Abstract:The haptic sense is an essential component of aesthetic evaluation that is often overlooked in today’s mobile internet age. Unlike hearing and vision, the sense of touch is less widely transmitted. Unfortunately, most aesthetic theories and explanations have focused solely on the visual and auditory senses, with minimal attention given to tactile evaluation. To address this gap in knowledge, we have collected studies on tactile aesthetics within the framework of experimental aesthetics from 2000 to 2022. After statistical generalization, (...) our findings suggest the following: The criteria for evaluating tactile aesthetics were mostly dichotomous, that is, positive (like/appreciation/pleasure) and negative (dislike/disgust/unpleasant). Tactile aesthetics predominantly involved the toucher dimension (synesthesia/need for touch/touch pattern) and the touch sample dimension (shape/type/texture), with the commonly overlooked factors of “need for touch” and “touch pattern.” Some studies did not restrict the shape and material of the touch samples. Based on our findings, we have systematically summarized and concluded what tactile factors influence aesthetic evaluation and have analyzed future research trends. (shrink)

The present studies examined whether implied tactile properties during language comprehension influence subsequent direct tactile perception, and the specificity of any such effects. Participants read sentences that implicitly conveyed information regarding tactile properties (e.g., Grace tried on a pair of thick corduroy pants while shopping) that were either related or unrelated to fabrics and varied in implied texture (smooth, medium, rough). After reading each sentence, participants then performed an unrelated rating task during which they felt and (...) rated the texture of a presented fabric. Results demonstrated that the texture properties implied in sentences influence direct tactile perception. Specifically, after reading about a smooth or rough texture, subsequent fabric ratings became notably smoother or rougher, respectively. However, we also show that there was some specificity to these effects: Fabric-related sentences elicited more specific and interactive effects on subsequent ratings. Together, we demonstrate that under certain circumstances, language comprehension can prime tactile representations and affect direct tactile perception. Results are discussed with regard to the nature and scope of multimodal mental simulation during reading. (shrink)

In the haptic domain, a double dissociation can be proposed on the basis of neurological deficits between tactile information for action, represented by tactile apraxia, and tactile information for perception, represented by tactile agnosia. We suggest that this dissociation comes from different networks, both involving the anterior intraparietal area of the posterior parietal cortex.

The strategies of action employed by a human subject in order to perceive simple 2-D forms on the basis of tactile sensory feedback have been modelled by an explicit computer algorithm. The modelling process has been constrained and informed by the capacity of human subjects both to consciously describe their own strategies, and to apply explicit strategies; thus, the strategies effectively employed by the human subject have been influenced by the modelling process itself. On this basis, good qualitative and (...) semi-quantitative agreement has been achieved between the trajectories produced by a human subject, and the traces produced by a computer algorithm. The advantage of this reciprocal modelling option, besides facilitating agreement between the algorithm and the empirically observed trajectories, is that the theoretical model provides an explanation, and not just a description, of the active perception of the human subject. (shrink)

The rubber hand paradigm is used to create the illusion of self-touch, by having the participant administer stimulation to a prosthetic hand while the Examiner, with an identical stimulus, administers stimulation to the participant’s hand. With synchronous stimulation, participants experience the compelling illusion that they are touching their own hand. In the current study, the robustness of this illusion was assessed using incongruent stimuli. The participant used the index finger of the right hand to administer stimulation to a prosthetic hand (...) while the Examiner used a paintbrush to administer stimulation to the participant’s left hand. The results indicate that this violation of tactile expectations does not diminish the illusion of self-touch. Participants experienced the illusion despite the use of incongruent stimuli, both when vision was precluded and when visual feedback provided clear evidence of the tactile mismatch. (shrink)

