Thesis Summary This thesis comprises of seven experimental chapters which demonstrate the ability for naïve observers to accurately distinguish between facial stimuli of individuals scoring high on measures of neuropsychiatric disorders such as depression, borderline and schizotypal personality disorders and autistic spectrum disorder. In the case of depression this ability was still apparent even when the stimuli was reduced to show just the eye and brow region. The findings that observers are able to accurately discriminate between this stimuli furthers the vast literature of face research, demonstrating that this simple stimuli can be used to discriminate traits previously only assessed using thin-slice video stimuli. In addition to this within each study observers were asked to make inferences about socially desirable personality traits, assessed using the big five personality traits. A consistent, negative, personality-type was attributed to individuals with high symptoms levels - commonly consisting of high levels of Neuroticism combined with low levels of Agreeableness and Extraversion. This downgrading of desirable personality traits for individuals scoring highly for neuropsychiatric traits has potential social implications for individuals with these disorders. The traits these individuals are seen to be lower in have been shown to be important in the development and maintenance of successful social relationships, thus if individuals with neuropsychiatric disorders are perceived to be lower in these traits there is the potential that they are at a disadvantage during social interactions. The final section of the thesis looks to link these findings to existing theories of neuropsychiatric disorders. Results demonstrate a masculine facial appearance associated with males with symptoms of autism, supporting Baron-Cohen’s (2002) masculinity hypothesis, and findings that individuals with eating disorders and depression are perceived to be more feminine lend support to Badcock and Crespi’s (2008) diametric hypothesis. These studies highlight a perceptual continuum of gender underlying observations of individuals with neuropsychiatric disorders, where autism lies at the masculine end with attributions of positive personality traits and psychotic disorders are at the feminine end with attributions of negative personality traits. These findings can be associated with Todorov, Said, Engell and Oosterhof’s (2008) theory that perceptions of facial stimuli lie on a two dimensional continuum of trustworthiness and dominance (including assumptions of masculinity). This suggests that perceptions of neuropsychiatric disorders may be attributable to an underlying continuum of social desirability, reflecting the findings of a downgrading of personality traits to high scoring individuals. This thesis extends current facial research, demonstrating that a number of common neuropsychiatric disorders can be distinguished from very simple facial stimuli. Not only this, but a distinct pattern of negative personality traits are attributed to individuals with high levels of neuropsychiatric traits. These combined with the perceptions of gender and the stereotypes associated with these perceptions have potential implications for social interaction. That is, if individuals with neuropsychiatric traits are perceived to have personality traits correlated with negative social connotations, others may be less likely to interact with them, reinforcing some of the symptoms of these disorders