The psychological significance of changes in skin temperature

Your lies don't leave me cold: Assessing direct, indirect and physiological measures of lie detection

People tend to be bad at detecting lies: When explicitly asked to infer whether others tell a lie or the truth, people often do not perform better than chance. However, increasing evidence suggests that implicit lie detection measures and potentially physiological measures may mirror observers' telling apart lies from truths after all. Implicit and physiological responses are argued to respond to lies as a threatening stimulus associated with a threat response. Subsequently, people who tell a lie should thus be liked and trusted less than those who tell the truth (indirect lie detection measures). In terms of physiology, a threat response should be associated with narrowing blood vessels (vasoconstriction), which should reduce peripheral skin blood flow. Consequently, we expected lower finger temperatures when confronted with a lie compared to the truth. We test lie detection using explicit and indirect measures, as well as using infrared thermal imaging as a physiological measure of lie detection. Participants (N = 95) observed videos of people telling lies or the truth about their social relationships, during which participants' fingertip temperature was recorded. Results suggested that the accuracy of explicit categorizations remained at chance level. Judgments of story-tellers' likability and trustworthiness (indirect measures of lie detection) showed no evidence that observers could tell apart liars and truthtellers: Those believed to be truthtellers were liked and trusted significantly more than those believed to be liars, even when this belief was mistaken. Physiological lie detection measured using thermal imaging also failed: Observers' fingertip temperatures did not significantly differ between lies and true stories. If at all, the temperature effects pointed in the opposite direction of the lies-as-threat expectations: Fingertip temperatures increased somewhat while confronted with lies compared to true stories. Results support the impression that people are bad at detecting lies, and cast doubt on whether fingertip temperature responses could be used as lie detection mechanisms.

Volition and control in law and in brain science: neurolegal translation of a foundational concept

The law assumes that healthy adults are generally responsible for their actions and have the ability to control their behavior based on rational and moral principles. This contrasts with some recent neuroscientific accounts of action control. Nevertheless, both law and neuroscience acknowledge that strong emotions including fear and anger may "trigger" loss of normal voluntary control over action. Thus, "Loss of Control" is a partial defense for murder under English law, paralleling similar defenses in other legal systems. Here we consider the neuroscientific evidence for such legal classifications of responsibility, particularly focussing on how emotional states modulate voluntary motor control and sense of agency. First, we investigate whether neuroscience could contribute an evidence-base for law in this area. Second, we consider the societal impact of some areas where legal thinking regarding responsibility for action diverges from neuroscientific evidence: should we be guided by normative legal traditions, or by modern understanding of brain functions? In addressing these objectives, we propose a translation exercise between neuroscientific and legal terms, which may assist future interdisciplinary research.

Recent Advances in Multiplexed Wearable Sensor Platforms for Real-Time Monitoring Lifetime Stress: A Review

Researchers are interested in measuring mental stress because it is linked to a variety of diseases. Real-time stress monitoring via wearable sensor systems can aid in the prevention of stress-related diseases by allowing stressors to be controlled immediately. Physical tests, such as heart rate or skin conductance, have recently been used to assess stress; however, these methods are easily influenced by daily life activities. As a result, for more accurate stress monitoring, validations requiring two or more stress-related biomarkers are demanded. In this review, the combinations of various types of sensors (hereafter referred to as multiplexed sensor systems) that can be applied to monitor stress are discussed, referring to physical and chemical biomarkers. Multiplexed sensor systems are classified as multiplexed physical sensors, multiplexed physical-chemical sensors, and multiplexed chemical sensors, with the effect of measuring multiple biomarkers and the ability to measure stress being the most important. The working principles of multiplexed sensor systems are subdivided, with advantages in measuring multiple biomarkers. Furthermore, stress-related chemical biomarkers are still limited to cortisol; however, we believe that by developing multiplexed sensor systems, it will be possible to explore new stress-related chemical biomarkers by confirming their correlations to cortisol. As a result, the potential for further development of multiplexed sensor systems, such as the development of wearable electronics for mental health management, is highlighted in this review.

Autonomic Nervous System Activity During Positive Emotions: A Meta-Analytic Review

Autonomic nervous system (ANS) activity is a fundamental component of emotional responding. It is not clear, however, whether positive emotional states are associated with differential ANS reactivity. To address this issue, we conducted a meta-analytic review of 120 articles (686 effect sizes, total N = 6,546), measuring ANS activity during 11 elicited positive emotions, namely amusement, attachment love, awe, contentment, craving, excitement, gratitude, joy, nurturant love, pride, and sexual desire. We identified a widely dispersed collection of studies. Univariate results indicated that positive emotions produce no or weak and highly variable increases in ANS reactivity. However, the limitations of work to date – which we discuss – mean that our conclusions should be treated as empirically grounded hypotheses that future research should validate.

Quantifying Occupational Stress in Intensive Care Unit Nurses: An Applied Naturalistic Study of Correlations Among Stress, Heart Rate, Electrodermal Activity, and Skin Temperature

OBJECTIVE

To identify physiological correlates to stress in intensive care unit nurses.

BACKGROUND

Most research on stress correlates are done in laboratory environments; naturalistic investigation of stress remains a general gap.

METHOD

Electrodermal activity, heart rate, and skin temperatures were recorded continuously for 12-hr nursing shifts (23 participants) using a wrist-worn wearable technology (Empatica E4).

RESULTS

Positive correlations included stress and heart rate (ρ = .35, p < .001), stress and skin temperature (ρ = .49, p < .05), and heart rate and skin temperatures (ρ = .54, p = .0008).

DISCUSSION

The presence and direction of some correlations found in this study differ from those anticipated from prior literature, illustrating the importance of complementing laboratory research with naturalistic studies. Further work is warranted to recognize nursing activities associated with a high level of stress and the underlying reasons associated with changes in physiological responses.

APPLICATION

Heart rate and skin temperature may be used for real-time detection of stress, but more work is needed to validate such surrogate measures.

Psychophysiology of positive and negative emotions, dataset of 1157 cases and 8 biosignals

Subjective experience and physiological activity are fundamental components of emotion. There is an increasing interest in the link between experiential and physiological processes across different disciplines, e.g., psychology, economics, or computer science. However, the findings largely rely on sample sizes that have been modest at best (limiting the statistical power) and capture only some concurrent biosignals. We present a novel publicly available dataset of psychophysiological responses to positive and negative emotions that offers some improvement over other databases. This database involves recordings of 1157 cases from healthy individuals (895 individuals participated in a single session and 122 individuals in several sessions), collected across seven studies, a continuous record of self-reported affect along with several biosignals (electrocardiogram, impedance cardiogram, electrodermal activity, hemodynamic measures, e.g., blood pressure, respiration trace, and skin temperature). We experimentally elicited a wide range of positive and negative emotions, including amusement, anger, disgust, excitement, fear, gratitude, sadness, tenderness, and threat. Psychophysiology of positive and negative emotions (POPANE) database is a large and comprehensive psychophysiological dataset on elicited emotions.

