Uta Sailer

• Pfabigan, Daniela Melitta; Frogner, Erik Rimestad; Asgari, Fatemeh & Sailer, Uta (2026). Appreciation of Social Experiences and Solitude in Everyday Life: The SOcial Experiences' daiLy Occurrence Scale (SOLO). Scandinavian Journal of Psychology. ISSN 0036-5564. doi: 10.1111/sjop.70146. Fulltekst i vitenarkiv Vis sammendrag

  While social interactions and actively chosen solitude both contribute to well‐being, existing measures focus solely on one dimension. We developed the SOcial experiences' daiLy Occurrence (SOLO) scale—a brief end‐of‐day diary measure capturing enjoyment of social interactions (including brief encounters with “weak ties”) and solitude experiences. Two scale development and validation studies were conducted: single‐day ( N  = 203) and 14‐day ( N  = 75) assessments. The final SOLO consists of 13 items forming two scales, the Social Interaction subscale and the Solitude subscale. Both scales demonstrated adequate psychometric properties and meaningful relationships with well‐being measures. The scales were independent, supporting the conceptualization of social enjoyment and solitude preference as distinct dimensions. The SOLO is therefore presented as two distinct scales. A composite score can be calculated if required, although subscale‐level analyses are recommended given the empirical independence of the two dimensions. The SOLO's brief format offers a practical compromise between ecological momentary assessment and retrospective measures, enabling investigation of the distinct roles of social engagement and solitude in everyday life.

• Mäki-Marttunen, Verónica; Sailer, Uta; Kopal, Jakub; Hagen, Espen; Shadrin, Alexey & Andreassen, Ole [Vis alle 8 forfattere av denne artikkelen] (2026). Large-Scale Neuroimaging and Genetic Analyses of the Human Thalamus in Loneliness. Biological Psychiatry: Global Open Science. 6(6), s. 100798–100798. doi: 10.1016/j.bpsgos.2026.100798. Fulltekst i vitenarkiv
• Asgari, Fatemeh; Vitelli, Valeria & Sailer, Uta (2026). Functional Structural Equation Modeling with Latent Variables. Structural Equation Modeling. ISSN 1070-5511. s. 1–9. doi: 10.1080/10705511.2026.2702102. Fulltekst i vitenarkiv Vis sammendrag

  Handling latent variables in Structural Equation Models (SEMs) where both the latent variables and their corresponding indicators are random curves presents significant challenges, especially with sparse data. We develop a novel family of Functional Structural Equation Models (FSEMs) incorporating latent variables modeled as Gaussian Processes (GPs). The model adapts to cases when the random curves’ realizations are observed over a sparse subset of the domain. To extract smooth estimates for the functional parameters, we employ a penalized likelihood approach and evaluate the performance of the proposed model using simulation studies and a real data example, suggesting our model performs well. Supplementary materials are available online.

• Jacobsen, Hilde K.; Tandberg, Bente S.; Kynø, Nina M & Sailer, Uta (2026). Exploring the association between parent touch attitudes and experiences with duration of skin-to-skin contact and holding in preterm infants. Early Human Development. ISSN 0378-3782. 214. doi: 10.1016/j.earlhumdev.2025.106476. Fulltekst i vitenarkiv Vis sammendrag

  Background Skin-to-skin contact (SSC) provides extensive benefits for preterm infants and is highly recommended. However, parental SSC duration in Neonatal Intensive Care Units (NICU) varies considerably, with contributing factors poorly understood. Parents' perspectives on, and prior experiences with touch may influence SSC duration. Aims To investigate how parental attitudes toward and experiences with touch relate to SSC and holding durations, and to explore how these durations vary by relationship (mother/father), infant gestational age (GA) and parents' level of education. Study design Observational Study. Subjects Parents (n = 123) of preterm infants (n = 69), GA 270–366, admitted to a Norwegian family-centered care NICU providing 24/7 parental presence, participated. Outcome measures Daily parental SSC and holding durations (one week), video-evaluation of occurrence of slow, gentle and faster stroking, and Touch Experiences and Attitudes Questionnaire. Results Mothers provided significantly more SSC (p = .024) and holding (p = .005) than fathers. Parents provided significantly more SSC for infants at GA 27–30 (p = .029) and GA 31–33 (p = .036) than for GA 34–36, while significantly more holding for GA 31–33 (p = .022) and GA 34–36 (p = .001) than GA 27–30. No relation between parents' touch attitudes and experiences, affective touch awareness, or education, and SSC and holding duration was observed. Conclusion Maternal status and GA predicted SSC and holding duration yet explained the variance only partially. Parents' touch attitudes and experiences showed no association. This suggests that contextual, clinical or systemic factors may predominantly determine SSC and holding provision.

• Pfabigan, Daniela M; Frogner, Erik Rimestad; Asgari, Fatemeh & Sailer, Uta (2025). Appreciation of social experiences and solitude in everyday life: the SOcial experiences’ daiLy Occurrence scale (SOLO). PsyArXiv. doi: 10.31234/osf.io/6psar_v2. Fulltekst i vitenarkiv Vis sammendrag

  While social interactions and actively chosen solitude both contribute to well-being, existing measures focus solely on one dimension. We developed the Social experiences' daiLy Occurrence (SOLO) scale—a brief end-of-day diary measure capturing enjoyment of social interactions (including brief encounters with "weak ties") and solitude experiences. Two validation studies were conducted: single-day (N=203) and 14-day (N=75) assessments. The final SOLO consists of 13 items forming two scales: "Being with others" and "Being alone". Both scales demonstrated adequate psychometric properties and meaningful relationships with well-being measures. The scales were independent, supporting conceptualization of social enjoyment and solitude preference as distinct dimensions. The SOLO's brief format offers a practical compromise between ecological momentary assessment and retrospective measures.

