The flash-lag effect is an illusion in which a moving object is perceived advanced beyond an aligned flash. The majority of research into the effect has been directed at specifying its source, though a small body of literature simply makes use of flash-lag to answer diverse questions about perception – without necessarily arbitrating between competing accounts of its nature. The current thesis expands on this little-explored potential of the flash-lag effect with the presentation of three papers reporting programmes of research that exploit the phenomenon to address issues unrelated to its cause. In the first paper it is shown that, like in visual flash-lag, a similar motion direction based anisotropy is evident in the motor version of the effect, in which one's unseen limb is perceived ahead of a flash. Specifically, the effect is greater for motion towards, rather than away from fixation. Furthermore, Paper I also demonstrates for the first time a motor flash-drag effect, in which one's unseen moving hand ‘drags' the perceived position of a nearby flash. It is argued that both of these findings are evidence of parallels between vision and action systems. Paper II takes advantage of the explicitly perceptual nature of the flash-lag effect to investigate whether the visuospatial perception of threatening objects is different to that of non-threatening objects. It is ultimately shown that when a moving stimulus is threatening, the flash-lag effect is greater, regardless of its direction of motion. Paper III shows that gamma movement (the apparent contraction of disappearing stimuli) adds to and subtracts from the forward displacement of contracting and expanding stimuli, respectively. Prior to these papers, however, an overview chapter reviews the flash-lag literature, and argues that the effect can be a useful tool for psychophysics, even without a consensus on its origin.

In order to rapidly get the gist of new scenes or recognise objects, the brain must have mechanisms to process the large amount of visual information which enters the eye. Previous research has shown that observers tend to extract the average feature from briefly seen sets of multiple stimuli that vary along a dimension (e.g., size), a phenomenon called ensemble perception. This thesis investigates ensemble perception of hue. Paper 1 (Maule, Witzel & Franklin, 2014) demonstrates that human observers have memories biased towards the mean hue of a rapidly-presented ensemble of colours. Paper 2 (Maule & Franklin, 2015) further shows that observers are able to identify the mean hue from a distractor fairly reliably, provided the range of hues is manageable. Paper 3 provides evidence that, while observers' settings of the mean hue converge quite closely on the true mean across many trials, the precision of those settings is low and does not support claims that ensemble perception can surpass the limits of visual working memory. Paper 4 found that adults with autism have an enhanced ability to discriminate members from non-members of multi-hue ensembles, and a similar ability to extract the mean hue compared to typical adults, but are worse at averaging small sets. Finally, paper 5 investigated colour afterimages in adults with autism and whether they are affected by top-down gist of a scene. It was found that afterimages were no different in autism compared to a typical group. Overall these studies provide the first comprehensive exploration of ensemble perception of hue, showing that observers can extract and estimate the mean hue of a rapidly-presented multi-colour ensemble with a small hue variance. The ability to average hue may be driven by a sub-sampling mechanism, but results from autistic adults suggests that it can be modulated by processing style.

Visual impairment is a global and potentially devastating affliction. Sensory substitution devices have the potential to lessen the impact of blindness by presenting vision via another modality. The chief motivation behind each of the chapters that follow is the production of more useful sensory substitution devices. The first empirical chapter (chapter two) demonstrates the use of interactive genetic algorithms to determine an optimal set of parameters for a sensory substitution device based on an auditory encoding of vision (“the vOICe”). In doing so, it introduces the first version of a novel sensory substitution device which is configurable at run-time. It also presents data from three interactive genetic algorithm based experiments that use this new sensory substitution device. Chapter three radically expands on this theme by introducing a general purpose, modular framework for developing visual-to-auditory sensory substitution devices (“Polyglot”). This framework is the fuller realisation of the Polyglot device introduced in the first chapter and is based on the principle of End-User Development (EUD). In chapter four, a novel method of evaluating sensory substitution devices using eye-tracking is introduced. The data shows both that the copresentation of visual stimuli assists localisation and that gaze predicted an auditory target location more reliably than the behavioural responses. Chapter five explores the relationship between sensory substitution devices and other tools that are used to acquire real-time sensory information (“sensory tools”). This taxonomy unites a range of technology from telescopes and cochlear implants to attempts to create a magnetic sense that can guide further research. Finally, in chapter six, the possibility of representing colour through sound is explored. The existence of a crossmodal correspondence between (equi-luminant) hue and pitch is documented that may reflect a relationship between pitch and the geometry of visible colour space.