Quantifying skin sensitivity caused by mechanical insults: A review

BACKGROUND

Skin sensitivity (SS) is a commonly occurring response to a range of stimuli, including environmental conditions (e.g., sun exposure), chemical irritants (e.g., soaps and cosmetics), and mechanical forces (e.g., while shaving). From both industry and academia, many efforts have been taken to quantify the characteristics of SS in a standardised manner, but the study is hindered by the lack of an objective definition.

METHODS

A review of the scientific literature regarding different parameters attributed to the loss of skin integrity and linked with exhibition of SS was conducted. Articles included were screened for mechanical stimulation of the skin, with objective quantification of tissue responses using biophysical or imaging techniques. Additionally, studies where cohorts of SS and non-SS individuals were reported have been critiqued.

RESULTS

The findings identified that the structure and function of the stratum corneum and its effective barrier properties are closely associated with SS. Thus, an array of skin tissue responses has been selected for characterization of SS due to mechanical stimuli, including: transepidermal water loss, hydration, redness, temperature, and sebum index. Additionally, certain imaging tools allow quantification of the superficial skin layers, providing structural characteristics underlying SS.

CONCLUSION

This review proposes a multimodal approach for identification of SS, providing a means to characterise skin tissue responses objectively. Optical coherence tomography (OCT) has been suggested as a suitable tool for dermatological research with clinical applications. Such an approach would enhance the knowledge underlying the multifactorial nature of SS and aid the development of personalised solutions in medical and consumer devices.

Effects of Emotional Expressiveness of a Female Digital Human on Loneliness, Stress, Perceived Support, and Closeness Across Genders: Randomized Controlled Trial

BACKGROUND

Loneliness is a growing public health problem that has been exacerbated in vulnerable groups during the COVID-19 pandemic. Social support interventions have been shown to reduce loneliness, including when delivered through technology. Digital humans are a new type of computer agent that show promise as supportive peers in health care. For digital humans to be effective and engaging support persons, it is important that they develop closeness with people. Closeness can be increased by emotional expressiveness, particularly in female relationships. However, it is unknown whether emotional expressiveness improves relationships with digital humans and affects physiological responses.

OBJECTIVE

The aim of this study is to investigate whether emotional expression by a digital human can affect psychological and physiological outcomes and whether the effects are moderated by the user's gender.

METHODS

A community sample of 198 adults (101 women, 95 men, and 2 gender-diverse individuals) was block-randomized by gender to complete a 15-minute self-disclosure conversation with a female digital human in 1 of 6 conditions. In these conditions, the digital human varied in modality richness and emotional expression on the face and in the voice (emotional, neutral, or no face; emotional or neutral voice). Perceived loneliness, closeness, social support, caring perceptions, and stress were measured after each interaction. Heart rate, skin temperature, and electrodermal activity were assessed during each interaction. 3-way factorial analyses of variance with post hoc tests were conducted.

RESULTS

Emotional expression in the voice was associated with greater perceptions of caring and physiological arousal during the interaction, and unexpectedly, with lower feelings of support. User gender moderated the effect of emotional expressiveness on several outcomes. For women, an emotional voice was associated with increased closeness, social support, and caring perceptions, whereas for men, a neutral voice increased these outcomes. For women, interacting with a neutral face was associated with lower loneliness and subjective stress compared with no face. Interacting with no face (ie, a voice-only black screen) resulted in lower loneliness and subjective stress for men, compared with a neutral or emotional face. No significant results were found for heart rate or skin temperature. However, average electrodermal activity was significantly higher for men while interacting with an emotional voice.

CONCLUSIONS

Emotional expressiveness in a female digital human has different effects on loneliness, social, and physiological outcomes for men and women. The results inform the design of digital human support persons and have theoretical implications. Further research is needed to evaluate how more pronounced emotional facial expressions in a digital human might affect the results.

TRIAL REGISTRATION

Australia New Zealand Clinical Trials Registry (ANZCTR) ACTRN12621000865819; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=381816&isReview.

An evaluation of thermal imaging as a welfare monitoring tool for captive chimpanzees

Among the growing list of novel tools with which to assess animal welfare is the use of thermal (infrared) imaging. The technology has already been utilized to identify emotional arousal in several nonhuman primate species, though most of these approaches have necessitated the use of relatively controlled settings. Here, we were interested to determine the feasibility of such techniques in a sanctuary setting in which chimpanzees were unrestrained and able to move freely around their enclosures. Furthermore, we sought to evaluate how such thermal images could be paired with corresponding long-term behavioral data and contribute to a multifactorial welfare monitoring system. Over a 6-month period, we simultaneously collected both behavioral and thermographic data on 29 chimpanzees living in four social groups. While we took a thermal image with every behavioral data point, we found that only a small proportion (6.38%) of the thermal images we captured were of sufficient quality to analyze. Most of these usable thermal images (55%) corresponded with a behavioral observation scored as "inactive," and thus other, less frequent behaviors are not so well represented in our final data set. From our data set, we were able to determine that nasal temperatures were relatively lower when chimpanzees were categorized in active behaviors compared to inactive behaviors, providing some validity measures to our approach. While there are other potential applications for thermal imaging in the behavioral management of chimpanzees, managers should consider the practical limitations of developing long-term welfare monitoring programs that rely on thermographic data.

Human and Human-Interfaced AI Interactions: Modulation of Human Male Autonomic Nervous System via Pupil Mimicry

Pupillary alterations in virtual humans induce neurophysiological responses within an observer. Technological advances have enabled rapid developments in artificial intelligence (AI), from verbal systems, to visual AI interfaces with the ability to express, and respond to emotional states of a user. Visual AI interfaces are able to change their physical parameters, such as pupil diameter. Pupillary changes can alter heart rate, however, effects on heart rate variability (HRV) are unknown. HRV, is an autonomic, non-conscious parameter which monitors sympathetic and parasympathetic nervous system (PNS) activity. N = 34 male participants aged between 19–33 were subjected to a number of conditions such as pupil dilation, constriction and blushing. The present research is the first to investigate the effects of virtual human interactions on human HRV. Outcomes of this study were obtained using eye tracking and HRV measurements. Pupil dilation relative to constriction presented in the female virtual partner induced a significant right pupillary diameter increase (p = 0.041) in human observers. Additionally, female virtual partner pupil constriction relative to dilation induced a significant increase in participants’ PNS HRV response (p = 0.036). These findings indicate the ability of a female virtual interaction partner to modulate parasympathetic autonomic functioning in young healthy male humans. This allows first insights into the effects of interacting with virtual AI interaction partners, on human autonomic functioning, and may aid development of future virtual humans, and their implementation into relevant clinical settings.