• Bierling, Antonie; Croy, Alexander; Bilem, Fatma; Bloy, Leah; Ho, Fiona Yan-Yee & Jimenez, Andres [Vis alle 19 forfattere av denne artikkelen] (2025). A standardized lexicon of body odor words crafted from 17 countries. Scientific Data. 12(325), s. 1–12. doi: 10.1038/s41597-025-04630-8. Fulltekst i vitenarkiv Vis sammendrag

  Body odors offer a unique window into the physiological and psychological profile of the emitter. This information, broadcast in nonverbal communication, significantly shapes social interactions. However, effectively digitizing body odors requires a precise framework for perceptual operationalization. Previous research has used a very limited number of verbal terms, such as pleasant, intense, or attractive, which fails to adequately capture qualitative differences. To address this gap, we elicited body odor descriptions from 2,607 participants across 17 countries and 13 languages. All these descriptions are presented here in one dataset, together with a condensed list of 25 body odor words (BOW). Those terms reliably differentiated between body states, and were validated in a separate study with a different group of 155 perceivers. The dataset, available as a web application, provides a novel operationalization of body odor impressions, which is a precondition for studying olfaction in human nonverbal communication, for perception-based digitization of body odors and for comparative studies.

• Sailer, Uta; Asgari, Fatemeh; Kristinsson, Jon Adalsteinn & Kvalem, Ingela Lundin (2025). The Interplay Between Social Factors and Metabolic Bariatric Surgery Outcomes—A 5-Year Prospective Study. Obesity Science & Practice. 11(2), s. 1–12. doi: 10.1002/osp4.70068. Fulltekst i vitenarkiv
• Sailer, Uta; Friedrich, Yvonne; Asgari, Fatemeh; Hassenzahl, Marc & Croy, Ilona (2024). Determinants for positive and negative experiences of interpersonal touch: context matters. Cognition & Emotion. ISSN 0269-9931. 38(4). doi: 10.1080/02699931.2024.2311800. Fulltekst i vitenarkiv Vis sammendrag

  The goal of the study was to determine which aspects of interpersonal touch interactions lead to a positive or negative experience. Previous research has focused primarily on physical characteristics. We suggest that this may not be sufficient to fully capture the complexity of the experience. Specifically, we examined how fulfilment of psychological needs influences touch experiences and how this relates to physical touch characteristics and situational factors. In two mixed-method studies, participants described their most positive and most negative interpersonal touch experience within a specific time frame. They reported fulfilment of nine needs, affect, intention, and reason for positivity/negativity, as well as the body part(s) touched, location, type of touch, interaction partner, and particular touch characteristics (e.g. humidity). Positive and negative touch experiences shared similar touch types, locations, and body parts touched, but differed in intended purpose and reasons. Overall, the valence of a touch experience could be predicted from fulfilment of relatedness, the interaction partner and initiator, and physical touch characteristics. Positive affect increased with need fulfilment, and negative affect decreased. The results highlight the importance of relatedness and reciprocity for the valence of touch, and emphasise the need to incorporate psychological needs in touch research.

• Sailer, Uta; Zucknick, Manuela Karola & Laeng, Bruno (2023). Caressed by music: Related preferences for velocity of touch and tempo of music? Frontiers in Psychology. 14. doi: 10.3389/fpsyg.2023.1135988. Fulltekst i vitenarkiv Vis sammendrag

  Given that both hearing and touch are ‘mechanical senses’ that respond to physical pressure or mechanical energy and that individuals appear to have a characteristic internal or spontaneous tempo, individual preferences in musical and touch rhythms might be related. We explored this in two experiments probing individual preferences for tempo in the tactile and auditory modalities. Study 1 collected ratings of received stroking on the forearm and measured the velocity the participants used for stroking a fur. Music tempo preferences were assessed as mean beats per minute of individually selected music pieces and via the adjustment of experimenter-selected music to a preferred tempo. Heart rate was recorded to measure levels of physiological arousal. We found that the preferred tempo of favorite (self-selected) music correlated positively with the velocity with which each individual liked to be touched. In Study 2, participants rated videos of repeated touch on someone else’s arm and videos of a drummer playing with brushes on a snare drum, both at a variety of tempos. We found that participants with similar rating patterns for the different stroking speeds did not show similar rating patterns for the different music beats. The results suggest that there may be a correspondence between preferences for favorite music and felt touch, but this is either weak or it cannot be evoked effectively with vicarious touch and/or mere drum beats. Thus, if preferences for touch and music are related, this is likely to be dependent on the specific type of stimulation.

• Sailer, Uta; Wurm, Franz & Pfabigan, Daniela M. (2023). Social and non-social feedback stimuli lead to comparable levels of reward learning and reward responsiveness in an online probabilistic reward task. Behavior Research Methods. ISSN 1554-351X. 56, s. 5161–5177. doi: 10.3758/s13428-023-02255-6. Fulltekst i vitenarkiv Vis sammendrag

  Social stimuli seem to be processed more easily and efficiently than non-social stimuli. The current study tested whether social feedback stimuli improve reward learning in a probabilistic reward task (PRT), in which one response option is usually rewarded more often than the other via presentation of non-social reward stimuli. In a pre-registered online study with 305 participants, 75 participants were presented with a non-social feedback stimulus (a star) and information about gains, which is typically used in published PRT studies. Three other groups (with 73–82 participants each) were presented with one of three social feedback stimuli: verbal praise, an attractive happy face, or a “thumbs up”-picture. The data were analysed based on classical signal detection theory, drift diffusion modelling, and Bayesian analyses of null effects. All PRT variants yielded the expected behavioural preference for the more frequently rewarded response. There was no processing advantage of social over non-social feedback stimuli. Bayesian analyses further supported the observation that social feedback stimuli neither increased nor decreased behavioural preferences in the PRT. The current findings suggest that the PRT is a robust experimental paradigm independent of the applied feedback stimuli. They also suggest that the occurrence of a processing advantage for social feedback stimuli is dependent on the experimental task and design.

