Trait evaluations of faces and voices: Comparing within- and between-person variability.
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ABSTRACT:
SUBMITTER: Lavan N
PROVIDER: S-EPMC7612101 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Recognizing familiar individuals is achieved by the brain by combining cues from several sensory modalities, including the face of a person and her voice. Here we used functional magnetic resonance (fMRI) and a whole-brain, searchlight multi-voxel pattern analysis (MVPA) to search for areas in which local fMRI patterns could result in identity classification as a function of sensory modality. We found several areas supporting face or voice stimulus classification based on fMRI responses, consistent with previous reports; the classification maps overlapped across modalities in a single area of right posterior superior temporal sulcus (pSTS). Remarkably, we also found several cortical areas, mostly located along the middle temporal gyrus, in which local fMRI patterns resulted in identity "cross-classification": vocal identity could be classified based on fMRI responses to the faces, or the reverse, or both. These findings are suggestive of a series of cortical identity representations increasingly abstracted from the input modality.
| S-EPMC5121604 | biostudies-other
Project description:BackgroundThe within-person and between-sensor variability of metrics from different interstitial continuous glucose monitoring (CGM) sensors in adults with type 2 diabetes not taking insulin is unclear.MethodsSecondary analysis of data from 172 participants from the Hyperglycemic Profiles in Obstructive Sleep Apnea randomized clinical trial. Participants simultaneously wore Dexcom G4 and Abbott Libre Pro CGM sensors for up to 2 weeks at baseline and again at the 3-month follow-up visit.ResultsAt baseline (up to 2 weeks of CGM), mean glucose for both the Abbott and Dexcom sensors was approximately 150 mg/dL (8.3 mmol/L) and time in range (70180 mg/dL [3.910.0 mmol/L]) was just below 80. When comparing the same sensor at 2 different time points (two 2-week periods, 3 months apart), the within-person coefficient of variation (CVw) in mean glucose was 17.4 (Abbott) and 14.2 (Dexcom). CVw for percent time in range: 20.1 (Abbott) and 18.6 (Dexcom). At baseline, the Pearson correlation of mean glucose from the 2 sensors worn simultaneously was r 0.86, root mean squared error (RMSE), 13 mg/dL (0.7 mmol/L); for time in range, r 0.88, RMSE, 8 percentage points.ConclusionsSubstantial variation was observed within sensors over time and across 2 different sensors worn simultaneously on the same individuals. Clinicians should be aware of this variability when using CGM technology to make clinical decisions.ClinicalTrials.gov Identifier: NCT02454153.
| S-EPMC9898170 | biostudies-literature
Project description:Our objective was to quantify short-term total within-person variability in standard and nontraditional kidney measures using national data.Repeated examination study of serum and urine kidney measures.Participants 18 years or older in the Third National Health and Nutrition Examination Survey (NHANES III) who had repeated blood and urine samples collected during visits occurring approximately 18 days apart.Standardized serum creatinine, standardized cystatin C, ?-trace protein (BTP), ?(2)-microglobulin (B2M), and urine albumin and creatinine. We calculated the within-person coefficient of variation (CV(w)), which includes both biological and analytical variability. We also evaluated the impact of variability on estimates of the prevalence of reduced estimated glomerular filtration rate and albuminuria.Serum cystatin C level demonstrated the lowest short-term within-person variability (CV(w) = 6.8%). Serum creatinine and B2M levels (CV(w) = 7.6% and 8.4%, respectively) also had low variability. BTP level had the most variability of the serum markers (CV(w) = 11.6%). As expected, urine albumin and urine creatinine measurements showed high variability (CV(w) >30% for both); however, albumin-creatinine ratio performed much better than either measure alone, with CV(w) of 11.3%. The effect of short-term variability on the prevalence of reduced estimated glomerular filtration rate was moderate, with an ~20% lower prevalence when defined based on single measurements compared to repeated application of the same test approximately 18 days apart. Repeated testing for albuminuria had a larger effect, showing a 33% lower prevalence of albuminuria when repeated testing was applied.Only 2 measurements available. General population with low prevalence of kidney disease.Our results suggest that creatinine, cystatin C, and B2M levels have similarly low short-term variability. BTP level was more variable compared with the other serum filtration markers. Urine albumin and creatinine levels were highly variable and may benefit from repeated assessments to reduce the misclassification of albuminuria.
