The science of interpersonal touch: an overview

Tactile input and empathy modulate the perception of ambiguous biological motion

Evidence has shown that task-irrelevant auditory cues can bias perceptual decisions regarding directional information associated with biological motion, as indicated in perceptual tasks using point-light walkers (PLWs) (Brooks et al., 2007). In the current study, we extended the investigation of cross-modal influences to the tactile domain by asking how tactile input resolves perceptual ambiguity in visual apparent motion, and how empathy plays a role in this cross-modal interaction. In Experiment 1, we simulated the tactile feedback on the observers' fingertips when the (upright or inverted) PLWs (comprised of either all red or all green dots) were walking (leftwards or rightwards). The temporal periods between tactile events and critical visual events (the PLW's feet hitting the ground) were manipulated so that the tap could lead, synchronize, or lag the visual foot-hitting-ground event. We found that the temporal structures between tactile (feedback) and visual (hitting) events systematically biases the directional perception for upright PLWs, making either leftwards or rightwards more dominant. However, this effect was absent for inverted PLWs. In Experiment 2, we examined how empathy modulates cross-modal capture. Instead of giving tactile feedback on participants' fingertips, we gave taps on their ankles and presented the PLWs with motion directions of approaching (facing toward observer)/receding (facing away from observer) to resemble normal walking postures. With the same temporal structure, we found that individuals with higher empathy were more subject to perceptual bias in the presence of tactile feedback. Taken together, our findings showed that task-irrelevant tactile input can resolve the otherwise ambiguous perception of the direction of biological motion, and this cross-modal bias was mediated by higher level social-cognitive factors, including empathy.

Preparing to caress: a neural signature of social bonding

It is assumed that social bonds in humans have consequences for virtually all aspects of behavior. Social touch-based contact, particularly hand caressing, plays an important role in social bonding. Pre-programmed neural circuits likely support actions (or predispositions to act) toward caressing contacts. We searched for pre-set motor substrates toward caressing by exposing volunteers to bonding cues and having them gently stroke a very soft cloth, a caress-like movement. The bonding cues were pictures with interacting dyads and the control pictures presented non-interacting dyads. We focused on the readiness potential, an electroencephalographic marker of motor preparation that precedes movement execution. The amplitude of the readiness potential preceding the grasping of pleasant emotional-laden stimuli was previously shown to be reduced compared with neutral ones. Fingers flexor electromyography measured action output. The rationale here is that stroking the soft cloth when previously exposed to bonding cues, a compatible context, would result in smaller amplitudes of readiness potentials, as compared to the context with no such cues. Exposure to the bonding pictures increased subjective feelings of sociability and decreased feelings of isolation. Participants who more frequently engage in mutual caress/groom a "significant other" in daily life initiated the motor preparation earlier, reinforcing the caress-like nature of the task. As hypothesized, readiness potentials preceding the caressing of the soft cloth were significantly reduced under exposure to bonding as compared to control pictures. Furthermore, an increased fingers flexor electromyographic activity was identified under exposure to the former as compared to the latter pictures. The facilitatory effects are likely due to the recruitment of pre-set cortical motor repertoires related to caress-like movements, emphasizing the distinctiveness of neural signatures for caress-like movements.

Sexuality and physical contact in National Social Life, Health, and Aging Project Wave 2

INTRODUCTION

Wave 2 of the National Social Life, Health, and Aging Project (NSHAP) includes new measures of sexual interest and behavior, as well as new measures of the context of sexual experience and the frequency and appeal of physical contact. This is the first time many of these constructs have been measured in a nationally representative sample.

METHOD

We describe the new measures and compare the distributions of each across gender and age groups, in some cases by partnership status.

RESULTS

Two components of sexuality decrease with age among both men and women: frequency of finding an unknown person sexually attractive and receptivity to a partner's sexual overtures. In contrast, the inclination to make one's self sexually attractive to others was a more complicated function of partner status, gender, and age: partnered women and unpartnered men made the most effort, with the more effortful gender's effort decreasing with age. Both men and women find nonsexual physical contact appealing but sexual physical contact is more appealing to men than women. Finally, two fifths of men and women report dissatisfaction with their partner's frequency of caring behaviors that make later sexual interactions pleasurable, and a fifth of women and a quarter of men who had vaginal sex in the past year report dissatisfaction with amount of foreplay.

DISCUSSION

These data offer the opportunity to characterize sexual motivation in older adulthood more precisely and richly and to examine how the context of sexual experience and the nonsexual aspects of physical intimacy correlate with sexual behavior, enjoyment, and problems.

Clinical effectiveness of osteopathic treatment in chronic migraine: 3-Armed randomized controlled trial

OBJECTIVE

To assess the effectiveness of OMT on chronic migraineurs using HIT-6 questionnaire, drug consumption, days of migraine, pain intensity and functional disability.

DESIGN

3-Armed randomized controlled trial setting: all patients admitted in the Department of Neurology of Ancona's United Hospitals, Italy, with a diagnosis of migraine and without chronic illness, were considered eligible for the study.

INTERVENTIONS

Patients were randomly divided into three groups: (1) OMT+medication therapy, (2) sham+medication therapy and (3) medication therapy only. Patients received 8 treatments in a study period of 6 months.

