The greatest genetic factor in how well we age cognitively is Apolipoprotein E (APOE), a single nucleotide polymorphism with three allelic variants: epsilon-2, epsilon-3 and epsilon-4 (hereafter ε2, ε3, ε4). The ε4 allele is associated with an increased risk of cognitive disadvantage in later life, however, the effects of this variant are not isolated to old-age, with some studies reporting cognitive advantages in youth. This thesis investigates the influence of APOE ε4 on cognition from mid-adulthood, a point in the lifespan when the detrimental effects of this allele may be emerging. This thesis begins with a systematic review and meta-analysis of the literature to-date, and suggests attention may be sensitive to ε4 differences in mid-adulthood, however, effects of the allele are not consistently shown, perhaps due to methodological limitations including the use of insensitive neuropsychological batteries (Chapter 1). Next, behavioural paradigms providing a sensitive index of both selective (Chapter 2) and executive attention (Chapter 3), suggest many attentional processes are intact in mid-age (45-55 years) ε4 carriers. Subtle deficits, however, are apparent on prospective memory (PM) and Stroop-switch paradigms, indicating a goal maintenance disadvantage. In addition, a proxy of cognitive reserve was found to moderate the effects of ε4 on executive attention in mid-adulthood (Chapter 4). Follow-up research used paradigms that target the distinct processes supporting focal and non-focal PM to interrogate the profile of change observed in mid-age ε4 carriers, identifying a profile of disadvantage consistent with that observed in pathological ageing (Chapter 5). PM, however, was not found to differentiate ε4 carriers in older individuals at heightened risk of converting to dementia (Chapter 6). Collectively, this research provides evidence for a profile of accelerated ageing in ε4 carriers, with subtle disadvantages apparent in executive attention by the end of the 5th decade.

Our phenomenological experience of what we see around us is of an accurate representation. However, such information is widely distributed in the brain so necessitates that some form of co-ordination of this information takes place to enable a coherent view of the world. The most prominently researched theory is Feature Integration Theory (Treisman, 1993). This proposes that accurate binding is dependent on the current spatial distribution of attention. Individual objects compete for attention via activity in a master map of locations with competition being modulated by grouping processes. When attention is distributed, features are randomly selected and a bound object can be perceived to be located at any position within the attentional window. However, there is evidence to suggest that in distributed attention, coarse location information is available and two alternative proposals have been put forward. The first suggests that it is the information from a unitary feature that can determine the perceived location of a bound object (Tsal & Lavie, 1988) and the second proposes that the information from all contributing features is averaged to provide the location information (Ashby et al, 1996). One way to determine which model best represents feature integration is to investigate the contribution each feature makes to the perceived location of a bound object by using the illusory conjunction paradigm in which an object is formed when the visual system binds together individual features from items located in different parts of the display. Results indicated that in briefly presented displays, perception can be subject to tritan-like shifts in colour space. No support for spatial averaging or for the random rule was found. Rather, there was a strong indication that the perceived location of illusory objects was sourced from a single feature supporting the unitary rule.

Gender stereotypes are activated spontaneously and unintentionally when certain role nouns are read. For example, people expect a builder to be male and a beautician to be female. Such gender inferences lead to processing difficulties when violations of stereotypical gender occur. The aim of this thesis was to devise strategies aimed at overcoming the activation of gender stereotype biases in English. Across nine studies, a variety of stereotype reduction strategies were investigated in conjunction with a judgement task, devised by Oakhill, Garnham and Reynolds (2005). This judgement task asked participants to decide, without deliberation, whether two terms presented onscreen could refer to one person. In the absence of a stereotype-reduction training, participants consistently showed evidence of succumbing to stereotype biases on stereotype incongruent pairings (e.g. Builder/ Mother) compared to stereotype congruent pairings (e.g. Builder/ Father). However, accuracy and response time performance to these incongruent pairings were found to significantly improve from pre-training levels to post-training levels through the use of stereotype reduction strategies such as providing participants with performance-related feedback (Experiment 1, Experiment 3), social consensus feedback (Experiment 4), combined social and accuracy feedback (Experiment 6) and counter-stereotype pictures (Experiment 8). A number of individual difference measures were also administered with the behavioural tasks. These explored whether individual differences in levels of ambivalent sexism, attitudes towards sexist language, sex role perception, and, among others, sexist pronoun use could moderate performance on the judgement task. The results from these additional tasks are described in Chapter 5. This thesis provides further evidence for the malleability of stereotype biases and delineates specific strategies through which stereotype biases can be overcome, to ultimately result in lower levels of stereotype endorsement.

