Pain is modulated by social context. Recent neuroimaging studies have shown that romantic partners can provide a potent form of social support during pain. However, such studies have only focused on passive support, finding a relatively late-onset modulation of pain-related neural processing. In this study, we examined for the first time dynamic touch by one’s romantic partner as an active form of social support. Specifically, 32 couples provided social, active, affective (vs active but neutral) touch according to the properties of a specific C-tactile afferent pathway to their romantic partners, who then received laser-induced pain. We measured subjective pain ratings and early N1 and later N2-P2 laser-evoked potentials (LEPs) to noxious stimulation, as well as individual differences in adult attachment style. We found that affective touch from one’s partner reduces subjective pain ratings and similarly attenuates LEPs both at earlier (N1) and later (N2-P2) stages of cortical processing. Adult attachment style did not affect LEPs, but attachment anxiety had a moderating role on pain ratings. This is the first study to show early neural modulation of pain by active, partner touch, and we discuss these findings in relation to the affective and social modulation of sensory salience.

Sense of agency-a feeling of control over one's actions and their outcomes-might include at least two components: free choice over which outcome to pursue and motoric control over the action causing the outcome. We orthogonally manipulated locus of outcome choice (free or instructed choice) and motoric control (active or passive movement), while measuring the perceived temporal attraction between actions and outcomes ( temporal binding) as an implicit marker of agency. Participants also rated stimulus intensity so that we could measure sensory attenuation, another possible implicit marker of agency. Actions caused higher or lower levels of either painful heat or mild electrotactile stimulation. We found that both motoric control and outcome choice contributed to outcome binding. Moreover, free choice, relative to instructed choice, attenuated the perceived magnitude of high-intensity outcomes, but only when participants made an active movement. Thus, choosing, not just doing, influences temporal binding and sensory attenuation, though in different ways. Our results show that these implicit measures of agency are sensitive to both voluntary motor commands and instrumental control over action outcomes.

The sense of agency refers to the feeling of control over one's actions, and, through them, over external events. One proposed marker of implicit sense of agency is 'intentional binding'-the tendency to perceive voluntary actions and their outcomes as close in time. Another is attenuation of the sensory consequences of a voluntary action. Here we show that the ability to choose an outcome through action selection contributes to implicit sense of agency. We measured intentional binding and stimulus intensity ratings using painful and non-painful somatosensory outcomes. In one condition, participants chose between two actions with different probabilities of producing high or low intensity outcomes, so action choices were meaningful. In another condition, action selection was meaningless with respect to the outcome. Having control over the outcome increased binding, especially when outcomes were painful. Greater sensory attenuation also tended to be associated with stronger binding of the outcome towards the action that produced it. Previous studies have emphasised the link between sense of agency and initiation of voluntary motor actions. Our study shows that the ability to control outcomes by discriminative action selection is another key element of implicit sense of agency. It also investigates, for the first time, the relation between binding and sensory attenuation for the same events.

Two recent studies have demonstrated that increases in arousal states lead to an increase people’s sense of agency, i.e., the subjective experience of controlling one’s own voluntary actions (Minohara et al. in Front Psychol 7:1165, 2016; Wen et al. in Conscious Cogn 36:87–95, 2015). We here extend these findings by showing that arousal states with negative emotional valence, such as fear and anger, decrease sense of agency. Anger and fear are negative emotional states. Anecdotally, they are often invoked as reasons for losing control, and neuroscientific evidence confirms important effects on the brain’s action control systems. Surprisingly, the subjective experience of acting in anger or fear has scarcely been investigated experimentally. Thus, the legal notion that these intense emotions may undermine normal voluntary control over actions and outcomes (the ‘Loss of Control’, a partial defence for murder) lacks any clear evidence base. In three laboratory experiments, we measured sense of agency using an implicit measure based on time perception (the “intentional binding” paradigm). These actions occurred in either an emotionally neutral condition, or in a fearful (experiments 1 and 2) or angry state (experiment 3). In line with our hypotheses, fear or anger reduced the subjective sense of control over an action outcome, even though the objective causal link between action and outcome remained the same. This gap between the objective facts of agency, and a reduced subjective experience of agency under emotional conditions, has important implications for society and law. Electronic supplementary material The online version of this article (10.1007/s00221-018-5461-6) contains supplementary material, which is available to authorized users.

