Investigating perceptual congruence between information and sensory parameters in auditory and vibrotactile displays

A fundamental interaction between a computer and its user(s) is the transmission of information between the two and there are many situations where it is necessary for this interaction to occur non-visually, such as using sound or vibration. To design successful interactions in these modalities, it is necessary to understand how users perceive mappings between information and acoustic or vibration parameters, so that these parameters can be designed such that they are perceived as congruent. This thesis investigates several data-sound and data-vibration mappings by using psychophysical scaling to understand how users perceive the mappings. It also investigates the impact that using these methods during design has when they are integrated into an auditory or vibrotactile display. To investigate acoustic parameters that may provide more perceptually congruent data-sound mappings, Experiments 1 and 2 explored several psychoacoustic parameters for use in a mapping. These studies found that applying amplitude modulation — or roughness — to a signal, or applying broadband noise to it resulted in performance which were similar to conducting the task visually. Experiments 3 and 4 used scaling methods to map how a user perceived a change in an information parameter, for a given change in an acoustic or vibrotactile parameter. Experiment 3 showed that increases in acoustic parameters that are generally considered undesirable in music were perceived as congruent with information parameters with negative valence such as stress or danger. Experiment 4 found that data-vibration mappings were more generalised — a given increase in a vibrotactile parameter was almost always perceived as an increase in an information parameter — regardless of the valence of the information parameter. Experiments 5 and 6 investigated the impact that using results from the scaling methods used in Experiments 3 and 4 had on users' performance when using an auditory or vibrotactile display. These experiments also explored the impact that the complexity of the context which the display was placed had on user performance. These studies found that using mappings based on scaling results did not significantly impact user's performance with a simple auditory display, but it did reduce response times in a more complex use-case

INTERACTIVE SONIFICATION STRATEGIES FOR THE MOTION AND EMOTION OF DANCE PERFORMANCES

The Immersive Interactive SOnification Platform, or iISoP for short, is a research platform for the creation of novel multimedia art, as well as exploratory research in the fields of sonification, affective computing, and gesture-based user interfaces. The goal of the iISoP’s dancer sonification system is to “sonify the motion and emotion” of a dance performance via musical auditory display. An additional goal of this dissertation is to develop and evaluate musical strategies for adding layer of emotional mappings to data sonification. The result of the series of dancer sonification design exercises led to the development of a novel musical sonification framework. The overall design process is divided into three main iterative phases: requirement gathering, prototype generation, and system evaluation. For the first phase help was provided from dancers and musicians in a participatory design fashion as domain experts in the field of non-verbal affective communication. Knowledge extraction procedures took the form of semi-structured interviews, stimuli feature evaluation, workshops, and think aloud protocols. For phase two, the expert dancers and musicians helped create test-able stimuli for prototype evaluation. In phase three, system evaluation, experts (dancers, musicians, etc.) and novice participants were recruited to provide subjective feedback from the perspectives of both performer and audience. Based on the results of the iterative design process, a novel sonification framework that translates motion and emotion data into descriptive music is proposed and described

Data Sonification in Creative Practice

Sonification is the process of data transmission with non-speech audio. While finding increasing acceptance as a scientific method, particularly where a visual representation of data is inadequate, it is still often derided as a ‘gimmick’. Composers have also shown growing interest in sonification as a compositional method. Both in science and in music, the criticism towards this method relates to poor aesthetics and gratuitous applications. This thesis aims to address these issues through an accompanying portfolio of pieces which use sonification as a compositional tool. It establishes the principles of ‘musification’, which can be defined as a sonification which uses musical structures; a sonification organised by musical principles. The practice-as-research portfolio explores a number of data sources, musical genres and science-music collaborations. The main contributions to knowledge derived from the project are a portfolio of compositions, a compositional framework for sonification and an evaluation framework for musification. This thesis demonstrates the validity of practice-as-research as a methodology in sonification research