MAIN OUTCOME MEASURES

Changing from baseline HIT-6 score.

RESULTS

105 subjects were included. At the end of the study, ANOVA showed that OMT significantly reduced HIT-6 score (mean change scores OMT-conventional care: -8.74; 95% confidence interval (CI) -12.96 to -4.52; p<0.001 and OMT-sham: -6.62; 95% CI -10.85 to -2.41; p<0.001), drug consumption (OMT-sham: RR=0.22, 95% CI 0.11-0.40; OMT-control: RR=0.20, 95% CI 0.10-0.36), days of migraine (OMT-conventional care: M=-21.06; 95% CI -23.19 to -18.92; p<0.001 and OMT-sham: -17.43; 95% CI -19.57 to -15.29; p<0.001), pain intensity (OMT-sham: RR=0.42, 95% CI 0.24-0.69; OMT-control: RR=0.31, 95% CI 0.19-0.49) and functional disability (p<0.001).

CONCLUSIONS

These findings suggest that OMT may be considered a valid procedure for the management of migraineurs. The present trial was registered on www.ClinicalTrials.gov (identifier: NCT01851148).

The brain's response to pleasant touch: an EEG investigation of tactile caressing

Somatosensation as a proximal sense can have a strong impact on our attitude toward physical objects and other human beings. However, relatively little is known about how hedonic valence of touch is processed at the cortical level. Here we investigated the electrophysiological correlates of affective tactile sensation during caressing of the right forearm with pleasant and unpleasant textile fabrics. We show dissociation between more physically driven differential brain responses to the different fabrics in early somatosensory cortex - the well-known mu-suppression (10-20 Hz) - and a beta-band response (25-30 Hz) in presumably higher-order somatosensory areas in the right hemisphere that correlated well with the subjective valence of tactile caressing. Importantly, when using single trial classification techniques, beta-power significantly distinguished between pleasant and unpleasant stimulation on a single trial basis with high accuracy. Our results therefore suggest a dissociation of the sensory and affective aspects of touch in the somatosensory system and may provide features that may be used for single trial decoding of affective mental states from simple electroencephalographic measurements.

The meaning of the virtual Midas touch: an ERP study in economic decision making

The Midas touch refers to the altruistic effects of a brief touch. Though these effects have often been replicated, they remain poorly understood. We investigate the psychophysiology of the effect using remotely transmitted, precisely timed, tactile messages in an economic decision-making game called Ultimatum. Participants were more likely to accept offers after receiving a remotely transmitted touch. Furthermore, we found distinct effects of touch on event-related potentials evoked by (a) feedback regarding accepted and rejected offers, (b) decision cues related to proposals, and (c) the haptic and auditory cues themselves. In each case, a late positive effect of touch was observed and related to the P3. Given the role of the P3 in memory-related functions, the results indicate an indirect relationship between touch and generosity that relies on memory. This hypothesis was further tested and confirmed in the positive effects of touch on later proposals.

Effect of a brief seated massage on nursing student attitudes toward touch for comfort care

BACKGROUND

While massage has been removed from nursing curricula, studies have reported massage as safe and effective for stress reduction, relaxation, pain relief, fatigue, and quality of life.

OBJECTIVE

To compare the efficacy of two intensities of touch administered during two seated massages on the attitudes of nursing students toward touch for their self-care and patient care.

PARTICIPANTS

Nursing students who volunteered gave institutional review board-approved written informed consent to undergo massage by a licensed massage therapist.

SETTINGS/LOCATION

A private room adjacent to the nursing lab in a school of nursing.

INTERVENTION

Brief seated massages of differing intensities. Each participant received low-intensity and high-intensity touch in a two-block, randomized order, within-subjects design. Linear mixed models nested within subject and random intercept analyses were used to test hypotheses in this two-treatment, two-sequence, two-period crossover design.

OUTCOME MEASURES

Health questionnaires/visual analogue scales pertaining to physical/affective/and attitudinal status were completed before and after each massage.

RESULTS

Twenty-nine participants (93% female, 83% single) completed the study. Before massage, the optimal intensity of touch anticipated for self-comfort was 6.6 (0=no pressure;10=most intense pressure imaginable). The mean touch intensities were 6.7 for high-intensity massage and 0.5 for low-intensity (p<0.001). The overall percentage differences (feeling better or worse) following massage were as follows: low intensity, 37.5% better; high intensity, 62.7% better (p<0.001). Significantly more improvement was reported for energy, pain, stress, and feeling physically uptight after high-intensity compared with low-intensity (p<0.03). Participants were more likely to both receive touch for self-care and provide touch for patient care after experiencing high- versus low-intensity massage (p<0.01).

CONCLUSIONS

High-intensity seated massage was more efficacious than low-intensity massage and positively influenced nursing student attitudes toward the inclusion of massage in self-care/patient care. The role of touch for self-care/patient care in the nursing curricula merits reconsideration.

