Individual Differences In Physiological Responses Research Articles

Emotion dysregulation and posttraumatic stress symptom severity: The influence of cortisol reactivity following idiographic emotion inductions.

Emotion dysregulation plays a central role in the etiology and maintenance of posttraumatic stress symptoms (PTSS). Individual differences in physiological responses to emotionally evocative events may influence the strength of this association. The objective of this study was to test whether cortisol reactivity following idiographic emotion induction tasks moderated the relation between emotion dysregulation and PTSS severity. Participants were 94 community women currently experiencing intimate partner violence and using substances (age: M = 40.5 years; 35.2% Black; 61.5% unemployed). PTSS severity was assessed at baseline via a clinician-administered diagnostic interview. Participants provided a self-report of emotion dysregulation at baseline. Samples of salivary cortisol were collected pre-, during, and postidiographic emotion inductions during an experimental session. A significant emotion dysregulation by cortisol reactivity interaction was found (b = 0.18, p = .02). Emotion dysregulation was related to PTSS severity for those with high (b = 0.13, p < .001), but not low (b = -0.001, p = .99), levels of cortisol reactivity following idiographic emotion inductions. Findings provide novel evidence of the interplay of emotion dysregulation and cortisol reactivity, an indicator of hypothalamic-pituitary-adrenal system axis stress reactivity, following emotionally evocative stimuli in relation to PTSS severity. Information from this study may help to identify individuals who are at highest risk of more severe PTSS. Future work is needed to replicate findings among diverse populations impacted by trauma (e.g., veterans, men). (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Beyond performance: the role of task demand, effort, and individual differences in ab initio pilots

Aviation safety depends on the skill and expertise of pilots to meet the task demands of flying an aircraft in an effective and efficient manner. During flight training, students may respond differently to imposed task demands based on individual differences in capacity, physiological arousal, and effort. To ensure that pilots achieve a common desired level of expertise, training programs should account for individual differences to optimize pilot performance. This study investigates the relationship between task performance and physiological correlates of effort in ab initio pilots. Twenty-four participants conducted a flight simulator task with three difficulty levels and were asked to rate their perceived demand and effort using the NASA TLX. We recorded heart rate, EEG brain activity, and pupil size to assess changes in the participants’ mental and physiological states across different task demands. We found that, despite group-level correlations between performance error and physiological responses, individual differences in physiological responses to task demands reflected different levels of participant effort and task efficiency. These findings suggest that physiological monitoring of student pilots might provide beneficial insights to flight instructors to optimize pilot training at the individual level.

Individual differences in physiological responses to effortful listening

Individual differences in physiological responses to effortful listening

Bold Behavior Is Associated with Genes That Regulate Energy Use but Does Not Covary with Body Condition in Food-Restricted Snails.

AbstractTheoretical models about the relationship between food restriction and individual differences in risk-taking behavior (i.e., boldness) have led to conflicting predictions: some models predict that food restriction increases boldness, while other models predict that food restriction decreases boldness. This discrepancy may be partially attributable to an underappreciation for animals' complex physiological responses to food restriction. To understand the proximate mechanisms mediating state-dependent boldness, we used freshwater snails (Helisoma trivolvis) to examine the relationships among food availability, body condition, boldness (latency to reemerge from shell and exploration), and mRNA expression of three genes (adenosine monophosphate-activated protein kinase [AMPK], molluscan insulin-like peptide [MIP], and serotonin receptor [5-HT]) involved in maintaining energy homeostasis during periods of moderate food restriction. Latency to reemerge and exploratory behavior decreased over time, but fed snails were bolder than fasted snails, suggesting that food restriction reduces bold behavior. Although food restriction decreased body condition, there was not a relationship between body condition and latency to reemerge from shell. However, expression of MIP was positively correlated with latency to reemerge from shell. Furthermore, AMPK was positively correlated with MIP and negatively correlated with body condition and 5-HT. Therefore, individual differences in physiological responses to food restriction, not overall body condition per se, appear to be more closely associated with state-dependent bold behavior. Finally, snails that experienced a novel assay environment returned to their initial "shy" behavior, suggesting that habituation to the assay environment may contribute to snails expressing bolder behavior over time.

