| In this study the genetic bases of expression of emotion was assessed by comparing similarity between monozygotic (MZ) twin pairs to dizygotic (DZ) twin pairs on a number of posed emotion tasks. This study was based on archival data, which was collected from 1979 to 1986 at the Department of Psychology and the Institute of Human Genetics at the University of Minnesota, Minneapolis.; This large-scale study involved a sample of twins and triplets who had been separated shortly after birth, reared apart, and reunited later in life. The Requested Facial Action Test (REFACT), an emotion task designed to assess different aspects of posed expression of emotion was administered to a small portion of the subjects who participated in this large study. The data for 27 MZ pairs and 19 DZ pairs were analyzed. The subjects ranged in age between 12 and 54 years (M = 38.01, SD = 10.14), were on average 5.34 months at the time of separation (SD = 8.44), with average age of 32 years (SD = 13) prior to the first reunion.; The REFACT task consisted of (1) Posing emotions; (2) Responding to questions regarding the posing of emotions; (3) Verbally requested bilateral facial actions; (4) Visually requested facial actions; and (5) verbally requested unilateral actions. Due to the limitations of this dissertation only a portion of this data was examined. Five hypotheses were examined, which proposed that MZ twin pairs would be more similar to one another compared to the DZ twins, in posed expression of emotions, intensity of posed emotions, amount of time taken to pose emotions, identification of the most difficult emotion to pose, and performance of "hard" visually requested facial actions.; The results of this study did not support the proposed hypotheses. A few significant findings (posed Anger) and nonsignificant effects in the predicted direction (posed Fear, posed expression across all emotions, and raising the inner corners of the eyebrows) were found, however, these findings were considered with caution.; The findings for this study were not consistent with the research conducted in the field of temperament and emotion. It was proposed that the lack of significant findings may be due to the fact that this study involved posed expressions of emotion rather than spontaneous expressions. Additionally, some methodological limitations may have also affected the results of this study. |