An oxytocin-induced facilitation of neural and emotional responses to social touch correlates inversely with autism traits

Social communication through touch and mutual grooming can convey highly salient socio-emotional signals and has been shown to involve the neuropeptide oxytocin (OXT) in several species. Less is known about the modulatory influence of OXT on the neural and emotional responses to human interpersonal touch. The present randomized placebo (PLC)-controlled within-subject pharmaco-functional magnetic resonance imaging (fMRI) study was designed to test the hypothesis that a single intranasal dose of synthetic OXT (24 IU) would facilitate both neural and emotional responses to interpersonal touch in a context- (female vs male touch) and trait- (autistic trait load) specific manner. Specifically, the experimental rationale was to manipulate the reward value of interpersonal touch independent of the intensity and type of actual cutaneous stimulation administered. Thus, 40 heterosexual males believed that they were touched by either a man or a woman, although in fact an identical pattern of touch was always given by the same female experimenter blind to condition type. Our results show that OXT increased the perceived pleasantness of female, but not male touch, and associated neural responses in insula, precuneus, orbitofrontal, and pregenual anterior cingulate cortex. Moreover, the behavioral and neural effects of OXT were negatively correlated with autistic-like traits. Taken together, this is the first study to show that the perceived hedonic value of human heterosexual interpersonal touch is facilitated by OXT in men, but that its behavioral and neural effects in this context are blunted in individuals with autistic traits.

Assessing Individual Differences in the Need for Interpersonal Touch and Need for Touch

The present study investigates individual differences in the automatic use of haptic information from interpersonal touch. We present a questionnaire assessing individual differences in the need for interpersonal touch (NFIPT), which was validated within an unrelated product-evaluation task. Before entering the laboratory, participants were briefly touched on the shoulder or received no touch. Assessing confidence and frustration within the following product-evaluation task, we examined moderating effects of NFIPT and additionally effects of need for touch (NFT). Results showed that higher NFIPT participants were more confident when they were briefly touched. Effects on frustration were only found for NFT. Results show that frustration was greater for individuals with higher NFT, when they could not touch the product during the evaluation task.

Touch Massage, a Rewarding Experience

This study aims to describe and analyze healthy individuals’ expressed experiences of touch massage (TM). Fifteen healthy participants received whole body touch massage during 60 minutes for two separate occasions. Interviews were analyzed by narrative analysis. Four identifiable storyline was found, Touch massage as an essential need, in this storyline the participants talked about a desire and need for human touch and TM. Another storyline was about, Touch massage as a pleasurable experience and the participants talked about the pleasure of having had TM. In the third storyline Touch massage as a dynamic experience, the informants talked about things that could modulate the experience of receiving TM. In the last storyline, Touch massage influences self-awareness, the participants described how TM affected some of their psychological and physical experiences. Experiences of touch massage was in general described as pleasant sensations and the different storylines could be seen in the light of rewarding experiences.

Why the body comes first: effects of experimenter touch on infants' word finding

The lexicon of 6-month-olds is comprised of names and body part words. Unlike names, body part words do not often occur in isolation in the input. This presents a puzzle: How have infants been able to pull out these words from the continuous stream of speech at such a young age? We hypothesize that caregivers' interactions directed at and on the infant's body may be at the root of their early acquisition of body part words. An artificial language segmentation study shows that experimenter-provided synchronous tactile cues help 4-month-olds to find words in continuous speech. A follow-up study suggests that this facilitation cannot be reduced to the highly social situation in which the directed interaction occurs. Taken together, these studies suggest that direct caregiver-infant interaction, exemplified in this study by touch cues, may play a key role in infants' ability to find word boundaries, and suggests that early vocabulary items may consist of words often linked with caregiver touches. A video abstract of this article can be viewed at http://youtu.be/NfCj5ipatyE.

Touch increases autonomic coupling between romantic partners

Interpersonal touch is of paramount importance in human social bonding and close relationships, allowing a unique channel for affect communication. So far the effect of touch on human physiology has been studied at an individual level. The present study aims at extending the study of affective touch from isolated individuals to truly interacting dyads. We have designed an ecological paradigm where romantic partners interact only via touch and we manipulate their empathic states. Simultaneously, we collected their autonomic activity (skin conductance, pulse, respiration). Fourteen couples participated to the experiment. We found that interpersonal touch increased coupling of electrodermal activity between the interacting partners, regardless the intensity and valence of the emotion felt. In addition, physical touch induced strong and reliable changes in physiological states within individuals. These results support an instrumental role of interpersonal touch for affective support in close relationships. Furthermore, they suggest that touch alone allows the emergence of a somatovisceral resonance between interacting individuals, which in turn is likely to form the prerequisites for emotional contagion and empathy.

Reach out and touch someone: anticipatory sensorimotor processes of active interpersonal touch

Anticipating the sensorimotor consequences of an action for both self and other is fundamental for action coordination when individuals socially interact. Somatosensation constitutes an elementary component of social cognition and sensorimotor prediction, but its functions in active social behavior remain unclear. We hypothesized that the somatosensory system contributes to social haptic behavior as evidenced by specific anticipatory activation patterns when touching an animate target (human hand) compared with an inanimate target (fake hand). fMRI scanning was performed during a paradigm that allowed us to isolate the anticipatory representations of active interpersonal touch while controlling for nonsocial sensorimotor processes and possible confounds because of interpersonal relationships or socioemotional valence. Active interpersonal touch was studied both as skin-to-skin contact and as object-mediated touch. The results showed weaker deactivation in primary somatosensory cortex and medial pFC and stronger activation in cerebellum for the animate target, compared with the inanimate target, when intending to touch it with one's own hand. Differently, in anticipation of touching the human hand with an object, anterior inferior parietal lobule and lateral occipital-temporal cortex showed stronger activity. When actually touching a human hand with one's own hand, activation was stronger in medial pFC but weaker in primary somatosensory cortex. The findings provide new insight on the contribution of simulation and sensory prediction mechanisms to active social behavior. They also suggest that literally getting in touch with someone and touching someone by using an object might be approached by an agent as functionally distinct conditions.

