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Background: Research concerning sexual selection suggests that ornaments and traits convey information that is valuable to observers when making decisions based on adaptive problems. In the animal kingdom males perform dynamic courtship displays and females assess such displays when choosing a mate. In humans however this avenue of research is in its infancy but an emerging field of study has sought to find out if dance movements, which are thought to be courtship displays, provide observers with condition dependent information. Objectives: i) To create a methodology that records dance movements with high accuracy whilst eliminating structural cues known to influence mate choice decisions while maintaining a highly realistic human form. ii) Use this methodology to assess whether traits of interest (health, fitness, strength and age) can be detected by observers. iii) To establish if particular movements are mediating perceptions of dance quality and their condition. Methods: A cutting edge motion capture system and professional animation software was used to record dances. Each male dancer either provided information on his health status, physical fitness, strength or age. Dance animations were shown to observers and their perceptions were correlated against the traits of interest. These were also correlated against basic biomechanical characteristics to establish possible mediators. Results: It was revealed that whilst health measures were not related to dance ratings, strength measures were and these perceptions were mediated by movements of the upper body. A final study found that age was detectable by male participants and related to masculinity ratings of female raters but no biomechanical mediators were found. Conclusion: Men and women are able to derive certain quality cues from observing male dance and in some instances biomechanical characteristics mediated this relationship. This provides evidence that dance may be used in the assessment of males in the context of sexual selection.

Background and Objectives: Literature from a number of domains suggests that intrasexual selection has been a strong mechanism in shaping men's traits and behaviour. Due to the physical conflict that men have historically engaged in with each other, it is theorised that we have developed cognitive mechanisms to assess physical dominance from a variety of cues. The aims of this thesis are to understand how physical dominance is encoded into the walking gait of men, and investigate how observers decode these cues. Design: All studies were quantitative and contained two stages, a stimuli creation and ratings of the stimuli. Stimuli creation utilised motion capture techniques to gather movement in a precise and digitised way. This involved placing 39 retroreflective markers on the major joints of the body to capture each body segment with six degrees of freedom. These were transformed into featureless avatars using professional animation software to ensure that anthropometric or other visual features (e.g., build, weight, hair, clothing) were not on display. Methods: Stimuli was presented to participants across four studies to rate on physical dominance and likelihood of crossing the road to avoid the man. Results: It was found that ratings of physical dominance had a consistent link with the strength and physical size of the man, where stronger and physically larger men were rated higher in physical dominance and were more likely to be avoided if they approached the observer on a dark night. Preliminary biomechanical analyses suggests that a pendulum like movement between the mid-hip and mid-back strongly increased perceptions of physical dominance. Participants were also able to differentiate between baseline and threatening walks in studies three and four, suggesting that men alter their movements when confronting an opponent. Conclusion: Overall, the findings suggest that men alter their movement when acting in a threatening manner, their build is clearly encoded into their gait, and the amount of swing in their motion may be a key factor in observer's perceptions of their dominance. Together, this thesis provides vital new knowledge into our understanding of how men have evolved to display physical dominance and that we can decode these cues and take action.

The current project explores the nature of embodiment, specifically how affective associations of physical posture interact with emotion in language. Previous research has established that perceptual and motor information is encoded alongside semantic representation, and physical feedback is used to support cognition. Evidence suggests that emotion is also embodied. Muscle feedback from the face is used to support recognition of valence in language. Observational studies also show that open and slumped body posture are associated with positive and negative emotion, respectively. However, little research investigates experimentally induced posture. Additionally, research typically employs self-referent and autobiographical language with little consideration for experimental control over language stimuli. The current projects makes important steps toward developing and validating controlled linguistic materials for emotion research. Further, the project aims to extend previously observed facilitation from facial feedback to the full body. Three repeated measures experiments compared the effects of open and slumped posture on three cognitive measures: explicit recognition of valence from sentences, memory of affective details from sentences, and memory from text. Results indicate that positive, but not negative or neutral sentences are susceptible to the influence of posture. Interestingly, explicit processing of emotion, i.e., recognising valence, was inhibited by open posture, while implicit access during the memory task revealed the classic facilitation effects proposed by embodiment research. Body feedback did not affect comprehension and memory from full text. These results are discussed in relation to three main claims. First, embodiment of emotion is observable in sentence processing, although potentially limited to specific valence types. Second, explicit and implicit processes require different levels of activation, and implicit, automatic access that does not involve conscious awareness of the emotive content is more reflective of the neural priming effects proposed by embodiment models. Third, the linguistic and conceptual complexity of longer text formats preclude embodied effects due to increased confounds from visual imagery, metaphor and other processes that do involve perceptual and sensory information, but not internal bodily feedback, and are thus not susceptible to the posture manipulations employed here. Finally, implications for future research involve continued validation and refinement of the language materials used for emotion research, with additional consideration for concreteness and imagery ratings, as well as embodied properties on the word level. Research should also consider exploring the bidirectional interplay between language and posture further.

