Prospective memory (PM) refers to remembering to remember and is essential for everyday living. Although recent research has focused upon PM deficits associated with recreational drug use, very little research to date has focused on smoking and PM. This thesis had four aims. Firstly, to verify whether PM deficits are associated with prolonged smoking could be replicated. Secondly, to observe whether such smoking-related deficits extended to objective measures of PM. Thirdly, to assess what effect, if any, abstinence from smoking had upon PM. Fourthly, to ascertain whether there was any difference in PM performance between regular (daily) smokers and social (binge) smokers. Participants were drawn primarily from undergraduates in North East universities. Studies 1–3 in this thesis studied self-reports and objective measures of PM in smokers, previous smokers and non-smokers. Across all three studies no consistent findings were observed on self-reported PM reflecting deficits associated with smoking, but smokers performed worse on the objective measures of PM than non-smokers, with previous smokers falling between the other two groups – suggesting that smokers’ PM is impaired and that those who stopped smoking appeared to recover a proportion of their PM function. Study 4 revealed smokers’ poor performance on objective tasks was not confounded by their being in a state of withdrawal. Studies 5 and 6 explored whether any difference was observed between ‘social’ (binge) smokers and ‘regular’ (daily) smokers on PM performance. Studies 5 and 6 found no difference between social and regular smokers on a video-based, nor a real-world PM task. Overall, it was concluded that self-reports of PM do not provide consistent findings (first aim), lowered PM performance on objective measures are associated with prolonged smoking (second aim), previous smokers show some recovery of PM function (third aim) and that the pattern of smoking does not affect PM performance in smokers’ (fourth aim).

The introduction to this thesis outlines the evolutionary theory of human mating behaviour and describes the process of vocal production and auditory perception in humans. In addition it provides a brief overview of some of the research studies examining the role of vocalisations in courtship and competitive behaviours in animals. The body of this thesis is then divided into three parts. Part 1 examined whether male vocal frequencies may be an honest signal of physical attributes such as body size, body shape and hormonal quality. Results of Study 1 found that fundamental frequency but not formant dispersion was related to age. The voices of younger (but post-pubertal) males had lower fundamental frequency. Furthermore, fundamental frequency was significantly negatively associated with shoulder and chest circumferences, shoulder-hip-ratio and body weight. A significant negative relationship was also found between formant dispersion and both weight and height and some measures of body shape. Study 2a and 2b then found evidence of a relationship between fundamental frequency and circulating testosterone in adult males with some evidence for diurnal variation in fundamental frequency (reflecting alterations in testosterone). Some limited evidence of a relationship between formant dispersion and circulating testosterone was also found. No relationship between prenatal testosterone or cortisol and vocal frequencies was observed. The second part of this thesis explored the role of the male voice in both inter and intra sexual selection. Study 3 examined perceptions of male voices by male listeners. Results revealed that the judgements made by male listeners concerning the age and physique of male speakers were broadly consistent with the relationships observed between physical characteristics and vocal frequencies in Study 1. Results also suggested that formant frequencies and not fundamental frequency indicate the dominance of a speaker but that both vocal parameters inform judgements that male listeners make about the attractiveness of male speakers to females. Study 4 examined perceptions of male voices by female listeners. Results suggest that both fundamental and formant frequencies influence judgements of attractiveness and dominance. In addition the relationship between visual and vocal attractiveness and dominance was examined. No relationship was observed between visual and vocal attractiveness although there was a significant relationship between visual and vocal dominance. The final section of this thesis examined the relative importance of the voice in comparison to the face within the context of attraction and dominance. Results of two studies suggest that vocal and visual attractiveness and dominance may not be related and that the relative importance of facial and vocal cues depends upon the judgement being made. The face appears to have a greater influence on attractiveness judgements but the voice appears to have a greater influence on judgements of dominance. The results of the studies reported in this thesis are discussed in relation to the findings of other researchers in the field which together provide evidence that the five criteria for sexual selection of communication signals (Snowden, 2004) are met by the deep voice of the human male.

