Behavioural Models of Risk-Taking in Human-Robot Tactile Interactions.

Touch can have a strong effect on interactions between people, and as such, it is expected to be important to the interactions people have with robots. In an earlier work, we showed that the intensity of tactile interaction with a robot can change how much people are willing to take risks. This study further develops our understanding of the relationship between human risk-taking behaviour, the physiological responses by the user, and the intensity of the tactile interaction with a social robot. We used data collected with physiological sensors during the playing of a risk-taking game (the Balloon Analogue Risk Task, or BART). The results of a mixed-effects model were used as a baseline to predict risk-taking propensity from physiological measures, and these results were further improved through the use of two machine learning techniques-support vector regression (SVR) and multi-input convolutional multihead attention (MCMA)-to achieve low-latency risk-taking behaviour prediction during human-robot tactile interaction. The performance of the models was evaluated based on mean absolute error (MAE), root mean squared error (RMSE), and R squared score (R2), which obtained the optimal result with MCMA yielding an MAE of 3.17, an RMSE of 4.38, and an R2 of 0.93 compared with the baseline of 10.97 MAE, 14.73 RMSE, and 0.30 R2. The results of this study offer new insights into the interplay between physiological data and the intensity of risk-taking behaviour in predicting human risk-taking behaviour during human-robot tactile interactions. This work illustrates that physiological activation and the intensity of tactile interaction play a prominent role in risk processing during human-robot tactile interaction and demonstrates that it is feasible to use human physiological data and behavioural data to predict risk-taking behaviour in human-robot tactile interaction.

Understanding the Effects of Tactile Grating Patterns on Perceived Roughness Over Ultrasonic Friction Modulation Surfaces.

OBJECTIVE: Our study aims to investigate the effects of grating patterns of perceived roughness on surfaces with ultrasonic friction modulation, and also to examine user performance of identifying different numbers of grating patterns. BACKGROUND: In designing grating-based tactile textures, the widths of low- and high-friction zones are a crucial factor for generating grating patterns that convey roughness sensation. However, few studies have explored the design space of efficient grating patterns that users can easily distinguish and identify via roughness perception. METHOD: Two experiments were carried out. In the first experiment, we conducted a magnitude estimation of perceived roughness for both low- and high-friction zones, each with widths of 0.13, 0.25, 0.38, 0.5, 1.0, 1.5, 2.0, 3.5, and 5.5 mm. In the second experiment, we required participants to identify 5 pattern groups with 2-6 patterns respectively. RESULTS: Perceived roughness fitted a linear trend for low- or high-friction zones with widths of 0.38 mm or lower. Perceived roughness followed an inverted U-shaped curve for low- or high-friction zones with widths greater than 0.5 mm but less than 2.0 mm. The peak points occurred at the widths of 0.38 mm for both low- and high-friction zones. The statistical analysis indicates that both low- and high-friction zones had similar effects on human perception of surface roughness. In addition, participants could memorize and identify up to four tactile patterns with identification accuracy rates higher than 90% and average reaction time less than 2.2 s. CONCLUSIONS: The relation between perceived roughness and varying widths of grating patterns follows linear or inverted U-shape trends. Participants could efficiently identify 4 or fewer patterns with high accuracy (>90%) and short reaction time (<2.2 s). APPLICATION: Our findings can contribute to tactile interface design such as tactile alphabets and target-approaching indicators.

[Tactile communication within the father-mother-baby triad]. / La communication tactile au sein de la triade père-mère-bébé.

This literature review focuses on tactile interactions between parents and their infants. Research on the dyad has explored both cultural differences in touch and the relationship between touch style and hormonal secretion in both parents. The few studies that have examined this communicative modality within the triad have investigated the frequency and type of parent-infant touch, as well as the effect of skin-to-skin contact on tactile interactions at three months postpartum.

Construction of Ultrasonic Tactile Force Feedback Model in Teleoperation Robot System.