Psychophysiological responses to potentially annoying heating, ventilation, and air conditioning noise during mentally demanding work.

Exposure to noise-or unwanted sound-is considered a major public health issue in the United States and internationally. Previous work has shown that even acute noise exposure can influence physiological response in humans and that individuals differ markedly in their susceptibility to noise. Recent research also suggests that specific acoustic properties of noise may have distinct effects on human physiological response. Much of the existing research on physiological response to noise consists of laboratory studies using very simple acoustic stimuli-like white noise or tone bursts-or field studies of longer-term workplace noise exposure that may neglect acoustic properties of the noise entirely. By using laboratory exposure to realistic heating, ventilation, and air conditioning (HVAC) noise, the current study explores the interaction between acoustic properties of annoying noise and individual response to working in occupational noise. This study assessed autonomic response to two acoustically distinct noises while participants performed cognitively demanding work. Results showed that the two HVAC noises affected physiological arousal in different ways. Individual differences in physiological response to noise as a function of noise sensitivity were also observed. Further research is necessary to link specific acoustic characteristics with differential physiological responses in humans.

Emotion Recognition From Multimodal Physiological Signals Using a Regularized Deep Fusion of Kernel Machine.

These days, physiological signals have been studied more broadly for emotion recognition to realize emotional intelligence in human-computer interaction. However, due to the complexity of emotions and individual differences in physiological responses, how to design reliable and effective models has become an important issue. In this article, we propose a regularized deep fusion framework for emotion recognition based on multimodal physiological signals. After extracting the effective features from different types of physiological signals, we construct ensemble dense embeddings of multimodal features using kernel matrices, and then utilize a deep network architecture to learn task-specific representations for each kind of physiological signal from these ensemble dense embeddings. Finally, a global fusion layer with a regularization term, which can efficiently explore the correlation and diversity among all of the representations in a synchronous optimization process, is designed to fuse generated representations. Experiments on two benchmark datasets show that this framework can improve the performance of subject-independent emotion recognition compared to single-modal classifiers or other fusion methods. Data visualization also demonstrates that the final fusion representation exhibits higher class-separability power for emotion recognition.

Analysis of multimodal physiological signals within and between individuals to predict psychological challenge vs. threat

Challenge and threat characterize distinct patterns of physiological response to a motivated performance task where the response patterns vary as a function of an individual's evaluation of task demands relative to his/her available resources to cope with the demands. Challenge and threat responses during motivated performance have been used to understand psychological, behavioral, and biological phenomena across many motivated performance domains. In this study, we aimed to investigate individual and group-level variations in physiological responding across a series of motivated performance tasks that vary in difficulty. The proposed approach is motivated by documented individual differences in physiological responses observed in motivated performance tasks, such that we first focus on individual differences in physiological responses rather than group-level comparisons. Then, through our analysis of individuals we identify sub-groups (i.e., clusters) of individuals that share common physiological patterns across tasks of varying difficulty and we perform across-subject analysis within each cluster. This is distinct from existing studies which typically do not examine individual vs. subgroup-specific patterns of physiological activity. Such an approach enables us to identify patterns in physiological responses that can be used to predict self-reported judgments of challenge vs. threat with higher accuracy in each subgroup compared to an analysis that includes the entire sample population as a single group. Specifically, three hypotheses were tested: (H1) individuals will have different sets of physiological patterns (features) across tasks of varying difficulty; (H2) there will be subgroups of individuals who share common salient physiological features across the subgroup clusters that differentiate their physiological responding across tasks of varying difficulty; and (H3) the accuracy of predicting self-reported judgments of challenge vs. threat across individuals will be higher within each subgroup with shared salient physiological features than across all subgroups or the entire sample with all computed features. To test these hypotheses, we developed an integrated analytic framework for multimodal physiological data analysis. We employed data from an existing experiment in which participants completed three mental arithmetic tasks of increasing difficulty during which different modalities of physiological data were collected. Analyses revealed three subgroups of participants who shared common features that best differentiated their within-individual physiological response patterns across tasks. Support vector machine (SVM) classifiers were trained using both shared features within each group and all computed features to predict challenge vs. threat states. Results showed that, the within-group classification model using group common features achieved higher self-report prediction accuracy compared to an alternative model trained on data from all participants without feature selection.