While it is certainly true that children - and adults - with learning disabilities have become more visible within society, we still have inadequate knowledge of people's understanding of learning disability. In particular, there is little or no information about the development of understanding among siblings of children with learning disabilities. The five studies presented here seek to provide relevant information. The first study forms part of a longitudinal investigation of siblings' conceptions (a) of their brothers' and sisters' disabilities; and (b) of the implications of these disabilities upon themselves and their disabled brothers and sisters. The next three studies compare (a) understanding of learning disability; (b) perceived social acceptability of children with learning disabilities; and (c) attainment of the normative concept of ability, amongst the siblings of children with severe and profound disabilities, children who have contact with others with disabilities in school and children who have no contact. These three studies identify children as young as 4 who are able to predict the difficulties that will be experienced by a child with severe learning disabilities, and children as young as 5 who can use adult-type explanations for why these difficulties occur. Having an older brother or sister with a learning disability promotes understanding. It is suggested that children's social experiences, - particularly language - facilitate early understanding, and that children who possess greater understanding of a disabled child's difficulties are consequently more likely to rate this child as having lower perceived social acceptability. The findings from these studies may help families and teachers who are concerned about young children's understanding and acceptance of other children with learning disabilities. The final study considers the adult general public's understanding of learning disability and was conducted in order that investigation with children could be considered within the context of adults' understanding.

The omega-3 polyunsaturated fatty acids (n-3 PUFAs) are a unique class of fatty acids that cannot be manufactured by the body, and must be acquired via dietary sources. In the UK, as well as in other Western nations, these ‘essential’ fatty acids are consumed in quantities that fall below government guidelines. This thesis examined the relationship between n-3 PUFAs and cognitive function and mood in healthy children (8-10 years) and adults (18-35 years), with a view to evaluate their efficacy for cognitive and mood enhancement in these populations. A second aim was to evaluate the effects of n-3 PUFAs on cerebral hemodynamics, a novel line of enquiry. Chapters 2 and 4 describe novel intervention studies that assessed the effects of n- 3 PUFA supplements on cognitive function and mood in healthy children and adults, respectively. In Chapter 3, the relationship between peripheral PUFA concentrations, a correlate of dietary PUFA intake, and cognitive and function and mood was examined for the first time in healthy adults. Chapter 5 describes a pilot trial in which Near Infrared Spectroscopy (NIRS) imaging technique was applied to investigate the cerebral hemodynamic effects of n-3 PUFA supplements. The results of this study were explored in more detail in Chapter 6, with the additional inclusion of parallel cognitive measures. Most notably, the behavioural data from the intervention studies described herein do not support the use of n-3 PUFA supplements for cognitive and mood enhancement in healthy children and adults not consuming appreciable amounts of oily fish. However, the results do suggest that supplementation with dietary n-3 PUFAs has an impact on peripheral fatty acid status and cerebral hemodynamics in healthy adults. Taken together, these findings suggest that, in healthy, cognitively intact individuals, short-term use of n-3 PUFA supplements has a minimal effect on behaviour; the impact of long-term n-3 PUFA dietary intake or supplement use over the course of the entire lifespan on behaviour should be addressed further.

Remembering to perform an intended task at the appropriate time (prospective memory) is an important aspect of memory functioning in the real world. Previous research has suggested that recreational drug use has a detrimental effect upon this ability. To date relatively few studies have investigated the effect of cannabis use on prospective memory performance. In addressing this hiatus, the present thesis extended this initial research to encompass three aims. Firstly, the thesis evaluated the psychometric properties of an objective prospective memory video procedure in order to mitigate criticisms associated with the use of self-report assessment of memory failures in many of these initial studies. Secondly, the thesis documents a series of quasi-experimental studies comparing cannabis users and non-users in order to examine the effect of cannabis use on prospective memory. Finally, the thesis explored the nature of the deficits observed in an attempt to better understand the neurobiological vulnerability of the cognitive processes underpinning prospective memory to the psychopharmacological effects of cannabis. The findings across all of the studies documented suggested that cannabis use, even in relatively light users with short duration of use, has a detrimental effect on prospective memory in young adults. In addition, the findings presented suggested that the deficits observed in current cannabis users recover on cessation of cannabis use and that time-based prospective memory was more vulnerable to the effects of cannabis use than event-based prospective memory. Furthermore, the findings presented suggested that these deficits arise as a consequence of problems in retrieval of the intentions rather than problems in their encoding and that these retrieval problems arise as a consequence of failures in cue identification rather than problems retrieving the task to be performed. The findings presented found no evidence that the prospective memory deficits observed were related to the number of joints smoked per week, duration of use, estimated lifetime consumption or to the age at which cannabis use commenced. Although the scale of the deficits appeared trivial with cannabis users recalling, on average, only two items fewer than nonusers, the magnitude of the effect was moderate suggesting practical significance, particularly as the deficits were observed in independent cohorts comprising cannabis users with light use and relatively short duration of use.

