Mirror-touch synaesthesia: the role of shared representations in social cognition

Synaesthesia is a condition in which one property of a stimulus results in conscious experiences of an additional attribute. In mirror-touch synaesthesia, the synaesthete experiences a tactile sensation on their own body simply when observing touch to another person. This thesis investigates the prevalence, neurocognitive mechanisms, and consequences of mirror-touch synaesthesia. Firstly, the prevalence and neurocognitive mechanisms of synaesthesia were assessed. This revealed that mirrortouch synaesthesia has a prevalence rate of 1.6%, a finding which places mirror-touch synaesthesia as one of the most common variants of synaesthesia. It also indicated a number of characteristics of the condition, which led to the generation of a neurocognitive model of mirror-touch synaesthesia. An investigation into the perceptual consequences of synaesthesia revealed that the presence of synaesthesia is linked with heightened sensory perception - mirror-touch synaesthetes showed heightened tactile perception and grapheme-colour synaesthetes showed heightened colour perception. Given that mirror-touch synaesthesia has been shown to be linked to heightened sensorimotor simulation mechanisms, the impact of facilitated sensorimotor activity on social cognition was then examined. This revealed that mirror-touch synaesthetes show heightened emotional sensitivity compared with control participants. To compliment this, two transcranial magnetic stimulation (TMS) studies were then conducted to assess the impact of suppressing sensorimotor activity on the expression recognition abilities of healthy adults. Consistent with the findings of superior emotion sensitivity in mirror-touch synaesthesia (where there is facilitated sensorimotor activity), suppressing sensorimotor resources resulted in impaired expression recognition across modalities. The findings of the thesis are discussed in relation to neurocognitive models of synaesthesia and of social cognition

How touch and hearing influence visual processing in sensory substitution, synaesthesia and cross-modal correspondences

Sensory substitution devices (SSDs) systematically turn visual dimensions into patterns of tactile or auditory stimulation. After training, a user of these devices learns to translate these audio or tactile sensations back into a mental visual picture. Most previous SSDs translate greyscale images using intuitive cross-sensory mappings to help users learn the devices. However more recent SSDs have started to incorporate additional colour dimensions such as saturation and hue. Chapter two examines how previous SSDs have translated the complexities of colour into hearing or touch. The chapter explores if colour is useful for SSD users, how SSD and veridical colour perception differ and how optimal cross-sensory mappings might be considered. After long-term training, some blind users of SSDs report visual sensations from tactile or auditory stimulation. A related phenomena is that of synaesthesia, a condition where stimulation of one modality (i.e. touch) produces an automatic, consistent and vivid sensation in another modality (i.e. vision). Tactile-visual synaesthesia is an extremely rare variant that can shed light on how the tactile-visual system is altered when touch can elicit visual sensations. Chapter three reports a series of investigations on the tactile discrimination abilities and phenomenology of tactile-vision synaesthetes, alongside questionnaire data from synaesthetes unavailable for testing. Chapter four introduces a new SSD to test if the presentation of colour information in sensory substitution affects object and colour discrimination. Chapter five presents experiments on intuitive auditory-colour mappings across a wide variety of sounds. These findings are used to predict the reported colour hallucinations resulting from LSD use while listening to these sounds. Chapter six uses a new sensory substitution device designed to test the utility of these intuitive sound-colour links for visual processing. These findings are discussed with reference to how cross-sensory links, LSD and synaesthesia can inform optimal SSD design for visual processing

Tailoring Digital Touch: An ethnography of designers' touch practices during garment prototyping and the potential for their digitisation

At a time of rapid digital transition in garment design industries and education, this thesis ethnographically documents garment designers’ use of touch and its role in meaning-making and understanding during garment prototyping. A novel diffractive ethnographic attention is utilised to attune to differing aspects of touch and felt experience, revealing the significance of the felt, kinaesthetic awareness of the moving body to garment prototyping. Further demonstrating that designers relate felt histories of material entanglement with their moving bodies to their contemporary experience. Development of felt histories is thus identified as a key means of designers’ enskillment, alongside moments of overlooked and informal skills sharing. A socio-material perspective informed by New Materialism is adopted to foreground the critical role of designers’ entanglement with non-human things in structuring their felt experience and deriving meaning from it. Significantly, this thesis demonstrates that sensations are perceived beyond the conventionally defined body in and through entangled tools and materials and that sensations are socio-materially mutable and can be altered by peers directing designers to touch and feel in particular ways. This problematises current haptic technologies, which simulate touch at physical and virtual boundaries. The ethnographic data is supplemented by two workshop studies facilitating garment designers to engage with prototypical digital touch technologies, enabling speculation on future digital touch tools more relevant to garment prototyping. The thesis analytically discusses differing theoretical stances on non-human agency in design and making and their implications for digital touch tools. It concludes by proposing a theoretical Framework of Garment Designers’ Felt Enskillment and making recommendations for the design of digital touch interfaces for garment prototyping. The findings of the thesis contribute to the fields of HCI, design and education, deepening academic understandings of designers’ sensory experience and the impact of digital processes, potentially informing future technology development

