was to identify drinking patterns and determine their intraindividual stability over the course of four weeks among a sample of adults from the general population. MethodsThe sample comprised 288 adults who reported drinking alcohol at least once per month (49% female; mean age = 33.1 years, SD = 12.8 years). Participants were recruited in the waiting area of a local registration office in northeastern Germany. Data were collected four times over four consecutive weeks by interview (once in the registration office and thrice by telephone). To assess alcohol consumption in the past seven days, timeline follow-back questions were administered each time. For data analysis, latent profile and latent transition analyses were applied. Indicators for latent classes were total number of drinks per seven days, number of drinking days, and number of days with heavy episodic drinking. ResultsThree classes of seven-day drinking patterns were identified at baseline: (a) light drinkers (77%), (b) moderate drinkers (18%), and (c) heavy drinkers (5%). Approximately one-fifth (21%) of baseline light drinkers and 94% of baseline moderate drinkers changed their drinking pattern at least once during the four weeks. The majority (81%) of baseline moderate drinkers also reported light drinking in at least one of the three subsequent weeks. ConclusionsOur findings suggest intraindividual changes in drinking patterns even during a short period of time. Instability of drinking patterns may potentially impair the assessment of light to moderate alcohol consumption when a quantity-frequency approach is applied.

Reproducibility of Force-Velocity Test Outputs Using 10-s Sprints Against Different Braking Forces

PURPOSE: The current study was aimed to examine the reproducibility of estimated peak power (PP) and estimated pedal velocity (PV) in a multi-trial 10-s all-out cycling test among adult athletes of different sports. METHODS: The sample comprised 22 adult male athletes (23.50±4.73 years). Stature, sitting height and body mass were measured. Leg length was estimated as stature minus sitting height. Thigh volume was estimated from anthropometry. Body volume was obtained from air displacement plethysmography and was subsequently converted to fat mass. Fat-free mass was derived. The short-term power outputs were assessed from the force-velocity test (FVT), using a friction-braked ergometer on two repeated occasions. Differences between repeated measurements were examined with paired t-test and effect sizes calculated. RESULTS: Mean values for session 1 (898 Watt, 142 rpm) and session 2 (906 Watt, 142 rpm) did not differ (p>0.05). Moreover, test-retest procedure evidenced reasonable intra-individual stability for estimated PP output. Technical error of measurement (TEM) was 31.9 Watt; % coefficient of variation (CV) was 3.5% and intra-class correlation coefficient (ICC) was 0.986. For PV, TEM was 5.4 rpm, %CV was 3.8 and ICC was 0.924. CONCLUSIONS: Estimated PP derived from the optimal load and correspondent PV outputs seemed to be reproducible in adult athletes. Future research may examine the agreement between the estimated outputs from the Force-Velocity Test (FVT) and measured outputs using the Wingate Anaerobic Test protocol using the optimal load from the FVT. Supported by FCT Grants SFRH/BPD/100470/2014, SFRH/BD/101083/2014 and SFRH/BD/121441/2016.

0452 Intra-individual Stability of Quantitative EEG as a Biomarker in Obstructive Sleep Apnea

0452 Intra-individual Stability of Quantitative EEG as a Biomarker in Obstructive Sleep Apnea

Children’s Problem Behaviors Trajectories of Poor- and Non Poor-Households on the Path to Learning Readiness and School Adjustment

Using data from the Panel Study on Korean Children, this study investigated whether children with high levels of problem behaviors adjusted more poorly on the 1st-grade than children with low levels of problem behaviors, and whether there was evidence of intra-individual stability in behavior problems over time. Data were analyzed by use of the Latent Growth Model and group differences analyses. Three findings were noteworthy. First, there was evidence of intra-individual and inter-individual variability in behavior problems between poor- and non-poor household children. Second, children with higher initial levels of internalizing and externalizing behaviors at 4 years had lower school readiness scores at 6 years. Finally, children with lower levels of school readiness at 6 years had lower school adjustment scores in 1st grade. The results discuss implications for future research and policies for preschool children. With mediating effect of school readiness, developmental trajectories of child’s problem behavior have been found to be predictors of delayed achievements in school. The results show that intervention programs are necessary for children with high levels of problem behavior. This study also showed that children who experienced poverty at home could have more difficulties in school readiness and school adjustment.