Prescriptive analytics for impulsive behaviour prevention using real-time biometrics

The present biometric market segment has been captured by compact, lightweight sensors which are capable of reading the biometric fluctuations of a user in real-time. This biometric market segment has further facilitated rise of a new ecosystem of wearable devices helpful in tracking the real-time physiological data for Healthcare-related analysis. However, the devices in the smart-wearable ecosystem are limited to capturing and displaying the biometrics without any prescriptive analytics. This paper addresses this gap to analyse the human emotion space based on an individual’s state of mind over the past 60 min and employs Deep Learning and Bayesian prediction techniques to predict the possibility of an impulsive outburst within upcoming few minutes. A lightweight smart processing device mounted with sensors captures the biometrics of the user and calibrate the same to the mental state of the user on a scale of zero to hundred. The results reveal that the deep learning algorithm along with the Bayesian probability module can predict the future mood fluctuations of the user with lower error than the other contemporary models. The predicted mood fluctuations has matched with the actual mood changes of the experimental subject within \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \pm 10 $$\end{document}±10 min of the predicted time index in 93% of the cases and within \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \pm 5 $$\end{document}±5 min in 82% of the cases.

Tears of joy, aesthetic chills and heartwarming feelings: Physiological correlates of Kama Muta

Situations involving increased closeness or exceptional kindness are often labeled as moving or touching and individuals often report bodily symptoms, including tears, goosebumps, and warmth in the body. Recently, the kama muta framework has been proposed as a cross-cultural conceptualization of these experiences. Prior research on kama muta has mostly relied on subjective reports. Thus, our main goal of the present project was to examine the pattern of physiological responses to kama muta inducing videos and compare it to the patterns for the similar, though distinct emotions of sadness and awe. One hundred forty-four Portuguese and Norwegian participants were individually exposed to all three emotion conditions. Several psychophysiological indexes of the autonomic nervous system were collected continuously during exposure, including cardiovascular, respiratory, and electrodermal activity, facial EMG, skin temperature, as well as piloerection and lachrymation using cameras. Overall, the results partly replicated previous findings on being moved experiences and self-report studies. Strong self-reported experiences of kama muta were associated with increased phasic skin conductance, skin temperature, piloerection, and zygomaticus activity, while they were associated with reduced heart rate, respiration rate, and tonic skin conductance. The physiological profile of kama muta was successfully distinguished from sadness and awe, partly corroborating self-report evidence. We obtained no clear evidence of a kama muta association with the occurrence of lachrymation or heart rate variability. Our findings provide a systematic overview of psychophysiological response to experiences of kama muta, and help to inform future research on this emotion and positive emotions in general.

Engagement in video and audio narratives: contrasting self-report and physiological measures

Stories play a fundamental role in human culture. They provide a mechanism for sharing cultural identity, imparting knowledge, revealing beliefs, reinforcing social bonds and providing entertainment that is central to all human societies. Here we investigated the extent to which the delivery medium of a story (audio or visual) affected self-reported and physiologically measured engagement with the narrative. Although participants self-reported greater involvement for watching video relative to listening to auditory scenes, stronger physiological responses were recorded for auditory stories. Sensors placed at their wrists showed higher and more variable heart rates, greater electrodermal activity, and even higher body temperatures. We interpret these findings as evidence that the stories were more cognitively and emotionally engaging at a physiological level when presented in an auditory format. This may be because listening to a story, rather than watching a video, is a more active process of co-creation, and that this imaginative process in the listener's mind is detectable on the skin at their wrist.

Cognitive Processes Unfold in a Social Context: A Review and Extension of Social Baseline Theory

Psychologists often assume that social and cognitive processes operate independently, an assumption that prompts research into how social context influences cognitive processes. We propose that social and cognitive processes are not necessarily separate, and that social context is innate to resource dependent cognitive processes. We review the research supporting social baseline theory, which argues that our default state in physiological, cognitive, and neural processing is to incorporate the relative costs and benefits of acting in our social environment. The review extends social baseline theory by applying social baseline theory to basic cognitive processes such as vision, memory, and attention, incorporating individual differences into the theory, reviewing environmental influences on social baselines, and exploring the dynamic effects of social interactions. The theoretical and methodological implications of social baseline theory are discussed, and future research endeavors into social cognition should consider that cognitive processes are situated within our social environments.

The Territory of my Body: Testosterone Prevents Limb Cooling in the Rubber Hand Illusion

The Rubber Hand Illusion (RHI) is an experimental paradigm for assessing changes in body ownership. Recent findings in the field suggest that social emotions can influence such changes and that empathic motivation in particular appears to positively predict the malleability of body representations. Since the steroid hormone, testosterone, is well known to interrupt certain forms of empathic processing, in the current study we investigated whether 0.5 mg of testosterone affected ownership indices of the RHI. Forty-nine females participated in a double-blind, placebo-controlled experiment in which the RHI was induced. Compared to placebo, testosterone had no effects on the alteration of subjective ownership over the rubber limb or on subjective sense of proprioceptive drift. However, unlike the placebo group, testosterone-treated participants did not display an objective decline in the temperature of their own (hidden) hand following induction of the illusion. These findings suggest that testosterone strengthens implicit but not explicit bodily self-representations. We propose that effective maintenance of implicit body boundaries can be regarded, conceptually, as a primary defensive state facilitating integrity of the self.

Brain and Body Emotional Responses: Multimodal Approximation for Valence Classification

In order to develop more precise and functional affective applications, it is necessary to achieve a balance between the psychology and the engineering applied to emotions. Signals from the central and peripheral nervous systems have been used for emotion recognition purposes, however, their operation and the relationship between them remains unknown. In this context, in the present work, we have tried to approach the study of the psychobiology of both systems in order to generate a computational model for the recognition of emotions in the dimension of valence. To this end, the electroencephalography (EEG) signal, electrocardiography (ECG) signal and skin temperature of 24 subjects have been studied. Each methodology has been evaluated individually, finding characteristic patterns of positive and negative emotions in each of them. After feature selection of each methodology, the results of the classification showed that, although the classification of emotions is possible at both central and peripheral levels, the multimodal approach did not improve the results obtained through the EEG alone. In addition, differences have been observed between cerebral and peripheral responses in the processing of emotions by separating the sample by sex; though, the differences between men and women were only notable at the peripheral nervous system level.

