The Role of Projection and Empathic Accuracy in Dyadic Perception between Older Twins

Dyadic perception between 108 older identical and same-sex fraternal twin pairs was examined using three different tasks: (i) an emotional sensitivity task, (ii) a Q-Sort rating of emotion-eliciting situations, and (iii) an assessment of each other’s personality traits. Idiographic analyses related judgements of self and co-twin within and between twins. Projection approached the reliability of the judgements and was significantly higher than both empathic accuracy and actual similarity, suggesting that the process of dyadic perception was mainly shaped by projection. Significant correlations between empathic accuracy and projection were caused by the similarity of the twins in self-judgements. Empathic accuracy was much weaker once projection was controlled, indicating that twins had used valid projection to improve accuracy. Similarity-controlled projection was still high and reflected the fact that the twins overestimated their similarity to a large extent. Contrary to expectation but consistent across the three tasks, identical and fraternal twins differed neither in levels of actual similarity, empathic accuracy and projection, nor in similarity-controlled empathic accuracy and projection.