Tactile C fibers and their contributions to pleasant sensations and to tactile allodynia

In humans converging evidence indicates that affective aspects of touch are signaled by low threshold mechanoreceptive C tactile (CT) afferents. Analyses of electrophysiological recordings, psychophysical studies in denervated subjects, and functional brain imaging, all indicate that CT primary afferents contribute to pleasant touch and provide an important sensory underpinning of social behavior. Considering both these pleasant and social aspects of gentle skin-to-skin contact, we have put forward a framework within which to consider CT afferent coding properties and pathways—the CT affective touch hypothesis. Recent evidence from studies in mice suggests that CTs, when activated, may have analgesic or anxiolytic effects. However, in neuropathic pain conditions, light touch can elicit unpleasant sensations, so called tactile allodynia. In humans, tactile allodynia is associated with reduced CT mediated hedonic touch processing suggesting loss of the normally analgesic effect of CT signaling. We thus propose that the contribution of CT afferents to tactile allodynia is mainly through a loss of their normally pain inhibiting role.

Touching moments: desire modulates the neural anticipation of active romantic caress

A romantic caress is a basic expression of affiliative behavior and a primary reinforcer. Given its inherent affective valence, its performance also would imply the prediction of reward values. For example, touching a person for whom one has strong passionate feelings likely is motivated by a strong desire for physical contact and associated with the anticipation of hedonic experiences. The present study aims at investigating how the anticipatory neural processes of active romantic caress are modulated by the intensity of the desire for affective contact as reflected by passionate feelings for the other. Functional magnetic resonance imaging scanning was performed in romantically involved partners using a paradigm that allowed to isolate the specific anticipatory representations of active romantic caress, compared with control caress, while testing for the relationship between neural activity and measures of feelings of passionate love for the other. The results demonstrated that right posterior insula activity in anticipation of romantic caress significantly co-varied with the intensity of desire for union with the other. This effect was independent of the sensory-affective properties of the performed touch, like its pleasantness. Furthermore, functional connectivity analysis showed that the same posterior insula cluster interacted with brain regions related to sensory-motor functions as well as to the processing and anticipation of reward. The findings provide insight on the neural substrate mediating between the desire for and the performance of romantic caress. In particular, we propose that anticipatory activity patterns in posterior insula may modulate subsequent sensory-affective processing of skin-to-skin contact.

Quantifying the sensory and emotional perception of touch: differences between glabrous and hairy skin

The perception of touch is complex and there has been a lack of ways to describe the full tactile experience quantitatively. Guest et al. (2011) developed a Touch Perception Task (TPT) in order to capture such experiences, and here we used the TPT to examine differences in sensory and emotional aspects of touch at different skin sites. We compared touch on three skin sites: the hairy arm and cheek, and the glabrous palm. The hairy skin contains C-tactile (CT) afferents, which play a role in affective touch, whereas glabrous skin does not contain CT afferents and is involved in more discriminative touch. In healthy volunteers, three different materials (soft brush, sandpaper, fur) were stroked across these skin sites during self-touch or experimenter-applied touch. After each stimulus, participants rated the tactile experience using descriptors in the TPT. Sensory and emotional descriptors were analyzed using factor analyses. Five sensory factors were found: Texture, Pile, Moisture, Heat/Sharp and Cold/Slip, and three emotional factors: Positive Affect, Arousal, and Negative Affect. Significant differences were found in the use of descriptors in touch to hairy vs. glabrous skin: this was most evident in touch on forearm skin, which produced higher emotional content. The touch from another was also judged as more emotionally positive then self-touch, and participants readily discriminated between the materials on all factors. The TPT successfully probed sensory and emotional percepts of the touch experience, which aided in identifying skin where emotional touch was more pertinent. It also highlights the potentially important role for CTs in the affective processing of inter-personal touch, in combination with higher-order influences, such as through cultural belonging and previous experiences.

In touch with your emotions: oxytocin and touch change social impressions while others' facial expressions can alter touch

Interpersonal touch is frequently used for communicating emotions, strengthen social bonds and to give others pleasure. The neuropeptide oxytocin increases social interest, improves recognition of others' emotions, and it is released during touch. Here, we investigated how oxytocin and gentle human touch affect social impressions of others, and vice versa, how others' facial expressions and oxytocin affect touch experience. In a placebo-controlled crossover study using intranasal oxytocin, 40 healthy volunteers viewed faces with different facial expressions along with concomitant gentle human touch or control machine touch, while pupil diameter was monitored. After each stimulus pair, participants rated the perceived friendliness and attractiveness of the faces, perceived facial expression, or pleasantness and intensity of the touch. After intranasal oxytocin treatment, gentle human touch had a sharpening effect on social evaluations of others relative to machine touch, such that frowning faces were rated as less friendly and attractive, whereas smiling faces were rated as more friendly and attractive. Conversely, smiling faces increased, whereas frowning faces reduced, pleasantness of concomitant touch - the latter effect being stronger for human touch. Oxytocin did not alter touch pleasantness. Pupillary responses, a measure of attentional allocation, were larger to human touch than to equally intense machine touch, especially when paired with a smiling face. Overall, our results point to mechanisms important for human affiliation and social bond formation.