This thesis identifies, in Nancy's The Fall of Sleep, a crucial critique of phenomenology. A criticism that demarcates, or limits, phenomenology in declaring: “There is no phenomenology of sleep”. Taking-up this challenge, we consider a number of ways that phenomenologists have, and could, approach sleep. Our thesis, however, does not simply offer possible responses to the problem but also finds, in these answers, important insights into the essence of the charge itself. Sleep and phenomenology are found to be mutually de-limiting – each binds the other, whilst offering foundational insights into its counterpart. Fundamentally, we bring phenomenologies of sleep, as opposed to simply phenomenology, into dialogue with this, Nancean, critique of phenomenology and with Nancy's account of sleep itself. We describe the distinctly different slumbering interpretations of sleep present, and conspicuously absent, in the work of: Husserl, Heidegger, and Levinas. Part I, after initially elaborating the challenge, presents a direct Husserlian counter, via a recent reconstituting of Husserl's late notes on sleep. The strengths and weaknesses of this phenomenological investigation sharpens the problem of sleep and leads us to pull back from consciousness-centred accounts. Part II, in contrast, develops our own hypothetical Heideggerian answer. This Part, the longest, uses Heidegger's existential and comparative analytics to ask ‘Does Dasein sleep?' This question reveals internal ambiguities of sleep – positioned between existence, life, and death. Part III withdraws from Heideggerian thinking through Levinas's incisive, and early, interpretation of sleep. This Levinasian retracting opens the possibility of returning to Nancy's challenge and corresponding description of sleep. Now this radical account is located in relation to, and in communication with, the somnological-phenomenological findings we have awakened in our thesis. The thesis ends by indicating a possible, future, return back from sleep to phenomenology – a dream, still hazy from sleep, of a somnolent phenomenology.

This thesis breaks new ground by attending to two contemporary developments in art and science. In art, computer-mediated interactive artworks comprise creative engagement between collaborating practitioners and a creatively participating audience, erasing all notions of a dividing line between them. The procedural character of this type of communicative real-time interaction replaces the concept of a finished artwork with a ‘field of artistic communication'. In science, the field of creativity research investigates creative thought as mental operations that combine and reorganise extant knowledge structures. A recent paradigm shift in cognition research acknowledges that cognition is embodied. Neither embodiment in cognition nor the ‘field of artistic communication' in interactive art have been assimilated by creativity research. This thesis takes an interdisciplinary approach to examine the embodied cognitive processes in a ‘field of artistic communication' using a media artwork called Sim-Suite as a case study research strategy. This interactive installation, created and exhibited in an authentic real-world context, engages three people to play on wobble-boards. The thesis argues that creative processes related to Sim-Suite operate within a continuum, encompassing collaborative artistic creation and cooperative creative participation. This continuum is investigated via mixed methods, conducting studies with qualitative and quantitative analysis. These are interpreted through a theoretical lens of embodied cognition principles, the 4E approaches. The results obtained demonstrate that embodied cognitive processes in Sim-Suite's ‘field of artistic communication' function on a continuum. We give an account of the creative process continuum relating our findings to the ‘embedded-extended-enactive lens', empirical studies in embodied cognition and creativity research. Within this context a number of topics and sub-themes are identified. We discuss embodied communication, aspects of agency, forms of coordination, levels of evaluative processes and empathetic foundation. The thesis makes conceptual, empirical and methodological contributions to creativity research.

Reversal learning deficits are a feature of many neuropsychiatric disorders, most notably schizophrenia. These deficits could be due, in part, to altered ability to dissipate either or both associations of previous positive (perseverance) and negative (learned non-reward) valence. Studies reported in this thesis developed an egocentric maze task and a visuospatial operant task for separate assessments of spatial reversal learning, perseverance and learned non-reward in mice. These tasks were subsequently used to assess the cognitive causes for altered performance after manipulations to brain systems recognised to be involved in reversal learning and relevant for human psychopathology, with a specific focus on schizophrenia. NMDA receptor (NMDAr) antagonism through acute phencyclidine did not affect reversal learning in the operant task, but caused general impairments in the maze task. Orbitofrontal (OFC) lesioned mice showed perseverative impairments in the operant task. Mice treated with the 5-HT2C receptor (5-HT2CR) antagonist SB242084 and 5-HT2CR KO mice showed facilitated reversal learning and decreased learned nonreward in the operant task. In the maze task, SB242084 decreased perseverance but increased learned non-reward, while 5-HT2CR KO mice showed perseverance and discrimination learning deficits. The final experimental chapter investigated the effect of SB242084 on touch-screen visual reversal learning in the rat. SB242084 retarded learning in this task. These studies demonstrate that previously non-reinforced associations can be of considerable importance in tasks of cognitive flexibility. The studies also show that the NMDAr, the 5-HT2CR, and the OFC, are involved in reversal learning and can modulate mechanisms related to both perseverance and learned non-reward. Moreover, in reversal learning, few effects of manipulations affecting PFC-functioning, or activity at the NMDAr and 5-HT2CR, generalise across the procedures in the visuospatial, egocentric spatial, and visual domains.