Multimodal integration is the formation of a coherent percept from different sensory inputs such as vision, audition, and somatosensation. Most research on multimodal integration in speech perception has focused on audio-visual integration. In recent years, audio-tactile integration has also been investigated, and it has been established that puffs of air applied to the skin and timed with listening tasks shift the perception of voicing by naive listeners. The current study has replicated and extended these findings by testing (...) the effect of air puffs on gradations of voice onset time along a continuum rather than the voiced and voiceless endpoints of the original work. Three continua were tested: bilabial (“pa/ba”), velar (“ka/ga”), and a vowel continuum (“head/hid”) used as a control. The presence of air puffs was found to significantly increase the likelihood of choosing voiceless responses for the two VOT continua but had no effect on choices for the vowel continuum. Analysis of response times revealed that the presence of air puffs lengthened responses for intermediate (ambiguous) stimuli and shortened them for endpoint (non-ambiguous) stimuli. The slowest response times were observed for the intermediate steps for all three continua, but for the bilabial continuum this effect interacted with the presence of air puffs: responses were slower in the presence of air puffs, and faster in their absence. This suggests that during integration auditory and aero-tactile inputs are weighted differently by the perceptual system, with the latter exerting greater influence in those cases where the auditory cues for voicing are ambiguous. (shrink)

The rubber hand paradigm is used to create the illusion of self-touch, by having the participant administer stimulation to a prosthetic hand while the Examiner, with an identical stimulus , administers stimulation to the participant’s hand. With synchronous stimulation, participants experience the compelling illusion that they are touching their own hand. In the current study, the robustness of this illusion was assessed using incongruent stimuli. The participant used the index finger of the right hand to administer stimulation to a prosthetic (...) hand while the Examiner used a paintbrush to administer stimulation to the participant’s left hand. The results indicate that this violation of tactile expectations does not diminish the illusion of self-touch. Participants experienced the illusion despite the use of incongruent stimuli, both when vision was precluded and when visual feedback provided clear evidence of the tactile mismatch. (shrink)

This study aimed to explore the psychophysical bases of multisensory surface stickiness perception by investigating how sensitively humans perceive different levels of stickiness intensity conveyed by auditory, tactile, and visual cues. First, we sorted five different sticky stimuli by perceived intensity in ascending order for each modality separately and evaluated the discrimination sensitivities of each participant using a fitted psychometric curve. Results showed that perceptual intensity orders were not identical to physical intensity order and that the sequential order (...) of perceived intensities for different modalities was inconsistent. Moreover, estimated perceptual sensitivities to surface stickiness indicated that auditory cues result in better discrimination sensitivity than tactile and visual cues. Second, we calculated the relative perceptual distances of stickiness intensities using multidimensional scaling. A follow-up statistical test demonstrated that the perceptual mapping of vision and touch are similar but that auditory perception is different. These results suggest that the discriminability of stickiness intensity is best served by auditory cues and that texture information processing in the auditory domain is distinctive from that of other modalities. (shrink)

There is a task-specificity in the visual-tactile interaction for perception: The polymodal posterior parietal cortex is related to the comparison of the shapes coded by different sensory modalities, whereas the lateral occipital complex is the part of the network for multimodal shape identification. These interactions may be mediated by some latent pathways potentiated by sensory deprivation or learning.

Tactile distance perception is believed to require that immediate afferent signals be referenced to a stored representation of body size and shape (the body model). For this ability, recent studies have reported that the stored body representations involved are highly distorted, at least in the case of the hand, with the hand dorsum represented as wider and squatter than it actually is. Here, we aim to define the neural basis of this phenomenon. In a behavioural experiment participants estimated (...) the distance between touches on two points by adjusting the length of a visually-presented line on the screen. The technique of multidensional scaling (MDS) was used to reconstruct a perceptual map of tactile space. Analysis of spatial distortion using Procrustes alignment showed that maps were stretched in the mediolateral hand axis. In order to determine the neural correlates of these body distortions, we performed an fMRI study. For each participant, we used a searchlight pattern classifier with Euclidean distance on pre-defined regions of interests (ROIs). In order to relate the representations between the different points and to computational models, we compare response-pattern dissimilarity matrices in these ROIs. Similar to the behavioural experiment, we used MDS to reconstruct maps of the neural representation of tactile space using the values from the dissimilarities matrices. We were able to reconstruct the perceptual map of tactile space in the contralateral primary somatosensory and motor cortices. This suggests that these areas are critical to generate the tactile representations of the dorsum of the hand. (shrink)