The use of infrared thermography to investigate emotions in common marmosets

Measuring body surface temperature changes with infrared thermography has recently been put forward as a non-invasive alternative measure of physiological correlates of emotional reactions. In particular, the nasal region seems to be highly sensitive to emotional reactions. Several studies suggest that nasal temperature is negatively correlated with the level of arousal in humans and other primates, but some studies provide inconsistent results. Our goal was to establish the use of infrared thermography to quantify emotional reactions in common marmosets (Callithrix jacchus), with a focus on the nasal region. To do so we exposed 17 common marmosets to a set of positive, negative and control stimuli (positive: preferred food, playback of food calls; negative: playback of aggressive vocalizations, teasing; control: no stimulus). We compared nasal temperature before and after the stimuli and expected that highly aroused emotional states would lead to a drop in nasal temperature. To validate the thermography measure, we coded piloerection of the tail as an independent measure of arousal and expected a negative correlation between the two measures. Finally, we coded physical activity to exclude its potential confounding impact on nasal temperature. Our results show that all predictions were met: the animals showed a strong decrease in nasal temperature after the presentation of negative arousing stimuli (teasing, playback of aggressive vocalizations). Furthermore, these changes in nasal temperature were correlated with piloerection of the tail and could not be explained by changes in physical activity. In the positive and the control conditions, we found systematic sex differences: in males, the preferred food, the playbacks of food calls, as well as the control stimulus led to an increase in nasal temperature, whereas in females the temperature remained stable (preferred food, control) or decreased (playback of food calls). Based on naturalistic observations that document higher food motivation and competition among female marmosets, as well as stronger reactions to separation from group members in male marmosets, these sex differences corroborate a negative correlation between arousal and nasal temperature. Overall, our results support that measuring nasal temperature by infrared thermography is a promising method to quantify emotional arousal in common marmosets in a fully non-invasive and highly objective way.

Iron and laterality effects on healing of cautery disbudding wounds in dairy calves

Hot-iron disbudding, the process of cauterizing the horn buds of calves or goat kids at an early age to prevent horn growth, is routinely practiced in dairy production. The wounds take weeks to heal and are painful to touch throughout this time. Possible strategies to hasten the healing of disbudding wounds are not well understood, but the type of iron used may be an important factor to consider. When evaluating strategies to hasten healing, a within-subjects design may be preferable, but laterality effects might act as a potential source of variation and confounding in this type of experiment. Our objectives were to compare healing after disbudding with 2 commercially available irons, and to determine whether wounds healed differently on the left versus the right side of the head. Ten Holstein calves 4 to 10 d of age were disbudded using the Rhinehart X50A electric disbudder (Rhinehart Development Corp., Spencerville, IN) on one horn bud and the Portasol gas disbudder (Portasol USA, Elmira, OR) on the other; side (left vs. right) was balanced between treatments. We scored wounds daily for the presence of 6 tissue types: attached necrotic tissue, detached necrotic tissue, exudate, granulation, crust, and epithelium. Surface temperature and size of the wound were measured twice-weekly using thermal and digital photographs, respectively. The type of iron used did not affect latency to re-epithelialize, which took on average (mean ± standard deviation) 53 ± 3 d and 55 ± 3 d for Portasol and Rhinehart wounds, respectively (range: 40-70 d). However, compared with Portasol wounds, those from the Rhinehart had fewer days of granulation tissue and tended to have more days of detached necrotic tissue. The Portasol tip had a smaller total surface area than the Rhinehart, which may have resulted in a less severe burn, causing the necrotic tissue to fall off sooner. The left side tended to re-epithelialize faster than the right side (mean ± standard error: left 51 ± 3 d; right 57 ± 3 d) and have fewer days of crust. Left-sided wounds were also cooler and tended to be smaller than those on the right. To assess the external validity of these laterality effects in our primary experiment (experiment A), we analyzed wound healing data from 2 other disbudding studies, one on calves (experiment B) and one on goat kids (experiment C). We observed laterality effects in the opposite direction in Experiment B, but negligible effects in experiment C, indicating that the differences in laterality had low external validity; the biological meaning of this asymmetry is unclear. Nonetheless, if using a within-subjects design, asymmetries in wound healing should be considered to avoid confounding effects. In conclusion, wounds from both irons took 7 to 8 wk to heal, on average; other strategies to accelerate healing should be explored.

Moving Through the Literature: What Is the Emotion Often Denoted Being Moved?

When do people say that they are moved, and does this experience constitute a unique emotion? We review theory and empirical research on being moved across psychology and philosophy. We examine feeling labels, elicitors, valence, bodily sensations, and motivations. We find that the English lexeme being moved typically (but not always) refers to a distinct and potent emotion that results in social bonding; often includes tears, piloerection, chills, or a warm feeling in the chest; and is often described as pleasurable, though sometimes as a mixed emotion. While we conclude that it is a distinct emotion, we also recommend studying it in a more comprehensive emotion framework, instead of using the ambiguous vernacular term being moved as a scientific term.

Methods for Evaluating Emotions Evoked by Food Experiences: A Literature Review

Besides sensory characteristics of food, food-evoked emotion is a crucial factor in predicting consumer's food preference and therefore in developing new products. Many measures have been developed to assess food-evoked emotions. The aim of this literature review is (i) to give an exhaustive overview of measures used in current research and (ii) to categorize these methods along measurement level (physiological, behavioral, and cognitive) and emotional processing level (unconscious sensory, perceptual/early cognitive, and conscious/decision making) level. This 3 × 3 categorization may help researchers to compile a set of complementary measures (“toolbox”) for their studies. We included 101 peer-reviewed articles that evaluate consumer's emotions and were published between 1997 and 2016, providing us with 59 different measures. More than 60% of these measures are based on self-reported, subjective ratings and questionnaires (cognitive measurement level) and assess the conscious/decision-making level of emotional processing. This multitude of measures and their overrepresentation in a single category hinders the comparison of results across studies and building a complete multi-faceted picture of food-evoked emotions. We recommend (1) to use widely applied, validated measures only, (2) to refrain from using (highly correlated) measures from the same category but use measures from different categories instead, preferably covering all three emotional processing levels, and (3) to acquire and share simultaneously collected physiological, behavioral, and cognitive datasets to improve the predictive power of food choice and other models.