Autism is a lifelong developmental condition, diagnosed on the basis of persistent social communication deficits and repetitive, restrictive patterns of behaviour. Autistic people form a heterogenous group, but many experience challenges compared to non-autistic people. Identifying and diagnosing autistic people can be beneficial in helping them to better understand themselves, and to access support and interventions. Not all autistic people are diagnosed however, and one group which is disproportionately affected is people with learning disability. Screening tools have the potential to facilitate and speed up diagnosis by highlighting those who should be assessed in more detail. Many existing screening tools are largely inaccessible to people with learning disability due to the level of language required to complete them. The overall aim of the thesis is to facilitate the diagnosis and support of people with autism, in particular those with learning disability, by developing more accessible screening tools. Chapter One provides an overview of the main issues to consider in the screening and diagnosis of autism, in those with and without learning disability. Chapter Two outlines the adaption of the Autism- Spectrum Quotient (AQ), with the aim of developing a more accessible version (AccAQ). The language of the AQ is simplified, and line drawings are added to enhance understanding. The results indicate that the original AQ and the adapted versions are equivalent in many ways, but the AccAQ still requires the person completing it to have some verbal communication, comprehension, and literacy skills. Chapter Three reports on a systematic review into the psychometric properties of autism screening tools used with people with learning disability. The review found that the majority of tools were lacking comprehensive validity and reliability data, were not specifically designed for use with people with learning disability, and required the input of an informant. Chapters Four to Six discuss the development of a new autism screening tool, which was designed specifically for people with learning disability and does not require the input of a third-party informant. Chapter Four reports on the results of interviews with stakeholders about the current autism diagnostic pathway, the role of screening as a part of the diagnostic process and the properties that would be desirable in a new screening tool to ensure it is both accessible and useful. Overall, this study highlighted the need for such a tool to have good psychometric properties, be clinically useful, user friendly, cost-effective, and minimize demands on users and those being screened. Chapter Five explored the literature that provided a theoretical basis for the inclusion of particular items within a behavioural screening tool. These are items that will prompt reactions which are indicative of the presence or absence of autistic traits: the concepts of empathy, mimicry, and contagion. These ideas are operationalised in a series of pilot studies which use existing video clips as stimuli and ask participants to self-report their responses to the videos. The results of a machine learning analysis, using cforest, showed that the self-reported responses were broadly predictive of the person's AQ score and provided proof of concept of the idea of a behavioural screening tool. Chapter Six extended this work. Here a set of custom stimuli were created and were viewed by autistic and non-autistic participants, with and without learning disability. Their reactions to these were self-reported and video recorded, and subsequently coded. The results indicated that, while scores on the behavioural screen could not discriminate between autistic and non-autistic participants, or predict self-reported AQ score, they did predict informant AQ scores. Overall, the thesis makes a novel and significant contribution to the literature by identifying tools which are currently available to screen for autism in people with learning disability, alongside adapting the AQ to be more accessible to a wider range of people. It provides proof of concept for a behavioural screening tool for autism, which is specifically designed for people with learning disability, that integrates stakeholder views and theoretical literature during its initial development and testing.