The ultrasonic phased array as an emerging interactive tool is increasingly used for aerial tactile interaction. However, there is almost no method to achieve remote variable force feedback through the ultrasonic phased array as far as we know. This article presents a force tactile feedback method for teleoperating robot systems that tracks the five fingers and forms a focus on the fingertips. First, the perceived size of the focus depends on the input parameters. The influence of the parameters on the physical output pressure intensity was obtained through physical test experiments. Then, the absolute threshold and difference threshold of human perception were studied through psychophysical experimental methods. Finally, the input parameters were selected according to the experimental results. According to the collected data, the construction of the force regression model was completed, and different parameters were mapped to the perceived intensity. The contact force generated in the actual operation is fed back to the haptic system, and the constructed model automatically adjusts the control parameters to ensure that the user's hand presents a sensory output corresponding to the intensity change. The entire force feedback system is evaluated, and results show that the system shows good perceptual quality.

Harnessing tactile waves to measure skin-to-skin interactions.

Skin-to-skin touch is an essential form of tactile interaction, yet there is no known method to quantify how we touch our own skin or someone else's skin. Skin-to-skin touch is particularly challenging to measure objectively, since interposing an instrumented sheet, no matter how thin and flexible, between the interacting skins is not an option. To fill this gap, we explored a technique that takes advantage of the propagation of vibrations from the locus of touch to pick up a signal that contains information about skin-to-skin tactile interactions. These "tactile waves" were measured by an accelerometer sensor placed on the touching finger. Applied pressure and speed had a direct influence on measured signal power when the target of touch was the self or another person. The measurements were insensitive to changes in the location of the sensor relative to the target. Our study suggests that this method has potential for probing behaviour during skin-to-skin tactile interactions and could be a valuable technique to study social touch, self-touch, and motor control. The method is non-invasive, easy to commission, inexpensive, and robust.

Multi-touch Interaction Data Analysis System (MIDAS) for 2-D tactile display research.

The study of haptic perception and cognition requires data about how humans interact with tactile surfaces in the context of performing cognitive tasks. MIDAS is a set of three tools for the digital capture, coding, analysis, and interpretation of time-series, multitouch, interactive behaviors on a tactile surface. The MIDAS-logger uses the current screen technology of tablet computers to capture touches (up to ten fingers at high spatial and temporal resolution) through conventional tactile graphics that are overlaid on the screen. The MIDAS-analyser is a software program for the qualitative and quantitative analysis of MIDAS-logger touch data, which includes a fully interactive visualization of the data and a yoked display of a conventional simultaneous video recording made of the interactions. MIDAS-tactile protocol analysis (TPA) provides a scheme and a method to enable the rich coding and interpretation of tactile behaviors over multiple spatial and temporal scales. The efficacy of MIDAS was assessed against a set of criteria drawn from the successes and limitations of prior approaches to the study of tactile interactions. To demonstrate the functions of MIDAS, its three components were used to capture, analyze, code, and interpret the behavior of an experienced user and an inexperienced user of tactile graphics as they performed a shape-matching task.

Multisensory temporal processing in own-body contexts: plausibility of hand ownership does not improve visuo-tactile asynchrony detection.

Tracking one's own body is essential for environmental interaction, and involves integrating multisensory cues with stored information about the body's typical features. Exactly how multisensory information is integrated in own-body perception is still unclear. For example, Ide and Hidaka (Exp Brain Res 228:43-50, 2013) found that participants made less precise visuo-tactile temporal order judgments (TOJ) when viewing hands in a plausible orientation (upright; typical for one's own hand) compared to an implausible orientation (rotated 180°). This suggests that viewing one's own body relaxes the precision for perceived visuo-tactile synchrony. In contrast, visuo-proprioceptive research shows improvements for multisensory temporal perception near one's own body in asynchrony detection tasks, implying an increase in precision. Hence, it is unclear whether viewed hand orientation generally modulates the ability to detect small asynchronies between vision and touch, or if this effect is specific to TOJ tasks. We investigated whether viewed hand orientation affects detection of visuo-tactile asynchrony. In two experiments, participants viewed model hands in anatomically plausible or implausible orientations. In one experiment, we stroked the hands to induce the rubber hand illusion. Participants were asked to detect short delays (40-280 ms) between vision (an LED flash on the model hand) and touch (a tap to fingertip of the participant's hidden hand) in a two-interval forced-choice task. Bayesian analyses show that our data provide strong evidence that viewed hand orientation does not affect visuo-tactile asynchrony detection. This study suggests the mechanisms for fine-grained time perception differ between visuo-tactile and visuo-proprioceptive contexts.