Western science claims to provide unique, objective information about the world. This is supported by the observation that peoples across cultures will agree upon a common description of the physical world. Further, the use of scientific instruments and mathematics is claimed to enable the objectification of science. In this work, carried out by reviewing the scientific literature, the above claims are disputed systematically by evaluating the definition of physical reality and the scientific method, showing that empiricism relies ultimately upon the human senses for the evaluation of scientific theories and that measuring instruments cannot replace the human sensory system. Nativist and constructivist theories of human sensory development are reviewed, and it is shown that nativist claims of core conceptual knowledge cannot be supported by the findings in the literature, which shows that perception does not simply arise from a process of maturation. Instead, sensory function requires a long process of learning through interactions with the environment. To more rigorously define physical reality and systematically evaluate the stability of perception, and thus the basis of empiricism, the development of the method of dimension analysis is reviewed. It is shown that this methodology, relied upon for the mathematical analysis of physical quantities, is itself based upon empiricism, and that all of physical reality can be described in terms of the three fundamental dimensions of mass, length and time. Hereafter the sensory modalities that inform us about these three dimensions are systematically evaluated. The following careful analysis of neuronal plasticity in these modalities shows that all the relevant senses acquire from the environment the capacity to apprehend physical reality. It is concluded that physical reality is acquired rather than given innately, and leads to the position that science cannot provide unique results. Rather, those it can provide are sufficient for a particular environmental setting.

This thesis explores whether colour terms (e.g., “red”, “blue”, “purple”, etc.) influence visual processing of colour, and if so, the time course of any effect. Broadly, this issue relates to debate concerning whether language affects the way we perceive the world (i.e., the theory of linguistic relativity). Three of the experiments conducted used the event-related potential method (ERP), taking electrophysiological measurements of visual processing and visual cognition in human participants. The ERP provides high-resolution information about the timing of neural activity in the brain and can therefore be used to effectively investigate the time course of a potential influence of colour terms on visual processing. The first study, using a behavioural approach, identified that colour terms can influence the detection of colours and colour-associated objects suppressed from awareness by continuous flash suppression. The second study found that a cross-linguistic difference in colour lexicons affected a post-perceptual ERP component (the P2-N2 complex), but not sensory ERP components occurring early in visual processing. However, the third study found that differences in colour naming within a language do affect an early sensory ERP component (the P1). The final study used ERPs to identify a post-perceptual neural marker (in the posterior P2 component) for the unique ‘pure' hues (red, yellow, green, and blue), which had previously only been defined and identified linguistically. All of the studies provide evidence that colour terms affect colour processing, and the specific time course of this effect is identified as being task-dependent. These findings have implications for broader debate about the influence of language on visual cognition and perception.

Very little research has been conducted on the development of taste perception in humans. Therefore there is a lack of knowledge, first, about how children perceive taste, especially when compared to what is known about how adults experience taste, and second, about the functioning and development of the gustatory system, including when the system is fully mature and functioning in an adult-like manner. The aims of this thesis were (i) to investigate the growth pattern of the tongue throughout childhood / adolescence, and (ii) to determine the state of maturity of some of the aspects of the sense of taste in mid-childhood. Overall, the data in this thesis indicate that children respond similarly to adults with regard to single-point measures of sensitivity and perceived intensity, but there are some differences in the overall temporal experience of taste, from onset of perception through to extinction, and the way in which it is perceived by adults and 8-9 year old children. The latter / Master of Science (Hons)

University of Technology, Sydney. Faculty of Humanities and Social Sciences. / It is the intention of this Doctor of Creative Arts to convey the complexity of viewing art in museums. Concentrating on both the physical and cultural contexts of art, I focus specifically on Italian museums that house artworks of the Renaissance. I argue that the viewing experience in these museums is formed at the intersection of cultures, histories, the past and the present, art and the subjectivity of the viewer's own gaze. In this project the personal, physical, cerebral, sensorial and temporal experiences of art are central to my concerns. The structure of this DCA combines my photographic art practice with this written reflection. I work with both the visual and the textual to most appropriately and effectively express my concerns with the Renaissance and Italian museums. In a peculiar act of doubling, I am making art about the experience of viewing it, and through image-making I am able both to explore and to comment more profoundly on the experience of these museums. While my research and writing at times responds to these images, it also inspires them. Here I integrate the past, history and art, with contemporary theories that are relevant in the study ofvision and today's art viewing, and rely on numerous writers across the broad .fields of visual arts, art history and theory, museology, historiography and cultural tourism. In surveying these extensive interwoven disciplines I engage with the magnitude of the social, historical and theoretical studies that converge in the museum viewer's field of vision. Beyond the glorious artworks themselves Italian Renaissance museums exhibit a dense visual and historic culture that provides an enriched viewing environment. They paradoxically intersect 'high' art with a phenomenal popularity that appears ever-expanding through endless reproductions and representations via modern technologies. Through examining these museums with their multiple histories and contexts I hope to argue for a slower, more considered engagement with art, that encourages the viewer to experience the sensual as well as the intellectual aspects that this opulent environment offers.