Entity and incremental theory of personality: Revisiting the validity of indicators

This article tests the validity of indicators of entitavist and incremental lay theories about the malleability of personality (Dweck, Hong, & Chiu, 1993; Levy, Stroessner, & Dweck, 1998) in a two-wave panel survey over a 12-month period. After controlling for systematic measurement error stemming from different directions of item wording, the indicators form a single dimension. Moreover, hypotheses concerning (non-)correlations with socio-demographic characteristics and psychological dispositions largely receive support from the evidence. Further, beliefs about the malleability of personality exhibit higher intra-individual stability than attributions when controlling for measurement error in structural equation modeling. However, beliefs do not influence these attributions.

Personality stability and change between age 12 and 14 predicts relationships, sexual activity and same-sex sexual attraction at age 14

Improving sexual and reproductive health remains a public health priority worldwide. This study explored the contribution of personality to adolescent sexual behaviour. In total, 3460 Australian adolescents (1748 boys, 1712 girls) were sampled at age 12 and age 14. Results showed that mean-level increases in neuroticism and extraversion, and mean-level decreases in conscientiousness, were associated with an increased likelihood of being sexually active at age 14. Mean-level increases in neuroticism (and for girls, lower levels of conscientiousness) were associated with an increased likelihood of same-sex sexual attraction at age 14. Intra-individual stability of extraversion was related to the number of adolescent relationships and same-sex sexual attraction. Sexual risk taking and pregnancy were too rare at age 14 to reliably explore correlates.

New Multiple Sclerosis Disease Severity Scale Predicts Future Accumulation of Disability.

The search for the genetic foundation of multiple sclerosis (MS) severity remains elusive. It is, in fact, controversial whether MS severity is a stable feature that predicts future disability progression. If MS severity is not stable, it is unlikely that genotype decisively determines disability progression. An alternative explanation tested here is that the apparent instability of MS severity is caused by inaccuracies of its current measurement. We applied statistical learning techniques to a 902 patient-years longitudinal cohort of MS patients, divided into training (n = 133) and validation (n = 68) sub-cohorts, to test four hypotheses: (1) there is intra-individual stability in the rate of accumulation of MS-related disability, which is also influenced by extrinsic factors. (2) Previous results from observational studies are negatively affected by the insensitive nature of the Expanded Disability Status Scale (EDSS). The EDSS-based MS Severity Score (MSSS) is further disadvantaged by the inability to reliably measure MS onset and, consequently, disease duration (DD). (3) Replacing EDSS with a sensitive scale, i.e., Combinatorial Weight-Adjusted Disability Score (CombiWISE), and substituting age for DD will significantly improve predictions of future accumulation of disability. (4) Adjusting measured disability for the efficacy of administered therapies and other relevant external features will further strengthen predictions of future MS course. The result is a MS disease severity scale (MS-DSS) derived by conceptual advancements of MSSS and a statistical learning method called gradient boosting machines (GBM). MS-DSS greatly outperforms MSSS and the recently developed Age Related MS Severity Score in predicting future disability progression. In an independent validation cohort, MS-DSS measured at the first clinic visit correlated significantly with subsequent therapy-adjusted progression slopes (r = 0.5448, p = 1.56e−06) measured by CombiWISE. To facilitate widespread use of MS-DSS, we developed a free, interactive web application that calculates all aspects of MS-DSS and its contributing scales from user-provided raw data. MS-DSS represents a much-needed tool for genotype-phenotype correlations, for identifying biological processes that underlie MS progression, and for aiding therapeutic decisions.

Choir versus Solo Singing: Effects on Mood, and Salivary Oxytocin and Cortisol Concentrations.

The quantification of salivary oxytocin (OXT) concentrations emerges as a helpful tool to assess peripheral OXT secretion at baseline and after various challenges in healthy and clinical populations. Both positive social interactions and stress are known to induce OXT secretion, but the relative influence of either of these triggers is not well delineated. Choir singing is an activity known to improve mood and to induce feelings of social closeness, and may therefore be used to investigate the effects of positive social experiences on OXT system activity. We quantified mood and salivary OXT and cortisol (CORT) concentrations before, during, and after both choir and solo singing performed in a randomized order in the same participants (repeated measures). Happiness was increased, and worry and sadness as well as salivary CORT concentrations were reduced, after both choir and solo singing. Surprisingly, salivary OXT concentrations were significantly reduced after choir singing, but did not change in response to solo singing. Salivary OXT concentrations showed high intra-individual stability, whereas salivary CORT concentrations fluctuated between days within participants. The present data indicate that the social experience of choir singing does not induce peripheral OXT secretion, as indicated by unchanged salivary OXT levels. Rather, the reduction of stress/arousal experienced during choir singing may lead to an inhibition of peripheral OXT secretion. These data are important for the interpretation of future reports on salivary OXT concentrations, and emphasize the need to strictly control for stress/arousal when designing similar experiments.