• Pfabigan, Daniela M.; Frogner, Erik Rimestad; Schéle, Erik; Thorsby, Per Medbøe; Skålhegg, Bjørn Steen & Dickson, Suzanne L. [Vis alle 7 forfattere av denne artikkelen] (2023). Ghrelin is related to lower brain reward activation during touch. Psychophysiology. ISSN 0048-5772. 61(2). doi: 10.1111/psyp.14443. Fulltekst i vitenarkiv Vis sammendrag

  The gut hormone ghrelin drives food motivation and increases food intake, but it is also involved in the anticipation of and response to rewards other than food. This pre-registered study investigated how naturally varying ghrelin concentrations affect the processing of touch as a social reward in humans. Sixty-seven volunteers received slow caressing touch (so-called CT-targeted touch) as a social reward and control touch on their shins during 3T functional imaging on two test days. On one occasion, participants were fasted, and on another, they received a meal. On each occasion, plasma ghrelin was measured at three time points. All touch was rated as more pleasant after the meal, but there was no association between ghrelin concentrations and pleasantness. CT-targeted touch was rated as the most pleasant and activated somatosensory and reward networks (whole brain). A region-of-interest in the right medial orbitofrontal cortex (mOFC) showed lower activation during all touches, the higher the ghrelin concentrations were. During CT-targeted touch, a larger satiety response (ghrelin decrease after the meal) was associated with higher mOFC activation, and this mOFC activation was associated with higher experienced pleasantness. Overall, higher ghrelin concentrations appear to be related to a lower reward value for touch. Ghrelin may reduce the value of social stimuli, such as touch, to promote food search and intake in a state of low energy. This suggests that the role of ghrelin goes beyond assigning value to food reward.

• Sailer, Uta; Wurm, Franz & Pfabigan, Daniela Melitta (2023). Social and non-social feedback stimuli lead to comparable levels of reward learning and reward responsiveness in an online probabilistic reward task. PsyArXiv. doi: 10.31234/osf.io/zm6gj. Fulltekst i vitenarkiv Vis sammendrag

  Social stimuli seem to be processed more easily and efficiently than non-social stimuli. The current study tested whether such a processing advantage increases reward preferences in a probabilistic reward task (PRT), in which one response option is usually rewarded more often than the other via presentation of non-social reward stimuli. In a pre-registered online study, 75 participants were presented with a non-social reward stimulus (a star) and information about gains, which is typically used in published PRT studies. Three other groups (with 73-82 participants each) were presented with one of three social reward stimuli: verbal praise, an attractive happy face, or thumbs up. All PRT variants yielded the expected behavioural preference for the more frequently rewarded response option, both in terms of classical signal-detection-theory analysis as well as in terms of drift diffusion modelling analysis. There was no processing advantage of social over non-social reward stimuli. Bayesian analyses further supported the observation that social reward stimuli did neither increase nor decrease behavioural preferences in the PRT. The current findings suggest that the PRT is a robust experimental paradigm independent of the applied reward stimuli.

• Edwards, Peter & Sailer, Uta (2023). Death in Music and Music in Death: Reflections on Mortality and Listening in the Performances of Marino Formenti. I Marx, Wolfgang (Red.), Music and Death. Funeral Music, Memory and Re-Evaluating Life.. Boydell & Brewer. ISSN 9781837650644. s. 155–169. Fulltekst i vitenarkiv
• Schneider, Ekaterina; Hopf, Dora; Aguilar-Raab, Corina; Scheele, Dirk; Neubauer, Andreas B & Sailer, Uta [Vis alle 9 forfattere av denne artikkelen] (2023). Affectionate touch and diurnal oxytocin levels: An ecological momentary assessment study. eLIFE. 12. doi: 10.7554/eLife.81241. Fulltekst i vitenarkiv Vis sammendrag

  Background: Affectionate touch, which is vital for mental and physical health, was restricted during the Covid-19 pandemic. This study investigated the association between momentary affectionate touch and subjective well-being, as well as salivary oxytocin and cortisol in everyday life during the pandemic. Methods: In the first step, we measured anxiety and depression symptoms, loneliness and attitudes toward social touch in a large cross-sectional online survey (N = 1050). From this sample, N = 247 participants completed ecological momentary assessments over 2 days with six daily assessments by answering smartphone-based questions on affectionate touch and momentary mental state, and providing concomitant saliva samples for cortisol and oxytocin assessment. Results: Multilevel models showed that on a within-person level, affectionate touch was associated with decreased self-reported anxiety, general burden, stress, and increased oxytocin levels. On a between-person level, affectionate touch was associated with decreased cortisol levels and higher happiness. Moreover, individuals with a positive attitude toward social touch experiencing loneliness reported more mental health problems. Conclusions: Our results suggest that affectionate touch is linked to higher endogenous oxytocin in times of pandemic and lockdown and might buffer stress on a subjective and hormonal level. These findings might have implications for preventing mental burden during social contact restrictions. Funding: The study was funded by the German Research Foundation, the German Psychological Society, and German Academic Exchange Service.

• Sailer, Uta; Riva, Federica; Lieberz, Jana; Campbell-Meiklejohn, Daniel; Scheele, Dirk & Pfabigan, Daniela Melitta (2023). Hungry for compliments? Ghrelin is not associated with neural responses to social rewards or their pleasantness. Frontiers in Psychiatry. 14. doi: 10.3389/fpsyt.2023.1104305. Fulltekst i vitenarkiv Vis sammendrag

  The stomach-derived hormone ghrelin motivates food search and stimulates food consumption, with highest plasma concentrations before a meal and lowest shortly after. However, ghrelin also appears to affect the value of non-food rewards such as interaction with rat conspecifics, and monetary rewards in humans. The present pre-registered study investigated how nutritional state and ghrelin concentrations are related to the subjective and neural responses to social and non-social rewards. In a cross-over feed-and-fast design, 67 healthy volunteers (20 women) underwent functional magnetic resonance imaging (fMRI) in a hungry state and after a meal with repeated plasma ghrelin measurements. In task 1, participants received social rewards in the form of approving expert feedback, or non-social computer reward. In task 2, participants rated the pleasantness of compliments and neutral statements. Nutritional state and ghrelin concentrations did not affect the response to social reward in task 1. In contrast, ventromedial prefrontal cortical activation to non-social rewards was reduced when the meal strongly suppressed ghrelin. In task 2, fasting increased activation in the right ventral striatum during all statements, but ghrelin concentrations were neither associated with brain activation nor with experienced pleasantness. Complementary Bayesian analyses provided moderate evidence for a lack of correlation between ghrelin concentrations and behavioral and neural responses to social rewards, but moderate evidence for an association between ghrelin and non-social rewards. This suggests that ghrelin’s influence may be restricted to non-social rewards. Social rewards implemented via social recognition and affirmation may be too abstract and complex to be susceptible to ghrelin’s influence. In contrast, the non-social reward was associated with the expectation of a material object that was handed out after the experiment. This may indicate that ghrelin might be involved in anticipatory rather than consummatory phases of reward.

