Kota, R. (2020). Theory of mind ability in opposite-sex twin females: The TTT hypothesis. The Young Researcher, 4 (1), 256-285. 

Abstract
This study researched the Twin Testosterone Transfer hypothesis, which predicts that “Female fetuses developing between two males [in the womb] tend to show masculinized … traits as adults ... due to the transfer of testosterone from male fetuses” (1). This study aimed to de- termine whether opposite-sex twin females had lower socio-cognitive ability as compared to single- ton females through the “Reading the Eyes Through the Mind Test” (RMET) test, which measures a form of social cognition known as “Theory of Mind”. Thus, the study tested the question, “Does the exposure to elevated levels of prenatal testosterone for opposite-sex twin females result in lower Theory of Mind ability?” Ultimately, the results showed that opposite-sex twin females have lower RMET scores, and therefore lower socio-cognitive ability than singleton females, thus validating the Twin Testosterone Transfer hypothesis.

Keywords: Twin Testosterone Transfer hypothesis, Theory of Mind, Social cognition, Opposite-sex twins.

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