Does noise sensitivity or attentional capacity predict cardiovascular responses to distracting sound?

Workplace noise may cause stress that has long-term implications for health. Employees in open-plan offices typically identify intermittently occurring background sounds as significant sources of stress, possibly because they distract attention away from intended tasks. Thus, individual differences in attention and noise sensitivity may explain individual differences in physiological responses to workplace noise. In previous research [Oliver, et al., in 176th Meeting of the Acoustical Society of America (2018)], we reported results from a preliminary analysis of 19 participants’ affective and electrodermal responses to working in background noise that included intermittent environmental sounds. Electrodermal responses were used as a measure of distraction because they constitute a primary component of the physiological orienting response, a multi-component response reflecting exogenous capture of attention. Our results suggested that individuals who are more sensitive to noise experienced greater frustration with the primary task, but there was no relationship between frustration and distraction as indexed by electrodermal responses. Here, we present additional analyses of an expanded dataset, focusing on attentional and cardiovascular measures (heart rate and pulse volume amplitude) previously linked to cognitive demand and noise annoyance (Francis et al., 2016) and relate these results to an overall characterization of the auditory orienting response.

Cortisol Stress Response Variability in Early Adolescence: Attachment, Affect and Sex.

Attachment, affect, and sex shape responsivity to psychosocial stress. Concurrent social contexts influence cortisol secretion, a stress hormone and biological marker of hypothalamic-pituitary-adrenal axis activity. Patterns of attachment, emotion status, and sex were hypothesized to relate to bifurcated, that is, accentuated and attenuated, cortisol reactivity. The theoretical framework for this study posits that multiple individual differences mediate a cortisol stress response. The effects of two psychosocial stress interventions, a modified Trier Social Stress Test for Teens and the Frustration Social Stressor for Adolescents were developed and investigated with early adolescents. Both of these protocols induced a significant stress reaction and evoked predicted bifurcation in cortisol responses; an increase or decrease from baseline to reactivity. In Study I, 120 predominantly middle-class, Euro-Canadian early adolescents with a mean age of 13.43years were studied. The girls' attenuated cortisol reactivity to the public performance stressor related significantly to their self-reported lower maternal-attachment and higher trait-anger. In Study II, a community sample of 146 predominantly Euro-Canadian middle-class youth, with an average age of 14.5years participated. Their self-reports of higher trait-anger and trait-anxiety, and lower parental attachment by both sexes related differentially to accentuated and attenuated cortisol reactivity to the frustration stressor. Thus, attachment, affect, sex, and the stressor contextual factors were associated with the adrenal-cortical responses of these adolescents through complex interactions. Further studies of individual differences in physiological responses to stress are called for in order to clarify the identities of concurrent protective and risk factors in the psychosocial stress and physiological stress responses of early adolescents.

Physiological and Relational Predictors of Mother-Infant Behavioral Coordination.

Coordinated social behavior and positive affect shared between parent and child in early life provide a foundation for healthy social and emotional development. We examined physiological (cardiac vagal responses) and relational (attachment security) predictors of dyadic behavioral coordination in a sample of 13-month-old infants and their mothers (N = 64). We tested whether cardiac vagal responses moderated the association between attachment security and behavioral coordination. The main effect of attachment on coordination was moderated by infant cardiac vagal tone (i.e., respiratory sinus arrhythmia [RSA] during rest). Securely attached infants with lower cardiac vagal tone were more behaviorally coordinated with their mothers; there was no association between attachment and coordination for infants with high cardiac vagal tone. Infants with greater increases in cardiac vagal reactivity (i.e., RSA during social engagement) exhibited greater behavioral coordination with their mothers regardless of attachment status. There were no effects for maternal cardiac vagal responses. These results illustrate how individual differences in physiological responses inform healthy early social-emotional functioning.