Haptic Foot Pedal: Influence of Shoe Type, Age, and Gender on Subjective Pulse Perception.

OBJECTIVE: This study investigates the influence of shoe type (sneakers and safety boots), age, and gender on the perception of haptic pulse feedback provided by a prototype accelerator pedal in a running stationary vehicle. BACKGROUND: Haptic feedback can be a less distracting alternative to traditionally visual and auditory in-vehicle feedback. However, to be effective, the device delivering the haptic feedback needs to be in contact with the person. Factors such as shoe type vary naturally over the season and could render feedback that is perceived well in one situation, unnoticeable in another. In this study, we evaluate factors that can influence the subjective perception of haptic feedback in a stationary but running car: shoe type, age, and gender. METHOD: Thirty-six drivers within three age groups (≤39, 40-59, and ≥60) took part. For each haptic feedback, participants rated intensity, urgency, and comfort via a questionnaire. RESULTS: The perception of the haptic feedback is significantly influenced by the interaction between the pulse's duration and force amplitude and the participant's age and gender but not shoe type. CONCLUSION: The results indicate that it is important to consider different age groups and gender in the evaluation of haptic feedback. Future research might also look into approaches to adapt haptic feedback to the individual driver's preferences. APPLICATION: Findings from this study can be applied to the design of an accelerator pedal in a car, for example, for a nonvisual in-vehicle warning, but also to plan user studies with a haptic pedal in general.

Philosophic reflections on the meaning of touch in nurse-patient interactions.

In this paper I examine the meaning of physical touch as it occurs in the nurse-patient interaction. There are two aspects of the nurse-patient relationship that are found in most nurse-patient interactions which together have profound implications for nurses as practitioners and as individual human persons. The first is the clinical intimacy of the nurse-patient relationship where nurses touch, rub, smooth, clean, dress and otherwise physically interact with patients. The other is the existential crisis, the possibility of loss, suffering and death that lurks at the horizon of most, if not all, healthcare encounters. Edmund Husserl, Merleau-Ponty and more recently Robert Sokolowski argue that tactile sensations and resultant perceptions are fundamental to all sensory perception. Further, they argue that tactile sensation is fundamental for the ongoing constitution of 'my' self as a person and for the development and exercise of human intersubjectivity. If tactile interaction is crucial to the development of our very selves as persons and a significant aspect of our interaction with patients includes direct or observed tactile sensations and if further these sensations occur around the context of existential crises for our patients, then nurse's very selves as persons are being challenged by these interactions. Here, then I examine the philosophical argument for the role of tactile sensations in our human development and briefly look at contemporary neurophysiologic research that supports this philosophical account. I then suggest ways such physical intimacy can lead to a strengthening or weakening of the person of the nurse and the nursing interaction and end with some thoughts about ways to support nurses in these activities.

Sensory Reweighting for Postural Control in Older Adults with Age-Related Hearing Loss.

There is growing evidence linking hearing impairments and the deterioration of postural stability in older adults. To our knowledge, however, no study to date has investigated the effect of age-related hearing loss on the sensory reweighting process during postural control. In the absence of data, much is unknown about the possible mechanisms, both deleterious and compensatory, that could underly the deterioration of postural control following hearing loss in the elderly. The aim of this study was to empirically examine sensory reweighting for postural control in older adults with age-related hearing loss as compared to older adults with normal hearing. The center of pressure of all participants was recorded using a force platform and the modified clinical test of sensory interaction and balance protocol. The results suggest that individuals with age-related hearing loss displayed increased somatosensory reliance relative to normal hearing younger adults. This increased reliance on somatosensory input does not appear to be effective in mitigating the loss of postural control, probably due to the concomitant deterioration of tactile and proprioceptive sensitivity and acuity associated with aging. Beyond helping to further define the role of auditory perception in postural control, these results further the understanding of sensory-related mechanisms associated with postural instability in older adults.

Delay and Speed of Visual Feedback of a Keystroke Cause Illusory Heaviness and Stiffness.

