THE HEARING BODY: How auditory perception influences body representation

The way we perceive, and represent, our physical body strongly predicts how we will interact with our environment. On the one hand, our awareness about the boundaries of our body, and its physical capabilities, influence our subsequent actions. For instance, we may ponder whether we can reach a particular object or whether there is enough space for us to get onto a crowded bus. On the other hand, the way in which we perceive how our body looks is critical to creating a sense of self-identity and therefore influences our self-esteem and our social interactions. Hence, understanding the mechanisms underlying body awareness is of great importance, not only for improving our knowledge about the nature of our sense of our own body, but also, given its links with self-esteem, action and our interactions, because of the impact this has on our wellbeing in social contexts.
Recent research has found that the mental representation we have of our body is not fixed but is continuously updated by the sensory and motor information received from interaction with our environment. For example, an artificial hand may feel like part of my body if I see it being touched at the same time that I feel my own, unseen, hand being touched in a similar way. This is the result of the integration of information coming from two different sensory channels - vision and touch. "I see something touching the artificial hand and I feel touch at the same time, therefore, the hand I see must be part of my body".
The primary aim of this project is to study the contribution of auditory cues to the representation of our body. Currently, there is no solid evidence linking auditory information to body-representation, although sound is known to be crucial for body perception. Unlike vision, audition provides information about the space surrounding our whole body. Like vision and touch, audition provides information about the body, via self-produced sounds, such as those associated with breathing or walking. These self-produced sounds provide crucial information about our body. For instance, the sounds produced when tapping on a surface with the hand inform us about the length and strength of our arm.
This project will investigate the importance of audition for body-representation by collecting data from a sample of over 200 adults. In the experiments, participants will be asked to execute specific actions (e.g. walking, throwing an object that creates sound) while the feedback sounds from their actions will be manipulated in real-time. The potential update in body-representation will be then quantified. We predict that altering self-produced sounds will alter body-representation. For instance, altering the perceived distance to the sound derived from tapping on a surface may give the impression that you have a longer/shorter arm.
The project will employ a multidisciplinary and innovative research methodology that will allow quantification, in parallel, of the changes evoked by altered self-produced sounds in 1) the perceived boundaries of the body, 2) the perceived possibilities for action and 3) the bodily-related emotional state (i.e. how one feels about one's body), given that the sense of one's body is tightly linked to action-awareness and self-esteem. This methodology provides a robust framework for discussing the nature of changes in body-representation and for integrating the research results into a multisensory model of body-representation.
This project will yield novel insights into the nature of the sense of body and, ultimately, will guide the design of audio-based applications that improve self-image, self-esteem, action patterns and social interaction to support wellbeing and self-directed rehabilitation. The extensive use of headphones and wearable devices (e.g. Apple iPod), and the increasing market for motion sensing input devices (e.g. Microsoft Kinect, e-textile) in society today, suggest excellent possibilities for these sound-based applications

This research has potential to contribute to the nation's wealth and health because it will propose how we can use sound-based technologies, for inducing changes in body-representation (BR), that increase awareness of action possibilities and trigger specific emotional states:

(i) At the business/industrial level the project will impact health and wellbeing information and communications technology applications, by establishing links with designers of sensory-augmentation systems for entertainment, rehabilitation, behavioural change and fitness, as well as Virtual Reality (VR). The project will benefit the commercial private sector by setting the basis for designing sound-based applications that promote healthier life style by improving people's self-image, self-esteem, self-efficacy, action patterns and social interaction. This may attract the interest of companies such as Microsoft, Apple, Fujitsu, Orange or Boots. The extensive use of headphones and wearable devices (e.g. Apple iPod) and the increasing market for motion-sensing input devices (e.g. Microsoft Kinect) in society today, provide an excellent potential for consumer applications. The links with these sectors will be initiated during the project and the impact may be quickly realised in full, contributing to the nation's economic performance.

(ii) A number of general public user groups could benefit from the potential sound-based applications, that may enhance the quality of life, health and wellbeing:
a) populations with clinical disorders linked to distortion of BR. Certain types of chronic pain, affecting nearly one in seven UK citizens, are accompanied by an alteration of BR, perceived motor capabilities and emotional distress [33] (e.g. complex regional pain syndrome-CRPS, phantom limb pain, fibromyalgia, focal dystonia). These conditions adversely affect psychological wellbeing and social and working life. Similar clinical disorders linked to distortions of BR are anosognosia for hemiplegia8 and anorexia nervosa [9].
b) the general population. Every year near 40,000 UK citizens undergo plastic surgery procedures that change their bodily appearance [38]. The fitness industry is also growing exponentially, which reflects general appearance/body-related concerns. Young people's body and self-esteem may be closely linked to their emotional and physical wellbeing. Older people are often concerned about what their body can do, to the detriment of their motor performance and emotional states [39]. Induced changes in BR may lead to improved self-esteem as a result of feeling good about one's body and may promote healthy behaviour and social interaction, which are central for enhancing the wellbeing of the general population.

I will undertake a series of activities during the project lifetime to engage with these populations, the organizations supporting the clinical cohorts (e.g. the NHS) and the industries developing interactive technology for therapy. The aim will be to examine the potential benefits of the research and to inform and shape the design of new technology for wellbeing, rehabilitation and entertainment. This can contribute to fostering the nation's health and wellbeing in the short-term. The project will open discussion on the potential benefits for the clinical groups by focusing on CRPS patients, who have a particularly altered BR (e.g. an affected limb may be perceived as larger than it actually is [36]). Part of the discussion will aim to identify other potential beneficiaries.

The project will impact on my research and professional skills and will consolidate my career and development into a future research leader, by providing me with a solid research base, project management and teaching/supervision skills, as well as strong links with other researchers, technology designers and users. Similar skill development opportunities will be given to any junior staff directly associated with this project.