It seems that there are important differences concerning the way in which space itself is presented in visual and tactile modalities. In the case of vision, it is usually accepted that visual objects are experienced as located in a visual field. However, it is controversial whether similar field-like characteristics can be attributed to the space in which tactile entities are experienced to be located. The paper investigates whether postulating the presence of a tactile field is justified. I (...) argue that the answer is both ‘yes’ and ‘no’ due to the dual nature of touch: touch is both an interoceptive modality that presents states of one’s body and an exteroceptive modality that presents external entities. More specifically, the interoceptive tactile space has a character of a spatial field. On the other hand, the exteroceptive tactile space does not have characteristics necessary for ascribing the field-status. (shrink)

The transmission, emergence, and dissemination of features of racial differentiation are based on the interplay of different sensory perceptions, as this contribution will illustrate. For this purpose, examples from ethnographic travelogues from German East Africa and from the time of German colonial rule were selected to examine the functioning of tactile perception by means of the descriptions of skin colors and skin decorations. The source material reveals multisensuality in the form of synesthesia of the sense of sight with (...) the sense of touch, in that the perception of tactile stimuli is determined less by direct touch and more by the visual representation of haptic properties. (shrink)

In the present paper, we will attempt to gain hints regarding the nature of tactile awareness in humans. At first, we will review some recent literature showing that an actual tactile experience can emerge in absence of any tactile stimulus (e.g., tactile hallucinations, tactile illusions). According to the current model of tactile awareness, we will subsequently argue that such (false) tactile perceptions are subserved by the same anatomo-functional mechanisms known to underpin actual (...) class='Hi'>perception. On these bases, we will discuss the hypothesis that tactile awareness is strongly linked to expected rather than actual stimuli. Indeed, this hypothesis is in line with the notion that the human brain has a strong predictive, rather than reactive, nature. (shrink)

It remains controversial whether touch is a truly spatial sense or not. Many philosophers suggest that, if touch is indeed spatial, it is only through its alliances with exploratory movement, and with proprioception. Here we develop the notion that a minimal yet important form of spatial perception may occur in purely passive touch. We do this by showing that the array of tactile receptive fields in the skin, and appropriately relayed to the cortex, may contain the same basic (...) informational building blocks that a creature navigating around its environment uses to build up a perception of space. We illustrate this point with preliminary evidence that perception of spatiotemporal patterns on the human skin shows some of the same features as spatial navigation in animals. We argue (a) that the receptor array defines a ‘tactile field’, (b) that this field exists in a minimal form in ‘skin space’, logically prior to any transformation into bodily or external spatial coordinates, and (c) that this field supports tactile perception without integration of concurrent proprioceptive or motor information. The basic cognitive elements of space perception may begin at lower levels of neural and perceptual organisation than previously thought. (shrink)

People’s awareness of tactile stimuli has been investigated in far less detail than their awareness of stimuli in other sensory modalities. In an attempt to fill this gap, we provide an overview of studies that are pertinent to the topic of tactile consciousness. We discuss the results of research that has investigated phenomena such as “change blindness”, phantom limb sensations, and numerosity judgments in tactile perception, together with the results obtained from the study of patients affected (...) by deficits that can adversely affect tactile perception such as neglect, extinction, and numbsense. The similarities as well as some of the important differences that have emerged when visual and tactile conscious information processing have been compared using similar experimental procedures are highlighted. We suggest that conscious information processing in the tactile modality cannot be separated completely from the more general processing of spatial information in the brain. Finally, the importance of considering tactile consciousness within the larger framework of multisensory information processing is also discussed. (shrink)

