Doctor of Philosophy (PhD)



Document Type



Schizotypy, a range of personality traits which confer liability for schizophrenia, is associated with significantly diminished social functioning and quality of life. Social dysfunction in all forms of schizotypy, including schizophrenia, is connected to blunted affect, or diminished expressivity, particularly facial expressions which are less frequent, intense, or long than typical. However, the mechanisms and treatments for blunted affect are, as yet, poorly understood and underdeveloped. In this project, two putative mechanisms of blunted affect were explored. The first involves cognitive load capacities, which are diminished in schizotypy, causing blunted affect – individuals do not have the cognitive resources to regulate their facial expressions in a socially productive way while managing competing demands (e.g., a dynamic social situation). The second pathway involves social motivation deficits, which are a characteristic trait of some forms of schizotypy, leading to fewer socially communicative expressions – essentially, individuals who are not socially motivated do not care to regulate their facial expressions. To maximize ecological validity, this study used an ambulatory assessment framework, where participants (N = 216, Mage = 19.68 , 76.9% women, 77.3% White) were asked to complete self- reports and cognitive tasks, as well as provide video of their facial expressions, while going about their daily lives. The two proposed mediators were modeled under an MSEM (multilevel structural equation modelling) framework to test the putative mechanisms for blunted affect. Contrary to hypotheses, metrics of expressivity were not related to self-reported negative schizotypy. Further, while metrics of expressivity suggesting blunted affect were related to decreased social motivation, they were also related, in a more tenuous fashion, to increased cognitive functioning. The results of this study suggest support for a more nuanced model of what blunted affect is – rather than a uniform decrease in expressivity, it may be a decrease in socially engaging and affiliative expressions. As well, these results provide preliminary evidence that in the moment social motivation is a pathway to blunted affect. Limitations to this study are reviewed, including technological difficulties and limitations to generalizability borne from the sample characteristics.



Committee Chair

Cohen, Alex