In two parts, this thesis examined retronasal perception of single odours, binary odour mixtures and odour-taste mixtures. Part 1, aimed to determine if perceived retronasal temporal order differs to that order perceived via the orthonasal pathway and if retronasal temporal order is a function of an odorant’s water solubility or nasal mucus solubility slowing the odorants progression to the olfactory epithelium via the longer retronasal route. Part 1 established that retronasal temporal perception of binary odour mixtures differs from orthonasal temporal perception and that nasal mucus solubility and the “stickiness”, mediated by volatility, are the factors determining the perceived retronasal order. It was further concluded that nasal mucus and not water was the most appropriate approximation to the composition of nasopharyngeal mucus. Part 2, aimed to determine if correct retronasal odour identification is a function of learned taste-associations and if correct retronasal odour identification is a function of the modality through which the odour is learned. Part 2, established that in simple binary odour-taste mixtures correct retronasal odour identification is not a function of learned taste-associations, nor do tastants suppress odours. However, it was concluded that mouth-learning experience does provide odours with an identification advantage retronasally, over odours that are not learned through the mouth. Overall, the Thesis demonstrated that differences exist between retronasal and orthonasal perception. Specifically, the perceived temporal order of components in binary odours mixtures is determined retronasally by an odour’s nasal mucus solubility and “stickiness”. The exploration of this mechanism in future research may provide a greater understanding of temporal odour perception and the means to increase odour mixture component identification beyond the current limit of three. Furthermore, retronasal odour and taste processing seem to occur independently of each other, as learned-associations between taste and odours do not impact on the accuracy of mixture component identification or intensity. It may be that it is mouth-learning experience or a relationship to food that is important to retronasal odour perception rather than any component congruency. Future research should aim to determine if it is mouth experience or the contribution of other stimuli such as tactile cues that contribute to the increase in retronasal identification accuracy. / Doctor of Philosophy (PhD)

University of Technology, Sydney. Faculty of Humanities and Social Sciences. / It is the intention of this Doctor of Creative Arts to convey the complexity of viewing art in museums. Concentrating on both the physical and cultural contexts of art, I focus specifically on Italian museums that house artworks of the Renaissance. I argue that the viewing experience in these museums is formed at the intersection of cultures, histories, the past and the present, art and the subjectivity of the viewer's own gaze. In this project the personal, physical, cerebral, sensorial and temporal experiences of art are central to my concerns. The structure of this DCA combines my photographic art practice with this written reflection. I work with both the visual and the textual to most appropriately and effectively express my concerns with the Renaissance and Italian museums. In a peculiar act of doubling, I am making art about the experience of viewing it, and through image-making I am able both to explore and to comment more profoundly on the experience of these museums. While my research and writing at times responds to these images, it also inspires them. Here I integrate the past, history and art, with contemporary theories that are relevant in the study ofvision and today's art viewing, and rely on numerous writers across the broad .fields of visual arts, art history and theory, museology, historiography and cultural tourism. In surveying these extensive interwoven disciplines I engage with the magnitude of the social, historical and theoretical studies that converge in the museum viewer's field of vision. Beyond the glorious artworks themselves Italian Renaissance museums exhibit a dense visual and historic culture that provides an enriched viewing environment. They paradoxically intersect 'high' art with a phenomenal popularity that appears ever-expanding through endless reproductions and representations via modern technologies. Through examining these museums with their multiple histories and contexts I hope to argue for a slower, more considered engagement with art, that encourages the viewer to experience the sensual as well as the intellectual aspects that this opulent environment offers.

Our senses take in a large amount of information, information that sometimes is congruent across sensory modalities. Crossmodal correspondences are the study of how this information across modalities is integrated by the brain, across which dimensions the correspondences exists, and how it affect us. In the present paper four experiments were conducted, in which potential crossmodal correspondences between audition, vision and olfaction were investigated. It was hypothesized that crossmodal correspondences between olfaction, vision and audition exist along different dimensions. The results showed significant correlations between olfaction and audition when volume varies, i.e., a high volume is associated to a high concentration of an odor, and a low volume is associated to a low concentration of an odor, and vice versa. Furthermore, existing correspondences between vision and audition is reconfirmed. In conclusion, the results provide support to the notion that crossmodal correspondences exists between all sensory modalities, although along different dimensions.