Psychological characterisation of sensory systems often focusses on minimal units of perception, such as thresholds, acuity, selectivity and precision. Research on how these units are aggregated to create integrated, synthetic experiences is rarer. We investigated mechanisms of somatosensory integration by asking volunteers to judge the total intensity of stimuli delivered to two fingers simultaneously. Across four experiments, covering physiological pathways for tactile, cold and warm stimuli, we found that judgements of total intensity were particularly poor when the two simultaneous stimuli had different intensities. Total intensity of discrepant stimuli was systematically overestimated. This bias was absent when the two stimulated digits were on different hands. Taken together, our results showed that the weaker stimulus of a discrepant pair was not extinguished, but contributed less to the perception of the total than the stronger stimulus. Thus, perception of somatosensory totals is biased towards the most salient element. 'Peak' biases in human judgements are well-known, particularly in affective experience. We show that a similar mechanism also influences sensory experience.

The distinctive experience of pain, beyond mere processing of nociceptive inputs, is much debated in psychology and neuroscience. One aspect of perceptual experience is captured by metacognition—the ability to monitor and evaluate one’s own mental processes. We investigated confidence in judgements about nociceptive pain (i.e. pain that arises from the activation of nociceptors by a noxious stimulus) to determine whether metacognitive processes contribute to the distinctiveness of the pain experience. Our participants made intensity judgements about noxious heat, innocuous warmth, and visual contrast (first-order, perceptual decisions) and rated their confidence in those judgements (second-order, metacognitive decisions). First-order task performance between modalities was balanced using adaptive staircase procedures. For each modality, we quantified metacognitive efficiency (meta-d’/d’)—the degree to which participants’ confidence reports were informed by the same evidence that contributed to their perceptual judgements—and metacognitive bias (mean confidence)—the participant’s tendency to report higher or lower confidence overall. We found no overall differences in metacognitive efficiency or mean confidence between modalities. Mean confidence ratings were highly correlated between all three tasks, reflecting stable inter-individual variability in metacognitive bias. However, metacognitive efficiency for pain varied independently of metacognitive efficiency for warmth and visual perception. That is, those participants who had higher metacognitive efficiency in the visual task also tended to have higher metacognitive efficiency in the warmth task, but not necessarily in the pain task. We thus suggest that some distinctive and idiosyncratic aspects of the pain experience may stem from additional variability at a metacognitive level. We further speculate that this additional variability may arise from the affective or arousal aspects of pain.

Our perception of where touch occurs on our skin shapes our interactions with the world. Most accounts of cutaneous localisation emphasise spatial transformations from a skin-based reference frame into body-centred and external egocentric coordinates. We investigated another possible method of tactile localisation based on an intrinsic perception of 'skin space'. The arrangement of cutaneous receptive fields (RFs) could allow one to track a stimulus as it moves across the skin, similarly to the way animals navigate using path integration. We applied curved tactile motions to the hands of human volunteers. Participants identified the location midway between the start and end points of each motion path. Their bisection judgements were systematically biased towards the integrated motion path, consistent with the characteristic inward error that occurs in navigation by path integration. We thus showed that integration of continuous sensory inputs across several tactile RFs provides an intrinsic mechanism for spatial perception.

The term ‘visual music’ refers to works of art in which both hearing and vision are directly or indirectly stimulated. Our ability to create, perceive, and appreciate visual music is hypothesised to rely on the same multisensory processes that support auditory – visual (AV) integration in other contexts. Whilst these mechanisms have been extensively studied, there has been little research on how these processes affect aesthetic judgments (of liking or preference). Studies of synaesthesia in which sound evokes vision and studies of cross-modal biases in non-synaesthetes have revealed non-arbitrary mappings between visual and auditory properties (eg high-pitch sounds being smaller and brighter). In three experiments, we presented members of the general population with animated AV clips derived from synaesthetic experiences and contrasted them with a number of control conditions. The control conditions consisted of the same clips rotated or with the colour changed, random AV pairings, or animated clips generated by non-synaesthetes. Synaesthetic AV animations were generally preferred over the control conditions. The results suggest that non-arbitrary AV mappings, present in the experiences of synaesthetes, can be readily appreciated by others and may underpin our tendency to engage with certain forms of art.