Stratified medicine for mental disorders

There is recognition that biomedical research into the causes of mental disorders and their treatment needs to adopt new approaches to research. Novel biomedical techniques have advanced our understanding of how the brain develops and is shaped by behaviour and environment. This has led to the advent of stratified medicine, which translates advances in basic research by targeting aetiological mechanisms underlying mental disorder. The resulting increase in diagnostic precision and targeted treatments may provide a window of opportunity to address the large public health burden, and individual suffering associated with mental disorders. While mental health and mental disorders have significant representation in the "health, demographic change and wellbeing" challenge identified in Horizon 2020, the framework programme for research and innovation of the European Commission (2014-2020), and in national funding agencies, clear advice on a potential strategy for mental health research investment is needed. The development of such a strategy is supported by the EC-funded "Roadmap for Mental Health Research" (ROAMER) which will provide recommendations for a European mental health research strategy integrating the areas of biomedicine, psychology, public health well being, research integration and structuring, and stakeholder participation. Leading experts on biomedical research on mental disorders have provided an assessment of the state of the art in core psychopathological domains, including arousal and stress regulation, affect, cognition social processes, comorbidity and pharmacotherapy. They have identified major advances and promising methods and pointed out gaps to be addressed in order to achieve the promise of a stratified medicine for mental disorders.

The social brain: neurobiological basis of affiliative behaviours and psychological well-being

The social brain hypothesis proposes that the demands of the social environment provided the evolutionary pressure that led to the expansion of the primate brain. Consistent with this notion, that functioning in the social world is crucial to our survival, while close supportive relationships are known to enhance well-being, a range of social stressors such as abuse, discrimination and dysfunctional relationships can increase the risk of psychiatric disorders. The centrality of the social world to our everyday lives is further exemplified by the fact that abnormality in social behaviour is a salient feature of a range of neurodevelopmental and psychiatric disorders. This paper aims to provide a selective overview of current knowledge of the neurobiological basis of our ability to form and maintain close personal relationships, and of the benefits these relationships confer on our health. Focusing on neurochemical and neuroendocrine interactions within affective and motivational neural circuits, it highlights the specific importance of cutaneous somatosensation in affiliative behaviours and psychological well-being and reviews evidence, in support of the hypothesis, that a class of cutaneous unmyelinated, low threshold mechanosensitive nerves, named c-tactile afferents, have a direct and specific role in processing affiliative tactile stimuli.

The human touch: skin temperature during the rubber hand illusion in manual and automated stroking procedures

A difference in skin temperature between the hands has been identified as a physiological correlate of the rubber hand illusion (RHI). The RHI is an illusion of body ownership, where participants perceive body ownership over a rubber hand if they see it being stroked in synchrony with their own occluded hand. The current study set out to replicate this result, i.e., psychologically induced cooling of the stimulated hand using an automated stroking paradigm, where stimulation was delivered by a robot arm (PHANToM^TM force-feedback device). After we found no evidence for hand cooling in two experiments using this automated procedure, we reverted to a manual stroking paradigm, which is closer to the one employed in the study that first produced this effect. With this procedure, we observed a relative cooling of the stimulated hand in both the experimental and the control condition. The subjective experience of ownership, as rated by the participants, by contrast, was strictly linked to synchronous stroking in all three experiments. This implies that hand-cooling is not a strict correlate of the subjective feeling of hand ownership in the RHI. Factors associated with the differences between the two designs (differences in pressure of tactile stimulation, presence of another person) that were thus far considered irrelevant to the RHI appear to play a role in bringing about this temperature effect.

A qualitative study of university students' perceptions of oral sex, intercourse, and intimacy

Oral sex is a common and normative part of young people's sexual behavior, yet there is concern that young people perceive oral sex as a casual, non-intimate behavior. The current study used a qualitative methodology to improve our understanding of the factors that contributed to university students' perceptions of the intimacy of sexual behaviors. Participants included 50 women and 35 men (17-24 years old) who responded to an open-ended intimacy questionnaire which asked them to describe the reasons for their perception of the relative intimacy of oral sex and intercourse. Responses were analyzed using conventional content analysis procedures. The majority (91 %) of participants perceived intercourse as more intimate than oral sex. Five key themes emerged from participant responses. Participants perceived intercourse as more intimate than oral sex because: (1) it is a symbol of love and commitment; (2) it is mutual; (3) it involves greater risks and benefits; and (4) oral sex is not discussed. A small subset perceived oral sex as more intimate than intercourse because (5) it required focusing on a partner. Overall, the findings highlight the role of formal and informal education in shaping young people's perceptions of the intimacy of sexual behavior.