Evaluating differences in Pavlovian fear acquisition and extinction as predictors of outcome from cognitive behavioural therapy for anxious children.

Extinction is a key theoretical model of exposure-based treatments, such as cognitive behavioural therapy (CBT). This study examined whether individual differences in physiological responses and subjective stimulus evaluations as indices of fear extinction predicted response to CBT. Thirty-two nonanxious comparisons and 44 anxious, 7-to-13-year-old children completed a Pavlovian conditioning and extinction task. Anxious children then completed group-based CBT. Skin conductance responses (SCRs) as well as subjective arousal and valence evaluations were measured in response to a conditioned stimulus paired with an aversive tone (CS+) and another conditioned stimulus presented alone (CS-). Both stimuli were presented alone during extinction. Diagnostic and symptom measures were completed before and after treatment. Like nonanxious comparisons, treatment responders did not acquire conditioned negative stimulus evaluations and displayed elevated SCRs that declined significantly across extinction trials. Nonresponders, by contrast, showed elevated negative stimulus evaluations of both CSs that were sensitive to extinction trials but showed no change in SCRs during extinction. Change in physiological but not evaluative indices of fear extinction predicted better treatment outcomes. Individual differences in evaluative and physiological indices of fear extinction might moderate response to CBT.

Attachment status and mother–preschooler parasympathetic response to the strange situation procedure

BackgroundEarly attachment relationships are important for children's development of behavioral and physiological regulation strategies. Parasympathetic nervous system activity, indexed by respiratory sinus arrhythmia (RSA), is a key indicator of self-regulation, with links to numerous developmental outcomes. Attachment-related changes in and associations between mother and child RSA during the Strange Situation procedure (SSP) can elucidate individual differences in physiological response to stress that are important for understanding the development of and intervention for psychopathology. MethodsA sample of 142 at-risk mothers and preschool-age children participated in the SSP and provided time-synchronized RSA data during the 7 episodes, which included 2 separations and 2 reunions. Attachment classifications were obtained using the Cassidy et al. (1992) coding system. Linear mixed-effects models were constructed to examine attachment-related change in RSA during the SSP and the concordance between mother and child RSA over time. ResultsFindings demonstrated attachment-related differences in children's RSA. Secure children's RSA was relatively stable over time, whereas insecure-avoidant children showed RSA increases during the first separation and insecure-resistant children's RSA declined across the SSP. Mothers showed RSA withdrawal during separation regardless of child's attachment classification. Mother–child RSA showed a positive concordance that was strongest in the insecure-resistant group, compared with the other groups. ConclusionsResults support attachment theories concerning parasympathetic response to stress and the role of the mother–child relationship in physiological regulation. Our findings advance previous research by focusing on at-risk mother–preschooler dyads within diverse attachment classifications.

The cognitive, affective and physiological impact of infant crying: a comparison of two laboratory methodologies

Objective: The present study investigated two experimental paradigms to explore whether individual differences in adult responses to crying were related to the method of presentation of the crying infant – namely, a video simulation or a life-like programmable doll. Background: The importance of understanding individual differences in caregiver responses to infant crying is well recognised, but assessment of caregiver responses presents considerable methodological challenges. Method: Participants were 106 female childless undergraduate students. Responses assessed included self-report measures of self-efficacy beliefs, feelings of empathy toward the crying infant, caregiver concern and irritation, and heart-rate reactivity. Participants were randomly allocated to exposure to either a life-like crying doll or to a video of a crying infant. Results: Compared to those in the video condition, participants exposed to the crying doll showed lower self-efficacy beliefs, experienced greater feelings of irritation and a greater change in heart-rate responses, p < .05, but no differences in feelings of concern or empathy towards the infant. Conclusion: Findings provide preliminary evidence that the crying doll paradigm may be a more ecologically valid approach to exploring the impact of crying on adults; however, methodological considerations related to individual differences in physiological responses need further clarification in future research.