• Sailer, Uta & Leknes, Siri (2022). Meaning makes touch affective. Current Opinion in Behavioral Sciences. ISSN 2352-1546. 44. doi: 10.1016/j.cobeha.2021.101099. Fulltekst i vitenarkiv Vis sammendrag

  The pleasantness of gentle stroking (CT-targeted touch) varies highly between individuals and studies, indicating that relevant factors may not be accounted for. We propose that the affective value of a touch event is determined by how well its perceived purpose matches the goals of the touch receiver. The perceived purpose or meaning of touch is in turn informed by the sensory characteristics together with the setting, person factors, and the touchee’s expectations. Affective touch is often a sign of affection, intended to soothe or show support. In a typical lab study however, the toucher is a stranger and its purpose is research. The purpose of laboratory touch is nevertheless compatible with the goal of participants, namely to contribute to research. To fully understand how the perception of affective touch emerges, more studies should directly manipulate participants’ beliefs about the purpose of touch.

• Pfabigan, Daniela M.; Vezzani, Cecilia; Thorsby, Per Medbøe & Sailer, Uta (2022). Sex difference in human olfactory sensitivity is associated with plasma adiponectin. Hormones and Behavior. ISSN 0018-506X. 145. doi: 10.1016/j.yhbeh.2022.105235. Fulltekst i vitenarkiv Vis sammendrag

  Energy deprivation as well as hormones that regulate appetite and eating can influence olfactory function. This study investigated olfactory sensitivity for a food-related and a non-food odour prior to and after a meal, and its relationship to the energy-regulating hormones ghrelin and adiponectin. The olfactory sensitivity for orange and rose (PEA) odour in healthy, normal-weight volunteers (19 women, 45 men, 1 undisclosed individual) was not affected by the consumption of a meal. Olfactory sensitivity was not associated with concentrations of circulating ghrelin. However, olfactory sensitivity was higher for women than for men, indicating better olfactory performance. This difference between women and men was related to concentrations of plasma adiponectin, an adipose-specific hormone. Adiponectin may thus explain why sex differences in olfactory sensitivity emerge, and may also account for some of the inconsistencies in previous findings on sex differences. Our findings add to the limited literature on the impact of stomach and adipose tissue-derived hormones on olfactory sensitivity. Further studies are needed to establish a causal link between circulating adiponectin and a sex difference in olfactory sensitivity.

• Pfabigan, Daniela Melitta; Hertel, Jens Kristoffer; Svanevik, Marius; Lindberg, Morten; Sailer, Uta & Hjelmesæth, Jøran Sture (2022). Single-centre, non-randomised clinical trial to investigate the effects of bariatric surgery on social experiences and biomarkers of well-being one year after surgery in individuals with severe obesity: a protocol for the Bariatric Surgery and Social Experiences (BaSES) study. medRxiv. doi: 10.1101/2022.12.21.22283770. Fulltekst i vitenarkiv Vis sammendrag

  Introduction Obesity is linked to increased loneliness and less enjoyment of social interactions. While bariatric surgery is the most effective treatment targeting morbid obesity, there is limited understanding as to whether patients experience social interactions differently after surgery. The Bariatric Surgery and Social Experiences Study (BaSES) is designed to assess potential changes in how much patients enjoy and engage in daily social interactions 1 year after Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). Methods and analysis Single-centre, non-randomised clinical trial carried out at the Morbid Obesity Centre at Vestfold Hospital Trust, Norway. Eligible patients will undergo either RYGB, SG or single anastomosis sleeve ileal bypass (SASI). The primary outcome measure is change in the social experience score (assessed with a questionnaire) from a pre-surgery to a follow-up assessment 1 year after RYGB and SG. The respective changes after SASI will be assessed and considered exploratory. Ethics and dissemination The most recent protocol version of this study was reviewed and approved by the Regional Committee for Medical Research Ethics South East Norway (REK sør-øst A) on the 29th of August 2022 (ref: 238406). The results will be disseminated to academic and health professional audiences and the public via publications in international peer-reviewed journals and conferences. Trial registration number NCT05207917 (ClinicalTrials.gov)

• Pfabigan, Daniela Melitta; Frogner, Erik Rimestad; Erik, Schéle; Thorsby, Per Medbøe; Skålhegg, Bjørn Steen & Dickson, Suzanne L. [Vis alle 7 forfattere av denne artikkelen] (2022). The “hunger” hormone ghrelin is associated with neural activation during touch, but not its affective experience. BioRxiv. ISSN 0362-4331. doi: 10.1101/2022.05.10.491384. Fulltekst i vitenarkiv
• Bendas, Johanna; Ree, Anbjørn; Pabel, Luise; Sailer, Uta & Croy, Ilona (2021). Dynamics of affective habituation to touch differ on the group and individual level. Neuroscience. ISSN 0306-4522. 464, s. 44–52. doi: 10.1016/j.neuroscience.2020.12.024. Fulltekst i vitenarkiv Vis sammendrag