Physiological and self-report responses of parents of children with autism spectrum disorder to children crying

Little is known about the physiological response of parents of children with Autism Spectrum Disorder (ASD) to crying of children who have already received the diagnosis of ASD. This study aimed to compare cardiac dynamics via Inter-Beat Interval (IBI) and self-reported emotional states of parents of children with ASD and of parents with typically developing (TD) children while listening to crying of children with ASD (ASD cry) and of typically developing children (TD cry). Analyses revealed higher IBI in parents of children with ASD than IBI in parents of TD children while listening to both cry groups; however no differences on self-reported emotional states were observed. Parents of children with ASD were calmer (higher IBI) than parents of TD children while listening to crying. However, ASD cry did not elicit different IBI compared to TD cry. ASD cry and TD cry were differentiated based on parents' self-responses about what they felt during the listening of crying, their physiological responses showed no differences. These results highlight the similarities and differences between self-reported emotional states and physiological responses of parents of children with ASD, and also point to the importance of monitoring parents' physiological responses in addition to their subjective responses.

Eye region surface temperature reflects both energy reserves and circulating glucocorticoids in a wild bird

Body temperature of endotherms shows substantial within- and between-individual variation, but the sources of this variation are not fully understood in wild animals. Variation in body temperature can indicate how individuals cope with their environment via metabolic or stress-induced effects, both of which may relate to depletion of energy reserves. Body condition can reflect heat production through changes to metabolic rate made to protect energy reserves. Additionally, changes in metabolic processes may be mediated by stress-related glucocorticoid secretion, which is associated with altered blood-flow patterns that affect regional body temperatures. Accordingly, both body condition and glucocorticoid secretion should relate to body temperature. We used thermal imaging, a novel non-invasive method of temperature measurement, to investigate relationships between body condition, glucocorticoid secretion and body surface temperature in wild blue tits (Cyanistes caeruleus). Individuals with lower body condition had lower eye-region surface temperature in both non-breeding and breeding seasons. Eye-region surface temperature was also negatively correlated with baseline circulating glucocorticoid levels in non-breeding birds. Our results demonstrate that body surface temperature can integrate multiple aspects of physiological state. Consequently, remotely-measured body surface temperature could be used to assess such aspects of physiological state non-invasively in free-living animals at multiple life history stages.

Skin temperature, sleep, and vigilance

A large number of studies have shown a close association between the 24-hour rhythms in core body temperature and sleep propensity. More recently, studies have have begun to elucidate an intriguing association of sleep with skin temperature as well. The present chapter addresses the association of sleep and alertness with skin temperature. It discusses whether the association could reflect common underlying drivers of both sleep propensity and skin vasodilation; whether it could reflect efferents of sleep-regulating brain circuits to thermoregulatory circuits; and whether skin temperature could provide afferent input to sleep-regulating brain circuits. Sleep regulation and concomitant changes in skin temperature are systematically discussed and three parallel factors suggested: a circadian clock mechanism, a homeostatic hourglass mechanism, and a third set of sleep-permissive and wake-promoting factors that gate the effectiveness of signals from the clock and hourglass in the actual induction of sleep or maintenance of alert wakefulness. The chapter moreover discusses how the association between skin temperature and arousal can change with sleep deprivation and insomnia. Finally it addresses whether the promising laboratory findings on the effects of skin temperature manipulations on vigilance can be applied to improve sleep in everyday life.

In utero testosterone exposure influences physiological responses to dyadic interactions in neurotypical adults

OBJECTIVE

We investigated how different levels of prenatal exposure to testosterone influence physiological reactions to dyadic interactions, hypothesising that higher levels of prenatal testosterone are linked to greater physiological responses.

METHOD

Autonomic nervous system responses to dyadic interactions focussed on social or physical norms were measured. Physiological assessment of excitability (heart rate, facial temperature) and a behavioural assessment (Likert items judgements) were run on 25 neurotypical participants who had distinct testosterone exposure levels in utero. In utero exposure to testosterone was assessed measuring 2D : 4D (ratio between the lengths of the index and the ring fingers).

RESULTS

Higher testosterone exposure participants showed greater physiological arousal: a greater heart rate decrease, independent from scenario type (p<0.05), and opposite facial temperature changes in response to social (increase) (vs.) physical scenarios (decrease) were found (Left-cheek: p<0.05; Right-cheek: p<0.05).

CONCLUSION

These findings suggest a long-term influence of prenatal environment on adults' physiological responses during social situations.

Biomusic: An Auditory Interface for Detecting Physiological Indicators of Anxiety in Children

For children with profound disabilities affecting communication, it can be extremely challenging to identify salient emotions such as anxiety. If left unmanaged, anxiety can lead to hypertension, cardiovascular disease, and other psychological diagnoses. Physiological signals of the autonomic nervous system are indicative of anxiety, but can be difficult to interpret for non-specialist caregivers. This paper evaluates an auditory interface for intuitive detection of anxiety from physiological signals. The interface, called "Biomusic," maps physiological signals to music (i.e., electrodermal activity to melody; skin temperature to musical key; heart rate to drum beat; respiration to a "whooshing" embellishment resembling the sound of an exhalation). The Biomusic interface was tested in two experiments. Biomusic samples were generated from physiological recordings of typically developing children (n = 10) and children with autism spectrum disorders (n = 5) during relaxing and anxiety-provoking conditions. Adult participants (n = 16) were then asked to identify "anxious" or "relaxed" states by listening to the samples. In a classification task with 30 Biomusic samples (1 relaxed state, 1 anxious state per child), classification accuracy, sensitivity, and specificity were 80.8% [standard error (SE) = 2.3], 84.9% (SE = 3.0), and 76.8% (SE = 3.9), respectively. Participants were able to form an early and accurate impression of the anxiety state within 12.1 (SE = 0.7) seconds of hearing the Biomusic with very little training (i.e., < 10 min) and no contextual information. Biomusic holds promise for monitoring, communication, and biofeedback systems for anxiety management.