True and false interindividual differences in the physiological response to an intervention.

What is the topic of this review? In 'personalized medicine', various plots and analyses are purported to quantify individual differences in intervention response, identify responders/non-responders and explore response moderators or mediators. What advances does it highlight? We highlight the impact of within-subject random variation, which is inevitable even with 'gold-standard' measurement tools/protocols and sometimes so substantial that it explains all apparent individual response differences. True individual response differences are quantified only by comparing the SDs of changes between intervention and comparator arms. When these SDs are similar, true individual response differences are clinically unimportant and further analysis unwarranted. Within the 'hot topic' of personalized medicine, we scrutinize common approaches for presenting and quantifying individual differences in the physiological response to an intervention. First, we explain how popular plots used to present individual differences in response are contaminated by random within-subject variation and the regression to the mean artefact. Using a simulated data set of blood pressure measurements, we show that large individual differences in physiological response can be suggested by some plots and analyses, even when the true magnitude of response is exactly the same in all individuals. Second, we present the appropriate designs and analysis approaches for quantifying the true interindividual variation in physiological response. It is imperative to include a comparator arm/condition (or derive information from a prior relevant repeatability study) to quantify true interindividual differences in response. The most important statistic is the SD of changes in the intervention arm, which should be compared with the same SD in the comparator arm or from a prior repeatability study in the same population conducted over the same duration as the particular intervention. Only if the difference between these SDs is clinically relevant is it logical to go on to explore any moderators or mediators of the intervention effect that might explain the individual response. To date, very few researchers have compared these SDs before making claims about individual differences in physiological response and their importance to personalized medicine.

Caffeine With and Without Sugar: Individual Differences in Physiological Responses During Rest

Background: The consumption of caffeine with and without sugar is endemic, but little is known about variation in individual physiological responses at rest. We have previously shown that the ingestion of caffeine with sugar increased the rate of carbon dioxide production more than when sugar alone was consumed. Objective: The aim of this study was to determine the effect of the ingestion of caffeine, sugar, and caffeine with sugar on carbon dioxide production and heart rate. Methods: In a crossover three-treatment design, 12 participants reported fasting on three separate days. Treatments were 1.33 mg/kg body weight caffeine only, 0.4 g/kg body weight sugar only, and caffeine with sugar. Breath-by-breath measurements of respiratory gas exchange and heart rate were recorded for 30 min before and after treatments. Data visualization techniques were used to examine the patterns of response. Results: Carbon dioxide production increased or remained the same with all three treatments. Caffeine alone slowed the...

Individual differences in the physiological effects of forest therapy based on Type A and Type B behavior patterns

BackgroundIn recent years, the physiological relaxation effects of natural environments have been widely exploited, and although individual differences in the effects of forest therapy are known, assessment methods have not been clearly established. This study used a classification based on Type A and Type B behavior patterns to explain individual differences in physiological responses to forest environments.MethodsWe performed physiological experiments in 44 forest and urban (controls) areas. In total, 485 male university students (age, 21.8 ± 1.6 years) participated in the study. The subjects were asked to visit forest or urban environments randomly and observe each landscape for 15 min. The subjects’ pulse rates and blood pressures were tested to evaluate their physiological responses. The Kwansei Gakuin daily life questionnaire was used to identify Type A and Type B behavior patterns in subjects.ResultsThe pulse rate was significantly lower in the Type B group after exposure to forest areas than after exposure to urban areas, whereas no significant difference was observed in the Type A group. In addition, the pulse rate was significantly lower in the low scoring subjects in the Type B group, which was consistent with changes in their diastolic blood pressure.ConclusionsThese results suggest that individual differences in pulse rate and blood pressure in response to forest environments can be explained by Type A and Type B behavior patterns.