  Slow stroking touch activates C-tactile (CT) fibres in the human skin and is typically described as pleasant. Over a longer duration of stroking, affective habituation sets in, indicated by a reduction in rated pleasantness. However, it is not clear whether the group level effect is represented on an individual level. We analyse the stability of individual ratings of slow stroking touch and their relationship to behavioural and physiological measures. Forty-eight participants (23 women) were repeatedly stroked with a velocity maximally activating CT fibres. The perceived pleasantness was rated on a visual analogue scale. In order to examine the stability of pleasantness ratings, the experiment was repeated after a couple of days. During the experiment, electrocardiogram (ECG) and facial-electromyography (EMG) data were recorded. On the group-level, previous results of affective habituation to touch were replicated and stable across sessions. On the individual level, however, less than half of the participants showed a significant reduction of pleasantness in the course of the experiment. Moreover, the remaining participants showed either no change, random rating behaviour or even an increase in pleasantness ratings during the course of the experiment. The individual response patterns were variable across sessions but stable above the chance level. Furthermore, the response patterns could not be explicitly associated with any of the behavioural or physiological measures. Our findings indicate a lack of group-to-individual generalizability for affective habituation to touch. The variability of rating patterns over time indicates that they are not conclusively determined by stable individual characteristics. Future research investigating touch should favour a more individual approach to the more commonly applied group analysis.

• Eckstein, Monika; Mamaev, Ilshat; Ditzen, Beate & Sailer, Uta (2020). Calming effects of touch in human, animal, and robotic interaction — Scientific state-of-the-art and technical advances. Frontiers in Psychiatry. 11, s. 1–17. doi: 10.3389/fpsyt.2020.555058. Fulltekst i vitenarkiv Vis sammendrag

  Small everyday gestures such as a tap on the shoulder can affect the way humans feel and act. Touch can have a calming effect and alter the way stress is handled, thereby promoting mental and physical health. Due to current technical advances and the growing role of intelligent robots in households and healthcare, recent research also addressed the potential of robotic touch for stress reduction. In addition, touch by non-human agents such as animals or inanimate objects may have a calming effect. This conceptual article will review a selection of the most relevant studies reporting the physiological, hormonal, neural, and subjective effects of touch on stress, arousal, and negative affect. Robotic systems capable of non-social touch will be assessed together with control strategies and sensor technologies. Parallels and differences of human-to-human touch and human-to-non-human touch will be discussed. We propose that, under appropriate conditions, touch can act as (social) signal for safety, even when the interaction partner is an animal or a machine. We will also outline potential directions for future research and clinical relevance. Thereby, this review can provide a foundation for further investigations into the beneficial contribution of touch by different agents to regulate negative affect and arousal in humans.

• Sailer, Uta; Hausmann, Marlene & Croy, Ilona (2020). Pleasantness Only?: How Sensory and Affective Attributes Describe Touch Targeting C-Tactile Fibers. Experimental Psychology. ISSN 1618-3169. 67(4), s. 224–236. doi: 10.1027/1618-3169/a000492. Fulltekst i vitenarkiv Vis sammendrag

  Abstract. When gently stroked with velocities between 0.1 and 30 cm/s, participants typically rate velocities around 3 cm/s as most pleasant, and the ratings follow an inverted u-shape. This pleasantness curve correlates often, but not always, with the firing rate of unmyelinated C-tactile (CT) afferents, leading to the notion that CT afferents code for the hedonic or emotional aspect of gentle touch. However, there is also evidence that CT firing does not necessarily equal pleasantness, and the range of attributes that CT afferents code for is not known. Here, participants were stroked with different velocities assumed to activate CT afferents to a different extent while they rated the touch on several sensory and emotional attributes. We expected an inverted u-shaped rating curve for pleasantness and other emotional attributes, but not for sensory attributes. Inverted u-shaped rating patterns were found for the emotional attributes “pleasant” and “not burdensome,” but also for the sensory attribute “rough.” CT-directed stimulation is thus not only experienced as hedonic. The sensations arising from CTs together with all other types of mechanoreceptors might be centrally integrated into a percept that represents those aspects which are most salient for the stimulation at hand.

• Schéle, Erik; Pfabigan, Daniela M.; Simrén, Joel; Sailer, Uta & Dickson, Suzanne L. (2020). Ghrelin Induces Place Preference for Social Interaction in the Larger Peer of a Male Rat Pair. Neuroscience. ISSN 0306-4522. 447(1), s. 148–154. doi: 10.1016/j.neuroscience.2020.01.027. Fulltekst i vitenarkiv Vis sammendrag

  Social interaction is important for survival in most social species including humans. To ensure social activities, individuals experience reward from social interaction, generating a powerfully reinforcing process. Here we hypothesized that reward from social interaction in a juvenile male rat pair may be enhanced by ghrelin, a circulating hormone that has been shown to enhance reward from other natural (e.g. food, sex) as well as artificial reinforcers (e.g. alcohol and other drugs of abuse). To this end, we assessed the impact of ghrelin and a ghrelin antagonist on preference for a chamber previously paired to the presence of a social partner in a conditioned place preference paradigm. We found that ghrelin increased and a ghrelin antagonist decreased preference for social interaction, but only in the heavier partner in a social pair. In addition, we found that administered ghrelin induced a positive association between preference for social interaction and body weight difference within socially interacting pairs, where larger ghrelin treated rats preferred social interaction, whereas smaller ghrelin treated rats avoided it, which raises the question if ghrelin could have a role in implementing social hierarchies in rats. In summary, we conclude that ghrelin signaling increases the reward from social interaction in a manner that reflects the degree of divergence in body weight between the social pair.