Tactile sensitivity in typical and atypical development

Ph. D. ThesisThe tactile sense is fundamental for typical development yet has been largely under studied in comparison to other sensory modalities of vision and audition. Some individuals exhibit unusual behavioural responses to sensory stimulation that would normally not be considered to be noxious. There has been an increase in research exploring these unusual sensory abnormalities over the last 10 years. Previously only reported anecdotally, some individuals are aversive to or withdraw from tactile stimulation. Referred to as tactile This thesis aims to explore tactile sensitivity in typically developing individuals and those individuals most likely to have sensory abnormalities, specifically Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD). Chapter one summarises literature on the importance of touch for development and introduces theories of tactile defensiveness. A questionnaire study explores texture preferences and aversions in Chapter two. Since little is known about texture preference in either typically developing children or those with ASD / ADHD the purpose of the questionnaire was to create a baseline of texture preference. A further study explored preference for texture complexity. Contrary to expectation, no differences in texture preference were found between comparison groups. Since no differences in texture preference were found, it was predicted that perhaps differences in unusual tactile response may be due to heightened sensitivity to texture for those individuals with sensory abnormalities. Chapter three investigated tactile sensitivity to fine texture and predicted that individuals with ASD would be more accurate at texture discrimination than typically developing individuals. No group difference was found in texture discrimination. In Chapter four, cross-modal matching of texture was explored. It was proposed that unusual tactile response observed in individuals with ASD may be due to difficulty matching visual and tactual information. In a series of studies, results found that individuals with ASD were impaired at matching texture information cross-modally. The inability to accurately match visual-tactual texture information may contribute to the negative tactile reactions observed in individuals with ASD and may provide insight into a possible contributing factor to tactile sensitivity in atypical development.defensiveness, this unusual tactile response has been explored primarily with the use of questionnaires. Literature reports both over-responsivity (hyper) and under-responsivity (hypo) to tactile stimulation in atypical development, for example exhibiting negative response to social touch or an extreme fascination with certain tactile stimulation. Tactile defensiveness affects many facets of behaviour, including motor development, learning and social interaction. In some extreme cases, individuals with tactile defensiveness will avoid human contact. To date, there is no systematic research examining tactile sensitivity in typical or atypical development despite these negative consequences for many aspects of development

Face evaluation: an embodied cognitive approach

American Psychological Association (PsycINFO Classification Categories and Codes) 2320 Sensory Perception 2340 Cognitive Processes 3000 Social Psychology 3040 Social Perception and Cognitionthesis intends to demonstrate that face evaluation can be embodied. Studies in the area of face evaluation suggest that face perception is linked to action. Given that actions depend on our bodies, face evaluation supposedly influence how our bodies will act. Furthermore, I intend to show that the action of our bodies can also influence face perception. In the first three empirical chapters, I tested the notion that judgments of social dominance result from an overgeneralization of properties that signal to the perceiver the potential for someone to act (i.e. physical strength). This may potentially influence our bodily actions. The results indicate that judgments of physical strength predict social dominance. In the last three empirical chapters, I tried to show that bodily actions can influence face evaluation. I showed that an expansive posture can reduce the perception of differences between facial levels of social dominance when compared to a constrictive posture. Participants in the expansive body posture also recreated a mental image of their self-face evidencing greater dominance than participants in a constrictive posture. Finally, I also demonstrated that the interaction between bodies through a multisensory stimulation can influence judgments and the recognition of trustworthiness in faces. Thus, the present thesis shows that face evaluation is embodiedEsta tese tem por objectivo demonstrar que a avaliação de faces pode ser corporalizada. Os estudos na área da avaliação de faces sugerem que a percepção facial está associada à acção. Sendo que as acções dependem dos nossos corpos, a avaliação de faces supostamente influenciará a forma como os nossos corpos irão actuar. Para além disso, pretende-se evidenciar que a acção corporal também pode influenciar a avaliação de faces. Nos três primeiros capítulos empíricos testou-se a noção de que os julgamentos de dominância social resultam de uma generalização de propriedades que sinalizam ao percipiente o potencial de alguém para agir (i.e. força física) o que poderá influenciar as acções corporais. Os resultados indicam que os julgamentos de força física predizem a dominância social. Nos últimos três capítulos empíricos, procurei demonstrar que as acções corporais podem influenciar a avaliação de faces. Demonstrei que uma postura expansiva em comparação com uma postura constritiva pode reduzir a percepção das diferenças entre os níveis faciais de dominância social. Os participantes numa postura corporal expansiva recriaram uma imagem mental do seu eu facial que evidencia uma maior dominância, comparativamente aos participantes numa postura constritiva. Finalmente, evidenciei que a interacção entre os corpos através de uma estimulação multissensorial pode influenciar os julgamentos e o reconhecimento do traço confiável nas faces. Assim, a presente investigação evidencia que a avaliação de faces é corporalizada

Models, Simulations, and the Reduction of Complexity

Modern science is a model-building activity. But how are models contructed? How are they related to theories and data? How do they explain complex scientific phenomena, and which role do computer simulations play? To address these questions which are highly relevant to scientists as well as to philosophers of science, 8 leading natural, engineering and social scientists reflect upon their modeling work, and 8 philosophers provide a commentary

Models, Simulations, and the Reduction of Complexity

Modern science is a model-building activity. But how are models contructed? How are they related to theories and data? How do they explain complex scientific phenomena, and which role do computer simulations play? To address these questions which are highly relevant to scientists as well as to philosophers of science, 8 leading natural, engineering and social scientists reflect upon their modeling work, and 8 philosophers provide a commentary