Huggable communication medium decreases cortisol levels

Interpersonal touch is a fundamental component of social interactions because it can mitigate physical and psychological distress. To reproduce the psychological and physiological effects associated with interpersonal touch, interest is growing in introducing tactile sensations to communication devices. However, it remains unknown whether physical contact with such devices can produce objectively measurable endocrine effects like real interpersonal touching can. We directly tested this possibility by examining changes in stress hormone cortisol before and after a conversation with a huggable communication device. Participants had 15-minute conversations with a remote partner that was carried out either with a huggable human-shaped device or with a mobile phone. Our experiment revealed significant reduction in the cortisol levels for those who had conversations with the huggable device. Our approach to evaluate communication media with biological markers suggests new design directions for interpersonal communication media to improve social support systems in modern highly networked societies.

Rough primes and rough conversations: evidence for a modality-specific basis to mental metaphors

How does our brain organize knowledge? Traditional theories assume that our knowledge is represented abstractly in an amodal conceptual network of formal logic symbols. The theory of embodied cognition challenges this view and argues that conceptual representations that constitute our knowledge are grounded in sensory and motor experiences. We tested this hypothesis by examining how the concept of social coordination is grounded metaphorically in the tactile sensation of roughness. Participants experienced rough or smooth touch before being asked to judge an ambiguous social interaction. Results revealed that rough touch made social interactions appear more difficult and adversarial, consistent with the rough metaphor. This impact of tactile cues on social impressions was accompanied by a network including primary and secondary somatosensory cortices, amygdala, hippocampus and inferior prefrontal cortex. Thus, the roughness of tactile stimulation affected metaphor-relevant (but not metaphor-irrelevant) behavioral and neural responses. Receiving touch from a rough object seems to trigger the application of associated ontological concepts (or scaffolds) even for unrelated people and situations (but not to unrelated or more general feelings). Since this priming was based on somatosensory brain areas, our results provide support for the theory that sensorimotor grounding is intrinsic to cognitive processes.

Touch as an interpersonal emotion regulation process in couples' daily lives: the mediating role of psychological intimacy

Interpersonal touch seems to promote physical health through its effects on stress-sensitive parameters. However, less is known about the psychological effects of touch. The present study investigates associations between touch and romantic partners' affective state in daily life. We hypothesized that this association is established by promoting the recipient's experience of intimacy. Both partners of 102 dating couples completed an electronic diary 4 times a day during 1 week. Multilevel analyses revealed that touch was associated with enhanced affect in the partner. This association was mediated by the partner's psychological intimacy. Touch was also associated with intimacy and positive affect in the actor. Finally, participants who were touched more often during the diary study week reported better psychological well-being 6 months later. This study provides evidence that intimate partners benefit from touch on a psychological level, conveying a sense of strengthened bonds between them that enhances affect and well-being.

Childhood maternal support and social capital moderate the regulatory impact of social relationships in adulthood

For this functional magnetic resonance imaging (fMRI) study, we assessed the impact of early social experiences on the social regulation of neural threat responding in a sample of 22 individuals that have been followed for over a decade. At 13 years old, a multidimensional measure of neighborhood quality was derived from parental reports. Three measures of neighborhood quality were used to estimate social capital-the level of trust, reciprocity, cooperation, and shared resources within a community. At 16 years old, an observational measure of maternal emotional support behavior was derived from a mother/child social interaction task. At 24 years old, participants were asked to visit our neuroimaging facility with an opposite-sex platonic friend. During their MRI visit, participants were subjected to the threat of electric shock while holding their friend's hand, the hand of an anonymous opposite-sex experimenter, or no hand at all. Higher adolescent maternal support corresponded with less threat-related activation during friend handholding, but not during the stranger or alone conditions, in the bilateral orbitofrontal cortex, inferior frontal gyrus and left insula. Higher neighborhood social capital corresponded with less threat-related activation during friend hand-holding in the superior frontal gyrus, supplementary motor cortex, insula, putamen and thalamus; but low childhood capital corresponded with less threat-related activation during stranger handholding in the same regions. Exploratory analyses suggest that this latter result is due to the increased threat responsiveness during stranger handholding among low social capital individuals, even during safety cues. Overall, early maternal support behavior and high neighborhood quality may potentiate soothing by relational partners, and low neighborhood quality may decrease the overall regulatory impact of access to social resources in adulthood.

Support system for decision making in the identification of risk for body dysmorphic disorder: a fuzzy model

PURPOSE

To develop a fuzzy linguistic model to quantify the level of distress of patients seeking cosmetic surgery. Body dysmorphic disorder (BDD) is a mental condition related to body image relatively common among cosmetic surgery patients; it is difficult to diagnose and is a significant cause of morbidity and mortality. Fuzzy cognitive maps are an efficient tool based on human knowledge and experience that can handle uncertainty in identifying or grading BDD symptoms and the degree of body image dissatisfaction. Individuals who seek cosmetic procedures suffer from some degree of dissatisfaction with appearance.

METHODS

A fuzzy model was developed to measure distress levels in cosmetic surgery patients based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), diagnostic criterion B for BDD. We studied 288 patients of both sexes seeking abdominoplasty, rhinoplasty, or rhytidoplasty in a university hospital.