• Croy, Ilona; Bierling, Antonie; Sailer, Uta & Ackerley, Rochelle (2020). Individual variability of pleasantness ratings to stroking touch over different velocities. Neuroscience. ISSN 0306-4522. doi: 10.1016/j.neuroscience.2020.03.030. Fulltekst i vitenarkiv Vis sammendrag

  Many studies have investigated the perception of tactile pleasantness over a range of stroking velocities. On average, pleasantness is low at slow (e.g. 0.3 cm/s) and fast (e.g. 30 cm/s) stroking velocities, but is rated highest at velocities between 1 and 10 cm/s. On a group level, this results in an inverted-U shape pleasantness ratings curve, which is described statistically by a negative quadratic equation. We reanalyzed the data from five earlier studies to investigate whether the inverted-U shape pleasantness curve at the group level is also present at the level of the individual, – a precondition for using tactile pleasantness perception as a diagnostic marker. We pooled the data from five studies with a total of 127 participants. Each study included a ‘standard condition’ of stroking on the dorsal forearm over different velocities (0.3, 1, 3, 10, 30 cm/s) and participants rated the pleasantness. Factors other than stroking velocity were also varied in these studies. On the whole-group level and in each study, pleasantness ratings produced a significant negative quadratic pleasantness curve over the stroking velocities. In individual participants, ratings varied greatly and only 42% of the participants showed a significant negative quadratic curve. The steepness of the inverted-U correlated only moderately across other experimental conditions, showing that the experimental circumstances can influence pleasantness ratings. Our findings have important implications for future work, where differences in the tactile pleasantness curve should not be used to predict or diagnose issues at an individual level.

• Ree, Anbjørn; Benda, Johanna; Pabel, Luise; Croy, Ilona & Sailer, Uta (2020). Right between the eyes: Corrugator muscle activity tracks the changing pleasantness of repeated slow stroking touch. Physiology and Behavior. ISSN 0031-9384. 222. doi: 10.1016/j.physbeh.2020.112903. Fulltekst i vitenarkiv Vis sammendrag

  Subjective reports and physiological responses provide different appraisals of sensory input. The coherence between subjective and physiological responses to repeated pleasant stimuli remains largely unexplored, and is particularly important in situations where subjective responses are prone to cognitive or contextual bias. Here, we investigate how subjective and physiological responses to repeated gentle touch correspond at two separate sessions and compare these to responses obtained when smelling an odorant. Forty-eight participants underwent 60 trials of skin-to-skin slow stroking touch directed to the forearm. We collected subjective pleasantness reports, recorded facial electromyography (EMG) of the corrugator and zygomaticus muscles and heart-rate variability (HRV). With increasing touch repetitions, mean ratings of pleasantness decreased and corrugator muscle activity increased during session 1, whereas zygomaticus activity remained largely unchanged during both sessions. HRV was significantly higher during the first session, but did not increase from baseline during either sessions. Touch was rated as more pleasant than odor, and demonstrated greater resilience to satiety than the odor responses. Facial EMG recordings of the corrugator muscle appear to be a relevant measure for capturing satiety effects in skin-to-skin touch. Zygomaticus and HRV responses were independent of the subjective appraisal of the gentle touch. Rather than being blueprints of the subjective reports, physiological responses appear to reflect different parts of the subjective experience. As such, an improved understanding of the subjective and physiological responses to pleasant stimuli may improve our understanding of the dynamic interactions that take place in shaping complex emotional phenomena, such as aversion and pleasantness.

• Triscoli, Chantal; Croy, Ilona & Sailer, Uta (2019). Depression predicts interpersonal problems partially through the attitude towards social touch. Journal of Affective Disorders. ISSN 0165-0327. 246, s. 234–240. doi: 10.1016/j.jad.2018.12.054. Fulltekst i vitenarkiv Vis sammendrag

  Introduction : Depression is associated with difficulties in interpersonal relationships, of which communication is an integral part. Communication can not only be effected by verbal means, but also non-verbally by touch. Against this background, the aim of the present study was to investigate the relationship between depression, interpersonal problems and the attitude towards social touch. Methods : 147 individuals (115 females; 21–71 years old) seeking treatment in a clinic for outpatient psychotherapy took part in the survey. Three questionnaires evaluating the level of depression (Beck Depression Questionnaire), the degree of interpersonal problems (Inventory of Interpersonal Problems) and the attitude towards social touch (Social Touch Questionnaire, were administered. Results : Highly depressed individuals had a more negative attitude towards social touch than non-to lowly depressed individuals. Highly depressed individuals particularly reported to dislike physical touch by not well-known people, but not by close ones. Highly depressed individuals also reported more interpersonal problems, with the level of depression predicting the degree of interpersonal problems. This relationship was partially mediated by the attitude towards social touch in general and, to a greater extent, by the dislike of physical touch by people not well-known in particular. Discussion : Given the role of social touch in the relationship between depression and interpersonal problems, the attitude towards touch may be taken into consideration in the therapy of depressed patients. We assume that a more positive attitude towards social touch can influence the ability to create and maintain interpersonal relationships.

• Strauss, Timmy; Rottstädt, Fabian; Sailer, Uta; Schellong, Julia; Hamilton, J. Paul & Raue, Claudia [Vis alle 8 forfattere av denne artikkelen] (2019). Touch aversion in patients with interpersonal traumatization. Depression and Anxiety. ISSN 1091-4269. 36(7), s. 635–646. doi: 10.1002/da.22914. Fulltekst i vitenarkiv Vis sammendrag

  We interpret the hippocampal suppression as an attempt to control traumatic memories, evoked by interpersonal touch. This mechanism may maintain the aversion of interpersonal touch in patients with interpersonal trauma‐related PTSD.

• Ree, Anbjørn; Morrison, India; Olausson, Håkan; Sailer, Uta; Heilig, Markus & Mayo, Leah M (2019). Using Facial Electromyography to Assess Facial Muscle Reactions to Experienced and Observed Affective Touch in Humans. Journal of Visualized Experiments. 145. doi: 10.3791/59228. Fulltekst i vitenarkiv Vis sammendrag

  "Affective" touch is believed to be processed in a manner distinct from discriminatory touch and to involve activation of C-tactile (CT) afferent fibers. Touch that optimally activates CT fibers is consistently rated as hedonically pleasant. Patient groups with impaired social-emotional functioning also show disordered affective touch ratings. However, relying on self-reported ratings of touch has many limitations, including recall bias and communication barriers. Here, we describe a methodological approach to study affective responses to touch via facial electromyography (EMG) that circumvents the reliance on self-report ratings. Facial EMG is an objective, quantitative, and non-invasive method to measure facial muscle activity indicative of affective responses. Responses can be assessed across healthy and patient populations without the need for verbal communication. Here, we provide two separate datasets demonstrating that CT-optimal and non-optimal touch elicit distinct facial muscle reactions. Moreover, facial EMG responses are consistent across stimulus modalities, e.g. tactile (experienced touch) and visual (observed touch). Finally, the temporal resolution of facial EMG can detect responses on timescales that supersede that of verbal reporting. Together, our data suggest that facial EMG is a suitable methodology for use in affective tactile research that can be used to supplement, or in some cases, supplant, existing measures.

