This thesis examines the cognitive and neural bases of expertise. In so doing, several psychological phenomena were investigated-imagery. memory and thinking-using different tasks, and a variety of techniques of data gathering, including standard behavioural experiments, questionnaires, eye-movement recording, and functional magnetic resonance imaging (fMRI). Chess players participated in all the studies, and chess tasks were used. The data confirmed the versatility and power of chess as a task environment, since the results provided fruitful information for the understanding of different human cognitive processes. The role of practice in this domain of expertise was examined. The strong view that extended deliberate practice is a necessary and sufficient condition for the acquisition of expert performance, did not receive support in this thesis. Alternatively, a less extreme position was adopted: extended practice is a necessary, but not a sufficient condition for the acquisition of expert performance. A search for individual differences in factors unrelated to chess practice was carried out. The sources of these individual differences, as well as the cognitive abilities in which individual differences may exist, were considered. One of the sources-the age at which serious practice starts-was a good predictor of chess skill. Handedness, which is supposed to be determined by environmental factors in utero, slightly differentiated chess players from non-players, but no differences in this variable were found between strong and the weak players. Regarding the cognitive abilities, chess players performed slightly better than the non-chess players in a spatial task. Individual differences were also considered within a single leyel of expertise-master level. Differences in forgetting rate in long-term memory and reaction time were observed for one of the masters. These results contributed to the improvement of an extant theory of expertise-template/CHREST [CHunks and REtrieval STructures] theory-by estimating values for some of its parameters based on the empirical data obtained, and by proposing the addition of a spatial short-term memory.

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A sequential arrangement of processing stages is incorporated into most theoretical models of person recognition (e.g., Bruce & Young, 1986). Simple familiar/unfamiliar decisions are earliest, followed by access to semantic information, followed by naming. To date, the stage involved in semantic decisions has received least attention. Thus, relatively little is known about how we store personal semantic information. More research into this stage is necessary if we are to better understand the organisation of semantic memory for familiar people. The primary aim of this dissertation is to provide new evidence relating to the storage and retrieval of such information. The first line of enquiry attempts to discriminate between two influential models in this area (Burton et.al., 1990 and Bredart et. al., 1995), by using a new method involving semantic judgement tasks in the traditional semantic priming paradigm. In one model (Burton et. al., 1990), semantic information is stored in a single undifferentiated pool. In the other model (Bredart et. al., 1995) semantic information is clustered into separate pools. The two types of account make different predictions about certain patterns of priming during information retrieval. The experiments reported here fail to discriminate between the models. Later experiments identify the locus of the reported semantic priming effects and provide an explanation of these findings within a structural model of person recognition.

Contemporary theories of causal induction have focussed largely on the question of how evidence in the form of covariations between causes and effects is used to compute measures of causal strength. A very important precursor enabling such computations is that the reasoner notices that a cause and effect have co-occurred. Standard laboratory experiments have usually bypassed this problem by presenting participants directly with covariational information. As a result, relatively little is known about how humans identify causal relations in real time. What evidence exists, however, paints a rather unflattering picture of human causal induction and converges to the conclusion that humans cannot identify causal relations if cause and effect are separated by more than a few seconds. Associative learning theory has interpreted these findings to indicate that temporal contiguity is essential to causal inference. I argue instead that contiguity is not essential, but that the influence of time in causal inference is crucially dependent on people's beliefs and expectations about the timeframe of the causal relation in question. First I demonstrate that humans are capable of dissociating temporal contiguity from causal strength; more specifically, they can learn that a given event exerts a stronger causal influence when it is temporally separated from the effect than when it is contiguous with it. Then I re-investigate a paradigm commonly used to study the effects of delay on human causal induction. My experiments employed one crucial additional manipulation regarding participants' awareness of potential delays. This manipulation was sufficient to reduce the detrimental effects of delay. Three other experiments employed a similar strategy, but relied on implicit instructions about the timeframe of the causal relation in question. Overall, results support the hypothesis that knowledge mediates the timeframe of covariation assessment in human causal induction. Implications for associative learning and causal power theories are discussed.