The polyphenol trans-resveratrol interacts with a number of mechanisms relevant to brain function and has demonstrated preserved and enhanced cognitive function in animal models as a result. Two of these mechanisms also suggest that resveratrol may be capable of acute cognitive enhancement: firstly via nitric oxide (NO)-mediated vasodilation leading to increased cerebral blood flow (CBF) and, in turn, increased neural access to the metabolic substrates oxygen and glucose; and secondly via enhanced mitochondrial oxidative phosphorylation which would be expected to increase the utilization of this enhanced provision of neural fuel. To date, research has yet to investigate the potentially CBF and cognitive enhancing effects of resveratrol in humans. This thesis aimed to redress this paucity and reports the findings from five placebo-controlled, double-blind, multiple-dose, acute and chronic resveratrol supplementation studies; all conducted in young, healthy human volunteers. Throughout this programme of studies the novel neuroimaging technique near-infrared spectroscopy (NIRS) has been utilized to monitor the effects of resveratrol on CBF in the prefrontal cortex. The cognitively demanding tasks utilized to assess cognitive function are all predominantly sub-served by this region of the brain. The consistent finding emerging from this thesis is that, acutely, resveratrol is a potent enhancer of the natural demand-driven increase in CBF and, in support of the hypothesis, also evinces significant enhancement of oxygen utilization. The lack of strong, replicable cognitive effects of resveratrol in this thesis however, suggests that resveratrol is not able to translate this increased access and utilization of metabolic substrates into improved cognitive performance in healthy, young adults.

The Spielman 3P and Cano-Saper models of insomnia focus on the role of stress in the development of insomnia. To date, the impact of both naturalistic stressors and experimental stressors upon sleep have been inconsistent, due to limitations including the varied nature of the stressor, the diverse nature of participants and the lack of standardised experimental protocols for measuring stress and sleep. In addition, previous research has tended not to include an objective marker of stress, and thus cannot confirm that the stressor employed reliably elicits physiological stress. This thesis aimed to examine the effects of stress upon sleep, firstly developing and testing a standard protocol to measure both subjective and objective stress and sleep in the same context. Cortisol, specifically the cortisol awakening response (CAR), was measured as a physiological marker of hypothalamic-pituitary-adrenal (HPA) axis activity and objective sleep was measured using polysomnography. The protocol was used in an experiment to examine the impact of anticipation on sleep and stress, and then tease apart the impact of anticipation and anticipation coupled with demand, on sleep and the CAR. The results of the thesis indicate that anticipation of stress alone is sufficient to disrupt subjective sleep, when teased apart from demand. The results of the thesis also indicate that the CAR is a marker of anticipation and with a potential secondary role as a marker of recovery. Theoretically, the thesis indicates that the precipitating dimension within the Spielman 3P model occurs irrespective of whether the stressor is anticipated or actual.