• Bessler, Ria; Bendas, Johanna; Sailer, Uta & Croy, Ilona (2019). The “Longing for Interpersonal Touch Picture Questionnaire”: Development of a new measurement for touch perception. International Journal of Psychology (IJP). ISSN 0020-7594. doi: 10.1002/ijop.12616. Fulltekst i vitenarkiv Vis sammendrag

  Touch is a crucial factor of physiological and psychological health in humans. A lack of touch in contrast is associated with adverse implications on mental health. A new “Longing for Interpersonal Touch Picture Questionnaire (LITPQ)” was developed and tested for its concurrent, predictive, discriminant and face validity as well as its relation to psychological distress. Six different types of touch were depicted and touch frequency and touch wish concerning different interaction partners assessed. A sample of 110 participants aged 18–56 years completed the LITPQ as well as an existing touch deprivation questionnaire and a questionnaire on mental health. Frequency and wish for touch were higher for close interaction partners than for strangers. For 72.7% of the participants, their touch wish exceeded the reported touch frequency. The LITPQ correlated moderately with the existing questionnaire for touch deprivation and was independent of relationship status or gender but positively correlated with depressiveness, anxiety and somatization. Measuring longing for touch is a very complex task considering the many aspects of subjective touch perception and confounds in the method of self‐report of touch. In our view, the LITPQ provides promising insights into this matter.

• Rosenberger, Lisa Anna; Ree, Anbjørn; Eisenegger, Christoph & Sailer, Uta (2018). Slow touch targeting CT-fibres does not increase prosocial behaviour in economic laboratory tasks. Scientific Reports. 8(1). doi: 10.1038/s41598-018-25601-7. Fulltekst i vitenarkiv Vis sammendrag

  Field studies have demonstrated that humans become more generous, helpful and compliant after having been touched by another person. Here, we explored whether these effects are larger for touch activating the C-tactile (CT) fibres, as it is ascribed a particular role in establishing and maintaining bonds and affiliative interactions. The role of CT-targeted and non-targeted touch on prosocial behaviour was investigated in three different experiments using a trust game and a task measuring individual differences in social value orientations (the SVO task). Whereas participants in general acted prosocially, there was no influence of CT-targeted touch on prosocial behaviour, both in comparison to non-CT-targeted control touch and visual (non-tactile) stimulation. The null findings were further corroborated by Bayesian statistics. Thus, under the controlled laboratory conditions employed, CT-targeted touch did not play a particular role in prosocial behaviour. This indicates that touch does not increase prosocial behaviour in the absence of meaningful social and psychological connotations. Any touch related effects on prosocial behaviour likely depends on the ecological validity of the situation.

• Ree, Anbjørn; Mayo, Leah M; Leknes, Siri & Sailer, Uta (2018). Touch targeting C-tactile afferent fibers has a unique physiological pattern: A combined electrodermal and facial electromyography study. Biological Psychology. ISSN 0301-0511. 140, s. 55–63. doi: 10.1016/j.biopsycho.2018.11.006. Fulltekst i vitenarkiv
• Triscoli, Chantal; Croy, Ilona; Olausson, Håkan & Sailer, Uta (2017). Touch between romantic partners: Being stroked is more pleasant than stroking and decelerates heart rate. Physiology and Behavior. ISSN 0031-9384. 177, s. 169–175. doi: 10.1016/j.physbeh.2017.05.006. Fulltekst i vitenarkiv
• Triscoli, Chantal; Croy, Ilona; Steudte-Schmiedgen, Susann; Olausson, Håkan & Sailer, Uta (2017). Heart rate variability is enhanced by long-lasting pleasant touch at CT-optimized velocity. Biological Psychology. ISSN 0301-0511. 128, s. 71–81. doi: 10.1016/j.biopsycho.2017.07.007. Fulltekst i vitenarkiv
• Kogler, Lydia; Sailer, Uta; Derntl, Birgit & Pfabigan, Daniela (2017). Processing expected and unexpected uncertainty is modulated by fearless-dominance personality traits - An exploratory ERP study on feedback processing. Physiology and Behavior. ISSN 0031-9384. 168, s. 74–83. doi: 10.1016/j.physbeh.2016.10.016. Fulltekst i vitenarkiv
• Sailer, Uta & Ackerley, Rochelle (2017). Exposure shapes the perception of affective touch. Developmental Cognitive Neuroscience. ISSN 1878-9293. doi: 10.1016/j.dcn.2017.07.008. Fulltekst i vitenarkiv
• Sailer, Uta; Triscoli, Chantal; Häggblad, Gisela; Hamilton, Paul; Olausson, Håkan & Croy, Ilona (2016). Temporal dynamics of brain activation during 40 minutes of pleasant touch. NeuroImage. ISSN 1053-8119. 139, s. 360–367. doi: 10.1016/j.neuroimage.2016.06.031. Fulltekst i vitenarkiv
• Sailer, Uta; Riva, Federica; Lieberz, Jana; Campbell-Meiklejohn, Daniel; Scheele, Dirk & Pfabigan, Daniela Melitta (2002). Hungry for compliments? Ghrelin is not associated with neural responses to social rewards or their pleasantness. BioRxiv. ISSN 0362-4331. doi: 10.1101/2022.11.18.516889. Fulltekst i vitenarkiv Vis sammendrag

