To date, there have almost no examples of families where a specific cognitive deficit is inherited with the preservation of closely allied cognitive systems. This thesis describes a series of investigations to define and characterise the phenotype of a large family (the JR family) with an apparently dominantly inherited disorder of verbal memory spanning four living generations. Initial neuropsychological assessment of affected family members revealed a pattern of preserved intelligence with superior nonverbal to verbal IQ. Impaired verbal knowledge, particularly vocabulary was seen. Verbal recall memory was significantly impaired but visual recall was intact. Discrepancies in IQ or memory abilities were not found in family members without the memory problem. Further investigations showed that the verbal memory deficit could not be explained by an underlying language disorder. Affected JR family members did not have generalised deficits in language processing or phonological short-term memory. However they did show deficits in subtests that placed high demands upon verbal memory, and those requiring the retention of semantic information. Evidence was then sought to test the hypothesis that pictorial support during encoding would improve prose recall. This was found to be the case, with pictures that were most semantically relevant being of most benefit. There was clearly a possibility, on the basis of preliminary findings, that the verbal memory deficit could be the result of lexical-semantic impairments in short-term memory. Typical lexical-semantic effects were seen in affected family member’s performance on word span tasks, but not sentence repetition tasks. Recall of sentences that required the retention of a high semantic load showed the greatest deficit compared to unrelated controls. Finally, a further set of experiments sought to establish whether affected JR cases had an underlying semantic processing deficit. This was not found, but a specific impairment in word knowledge, particularly abstract word knowledge was revealed. The results of these studies are interpreted using structural and processing models of memory. Conclusions indicate, provisionally, that the verbal memory deficit seen in affected JR cases is the consequence of an impaired binding mechanism between phonological and semantic representations at the interface of short-term and long-term memory.

Humans interact with the world through voluntary, goal-directed action. A phenomenal corollary of this capacity is the sense of agency. This refers to the conscious experience one has of one's own agency; the sense in which actions and their results are caused or controlled by one's ‘Self’. Recent accounts have tended to emphasise either the role of efferent processes within the motor system or the role of general-purpose inferential mechanisms in the sense of agency. In this thesis these different accounts of agency, and their neural substrates, were systematically investigated. It was found that the sense of agency is best understood as a combination of both mechanisms. Several factors selectively influencing the two mechanisms were identified across a series of behavioural experiments in healthy volunteers. Physiological experiments confirmed the efferent contribution to the sense of agency, and identified it with the pre-supplementary motor area. The importance of the sense of agency to normal human functioning can be seen in certain disorders. Abnormal sense of agency profoundly impacts the overall sense of self and also social functioning. This thesis investigated the sense of agency in Schizophrenia and Parkinson's disease. Abnormalities in the sense-of agency were found in both clinical groups, and these abnormalities were explained by known pathophysiology and cognitive impairments in these groups.

Embodied theories of cognition state that the body plays a central role in cognitive representation. Under this description semantic representations, which constitute the meaning of words and sentences, are simulations of real experience that directly engage sensory and motor systems. This predicts interactions between comprehension and perception at low levels, since both engage the same systems, but the majority of evidence comes from picture judgements or visuo-spatial attention therefore it is not clear which visual processes are implicated. In addition, most of the work has concentrated on sentences rather than single words although theories predict that the semantics of both should be grounded in simulation. This investigation sought to systematically explore these interactions, using verbs that refer to upwards or downwards motion and sentences derived from the same set of verbs. As well as looking at visuo-spatial attention, we employed tasks routinely used in visual psychophysics that access low levels of motion processing. In this way we were able to separate different levels of visual processing and explore whether interactions between comprehension and perception were present when low level visual processes were assessed or manipulated. The results from this investigation show that: (1) There are bilateral interactions between low level visual processes and semantic content (lexical and sentential). (2) Interactions are automatic, arising whenever linguistic and visual stimuli are presented in close temporal contiguity. (3) Interactions are subject to processes within the visual system such as perceptual learning and suppression. (4) The precise content of semantic representations dictates which visual processes are implicated in interactions. The data is best explained by a close connection between semantic representation and perceptual systems when information from both is available it is automatically integrated. However, it does not support the direct and unmediated commitment of the visual system in the semantic representation of motion events. The results suggest a complex relationship between semantic representation and sensory-motor systems that can be explained by combining task specific processes with either strong or weak embodiment.