Les résultats quantitatifs que la psychologie et la physiologie n'ont cessé d'accumuler depuis le début du siecle à propos du sens tactile laissent apparaître aujourd'hui une certaine ambiguïteé. D'un côté en effet, la préoccupation de connaître les sensibilities cutanées spécifiques telles qu'elles se présentent de manière isolée à l'analyse objective des récepteurs stimulés: les sensations de chaud et de froid, de pression et de contact, de douleur, de vibration. D'un autre côté, le désir de sauvegarder l'unité fonctionnelle du sens (...) tactile c.a.d. sa spécificité propre par rapport aux quatre autres sens traditionnels. Ainsi, par exemple, une analyse neurophysiologique des récepteurs tactiles5 ne manque pas de mentionner plusieurs catégories fonctionnelles de la sensibilité cutanée: la douleur, comme signal d'un danger qui peut menacer l'existence de l'organisme; la perception des qualités d'un objet, comme intégration du toucher et de la kinesthésie au cours d'une exploration active de la main; les expériences somatiques complexes telles que le chatouillement et les sensations sexuelles. Pour le phénoménologue, un tel compromis s'apparente à une confusion et provient des positions épistémologiques qui ont animé l'orientation méthodologique des recherches, depuis la psychophysiologie mécaniste jusqu'à la psychologie cybernétique de l'information sensorielle. En cela, la domaine de la sensation tactile reste l'apanage de la psychophysique, et nous tenterons de clarifier pourquoi cette position ne peut aboutir qu'à des résultats problématiques. A partir d'une psychologie anthropologique du sens tactile,14 nous défendrons l'idée d'une psychologie comparée qui permettrait une investigation empirique, objective des comportements animaux, sur la base de prolégomènes phénoménologiques. (shrink)

The simultaneous perception of multimodal sensory information is important for effective reactions to the external environment. In relation to the effect on time perception, voluntary movement and rhythmic stimuli have already been identified in previous studies to be associated with improved accuracy of temporal order judgments. Here, we examined whether the combination of voluntary movement and rhythmic stimuli improves the just noticeable difference in audio-tactile TOJ Tasks. Four different experimental conditions were studied, involving two types of movements (...) and two types of stimulus presentation. In the voluntary movement condition, after the auditory stimulus participants moved their right index finger voluntarily and naturally, while in the involuntary movement condition, their right index finger was moved by the tactile device. The stimuli were provided in a rhythmic or one-time only manner by hitting inside the first joint of the participants' right index finger using a tactile device. Furthermore, in the rhythmical tactile conditions, tactile stimuli were presented rhythmically to the right index finger 5 times consecutively. On the other hand, in the one-time tactile conditions, tactile stimuli was presented one-time only to the right index finger. Participants made an order judgment for the fifth tactile stimuli and the first and only auditory stimuli. In our TOJ tasks, auditory-tactile stimulus pairs were presented to participants with varying stimulus-onset asynchronies. For the two stimuli presented at a time that were shifted by the SOA, the participants were asked to judge which one was presented first, and they were given a two-choice answer. Using a non-parametric test, our results showed that voluntary movement and rhythmic tactile stimuli were both effective in improving the JNDs in TOJ Tasks. However, in the combination of voluntary movement and rhythmic tactile stimuli, we found that there was no significant difference in JNDs in our experiments. (shrink)

Change blindness, the surprising inability of people to detect significant changes between consecutively-presented visual displays, has recently been shown to affect tactile perception as well. Visual change blindness has been observed during saccades and eye blinks, conditions under which people’s awareness of visual information is temporarily suppressed. In the present study, we demonstrate change blindness for suprathreshold tactile stimuli resulting from the execution of a secondary task requiring bodily movement. In Experiment 1, the ability of participants to (...) detect changes between two sequentially-presented vibrotactile patterns delivered on their arms and legs was compared while they performed a secondary task consisting of either the execution of a movement with the right arm toward a visual target or the verbal identification of the target side. The results demonstrated that a motor response gave rise to the largest drop in perceptual sensitivity in detecting changes to the tactile display. In Experiment 2, we replicated these results under conditions in which the participants had to detect tactile changes while turning a steering wheel instead. These findings are discussed in terms of the role played by bodily movements, sensory suppression, and higher order information processing in modulating people’s awareness of tactile information across the body surface. (shrink)

Because philosophical reflections on touch usually start from our ability to perceive properties of objects, they tend to overlook features of touch that are crucial to correct understanding of tactual perception. This paper brings out these features and uses them to develop a general reconception of the sense of touch. I start by taking a fresh look at our ability to feel, in order to reveal its vital role. This sheds a different light on the skin's perceptual potential. While (...) it is commonly observed that tactile experiences have two intentional objects, an external object and one's own body, I will advance a more accurate alternative: in tactile experiences, one becomes aware of what one's body undergoes. This alternative not only fits better with tactility's vital role; it is also key to explaining how active touching provides for a unique contribution to our perceptual relation to material objects. By thus connecting tactility's vital role to the way we rely on touch while manipulating objects, this essay offers a cross-sectional survey of our tactile powers that reveals the interplay between sensing and touching. (shrink)