  The stomach-derived hormone ghrelin motivates food search and stimulates food consumption, with highest plasma concentrations before a meal and lowest shortly after. However, ghrelin also appears to affect the value of non-food rewards such as interaction with rat conspecifics, and monetary rewards in humans. The present pre-registered study investigated how nutritional state and ghrelin concentrations are related to the subjective and neural responses to social and non-social rewards. In a cross-over feed- and-fast design, 67 healthy volunteers (20 women) underwent functional magnetic resonance imaging (fMRI) in a hungry state and after a meal with repeated plasma ghrelin measurements. In task 1, participants received social rewards in the form of approving expert feedback, or non-social computer reward. In task 2, participants rated the pleasantness of compliments and neutral statements. Nutritional state and ghrelin concentrations did not affect the response to social reward in task 1. In contrast, ventromedial prefrontal cortical activation to non-social rewards was reduced when the meal strongly suppressed ghrelin. In task 2, fasting increased activation in the right ventral striatum during all statements, but ghrelin concentrations were neither associated with brain activation nor with experienced pleasantness. Complementary Bayesian analyses provided moderate evidence for a lack of correlation between ghrelin concentrations and behavioral and neural responses to social rewards, but moderate evidence for an association between ghrelin and non-social rewards. This suggests that ghrelin’s influence may be restricted to non-social rewards. Social rewards implemented via social recognition and affirmation may be too abstract and complex to be susceptible to ghrelin’s influence. In contrast, the non-social reward was associated with the expectation of a material object that was handed out after the experiment. This may indicate that ghrelin might be involved in anticipatory rather than consummatory phases of reward.

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• Pfabigan, Daniela Melitta; Hertel, Jens Kristoffer; Svanevik, Marius; Lindberg, Morten; Sailer, Uta & Hjelmesæth, Jøran Sture (2023). Single-centre, non-randomised clinical trial at a tertiary care centre to investigate 1-year changes in social experiences and biomarkers of well-being after bariatric surgery in individuals with severe obesity: protocol for the Bariatric Surgery and Social Experiences (BaSES) study. BMJ open gastroenterology. doi: 10.1136/bmjopen-2022-071332. Fulltekst i vitenarkiv Vis sammendrag

  Introduction Obesity is linked to increased loneliness and less enjoyment of social interactions. While bariatric surgery is the most effective treatment targeting severe obesity, there is limited understanding as to whether patients experience social interactions differently after surgery. The Bariatric Surgery and Social Experiences study is designed to assess potential changes in how much patients enjoy and engage in daily social interactions 1 year after Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). Methods and analysis Single-centre, non-randomised clinical trial carried out at the Department of Endocrinology, Obesity and Nutrition at Vestfold Hospital Trust, Norway. Eligible patients (N=113) will undergo either RYGB, SG or single anastomosis sleeve ileal (SASI) bypass. The primary outcome measure is change in the social experience score (assessed with a questionnaire) from a presurgery to a follow-up assessment 1 year after RYGB and SG. The respective changes after SASI bypass will be assessed and considered exploratory. Ethics and dissemination The most recent protocol version of this study was reviewed and approved by the Regional Committee for Medical Research Ethics South East Norway (REK sør-øst A) on 29 August 2022 (ref: 238406). The results will be disseminated to academic and health professional audiences and the public via publications in international peer-reviewed journals and conferences.

• Jacobsen, Hilde; Sailer, Uta; Tandberg, Bente & Kynø, Nina M (2023). Is parental attitude related to the amount of time they devote to skin-to-skin contact with their preterm infant? Fulltekst i vitenarkiv
• Jacobsen, Hilde Kristin; Tandberg, Bente; Kynø, Nina M & Sailer, Uta (2023). Is parental attitude related to the amount of time they devote to skin-to-skin contact with their preterm infant? Fulltekst i vitenarkiv
• Sailer, Uta; Riva, Federica & Pfabigan, Daniela Melitta (2022). DOES THE HUNGER HORMONE GHRELIN INFLUENCE THE BRAIN'S RESPONSE TO SOCIAL RECOGNITION? Psychophysiology. ISSN 0048-5772. 59(S1), s. S68–S68. doi: 10.1111/psyp.14144. Fulltekst i vitenarkiv
• Pfabigan, Daniela M.; Ree, Anbjørn & Sailer, Uta (2021). Being hungry decreases the pleasantness of touch. Fulltekst i vitenarkiv
• Croy, Ilona & Sailer, Uta (2021). Zurücktreten, bitte! Psychologie heute. ISSN 0340-1677. s. 40–44. Fulltekst i vitenarkiv
• Pfabigan, Daniela M. & Sailer, Uta (2021). BEING FASTED REDUCES TOUCH REWARD. Fulltekst i vitenarkiv Vis sammendrag

  Hunger constitutes one of the strongest motivators in the animal kingdom with the potential to override almost all competing incentives. While short-term hunger is ubiquitous in our daily lives, we do not know whether it is strong enough to override strong interpersonal incentives such as affective touch. Thus, this neuroimaging study investigated whether touch reward is influenced by one’s metabolic state. In a within-subject study, 60 participants (16 women) remained once fasted, while they started the other test session with a standardized meal. All rated pleasantness and stimulus intensity for slow (0.3cm/s), CT-targeted (3cm/s), and fast (30cm/s) touch applied to the right shin. For 45 participants (11 women), 3T fMRI data were collected during touch processing. Touch was rated as more pleasant when participants were satiated than when fasted. Additionally, participants rated CT-targeted touch as most pleasant. In accordance, brain activation was enhanced in the right supramarginal gyrus and bilateral paracingulate areas during CT-targeted touch when participants were satiated compared to fasted (cluster-level FWE-corrected p<.05). The more participants reported to enjoy CT-targeted touch when satiated compared to being fasted, the higher the corresponding activation levels in paracingulate areas. Our results are in line with animal studies on motivational hierarchies, as fasting obviously decreased the pleasantness of affective touch. This suggests that metabolic needs can overshadow the rewarding effects of otherwise pleasant stimuli provided in another modality.

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