RESULTS

Patient distress ranged from "none" to "severe" (range=7.5-31.6; cutoff point=18; area under the ROC curve=0.923). There was a significant agreement between the fuzzy model and DSM-IV criterion B (kappa=0.805; p<0.001).

CONCLUSION

The fuzzy model measured distress levels with good accuracy, indicating that it can be used as a screening tool in cosmetic surgery and psychiatric practice.

Descriptive experiences and sexual vs. nurturant aspects of cuddling between adult romantic partners

Touch is a critical factor in intimate bonds between romantic partners. Although cuddling is a key expression of intimacy, it has received little empirical attention. Past research suggests that cuddling has some sexual aspects (e.g., it increases testosterone [T]), but there are theoretical reasons to expect cuddling to also involve nurturant intimacy (which should decrease T). In this article, we examined the phenomenon of partner cuddling to: (1) provide a descriptive examination; (2) determine if cuddling involved only nurturant intimacy or also sexual intimacy; and (3) test whether cuddling was perceived as nurturant but experienced as sexual. Via an online questionnaire, 514 participants (338 women) responded to quantitative and qualitative questions about cuddling with their romantic partners. Results suggested that cuddling occurred frequently and for relatively long durations, and was viewed very positively. Findings also showed that cuddling was perceived as nurturant and non-sexual but was experienced as at least somewhat sexual, which may explain why past research had found that cuddling increased T. Correlational analyses linked cuddling frequency and enjoyment positively with partnered sexual activities, but negatively with solitary sexuality. Results were discussed relative to evolutionary theories of distinct but overlapping neurobiological systems underlying pair bonding that involve sexual and nurturant intimacy.

The influence of political jurisdiction, age, and sex on handholding in public by same-sex couples

Three hundred-forty lesbians and 62 gay males, largely from North America and in partnered relationships, completed online surveys that explored what handholding means to same-sex couples. The data suggest that lesbians in the United States are more likely now than ¼ century ago to hold hands in public spaces. Younger lesbians are more likely to hold hands in public than older lesbians, and Canadian lesbians hold hands more often in public than American lesbians. In response to the question, "What does handholding mean to you?," 26% of the female respondents from North America overtly referred to public handholding as either a political act or a risky behavior. The number of comments of that nature was similar, regardless of whether the lesbians resided in the United States or Canada. Data suggest that full acceptance of same-sex couples in public spaces has not yet occurred, even in jurisdictions where same-sex couples have the same legal rights as heterosexual couples. Although the sample size for males was too small to analyze the influence of age or political jurisdiction on public handholding, males, in general, were significantly less likely than females to view handholding as a means of staying "connected" with their partners.

Virtually naked: virtual environment reveals sex-dependent nature of skin disclosure

The human tendency to reveal or cover naked skin reflects a competition between the individual propensity for social interactions related to sexual appeal and interpersonal touch versus climatic, environmental, physical, and cultural constraints. However, due to the ubiquitous nature of these constraints, isolating on a large scale the spontaneous human tendency to reveal naked skin has remained impossible. Using the online 3-dimensional virtual world of Second Life, we examined spontaneous human skin-covering behavior unhindered by real-world climatic, environmental, and physical variables. Analysis of hundreds of avatars revealed that virtual females disclose substantially more naked skin than virtual males. This phenomenon was not related to avatar hypersexualization as evaluated by measurement of sexually dimorphic body proportions. Furthermore, analysis of skin-covering behavior of a population of culturally homogeneous avatars indicated that the propensity of female avatars to reveal naked skin persisted despite explicit cultural norms promoting less revealing attire. These findings have implications for further understanding how sex-specific aspects of skin disclosure influence human social interactions in both virtual and real settings.

The human somatosensory system: from perception to decision making

Pioneering human and animal research has yielded a better understanding of the brain networks involved in somatosensory perception and decision making. New methodical achievements in combination with computational formalization allow research questions to be addressed which increasingly reflect not only the complex sensory demands of real environments, but also the cognitive ones. Here, we review the latest research on somatosensory perception and decision making with a special focus on the recruitment of supplementary brain networks which are dependent on the situation-associated sensory and cognitive demands. We also refer to literature on sensory-motor integration processes during visual decision making to delineate the complexity and dynamics of how sensory information is relayed to the motor output system. Finally, we review the latest literature which provides novel evidence that other everyday life situations, such as semantic decision making or social interactions, appear to depend on tactile experiences; suggesting that the sense of touch, being the first sense to develop ontogenetically, may essentially support later development of other conceptual knowledge.

Dyadic Power Theory, Touch, and Counseling Psychology

Smith, Vogel, Madon, and Edwards’ (2011) recent article tested dyadic power theory (DPT) by examining the use of touch as a compliance-gaining tactic in the conflicts of married couples. In this response, we raise a methodological issue about the touch behaviors examined by Smith et al. and also pose a theoretical critique that their test of DPT violates an important scope condition of the theory. They did not examine differences between power-equal and power-unequal dyads, but instead they state that topic selection provides an actor with legitimate authority (and thus greater perceived power) and therefore the actor would touch their partner more to influence the partner. In contrast, DPT predicts that actors will use control attempts such as touch more when they are equal in power than when they are unequal. We believe DPT is relevant to touch in marital conflicts and provide a preliminary statement of that idea.