Imposing a delay between an action (e.g., a limb movement) and its related visual feedback (e.g., a cursor movement on the display) induces a peculiar sensation of heaviness or stiffness. Earlier studies have examined this delay-induced heaviness or stiffness sensation in relation to the non-arbitrary causal relationship between an action and its effect. Here, "non-arbitrary causal relationship" means that an action produces a specific and deterministic pattern of visual feedback; for example, a leftward limb movement consistently and deterministically causes a leftward visual motion. In modern graphical user interfaces, on the other hand, users often control visual information by pressing keys, wherein the relationship between the keystroke and the change in visual information is arbitrary. The present study examined whether the sensation of heaviness, stiffness and bumpiness could be caused when participants' keystroke produced a delayed arbitrary visual feedback. Participants were asked to press and hold down an assigned key to cause temporal luminance changes in a square centered on the display, an arbitrary visual feedback of their keystroke. Not only the onset delay of the temporal luminance change from the participant's keystroke but also the speed of the temporal luminance change were examined as a visual cue to heaviness, stiffness, or bumpiness. In Experiment 1, the participants' task was to give a rating for the strength of the heaviness, stiffness, or bumpiness perceived when they pressed the key. Our results showed that the heaviness and stiffness ratings increased as the delay increased and decreased as the speed increased. To check whether the manipulation of the delay and speed of the visual feedback caused changes in the subjective evaluation of sensorimotor incongruence, in Experiment 2, we asked the participants to give a rating for the sense of agency. The rating scores decreased as the delay increased and increased as the speed increased. The delay and speed influenced the rating scores for the sense of agency in the opposite direction to those for heaviness/stiffness. We discuss that the brain determines the heaviness and stiffness during a keystroke based on internalized statistics relating to the delay and speed of the action feedback.

Neuroendocrine mechanisms involved in the physiological effects caused by skin-to-skin contact - With a particular focus on the oxytocinergic system.

The positive clinical effects caused by skin-to-skin contact immediately after birth or after repeated skin-to-skin contact of premature infants (kangaroo care) or fullterm infants are well documented in the literature. However, information regarding the physiological mechanisms mediating these effects are surprisingly scarce and incomplete. In this article the oxytocinergic system and the cutaneous sensory pathways by which the oxytocinergic system is activated in response to skin-to-skin contact are presented in more detail. In addition, we discuss how the effects of skin-to-skin treatment can be attributed to different aspects of the effect spectrum of the oxytocinergic or calm and connection system. The structure of the oxytocinergic system, comprising the peripheral (circulating, hormonal) and the central (neurotransmitter) components, as well as, the pathways and mechanisms by which these functions are coordinated are described. Also the various effects induced by the oxytocinergic system (the calm and connection system) are reviewed. The sensory pathways, which include visual, auditory, olfactory and tactile stimuli, given and received by both mother and newborn and which activate the oxytocinergic system in response to skin-to-skin contact, are reviewed. A special emphasis is placed on the role of cutaneous sensory nerves and their activation by touch, light pressure and in particular warmth. The important role of the rise and the pulsatility of maternal temperature in mediating the positive effects of skin-to-skin contact in the newborn is highlighted. The concept of maternal giving of warmth and its possible link to the experience of trust and safety in the newborn is discussed from an evolutionary perspective. The effects induced by skin-to-skin contact can be attributed to the different functions of the oxytocinergic system. Ameliorated social interaction (e.g., more tactile and auditory interaction, more sensitive and synchronous interaction between mother and baby, the baby's crawling behavior) are expressions of oxytocin's ability to stimulate social interaction. The decreased levels of fear and stress are expressions of oxytocin's ability to reduce the activity of the amygdala and of the stress system, e.g. the activity in the HPA-axis and the sympathetic nervous system. Increased HRV, increased activity in endocrine system of the gastrointestinal tract as well as stimulation of growth and maturation are examples of oxytocin's ability to stimulate the activity of the parasympathetic nervous system and other peripheral and central mechanisms related to restoration and growth. The propensity of different types of treatment with skin-to-skin contact to induce long-term effects is also highlighted. We propose that the sustained effects caused by skin-to-skin contact are induced by an enduring shift in the balance between the oxytocinergic system (the calm and connection system) and the stress system (fight flight reaction) in favor of the oxytocinergic system. This shift leads to a sustained decrease in the HPA-axis and the sympathetic nervous system probably involving alpha 2-adrenoceptors. It is of clinical importance to be aware of the mechanisms by which skin-to-skin contact induces short and longterm positive effects in parents and newborns. If ward routines are adapted to ascertain a maximal stimulation of these mechanisms, the function of the oxytocinergic system will be optimized, which will be linked to a better clinical outcome for parents and newborns.