According to rich views of consciousness (e.g., James, Searle), we have a constant, complex flow of experience (or 'phenomenology') in multiple modalities simultaneously. According to thin views (e.g., Dennett, Mack and Rock), conscious experience is limited to one or a few topics, regions, objects, or modalities at a time. Existing introspective and empirical arguments on this issue (including arguments from 'inattentional blindness') generally beg the question. Participants in the present experiment wore beepers during everyday activity. When a beep sounded, they (...) were to take note of the conscious experience, if any, they were having at the last undisturbed moment immediately prior to the beep. Some participants were asked to report any experience they could remember. Others were asked simply to report whether there was visual experience or not (and if so, what it was). Still others were asked about experience in the far right visual field, or tactile experience, or tactile experience in the left foot. A majority of participants in the full experience and the visual conditions reported visual experience in every single sample. Tactile and peripheral visual experience were reported less often. However, the proper interpretation of these results is uncertain. (shrink)

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. (shrink)

ABSTRACT The aim of this paper is to draw important parallels between the way in which configured pictorial practices of early Cubism interpreted the idea of tactile space and the phenomenological concept of existential spatiality. It is argued that in dispensing with the “illusion of perspectival space” and deconstructing geometrical perspective, several Cubist artists developed a position of multi-perspectival realism with respect to what remains ungraspable in the three-dimensional visual rendering of space. Tactile space is the main theme (...) of early Cubist painting. Tactility remains concealed by linear perspective and three-dimensional space, and existentially primordial tactile space turns out to be the ungraspable which Cubist experiments has to disclose. At the same time, these artists succeeded in avoiding any kind of a reification of space as something that statically embraces what is situated in it. The paper is also preoccupied with Cubist “geometrical experimentation”. The claim is defended that it is precisely this experimentation that most essentially anticipates Heidegger’s analyses of the spatiality of the ready-to-hand and the spatiality of being-in-the-world. Parallels are also drawn with Merleau-Ponty’s spatiality of the perceiving-tactile body which was chiefly focused on the presupposition that the visibility attained through visual perception is imbued with invisibility stemming from the immediate tactility relating the perceiving body and the perceived entities – a presupposition shared by the early Cubists and the French phenomenologist. (shrink)

Based on sensory integration theory, six fabric samples containing tactile and visual stimuli were selected using the sensory perceptions of designers and combined with balls. Experiments involving these toys were implemented with 15 families with preschool-aged high-functioning autistic children. The results showed that loose sequin , which possessed equal tactile and visual intensities, was strongly correlated with frequent smiling/laughing and high enjoyment levels. The fabric provided a loose tactile sensation regarding surface interweave uniformity and a bright visual (...) sensation regarding visually perceived luster; suede exhibited a greater tactile intensity than visual intensity and was correlated with eye contact and activity response. This fabric possessed a smooth visual sensation regarding visually perceived smoothness; and loose sequin , which possessed equal tactile and visual intensities, was highly correlated with finger pointing and initiation. This fabric offered a thin tactile sensation regarding surface interweave thickness and a bright visual sensation regarding visually perceived luster. We suggest applying fabrics to composite toys. Specifically, loose sequin can be used initially to encourage autistic children to interact; subsequently, suede can enable sustained parent-child interaction. The experimental results provide a reference for establishing an innovative toy-design method for autistic children. Keywords: autism; sensory integration theory; parent-child interaction; toys. (shrink)

We examined the neural basis of tactile distance perception by analyzing activity patterns induced by tactile stimulation of nine points on a 3 x 3 square grid on the hand dorsum using functional magnetic resonance (fMRI). We used a searchlight approach within pre-defined regions of interests (ROIs) to compute the pairwise Euclidean distances between the activity patterns elicited by tactile stimulation. Then, we used multidimensional scaling (MDS) to reconstruct skin space at the neural level and compare (...) it with skin space at the perceptual level. Our reconstructions of the shape of skin space in contralateral primary somatosensory (SI) and motor (M1) cortices reveal that it is distorted in a way that matches the perceptual shape of skin space. This suggests that early sensorimotor areas are critical to processing tactile distance perception. (shrink)