Neural correlates of fear-induced sympathetic response associated with the peripheral temperature change rate

Activation of the sympathetic nervous system is essential for coping with environmental stressors such as fearful stimuli. Recent human imaging studies demonstrated that activity in some cortical regions, such as the anterior cingulate cortex (ACC) and anterior insula cortex (aIC), is related to sympathetic activity. However, little is known about the functional brain connectivity related to sympathetic response to fearful stimuli. The participants were 32 healthy, right-handed volunteers. Functional magnetic resonance imaging (fMRI) was used to examine brain activity when watching horror and control movies. Fingertip temperature was taken during the scanning as a measure of sympathetic response. The movies were watched a second time, and the degree of fear (9-point Likert-type scale) was evaluated every three seconds. The brain activity of the ACC, bilateral aIC, and bilateral anterior prefrontal cortex (aPFC) was correlated with the change rate of fingertip temperature, with or without fearful stimuli. Functional connectivity analysis revealed significantly greater positive functional connectivity between the amygdala and the ACC and between the amygdala and the aIC when watching the horror movie than when watching the control movie. Whole-brain psycho-physiological interaction (PPI) analysis revealed that the functional connectivity between the left amygdala and the ACC was modulated according to the fear rating. Our results indicate that the increased functional connectivity between the left amygdala and the ACC represents a sympathetic response to fearful stimuli.

"The face of ostracism": The impact of the social categorization on the thermal facial responses of the target and the observer

Ostracism has been shown to elicit pain in both the target and the observers. Two experiments investigated the autonomic thermal signature associated with an ostracism experience and assessed whether and how social categorization impacts the autonomic arousal of both the target and the observer. Autonomic response was assessed using thermal infrared imaging, recording facial temperature variation during an online game of ball toss (i.e., Cyberball). Social categorization was manipulated using a minimal group paradigm. The results show a more intense autonomic response during ostracism (vs. inclusion), marked by an increase in facial temperature in the nose and the perioral area. This autonomic response is stronger when individuals are ostracized by ingroup (vs. outgroup) members. Similar pattern of temperature variations emerge when individuals observe an ostracism episode involving ingroup members. Our findings advance the understanding of psycho-physiological mechanisms underlying the ostracism experience and emphasize the impact of social categorization in such mechanisms.

Transdermal neuromodulation of noradrenergic activity suppresses psychophysiological and biochemical stress responses in humans

We engineered a transdermal neuromodulation approach that targets peripheral (cranial and spinal) nerves and utilizes their afferent pathways as signaling conduits to influence brain function. We investigated the effects of this transdermal electrical neurosignaling (TEN) method on sympathetic physiology under different experimental conditions. The TEN method involved delivering high-frequency pulsed electrical currents to ophthalmic and maxillary divisions of the right trigeminal nerve and cervical spinal nerve afferents. Under resting conditions, TEN significantly suppressed basal sympathetic tone compared to sham as indicated by functional infrared thermography of facial temperatures. In a different experiment, subjects treated with TEN reported significantly lower levels of tension and anxiety on the Profile of Mood States scale compared to sham. In a third experiment when subjects were experimentally stressed TEN produced a significant suppression of heart rate variability, galvanic skin conductance, and salivary α-amylase levels compared to sham. Collectively these observations demonstrate TEN can dampen basal sympathetic tone and attenuate sympathetic activity in response to acute stress induction. Our physiological and biochemical observations are consistent with the hypothesis that TEN modulates noradrenergic signaling to suppress sympathetic activity. We conclude that dampening sympathetic activity in such a manner represents a promising approach to managing daily stress.

Three physiological responses in fathers and non-fathers' to vocalizations of typically developing infants and infants with Autism Spectrum Disorder

Children with ASD, even before receiving a formal diagnosis, express atypical patterns of distress vocalizations (namely, episodes of crying). Their cries have higher fundamental frequencies, shorter inter-bout pauses, and fewer utterances. Cries of children with ASD are also perceived differently from other cries, and these perceptual differences may alter parent-infant interaction. This study assessed multiple physiological responses in fathers and non-fathers to atypical distress vocalizations (cries of children with ASD), acoustically matched typical distress vocalizations (cries of typically developing children), and positive vocalizations (laughter of typically developing children). The experimental procedures were designed to measure how components of the autonomic nervous system respond to typical and atypical infant vocalizations. Three convergent methodologies (Galvanic Skin Response-GSR; cardiac dynamics via Inter-Beat Interval-IBI; right hand temperature change-RHTC) were performed on two groups with contrasting caregiving experience: fathers of typically developing children (n=10) and non-fathers (n=10). Inferential statistical analysis compared the two groups (fathers, non-fathers) and three stimulus types (ASD cry, typical cry, laughter) for the three measures (GSR, IBI, RHTC). Both fathers and non-fathers showed greater negative responses (increased GSR) to ASD cries compared to typical cries and laughter. Fathers showed higher IBI and greater temperature increases (RHTC) than non-fathers while listening to typical and atypical cries. Fathers and non-fathers showed more emotional arousal mediated by sympathetic activation while listening to cries of children with ASD. Fathers were calmer and acted more promptly than non-fathers while listening to typical cries, perhaps because the fathers had more experience in caring for crying infants. These findings point to similarities and differences in fathers' and non-fathers' physiological responsiveness to cries of children with ASD and might guide specific intervention programs for parents of children at risk of ASD.

Unconscious deception detection measured by finger skin temperature and indirect veracity judgments-results of a registered report

A pre-registered experiment was conducted to examine psychophysiological responses to being lied to. Bridging research on social cognition and deception detection, we hypothesized that observing a liar compared to a truth-teller would decrease finger skin temperature of observers. Participants first watched two targets while not forewarned that they would later be asked to judge (direct and indirect) veracity, and then watched another two targets while forewarned about this. During both these phases finger skin temperature was measured. Findings pertaining to temperature partly confirmed our main hypothesis. When participants were observing a liar, irrespective of being forewarned, on average finger skin temperature declined over time. In the forewarned phase, temperature trajectories of truth-tellers were higher than those of liars, however, in the not forewarned phase, this pattern was reversed. Results confirmed our further hypotheses that participants judge liars as less likeable and less trustworthy than truth-tellers-an indication of indirect deception detection. Our hypothesis that the effect size for trustworthiness would be bigger than that of liking was not supported by the data. Additionally, and also confirming our hypothesis, participants performed around chance level when directly judging whether the target person was lying. Exploratory analyses are reported with regard to truth bias and dependency between direct and indirect veracity judgments. Limitations and directions for future work related to the existence of psychophysiological indicators of deception detection are discussed.