| S-EPMC3628297 | biostudies-literature
Project description:BackgroundWithin-person variability in measured values of a risk factor can bias its association with disease. We investigated the extent of regression dilution bias in calculated variables and its implications for comparing the aetiological associations of risk factors.MethodsUsing a numerical illustration and repeats from 42,300 individuals (12 cohorts), we estimated regression dilution ratios (RDRs) in calculated risk factors [body-mass index (BMI), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR)] and in their components (height, weight, waist circumference, and hip circumference), assuming the long-term average exposure to be of interest. Error-corrected hazard ratios (HRs) for risk of coronary heart disease (CHD) were compared across adiposity measures per standard-deviation (SD) change in: (i) baseline and (ii) error-corrected levels.ResultsRDRs in calculated risk factors depend strongly on the RDRs, correlation, and comparative distributions of the components of these risk factors. For measures of adiposity, the RDR was lower for WHR [RDR: 0.72 (95% confidence interval 0.65-0.80)] than for either of its components [waist circumference: 0.87 (0.85-0.90); hip circumference: 0.90 (0.86-0.93) or for BMI: 0.96 (0.93-0.98) and WHtR: 0.87 (0.85-0.90)], predominantly because of the stronger correlation and more similar distributions observed between waist circumference and hip circumference than between height and weight or between waist circumference and height. Error-corrected HRs for BMI, waist circumference, WHR, and WHtR, were respectively 1.24, 1.30, 1.44, and 1.32 per SD change in baseline levels of these variables, and 1.24, 1.27, 1.35, and 1.30 per SD change in error-corrected levels.ConclusionsThe extent of within-person variability relative to between-person variability in calculated risk factors can be considerably larger (or smaller) than in its components. Aetiological associations of risk factors should be compared through the use of error-corrected HRs per SD change in error-corrected levels of these risk factors.
| S-EPMC3733701 | biostudies-literature
Project description:IntroductionYouth who carry firearms-and peers that surround them-are at increased risk for violent injuries. Because firearm carriage behaviors can change over time within an individual, it is important to identify individual and social-contextual determinants that explain this within-person variability in carriage.MethodsThe authors identified individual and social-contextual determinants of firearm carriage in the past 6 months using multilevel logistic models on 5 waves of panel data from the Flint Youth Injury Study (n=597; ages 14-24 years), collected in 2009-2011 and analyzed in 2019.ResultsRegarding within-person effects, when an individual had more positive peer affiliations than their average, their odds of carrying a firearm decreased (OR=0.88; 95% CI=0.81, 0.96). Conversely, an individual's odds of carrying a firearm increased when they had more negative peer affiliations (OR=1.08, 95% CI=1.02, 1.14), experienced more victimization (OR=1.03, 95% CI=1.01, 1.05), perceived greater community violence (OR=1.12, 95% CI=1.05, 1.21), or exhibited greater retaliatory attitudes (OR=1.10, 95% CI=1.01, 1.19) than their average.ConclusionsPeer affiliations, victimization, community violence perceptions, and retaliatory attitudes explain within-person variability in firearm carriage. Strategies for reducing carriage among youth should consider individual- and environmental-level interventions to address these individual and social-contextual determinants.
| S-EPMC7483893 | biostudies-literature
Project description:Background. In recent years, researchers have investigated the relationship between facial width-to-height ratio (FWHR) and a variety of threat and dominance behaviours. The majority of methods involved measuring FWHR from 2D photographs of faces. However, individuals can vary dramatically in their appearance across images, which poses an obvious problem for reliable FWHR measurement. Methods. I compared the effect sizes due to the differences between images taken with unconstrained camera parameters (Studies 1 and 2) or varied facial expressions (Study 3) to the effect size due to identity, i.e., the differences between people. In Study 1, images of Hollywood actors were collected from film screenshots, providing the least amount of experimental control. In Study 2, controlled photographs, which only varied in focal length and distance to camera, were analysed. In Study 3, images of different facial expressions, taken in controlled conditions, were measured. Results. Analyses revealed that simply varying the focal length and distance between the camera and face had a relatively small effect on FWHR, and therefore may prove less of a problem if uncontrolled in study designs. In contrast, when all camera parameters (including the camera itself) are allowed to vary, the effect size due to identity was greater than the effect of image selection, but the ranking of the identities was significantly altered by the particular image used. Finally, I found significant changes to FWHR when people posed with four of seven emotional expressions in comparison with neutral, and the effect size due to expression was larger than differences due to identity. Discussion. The results of these three studies demonstrate that even when head pose is limited to forward facing, changes to the camera parameters and a person's facial expression have sizable effects on FWHR measurement. Therefore, analysing images that fail to constrain some of these variables can lead to noisy and unreliable results, but also relationships caused by previously unconsidered confounds.