Coping with strangers: how familiarity and active interactions shape group coordination in Corydoras aeneus.

Social groups composed of familiar individuals exhibit better coordination than unfamiliar groups; however, the ways familiarity contributes to coordination are poorly understood. Prior social experience probably allows individuals to learn the tendencies of familiar group-mates and respond accordingly. Without prior experience, individuals would benefit from strategies for enhancing coordination with unfamiliar others. We used a social catfish, Corydoras aeneus, that uses discrete, observable tactile interactions to assess whether active interactions could facilitate coordination, and how their role might be mediated by familiarity. We describe this previously understudied physical interaction, 'nudges', and show it to be associated with group coordination and cohesion. Furthermore, we investigated nudging and coordination in familiar/unfamiliar pairs. In all pairs, we found that nudging rates were higher during coordinated movements than when fish were together but not coordinating. We observed no familiarity-based difference in coordination or cohesion. Instead, unfamiliar pairs exhibited significantly higher nudging rates, suggesting that unfamiliar pairs may be able to compensate for unfamiliarity through increased nudging. By contrast, familiar individuals coordinated with comparatively little nudging. Second, we analysed nudging and cohesion within triplets of two familiar and one unfamiliar individual (where familiar individuals had a choice of partner). Although all individuals nudged at similar rates, the unfamiliar group-mate was less cohesive than its familiar group-mates and spent more time alone. Unfamiliar individuals that nudged their group-mates more frequently exhibited higher cohesion, indicating that nudging may facilitate cohesion for the unfamiliar group-mate. Overall, our results suggest that nudges can mitigate unfamiliarity, but that their usage is reduced in the case of familiar individuals, implying a cost is associated with the behaviour.

Tactile stimulation disambiguates the perception of visual motion paths.

Although visual perception traditionally has been considered to be impenetrable by non-visual information, there are a rising number of reports discussing cross-modal influences on visual perception. In two experiments, we investigated how coinciding vibrotactile stimulation affects the perception of two discs that move toward each other, superimpose in the center of the screen, and then move apart. Whereas two discs streaming past each other was the dominant impression when the visual event was presented in isolation, a brief coinciding vibrotactile stimulation at the moment of overlap biased the visual impression toward two discs bouncing off each other (Experiment 1). Further, the vibrotactile stimulation actually changed perceptual processing by reducing the amount of perceived overlap between the discs (Experiment 2), which has been demonstrated to be associated with a higher proportion of bouncing impressions. We propose that tactile-induced quantitative changes in the visual percept might alter the quality of the visual percept (from streaming to bouncing), thereby adding to the understanding of how cross-modal information interacts with early visual perception and how this interaction influences subsequent visual impressions.

Multi-Scale Coordination of Distinctive Movement Patterns During Embodied Interaction Between Adults With High-Functioning Autism and Neurotypicals.

Autism Spectrum Disorder (ASD) can be understood as a social interaction disorder. This requires researchers to take a "second-person" stance and to use experimental setups based on bidirectional interactions. The present work offers a quantitative description of movement patterns exhibited during computer-mediated real-time sensorimotor interaction in 10 dyads of adult participants, each consisting of one control individual (CTRL) and one individual with high-functioning autism (HFA). We applied time-series analyses to their movements and found two main results. First, multi-scale coordination between participants was present. Second, despite this dyadic alignment and our previous finding that individuals with HFA can be equally sensitive to the other's presence, individuals' movements differed in style: in contrast to CTRLs, HFA participants appeared less inclined to sustain mutual interaction and instead explored the virtual environment more generally. This finding is consistent with social motivation deficit accounts of ASD, as well as with hypersensitivity-motivated avoidance of overstimulation. Our research demonstrates the utility of time series analyses for the second-person stance and complements previous work focused on non-dynamical and performance-based variables.

Development of mother-infant interaction in tickling play: The relationship between infants' ticklishness and social behaviors.