Racial identity and autonomic responses to racial discrimination

Several studies identify racial identity-the significance and meaning that individuals attribute to race-as a mitigating factor in the association between racial discrimination and adjustment. In this study, we employed a visual imagery paradigm to examine whether racial identity would moderate autonomic responses to blatant and subtle racial discrimination analogues with Black and White perpetrators. We recruited 105 African American young adults from a public, southeastern university in the United States. The personal significance of race as well as personal feelings about African Americans and feelings about how others view African Americans moderated autonomic responses to the vignettes. We use polyvagal theory and a stress, appraisal, and coping framework to interpret our results with an eye toward elucidating the ways in which racial identity may inform individual differences in physiological responses to racial discrimination.

Personality, emotion, and individual differences in physiological responses

A dominant paradigm in biopsychological personality research seeks to establish links between emotional and motivational traits and habitual, transsituationally consistent individual differences in measures of physiological activity. An alternative approach conceptualizes traits as dispositions that are only operative in certain situational contexts and consequently predicts associations between emotional and motivational traits and physiological activity only for trait-relevant situational contexts in which the physiological systems underlying the traits in question are engaged. In the present paper we first examine and contrast these personistic and interactionistic conceptualizations of personality and personality–physiology associations and then present data from several large studies ( N > 100) in which electrocortical (e.g., frontal alpha asymmetry) and somatovisceral parameters were measured in various situational contexts (e.g., after the induction of either anger, or fear, or anxiety). As predicted by the interactionistic conceptualization of traits as dispositions the situational context and its subjective representation by the participants moderated the personality–physiology relationships for measures of both central and peripheral nervous system activity. We conclude by outlining the implications of the interactionistic approach for biopsychological personality research.

Ambulatory monitoring of activity levels of individuals in the sub-acute stage following stroke: a case series

BackgroundThere is an important need to better understand the activities of individual patients with stroke outside of structured therapy since this activity is likely to have a profound influence on recovery. A case-study approach was used to examine the activity levels and associated physiological load of patients with stroke throughout a day.MethodsActivities and physiologic measures were recorded during a continuous 8 hour period from 4 individuals in the sub-acute stage following stroke (ranging from 49 to 80 years old; 4 to 8 weeks post-stroke) in an in-patient rehabilitation hospital.ResultsBoth heart rate (p = 0.0207) and ventilation rate (p < 0.0001) increased as intensity of activity increased. Results revealed individual differences in physiological response to daily activities, and large ranges in physiological response measures during 'moderately' and 'highly' therapeutic activities.ConclusionActivity levels of individuals with stroke during the day were generally low, though task-related changes in physiologic measures were observed. Large variability in the physiological response to even the activities deemed to be greatest intensity suggests that inclusion of such extended measurement of physiologic measures may improve understanding of physiological profile that could guide elements of the physical therapy prescription.

Stable individual differences in physiological response to stressors: implications for stress-elicited changes in immune related health

Stress reactivity refers to a stable individual difference in response to stressors. This article addresses three questions about reactivity: (1) Are cardiovascular, endocrine, and immune responses to acute laboratory stressors stable over time and across stressor tasks? (2) Are cardiovascular, endocrine, and immune reactors the same people? and (3) Are reactive people more vulnerable to stressor-induced effects on susceptibility to infectious disease? We conclude that for many individual indicators of physiological responsiveness to stressors there is moderate stability over time and across stressor tasks indicating the possible existence of underlying dispositional characteristics; the commonality of immune and cardiovascular and hormonal responses to stress depend on the nature of regulation of the immune response being assessed; reactivity appears to have implications for vulnerability to stressor-associated disease risk (stress-by-reactivity interaction) in the natural environment, but the exact nature of this vulnerability is not as yet entirely clear.