Real-Time Electroencephalogram Sonification for Neurofeedback

Electroencephalography (EEG) is the measurement via the scalp of the electrical activity of the brain. The established therapeutic intervention of neurofeedback involves presenting people with their own EEG in real-time to enable them to modify their EEG for purposes of improving performance or health. The aim of this research is to develop and validate real-time sonifications of EEG for use in neurofeedback and methods for assessing such sonifications. Neurofeedback generally uses a visual display. Where auditory feedback is used, it is mostly limited to pre-recorded sounds triggered by the EEG activity crossing a threshold. However, EEG generates time-series data with meaningful detail at fine temporal resolution and with complex temporal dynamics. Human hearing has a much higher temporal resolution than human vision, and auditory displays do not require people to focus on a screen with their eyes open for extended periods of time – e.g. if they are engaged in some other task. Sonification of EEG could allow more rapid, contingent, salient and temporally detailed feedback. This could improve the efficiency of neurofeedback training and reduce the number and duration of sessions for successful neurofeedback. The same two deliberately simple sonification techniques were used in all three experiments of this research: Amplitude Modulation (AM) sonification, which maps the fluctuations in the power of the EEG to the volume of a pure tone; and Frequency Modulation (FM) sonification, which uses the changes in the EEG power to modify the frequency. Measures included, a listening task, NASA task load index; a measure of how much work it was to do the task, Pre & post measures of mood, and EEG. The first experiment used pre-recorded single channel EEG and participants were asked to listen to the sound of the sonified EEG and try and track the activity that they could hear by moving a slider on a computer screen using a computer mouse. This provided a quantitative assessment of how well people could perceive the sonified fluctuations in EEG level. The tracking accuracy scores were higher for the FM sonification but self-assessments of task load rated the AM sonification as easier to track. The second experiment used the same two sonifications, in a real neurofeedback task using participants own live EEG. Unbeknownst to the participants the neurofeedback task was designed to improve mood. A Pre-Post questionnaire showed that participants changed their self-rated mood in the intended direction with the EEG training, but there was no statistically significant change in EEG. Again the FM sonification showed a better performance but AM was rated as less effortful. The performance of sonifications in the tracking task in experiment 1 was found to predict their relative efficacy at blind self-rated mood modification in experiment 2. The third experiment used both the tracking as in experiment 1 and neurofeedback tasks as in experiment 2, but with modified versions of the AM and FM sonifications to allow two-channel EEG sonifications. This experiment introduced a physical slider as opposed to a mouse for the tracking task. Tracking accuracy increased, but this time no significant difference was found between the two sonification techniques on the tracking task. In the training task, once more the blind self-rated mood did improve in the intended direction with the EEG training, but as again there was no significant change in EEG, this cannot necessarily be attributed to the neurofeedback. There was only a slight difference between the two sonification techniques in the effort measure. In this way, a prototype method has been devised and validated for the quantitative assessment of real-time EEG sonifications. Conventional evaluations of neurofeedback techniques are expensive and time consuming. By contrast, this method potentially provides a rapid, objective and efficient method for evaluating the suitability of candidate sonifications for EEG neurofeedback

Designing multi-sensory displays for abstract data

The rapid increase in available information has lead to many attempts to automatically locate patterns in large, abstract, multi-attributed information spaces. These techniques are often called data mining and have met with varying degrees of success. An alternative approach to automatic pattern detection is to keep the user in the exploration loop by developing displays for perceptual data mining. This approach allows a domain expert to search the data for useful relationships and can be effective when automated rules are hard to define. However, designing models of the abstract data and defining appropriate displays are critical tasks in building a useful system. Designing displays of abstract data is especially difficult when multi-sensory interaction is considered. New technology, such as Virtual Environments, enables such multi-sensory interaction. For example, interfaces can be designed that immerse the user in a 3D space and provide visual, auditory and haptic (tactile) feedback. It has been a goal of Virtual Environments to use multi-sensory interaction in an attempt to increase the human-to-computer bandwidth. This approach may assist the user to understand large information spaces and find patterns in them. However, while the motivation is simple enough, actually designing appropriate mappings between the abstract information and the human sensory channels is quite difficult. Designing intuitive multi-sensory displays of abstract data is complex and needs to carefully consider human perceptual capabilities, yet we interact with the real world everyday in a multi-sensory way. Metaphors can describe mappings between the natural world and an abstract information space. This thesis develops a division of the multi-sensory design space called the MS-Taxonomy. The MS-Taxonomy provides a concept map of the design space based on temporal, spatial and direct metaphors. The detailed concepts within the taxonomy allow for discussion of low level design issues. Furthermore the concepts abstract to higher levels, allowing general design issues to be compared and discussed across the different senses. The MS-Taxonomy provides a categorisation of multi-sensory design options. However, to design effective multi-sensory displays requires more than a thorough understanding of design options. It is also useful to have guidelines to follow, and a process to describe the design steps. This thesis uses the structure of the MS-Taxonomy to develop the MS-Guidelines and the MS-Process. The MS-Guidelines capture design recommendations and the problems associated with different design choices. The MS-Process integrates the MS-Guidelines into a methodology for developing and evaluating multi-sensory displays. A detailed case study is used to validate the MS-Taxonomy, the MS-Guidelines and the MS-Process. The case study explores the design of multi-sensory displays within a domain where users wish to explore abstract data for patterns. This area is called Technical Analysis and involves the interpretation of patterns in stock market data. Following the MS-Process and using the MS-Guidelines some new multi-sensory displays are designed for pattern detection in stock market data. The outcome from the case study includes some novel haptic-visual and auditory-visual designs that are prototyped and evaluated

Sonification of exosolar planetary systems

The purpose of this research is to investigate sonification techniques suitable for astronomers to explore exosolar planetary data. Four studies were conducted, one with sonification specialists and three with exosolar planetary astronomers. The first study was to establish existing practices in sonification design and obtain detailed information about design processes not fully communicated in published papers. The other studies were about designing and evaluating sonifications for three different fields of exosolar astronomy. One, to sonify atmospheric data of an exoplanet in a habitable zone. Another, to sonify accretion discs located in newly developing exosolar systems. The third sonification, planet detection in an asteroid belt. User-centred design was used so that mappings of the datasets could be easily comprehensible. Each sonification was designed to sound like the natural elements that were represented in the data. Spatial separation between overlapping datasets can make hidden information more noticeable and provide additional dimensionality for sound objects. It may also give a more realistic interpretation of the data object in a real-world capacity. Multiple psychoacoustic mappings can convey data dimensionality and immediate recognition of subtle changes. Sound design aesthetics that mimic natural sounds were more relatable for the user. Sonification has been effective within the context of these studies offering new insight by unmasking previously unnoticed data particulars. It has also given the astronomers a broader understanding of the dimension of the data objects that they study and their temporal-spatial behaviours. Future work pertains to the further development and creation of a sonification model consisting of different aspects of exosolar astronomy that could be developed for a platform that houses different data related to this field of study