In everyday life both adults and children are faced with the problem of judging who owns an object. Past research has indicated that adults and children may base their decisions on who was seen possessing an object first (the first possessor bias) or the person with whom an initial visual association was created. The current thesis aimed to investigate this, and ascertain whether children and adults maintain their bias to choose the first possessor of an object as its owner when other competing information regarding ownership is available. Chapters 2 and 3 used between subjects factorial designs in which adults (aged 18-60) and children (aged 3-4 years) viewed a number of stories of characters possessing objects in a variety of different scenarios. After viewing each story participants were required to judge which character owned the object. Results showed that when adults and children had no information, other than who possessed an object first, they chose the first possessor as the owner of the object. However when other competing information, such as the gender or age stereotype of the object, or who had constructive possession of the object, was available both adults and children disregarded their first possessor bias and made decisions in line with this other information. Chapter 4 used a between subjects factorial design and a mixed factorial design. The aim of the experiments was to ascertain whether adults and children take the history of an object into account when deciding who owns an object. Adults (aged 18-60) and children (aged 3-4 years) were shown stories in which one character wore and object and another character held an object. Information was given to help participants infer the history of each of the objects in the stories. Following each story participants were asked to judge who owned the object. Results demonstrated that both adults and children take the history of an object into account in their ownership decisions, and privilege this information above other competing information such as visual association, but that adults do this more reliably than children. All the experiments in this thesis demonstrated that when there is no other information available both adults and children base their decisions on who was seen possessing an object first. However when other information is available both adults and children take this into account in their decisions. Adults and children may use the information in order to reconstruct the history of an object to ascertain who had contact with it in the past and therefore who may have a legitimate claim of ownership over it.

Background: The psychological wellbeing of individuals may be disrupted through experiencing periods of elevated mood, known as mania. Identifying processes which may be used to predict the onset of mania may be helpful in the development of more specialised psychological interventions. The research explores the cognitive processes which may contribute to the development of elevated mood episodes. Methods: The research addresses this question through a review of the literature which is used to inform the current investigation. The study considers how coping style and attachment style may be used to predict the onset of elevated mood in undergraduate and postgraduate university students (n=100). Participants completed the Relationship Questionnaire (RQ; Bartholomew and Horowitz, 1991), the Brief COPE (Carver, 1997) and the Goldberg Mania Questionnaire (GMQ: Goldberg, 1993). Regression analyses were conducted to explore the data. The reflective paper highlights some of the methodological limitations, clinical implications and ethical considerations of the study. Results: The literature review revealed that cognitions such as positive rumination, specific beliefs about the self and a positive cognitive style were implicated in the development of manic experiences. The empirical study found that a preoccupied attachment style, and coping strategies of denial distraction and humour were significant predictors of elevated mood. Discussion: The clinical implications regarding how the results may inform clinical practice through psychological interventions such as cognitive behavioural therapy are discussed. Limitations included the cross sectional design methodology, the use of online questionnaires and difficulties in generalisation. Conclusions: Attachment style and coping strategies may be used to predict the onset of elevated moods. This may be useful for the development of new psychological interventions in mania. The thesis provides further clarification regarding psychological factors involved in the development of mania and identifies possible new areas for further exploration.

Post-traumatic growth refers to the positive changes people can experience after a traumatic event, because of highly stressful life circumstances. Changes attributed to post-traumatic growth include changes in life philosophy, personal growth and more meaningful relationships. The person closest to an individual is often their partner, and whilst something is known about post-traumatic growth after a spinal cord injury, the experiences of partners of people with spinal cord injury are much less researched. This project aims to gain insight of the experience of post-traumatic growth for non-injured partners. The literature review focuses on the experiences of post-traumatic growth when a partner has had a spinal cord injury. Published articles were identified, searched and critically appraised. The following themes emerged: burden of care, coping strategies, time for self and independence, communication, support, better relationships and leisure. The review highlighted a gap in the evidence base regarding the experiences of post-traumatic growth in partners of people who have had a spinal cord injury. The empirical paper investigates this phenomenon. A qualitative methodology analysis, using interpretative phenomenological analysis (IPA), was conducted in order to explore the experiences of post-traumatic growth in partners of people who have experienced spinal cord injury. The themes were identified from an analysis of partner interviews. The implications for clinical practice are discussed. Finally, the reflective review presents the researcher’s experience of the research project throughout the process. The author offers a reflective account of the research journey, and discusses the issues that arose relating to ethics, confidentiality and power differentials.