| S-EPMC4793305 | biostudies-literature
Project description:Sexual consent is often conceptualized as an internal willingness to engage in sexual activity, which can be communicated externally to a sexual partner. Internal sexual consent comprises feelings of physical response, safety/comfort, arousal, agreement/want, and readiness; external sexual consent includes communication cues that may be explicit or implicit and verbal or nonverbal. Most previous research on sexual consent has focused on between-person differences; little attention has been devoted to examining the within-person variation of sexual consent across time. We conducted a 28-day experience sampling methodology (ESM) study with a sample of adults (N = 113) to assess fluctuations in internal and external sexual consent across a given person's sexual events. We found that more than 50% and up to 80% of the variance in sexual consent scores could be accounted for by within-person variability. The type of sexual behavior participants engaged in during a sexual event predicted their internal and external consent. Further, internal consent feelings predicted external consent communication. Overall, our findings provided initial evidence regarding the extent that situational contexts are relevant for sexual consent. ESM study designs may be used to further investigate the potential contextual, intrapersonal, and interpersonal factors associated with internal and external sexual consent.
| S-EPMC9239691 | biostudies-literature
Project description:Plant traits are commonly used to predict ecosystem-level processes, but the validity of such predictions is dependent on the assumption that trait variability between species is greater than trait variability within a species-the robustness assumption. Here, we compare leaf trait intraspecific and interspecific variability depending on geographical differences between sites and 5 years of experimental herbivore exclusion in two vegetation types of subalpine grasslands in Switzerland. Four leaf traits were measured from eight herbaceous species common to all 18 sites. Intraspecific trait variability differed significantly depending on site and herbivory. However, the amount and structure of variability depended on the trait measured and whether considering leaf traits separately or multiple leaf traits simultaneously. Leaf phosphorus concentration showed the highest intraspecific variability, while specific leaf area showed the highest interspecific variability and displayed intraspecific variability only in response to herbivore exclusion. Species identity based on multiple traits was not predictable. We find intraspecific variability is an essential consideration when using plant functional traits as a common currency not just species mean traits. This is particularly true for leaf nutrient concentrations, which showed high intraspecific variability in response to site differences and herbivore exclusion, a finding which suggests that the robustness assumption does not always hold.
| S-EPMC6661350 | biostudies-literature
Project description:ObjectivesWe aimed at examining between-person and within-person associations across age trajectories of perceptual speed and loneliness in old age.MethodWe applied multilevel models to 4 waves of data collected over 6 years from 1,491 participants of the Berlin Aging Study II (60-88 years at baseline, 50% women) to disentangle between-person and within-person associations across age trajectories of perceptual speed and both emotional and social loneliness. Sex and education were considered as relevant individual characteristics and included as covariates in the model.ResultsAnalyses revealed that on average perceptual speed exhibited moderate within-person age-related declines, whereas facets of loneliness were rather stable. Perceptual speed did not predict age trajectories of emotional or social loneliness, at either the between- or within-person level. In contrast, loneliness discriminated individuals at the between-person level, such that those feeling emotionally or socially more lonely showed lower cognitive performance than those feeling emotionally or socially less lonely. Predictive effects of social loneliness were stronger for relatively young people (i.e., in their mid to late 60s) than for relatively older participants (i.e., in their 80s). In addition, predictive effects of social loneliness for perceptual speed at the within-person level were modest and deviated in direction and size from between-person social loneliness effects among those in their mid- to late 60s, whereas they did not among those in their 80s.DiscussionWe conclude that loneliness may serve as a precursor for basic cognitive functioning in old age and suggest routes for further inquiry.
| S-EPMC8755905 | biostudies-literature
Project description:Our voices sound different depending on the context (laughing vs. talking to a child vs. giving a speech), making within-person variability an inherent feature of human voices. When perceiving speaker identities, listeners therefore need to not only 'tell people apart' (perceiving exemplars from two different speakers as separate identities) but also 'tell people together' (perceiving different exemplars from the same speaker as a single identity). In the current study, we investigated how such natural within-person variability affects voice identity perception. Using voices from a popular TV show, listeners, who were either familiar or unfamiliar with this show, sorted naturally varying voice clips from two speakers into clusters to represent perceived identities. Across three independent participant samples, unfamiliar listeners perceived more identities than familiar listeners and frequently mistook exemplars from the same speaker to be different identities. These findings point towards a selective failure in 'telling people together'. Our study highlights within-person variability as a key feature of voices that has striking effects on (unfamiliar) voice identity perception. Our findings not only open up a new line of enquiry in the field of voice perception but also call for a re-evaluation of theoretical models to account for natural variability during identity perception.
| S-EPMC6767376 | biostudies-literature