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To increase fitness for survival, organisms not only passively react to environmental changes but also actively predict future events to prepare for potential hazards within their environment. Accumulating evidence indicates that the human brain is a remarkable predictive machine which constantly models causal relationships and predicts future events. This ‘predictive processing' framework, a prediction-based form of Bayesian inference, states that the brain continuously generates and updates predictions about incoming sensory signals. This framework has been showing notable explanatory power in understanding the mechanisms behind both human behaviour and neurophysiological data and elegantly specifies the underlying computational principles of the neural system. However, even though predictive processing has the potential to provide a unified theory of the brain (Karl Friston, 2010), we still have a limited understanding about fundamental aspects of this model, such as how it deals with different types of information, learns statistical regularities and perhaps most fundamentally of all what its relationship to conscious experience is. This thesis aims to investigate the major gaps in our current understanding of the predictive processing framework via a series of studies. Study 1 investigated the fundamental relationship between unconscious statistical inference reflected by predictive processing and conscious access. It demonstrated that predictions that are in line with sensory evidence accelerate conscious access. Study 2 investigated how low level information within the sensory hierarchy is dealt with by predictive processing and regularity learning mechanisms through “perceptual echo” in which the cross-correlation between a sequence of randomly fluctuating luminance values and occipital electrophysiological (EEG) signals exhibits a long-lasting periodic (~100ms cycle) reverberation of the input stimulus. This study identified a new form of regularity learning and the results demonstrate that the perceptual echo may reflect an iterative learning process, governed by predictive processing. Study 3 investigated how supra-modal predictive processing is capable of learning regularities of temporal duration and also temporal predictions about future events. This study revealed a supramodal temporal prediction mechanism which processes auditory and visual temporal information and integrates information from the duration and rhythmic structures of events. Together these studies provide a global picture of predictive processing and regularity learning across differing types of predictive information.

The sense of agency is the experience of being the initiator of our intentional actions and their outcomes. According to higher order thought theory, a representation becomes conscious when there is a higher order state about it. Thus conscious experience, including that of intentions, is metacognitive. The experience of involuntariness characteristic of hypnotic responding may be attributable to the formation and maintenance of inaccurate metacognitive higher order states of intending. Conversely, the practice of Buddhist mindfulness meditation may develop accurate metacognition, including higher order states of intending. Highly hypnotisable people and mindfulness meditators may therefore occupy two ends of a spectrum of metacognitive ability with regard to unconscious intentions. The presented research investigated predicted trait differences in cognitive tasks which directly or indirectly reflect metacognition of intentions: the timing of an experience of an intention to move and the compressed time interval between a voluntary action and its outcome, known as intentional binding. As an implicit measure of sense of agency, intentional binding was also employed to investigate the veridicality of reports of the experience of involuntariness in hypnotic responding. Additionally, while hypnosis presents a unique opportunity to investigate reliable changes in agentic experience, existing hypnosis screening instruments are time consuming and present a barrier to wider adoption of hypnosis as an instrument for studying consciousness. Here a revised, time-efficient hypnosis screening procedure (the SWASH) is presented. Consistent with predictions, highly hypnotisable groups reported later awareness of motor intentions than less hypnotisable groups and meditators earlier awareness than non-meditators. In an intentional binding task, high hypnotisables showed less binding of an action-outcome toward an action (outcome binding) than low hypnotisables and meditators more outcome binding than non-meditators. Outcome binding was reduced in post-hypnotic involuntary action compared to voluntary action. It is proposed that intentional binding is driven by a cue combination mechanism and that these differences reflect varying precision of motor intention related information in reported timing judgements. The SWASH was found to be a reliable hypnosis screening instrument.