Close to you: embodied simulation for peripersonal space in primary somatosensory cortex

Background

An increasing body of evidence has demonstrated that in contrast to the classic understanding the primary somatosensory cortex (SI) reflects merely seen touch (in the absence of any real touch on the own body). Based on these results it has been discussed that SI may play a role in understanding touch seen on other bodies. In order to further examine this understanding of observed touch, the current study aimed to test if mirror-like responses in SI are affected by the perspective of the seen touch. Thus, we presented touch on a hand and close to the hand either in first-person-perspective or in third-person-perspective.

Principal Findings

Results of functional magnetic resonance imaging (fMRI) revealed stronger vicarious brain responses in SI/BA2 for touch seen in first-person-perspective. Surprisingly, the third-person viewpoint revealed activation in SI both when subjects viewed a hand being stimulated as well as when the space close to the hand was being touched.

Conclusions/Significance

Based on these results we conclude that vicarious somatosensory responses in SI/BA2 are affected by the viewpoint of the seen hand. Furthermore, we argue that mirror-like responses in SI do not only reflect seen touch, but also the peripersonal space surrounding this body (in third-person-perspective). We discuss these findings with recent studies on mirror responses for action observation in peripersonal space.

Sexual touching and difficulties with sexual arousal and orgasm among U.S. older adults

Little is known about the non-genitally-focused sexual behavior of those experiencing sexual difficulties. The objective of this study was to review the theory supporting a link between sexual touching and difficulties with sexual arousal and orgasm, and to examine associations between these constructs among older adults in the United States. The data were from the 2005-2006 National Social Life Health and Aging Project, which surveyed 3,005 community-dwelling men and women ages 57-85 years. The 1,352 participants who had had sex in the past year reported on their frequency of sexual touching and whether there had been a period of several months or more in the past year when they were unable to climax, had trouble getting or maintaining an erection (men) or had trouble lubricating (women). Women also reported how often they felt sexually aroused during partner sex in the last 12 months. The odds of being unable to climax were greater by 2.4 times (95% CI 1.2-4.8) among men and 2.8 times (95% CI 1.4-5.5) among women who sometimes, rarely or never engaged in sexual touching, compared to those who always engaged in sexual touching, controlling for demographic factors and physical health. These results were attenuated but persisted after controlling for emotional relationship satisfaction and psychological factors. Similar results were obtained for erectile difficulties among men and subjective arousal difficulties among women, but not lubrication difficulties among women. Infrequent sexual touching is associated with arousal and orgasm difficulties among older adults in the United States.

Interpersonal touch: physiological effects in critical care

INTRODUCTION

Nurses use several forms of touch in patient encounters. Interpersonal touch elicits specific physiological and psychological responses, including neuroendocrine effects and reduction of stress. Critical illness is a state of excessive physiological and psychological stress.

AIMS

To critically review evidence on the effect of touch on physiological outcomes in critically ill individuals. Results of intervention studies in adult critical care settings were reviewed along with supportive evidence from studies in other populations.

METHODS

Critical literature review based on studies published in MEDLINE, PubMed, Cinahl, Embase, and Cochrane databases.

RESULTS

Eleven studies were reviewed. Significant effects of interpersonal touch included lower systolic and diastolic blood pressure and respiratory rate, improved sleep, and decreased pain. Almost no results were replicated owing to discrepancies among studies. Although the effect of touch on cardiovascular autonomic status appears considerable, several confounders must be considered. In noncritically ill populations, replicable findings included increased urinary dopamine and serotonin, natural killer cytotoxic activity, and salivary chromogranin. Effects on plasma cortisol and immune cells were variable. Effects appear to vary according to amount of pressure, body site, duration, and timing: Moderate pressure touch may elicit a parasympathetic response in contrast to light touch, which may elicit a sympathetic response. Moreover, touch effects may be mediated by the density of autonomic innervation received by the body areas involved and repetition of sessions.

CONCLUSION

The physiological pathway mediating the effects of touch is unclear. Although no concrete conclusions can be drawn, research evidence suggests that touch interventions may benefit critically ill individuals.

Tactual perception: a review of experimental variables and procedures

This paper reviews the literature on tactual perception. Throughout this review, we will highlight some of the most relevant aspects in the touch literature: type of stimuli; type of participants; type of tactile exploration; and finally, the interaction between touch and other senses. Regarding type of stimuli, we will analyse studies with abstract stimuli such as vibrations, with two- and three-dimensional stimuli, and also concrete stimuli, considering the relation between familiar and unfamiliar stimuli and the haptic perception of faces. Under the "type of participants" topic, we separated studies with blind participants, studies with children and adults, and also performed an overview of sex differences in performance. The type of tactile exploration is explored considering conditions of active and passive touch, the relevance of movement in touch and the relation between haptic exploration and time. Finally, interactions between touch and vision, touch and smell and touch and taste are explored in the last topic. The review ends with an overall conclusion on the state of the art for the tactual perception literature. With this work, we intend to present an organised overview of the main variables in touch experiments, compiling aspects reported in the tactual literature, and attempting to provide both a summary of previous findings, and a guide to the design of future works on tactual perception and memory, through a presentation of implications from previous studies.