This study examined the development of mother-infant tickling interaction and the relationship between infants' ticklishness and social behaviors including infants' looking at mothers' face, mothers' narrative tickling, and mothers' laughter. Twenty-two Japanese infants aged 5 months (n=10, five girls) and 7 months (n=12, four girls) and their mothers were videotaped. Results revealed that the mothers' narrative tickling was more frequent at 7 than at 5 months and the infants' strong ticklishness showed the same tendency. The infants' strong ticklishness was linked with the occurrence of other social behaviors. In conclusion, infants' ticklishness was heavily connected with social behaviors. The mode of the tickling interaction at 7 months was different from that at 5 months especially in the increase of mother's narrative tickling. A possible function of such mother's narrative tickling to facilitate infant active communication at a higher cognitive level including anticipation, was discussed.

Speed-Dial: A Surrogate Mouse for Non-Visual Web Browsing.

Sighted people can browse the Web almost exclusively using a mouse. This is because web browsing mostly entails pointing and clicking on some element in the web page, and these two operations can be done almost instantaneously with a computer mouse. Unfortunately, people with vision impairments cannot use a mouse as it only provides visual feedback through a cursor. Instead, they are forced to go through a slow and tedious process of building a mental map of the web page, relying primarily on a screen reader's keyboard shortcuts and its serial audio readout of the textual content of the page, including metadata. This can often cause content and cognitive overload. This paper describes our Speed-Dial system which uses an off-the-shelf physical Dial as a surrogate for the mouse for non-visual web browsing. Speed-Dial interfaces the physical Dial with the semantic model of a web page, and provides an intuitive and rapid access to the entities and their content in the model, thereby bringing blind people's browsing experience closer to how sighted people perceive and interact with the Web. A user study with blind participants suggests that with Speed-Dial they can quickly move around the web page to select content of interest, akin to pointing and clicking with a mouse.

Vision affects tactile target and distractor processing even when space is task-irrelevant.

The human brain is adapted to integrate the information from multiple sensory modalities into coherent, robust representations of the objects and events in the external world. A large body of empirical research has demonstrated the ubiquitous nature of the interactions that take place between vision and touch, with the former typically dominating over the latter. Many studies have investigated the influence of visual stimuli on the processing of tactile stimuli (and vice versa). Other studies, meanwhile, have investigated the effect of directing a participant's gaze either toward or else away from the body-part receiving the target tactile stimulation. Other studies, by contrast, have compared performance in those conditions in which the participant's eyes have been open versus closed. We start by reviewing the research that has been published to date demonstrating the influence of vision on the processing of tactile targets, that is, on those stimuli that have to be attended or responded to. We outline that many - but not all - of the visuotactile interactions that have been observed to date may be attributable to the direction of spatial attention. We then move on to focus on the crossmodal influence of vision, as well as of the direction of gaze, on the processing of tactile distractors. We highlight the results of those studies demonstrating the influence of vision, rather than gaze direction (i.e., the direction of overt spatial attention), on tactile distractor processing (e.g., tactile variants of the negative-priming or flanker task). The conclusion is that no matter how vision of a tactile distractor is engaged, the result would appear to be the same, namely that tactile distractors are processed more thoroughly.

Modulation of tactile duration judgments by emotional pictures.

Judging the duration of emotional stimuli is known to be influenced by their valence and arousal values. However, whether and how perceiving emotion in one modality affects time perception in another modality is still unclear. To investigate this, we compared the influence of different types of emotional pictures-a picture of threat, disgust, or a neutral picture presented at the start of a trial-on temporal bisection judgments of the duration of a subsequently presented vibrotactile stimulus. We found an overestimation of tactile duration following exposure to pictures of threat, but not pictures of disgust (even though these scored equally high on arousal), in a short-range temporal bisection task (range 300/900 ms). Follow-up experiments revealed that this duration lengthening effect was abolished when the range to be bisected was increased (1000/1900 ms). However, duration overestimation was maintained in the short-range bisection task regardless of whether the interval between the visual and tactile events was short or long. This pattern is inconsistent with a general arousal interpretation of duration distortion and suggests that crossmodal linkages in the processing of emotions and emotional regulation are two main factors underlying the manifestation of crossmodal duration modulation.