Baby, you light-up my face: culture-general physiological responses to infants and culture-specific cognitive judgements of adults

Infants universally elicit in adults a set of solicitous behaviors that are evolutionarily important for the survival of the species. However, exposure, experience, and prejudice appear to govern adults' social choice and ingroup attitudes towards other adults. In the current study, physiological arousal and behavioral judgments were assessed while adults processed unfamiliar infant and adult faces of ingroup vs. outgroup members in two contrasting cultures, Japan and Italy. Physiological arousal was investigated using the novel technique of infrared thermography and behavioral judgments using ratings. We uncovered a dissociation between physiological and behavioral responses. At the physiological level, both Japanese and Italian adults showed significant activation (increase of facial temperature) for both ingroup and outgroup infant faces. At the behavioral level, both Japanese and Italian adults showed significant preferences for ingroup adults. Arousal responses to infants appear to be mediated by the autonomic nervous system and are not dependent on direct caregiving exposure, but behavioral responses appear to be mediated by higher-order cognitive processing based on social acceptance and cultural exposure.

Using Infrared Thermography to Assess Emotional Responses to Infants

Adult-infant interactions operate simultaneously across multiple domains and at multiple levels - from physiology to behavior. Unpackaging and understanding them, therefore, involves analysis of multiple data streams. In this study, we tested physiological responses and cognitive preferences for infant and adult faces in adult females and males. Infrared thermography was used to assess facial temperature changes as a measure of emotional valence, and we used a behavioral rating system to assess adults' expressed preferences. We found greater physiological activation in response to infant stimuli in females than males. As for cognitive preferences, we found greater responses to adult stimuli than to infant stimuli, both in males and females. The results are discuss in light of the Life History Theory. Finally, we discuss the importance of integrating the two data streams on our conclusions.

Registered report: measuring unconscious deception detection by skin temperature

Findings from the deception detection literature suggest that although people are not skilled in consciously detecting a liar, they may intuit that something about the person telling a lie is off. In the current proposal, we argue that observing a liar influences the observer's physiology even though the observer may not be consciously aware of being lied to (i.e., the observers' direct deception judgment does not accurately differentiate between liars and truth-tellers). To test this hypothesis, participants' finger temperature will be measured while they watch videos of persons who are either honest or dishonest about their identity. We hypothesize that skin temperature will be lower when observing a liar than when observing a truth-teller. Additionally, we test whether perceiving a liar influences finger skin temperature differently when an individual is, or is not, alerted to the possibility of deceit. We do this by varying participants' awareness of the fact that they might be lied to. Next to measuring physiological responses to liars and truth-tellers, self-reported direct and indirect veracity judgments (i.e., trustworthiness and liking) of the target persons will be assessed. We hypothesize that indirect veracity judgments will better distinguish between liars and truth-tellers than direct veracity judgments.

Autonomic responses to correct outcomes and interaction errors during single-switch scanning among children with severe spastic quadriplegic cerebral palsy

BACKGROUND

The combination of single-switch access technology and scanning is the most promising means of augmentative and alternative communication for many children with severe physical disabilities. However, the physical impairment of the child and the technology's limited ability to interpret the child's intentions often lead to false positives and negatives (corresponding to accidental and missed selections, respectively) occurring at rates that frustrate the user and preclude functional communication. Multiple psychophysiological studies have associated cardiac deceleration and increased phasic electrodermal activity with self-realization of errors among able-bodied individuals. Thus, physiological measurements have potential utility at enhancing single-switch access, provided that such prototypical autonomic responses exist in persons with profound disabilities.

METHODS

The present case series investigated the autonomic responses of three pediatric single-switch users with severe spastic quadriplegic cerebral palsy, in the context of a single-switch letter matching activity. Each participant exhibited distinct autonomic responses to activity engagement.

RESULTS

Our analysis confirmed the presence of the autonomic response pattern of cardiac deceleration and increased phasic electrodermal activity following true positives, false positives and false negatives errors, but not subsequent to true negative outcomes.

CONCLUSIONS

These findings suggest that there may be merit in complementing single-switch input with autonomic measurements to improve augmentative and alternative communications for pediatric access technology users.

Psychophysiological correlates of the disposition effect

We assess the psychophysiological characteristics underlying the disposition effect and find that subjects showing greater disposition effect are those who sweat more and present lower body temperature and heart rate.

Cold-blooded loneliness: social exclusion leads to lower skin temperatures

Being ostracized or excluded, even briefly and by strangers, is painful and threatens fundamental needs. Recent work by Zhong and Leonardelli (2008) found that excluded individuals perceive the room as cooler and that they desire warmer drinks. A perspective that many rely on in embodiment is the theoretical idea that people use metaphorical associations to understand social exclusion (see Landau, Meier, & Keefer, 2010). We suggest that people feel colder because they are colder. The results strongly support the idea that more complex metaphorical understandings of social relations are scaffolded onto literal changes in bodily temperature: Being excluded in an online ball tossing game leads to lower finger temperatures (Study 1), while the negative affect typically experienced after such social exclusion is alleviated after holding a cup of warm tea (Study 2). The authors discuss further implications for the interaction between body and social relations specifically, and for basic and cognitive systems in general.

Real-time closed-loop control of cognitive load in neurological patients during robot-assisted gait training

Cognitively challenging training sessions during robot-assisted gait training after stroke were shown to be key requirements for the success of rehabilitation. Despite a broad variability of cognitive impairments amongst the stroke population, current rehabilitation environments do not adapt to the cognitive capabilities of the patient, as cognitive load cannot be objectively assessed in real-time. We provided healthy subjects and stroke patients with a virtual task during robot-assisted gait training, which allowed modulating cognitive load by adapting the difficulty level of the task. We quantified the cognitive load of stroke patients by using psychophysiological measurements and performance data. In open-loop experiments with healthy subjects and stroke patients, we obtained training data for a linear, adaptive classifier that estimated the current cognitive load of patients in real-time. We verified our classification results via questionnaires and obtained 88% correct classification in healthy subjects and 75% in patients. Using the pre-trained, adaptive classifier, we closed the cognitive control loop around healthy subjects and stroke patients by automatically adapting the difficulty level of the virtual task in real-time such that patients were neither cognitively overloaded nor under-challenged.

Sleep, vigilance, and thermosensitivity

The regulation of sleep and wakefulness is well modeled with two underlying processes: a circadian and a homeostatic one. So far, the parameters and mechanisms of additional sleep-permissive and wake-promoting conditions have been largely overlooked. The present overview focuses on one of these conditions: the effect of skin temperature on the onset and maintenance of sleep, and alertness. Skin temperature is quite well suited to provide the brain with information on sleep-permissive and wake-promoting conditions because it changes with most if not all of them. Skin temperature changes with environmental heat and cold, but also with posture, environmental light, danger, nutritional status, pain, and stress. Its effect on the brain may thus moderate the efficacy by which the clock and homeostat manage to initiate or maintain sleep or wakefulness. The review provides a brief overview of the neuroanatomical pathways and physiological mechanisms by which skin temperature can affect the regulation of sleep and vigilance. In addition, current pitfalls and possibilities of practical applications for sleep enhancement are discussed, including the recent finding of impaired thermal comfort perception in insomniacs.