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Section I reports the findings of previous investigators into problems of speed of performance on mental tests and the effect of distraction on speed and accuracy of performance. The majority of the subjects of the investigation were psychoneurotic in-patients and the tests used were progressive Matrices, the Mill Hill Vocabulary Scale, the Thematic Apperception Test and the Porteus Mazes. Section II deals with the scores obtained by individuals suffering from different forms of psychoneurotic illness on Progressive Matrices and the Mill Hill Vocabulary Scale and the ratio between these scores when Progressive Matrices is used with and without a time limit. The main finding is that anxiety states, reactive depressives and obsessionals have a considerably higher general intellectual ability: vocabulary ratio than psychopaths and hysterics. This result is contrary to previous findings. An explanation of this difference, partly in terms of speed of performance, is offered. Section III is concerned principally with the productivity and fluency of subjects on the Thematic Apperception Test and subsidiarity with analysis of the content of their stories. Section IV deals with temperamental differences, particularly with regard to speed of performance, on the Porteus Mazes. Experiments are reported in Section V which were designed to determine the effect of distraction and of electroconvulsive therapy on Maze performance in general and on psychomotor retardation in particular. Section VI interrelates the results reported in the preceding Sections and shows that there are significant though relatively low, correlations between the speeds of performance on the tests used. The main concern has, however, been with the significance of the findings for diagnostic and psychodynamic purposes rather than with the existence or non-existence of a general speed factor. Section VII contains a general summary together with the main conclusions to be drawn from the investigation.

The treatments involved in cancers of the blood and bone marrow can be physically and psychologically challenging and be associated with adverse secondary effects, including cognitive impairment. The incidence and severity of treatment-related cognitive impairment varies widely, however it can significantly impact quality of life by interfering with patients’ activities of daily living, relationships and future plans. It can also pose challenges for the patients’ caregivers, an area which has received comparatively less research attention. The aim of this study was to investigate caregivers’ experiences of treatment-related cognitive impairment in patients who have undergone Haematopoietic Stem Cell Transplant (HSCT); how they coped, both practically and emotionally, and what supports they believe could help them. Participants were caregivers to individuals who had undergone HSCT within the past 20 years and who had reported cognitive changes at the HSCT Late Effects Clinic, Beatson West of Scotland Cancer Centre. Five participants completed a single semi-structured interview. The data was then analysed using Interpretative Phenomenological Analysis (IPA). Results of this analysis illustrated four super-ordinate themes: noticing change; managing expectations, managing personal feelings and commitment. Findings from the current study highlighted the importance of caregiver education regarding post HSCT cognitive and behavioural changes and providing caregiver emotional support. Future research should explore the mutual needs of both care recipient and caregiver.

To increase the high frequency speech information available to the sensory-neural deaf, with low-frequency residual hearing only, a frequency "recoding" device was constructed which "shifts" a selected band of high frequency speech information and superimposes it on the low frequency range, in a manner designed to maintain the 'speechlike' nature of the "recoded" input signal (patent applied for). The design and evaluation of the "recoding" device are considered in the context of factors likely to be involved in the acquisition of "recoded" speech, e.g. the separation of sounds that are ' speechlike' from those that are not, by the ear-brain system, the interaction in speech processing of auditory, visual and kinaesthetic cues, and the influence of already established strategies for processing "non-recoded" speech on the acquisition of altered strategies for "recoded" speech. The 'speechlike' nature and the utility of the "recoding" were assessed (a) in a simulation study involving normal hearing subjects under simulated deafness conditions, and (b) in a validation study with sensory-neural deaf children. In the simulation study significant improvements in the ability to imitate CVC nonsense syllables were brought about both by "recoding" and by visual cues (from articulatory movements) without formal discrimination or3imitation training, the "recoded" high frequency information contributing in particular to imitation of "manner" and "place" of articulation of phonemes with major energy components in the "recoded" High Frequency region (HF phonemes). Further, in the validation study, "recoding" produced a significant improvement in the articulation learning of HF phonemes, indicating (together with the simulation study findings) that the "recoded" signals were sufficiently 'speechlike' to be of use to the ear-brain system in speech processing. It was concluded therefore that the generality of utility (to the hearing impaired) of the "recoding" mode proposed, merits serious further investigation.

Notre travail de thèse s’inscrit à la jonction de trois axes théoriques traditionnellement disjoints : la persuasion (Bromberg et Trognon, 2006 ; Girandola, 2003), l’engagement (Joule et Beauvois, 1998, 2002) et les représentations sociales (Moscovici, 1961). En situation de communication engageante, les individus réalisent un acte préparatoire avant de prendre connaissance d’un message à visée persuasive. En ce qui concerne le concept des représentations sociales, les chercheurs étudient les croyances communément partagées par les membres d’un groupe et leur structure. La théorie du noyau central (Abric, 1976) pose qu’une représentation sociale est composée de deux types d’éléments : centraux vs. périphériques. L’intérêt de ce rapprochement théorique est d'allier plusieurs champs théoriques traditionnellement disjoints dans le processus lié au changement d'attitude et de comportement. L’idée centrale de notre travail peut être posée en ces termes : dans quelle mesure une procédure de communication engageante peut-elle être optimisée en activant des éléments centraux d’une représentation sociale dans l’acte préparatoire et le message ? / Our thesis is at the junction of three traditionally separated theoretical axes : persuasion (Bromberg et Trognon, 2006 ; Girandola, 2003), engagement (Joule et Beauvois, 1998, 2002) and social representations (Moscovici, 1961).