Judging by introspection and intuition, most of us would agree that the we become conscious of events in the external physical world when we pay attention to them and things we notice (i.e., become conscious of) are the ones that attract our attention. A long tradition of investigations in psychology and neuroscience also confirm that attention and awareness go hand in hand. Recently, however, the validity of this intuition has been questioned. This thesis addresses the hypothesis that attention and awareness might be disentangled at behavioural and neurobiological levels. Two main questions were: (1) does allocation / withdrawal of attention to / from unconscious stimuli affect the contents of subconscious processing and if so, could one demonstrate such modulations at the perceptual levels of processing? (2) What are the neural substrates of attentional selection of unconscious perception? In order to address these questions I adopted the framework of Load Theory combined with a recently developed technique called Continuous Flash Suppression (which combines binocular rivalry with dichoptic masking allowing for prolonged periods of unconscious exposure to visual stimuli). In 7 behavioural experiments I demonstrated (1) orientation-specific adaptation to unconscious gratings (rendered invisible by CFS); (2) such subconscious orientation processing was modulated by attentional load in a concurrent orthogonal foveal task as well as by sustained spatial attention. Finally, using functional magnetic resonance imaging (fMRI) I showed that human primary visual cortex (Vl) response to invisible stimuli was also modulated by attentional load. My findings join a-number of recent works in challenging the traditional view that attention and awareness are one and the same as well as the idea that attention acts as the gate-keeper to awareness. They also support the suggestion that neither the availability of attentional capacity for stimulus processing nor allocation of spatial attention can be a sufficient condition for awareness.

This thesis is about the neural mechanisms that underpin the expression of emotion in the human face and emotional modulation of behavioural responses. I designed 5 integrated studies and used functional magnetic resonance imaging (fMRI) to address specifically the neural mechanisms underlying human facial expression and emotional response. This work complements studies of emotion perception and subjective affective experience to provide a more comprehensive understanding of human emotions. I examined the neural underpinnings of emotional facial expression in three studies. I first demonstrated that emotional (compared to non-emotional) facial expression is not a purely motoric process but engages affective centres, including amygdala and rostral cingulate gyrus. In a second study I developed the concept of emotion contagion to demonstrate and verify a new interference effect (emotion expression interference, EEI). There is a cost (in reaction time and effort) to over-riding pre-potent tendency to mirror the emotional expressions of others. Several neural centres supporting EEI were identified (inferior frontal gyrus, superior temporal sulcus and insula), with their activity across subject predicting individual differences in personal empathy and emotion regulation. In a third study I examined an interesting phenomenon in our daily social life: how our own emotional facial expressions influence our judgment of the emotional signals of other people I explored this issue experimentally to examine the behavioural and neural consequences of posing positive (smiling) and negative (frowning) emotional expressions on judgments of perceived facial expressions. Reciprocal interactions between an emotion centre (amygdala) and a social signal processing region (superior temporal sulcus) were quantified. My analysis further revealed that the biasing of emotion judgments by one's own facial expression works through changes in connectivity between posterior brain regions (specifically from superior temporal sulcus to post-central cortex). I further developed two versions of an emotion GO/NOGO task to probe the impact of affective processing on behavioural responses. GO represents response execution and NOGO represents response inhibition. I therefore investigated how different emotions modulate both these complementary response dimensions (i.e. execution and inhibition). This research line is pertinent to a major theme within emotion theory, in which emotion is defined in terms of response patterns (e.g. approach and withdrawal). My results confirmed that both emotional processing and induced emotional states have robust modulatory effects on neural centres supporting response execution and response inhibition. Importantly, my results argue for emotion as a context for response control. My work extends our understanding of human emotion in terms of the nature and effect of its expression and its influence on response system.

The theory of R. L. Gregory that certain visual illusions are caused by the inappropriate action of a constancy-scaling mechanism was critically examined. Several unsuccessful attempts were made to replicate his experimental findings that certain ambiguous figures, such as the M-L illusion, appear 3-dimensional in a particular way when presented in reduced cue conditions. It was noted that the depth effect reported by Gregory was not large enough to explain all the illusory distortion in his figures. It was suggested that this might be because his apparatus allowed certain cues which could be used to determine the true form of the figures and thus destroy or reduce any 3-dimensional effects. The experimental results suggested that this was not so. In later experiments it proved possible to repeat Gregory's results only by inducing Ss to adopt a specific perceptual set. If this was not done Ss tended to see the figures in different ways which often changed over time. Combined analysis of the results of all Ss on many different figures showed a slight tendency for the central part of any Gestalt or figure to appear nearer than other parts. Two possible hypotheses were advanced to explain this result but further experimentation suggested that both were inadequate. Experimental evidence is provided that the Ponzo illusion is the result, of a shrinkage of the lower line rather than an expansion of the upper line, as is generally thought. This and other evidence is interpreted as suggesting that even this illusion may not have a perspective component. Taken as a whole the results suggest that any perspective theory of the illusions will prove inadequate. It is finally suggested that further research be directed towards inhibition type theories.

This work is conducted at two levels to meet the requirements of this research. The first objective is to develop a better understanding of how to design better sound-only games for a wide range of users. A new theoretical framework has been crafted to achieve this objective (Human Understanding Theory of Novel Games with Simplex, or the HUNGS theory). Such a theory aims to capture the current consensus about user requirements (as far as it is possible to do so) whilst understanding the principles and practices of interactive systems, namely the design of accessible sound-only games. The second objective is to understand better the psychology of intended users of such games. The importance of the present work is to test psychological concepts in the very different and very popular context of computer games. Implications found for users at work or working on serious tasks may not generalize to game players. To achieve the second requirement, a number of existing games were explored before a new game was designed (namely the Totally Lost game), using a range of methods. The Totally Lost game and different versions of the same game have been designed and evaluated based on user experiences.

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