Autonomic nervous system activity in emotion: a review

Autonomic nervous system (ANS) activity is viewed as a major component of the emotion response in many recent theories of emotion. Positions on the degree of specificity of ANS activation in emotion, however, greatly diverge, ranging from undifferentiated arousal, over acknowledgment of strong response idiosyncrasies, to highly specific predictions of autonomic response patterns for certain emotions. A review of 134 publications that report experimental investigations of emotional effects on peripheral physiological responding in healthy individuals suggests considerable ANS response specificity in emotion when considering subtypes of distinct emotions. The importance of sound terminology of investigated affective states as well as of choice of physiological measures in assessing ANS reactivity is discussed.

Infrared thermal imaging as a physiological access pathway: a study of the baseline characteristics of facial skin temperatures

In this study we examine the baseline characteristics of facial skin temperature, as measured by dynamic infrared thermal imaging, to gauge its potential as a physiological access pathway for non-verbal individuals with severe motor impairments. Frontal facial recordings were obtained from 12 asymptomatic adults in a resting state with a high-end infrared thermal imaging system. From the infrared thermal recordings, mean skin temperature time series were generated for regions of interest encompassing the nasal, periorbital and supraorbital areas. A 90% bandwidth for all regions of interest was found to be in the 1 Hz range. Over 70% of the time series were identified as nonstationary (p<0.05), with the nonstationary mean as the greatest contributing source. Correlation coefficients between regions were significant (p<0.05) and ranged from values of 0.30 (between periorbital and supraorbital regions) to 0.75 (between contralateral supraorbital regions). Using information measures, we concluded that the greatest degree of information existed in the nasal and periorbital regions. Mutual information existed across all regions but was especially prominent between the nasal and periorbital regions. Results from this study provide insight into appropriate analysis methods and potential discriminating features for the application of facial skin temperature as a physiological access pathway.

Putting the altruism back into altruism: the evolution of empathy

Evolutionary theory postulates that altruistic behavior evolved for the return-benefits it bears the performer. For return-benefits to play a motivational role, however, they need to be experienced by the organism. Motivational analyses should restrict themselves, therefore, to the altruistic impulse and its knowable consequences. Empathy is an ideal candidate mechanism to underlie so-called directed altruism, i.e., altruism in response to anothers's pain, need, or distress. Evidence is accumulating that this mechanism is phylogenetically ancient, probably as old as mammals and birds. Perception of the emotional state of another automatically activates shared representations causing a matching emotional state in the observer. With increasing cognition, state-matching evolved into more complex forms, including concern for the other and perspective-taking. Empathy-induced altruism derives its strength from the emotional stake it offers the self in the other's welfare. The dynamics of the empathy mechanism agree with predictions from kin selection and reciprocal altruism theory.

Cardiovascular, electrodermal, and respiratory response patterns to fear- and sadness-inducing films

Responses to fear- and sadness-inducing films were assessed using a broad range of cardiovascular (heart rate, T-wave amplitude, low- and high-frequency heart rate variability, stroke volume, preejection period, left-ventricular ejection time, Heather index, blood pressure, pulse amplitude and transit time, and finger temperature), electrodermal (level, response rate, and response amplitude), and respiratory (rate, tidal volume and its variability, inspiratory flow rate, duty cycle, and end-tidal pCO(2)) measures. Subjective emotional experience and facial behavior (Corrugator Supercilii and Zygomaticus Major EMG) served as control measures. Results indicated robust differential physiological response patterns for fear, sadness, and neutral (mean classification accuracy 85%). Findings are discussed in terms of the fight-flight and conservation-withdrawal responses and possible limitations of a valence-arousal categorization of emotion in affective space.

Decrease in nasal temperature of rhesus monkeys (Macaca mulatta) in negative emotional state

We established an infrared thermographic system for the detection of emotion-related temperature changes in rhesus monkeys (Macaca mulatta). We continuously measured temperatures of various facial regions of four rhesus monkeys during the presentation of a potentially 'threatening' person, i.e., a person in a laboratory coat with a catching net, who entered the experimental room and approached the monkeys. The temperatures were also measured before and after the presentation of the 'stimulation period.' The temperature of the nasal region decreased significantly within 10-30 s, and continued to decrease throughout the stimulation period. During this period, the monkeys frequently expressed silent bared-teeth face, staring open-mouth face, and lip-smacking, all of which were expressions of a negative emotion. Assuming that the monkeys experience the negative emotion when viewing the potentially threatening stimulus, we conclude that the decrease in nasal skin temperature is relevant to the alteration of the emotional state. The present findings suggest that nasal temperature can be a reliable and accurate indicator of a change from neutral to negative in emotional state of non-human primates.

The psychophysiology of real-time financial risk processing

A longstanding controversy in economics and finance is whether financial markets are governed by rational forces or by emotional responses. We study the importance of emotion in the decision-making process of professional securities traders by measuring their physiological characteristics (e.g., skin conductance, blood volume pulse, etc.) during live trading sessions while simultaneously capturing real-time prices from which market events can be detected. In a sample of 10 traders, we find statistically significant differences in mean electrodermal responses during transient market events relative to no-event control periods, and statistically significant mean changes in cardiovascular variables during periods of heightened market volatility relative to normal-volatility control periods. We also observe significant differences in these physiological responses across the 10 traders that may be systematically related to the traders' levels of experience.

Temperature asymmetry and behavior

Asymmetries in the surface temperature of the fingertips of the right and left hands were gathered on four independent samples of children ranging in age from 4 to 8 years (N = 398) while watching film clips in order to determine if the direction or magnitude of asymmetry was related to behavioral signs of fear or inhibition. The left index finger was cooler than the right index finger for all four groups. The right ring finger was cooler than the left ring finger for two of the four groups, and of similar temperature for the other two groups. There was no relation between direction of asymmetry and behavior and only a modest relation between a large temperature asymmetry between the index fingers and behavioral signs of very high fear or inhibition. There was no relation between asymmetry and fear or inhibition across all children, suggesting the utility of examining extreme scores.