A new study in the Journal of Communication links verbal aggression to prenatal testosterone exposure. The lead researcher, at University at Buffalo - The State University of New York, used the 2D:4D measure to predict verbal aggression. This study is the first to use this method to examine prenatal testosterone exposure as a determinant of a communication trait.
Allison Z. Shaw, University at Buffalo - The State University of New York, Michael R. Kotowski, University of Tennessee, and Franklin J. Boster and Timothy R. Levine, Michigan State University, predicted that a neuroendocrine factor, prenatal testosterone, would lead to more verbal aggression. In order to investigate this, Shaw and colleagues used the 2D:4D measure, which is the ratio of the length of the second digit (index finger) to the length of the fourth digit (ring finger), to measure prenatal testosterone exposure. This method involved measuring each finger from where it meets the palm of the hand to the tip. In addition, each hand was photocopied individually with the palm flat, facing downward, with the fingers splayed naturally, and the same measures were made from the photocopy. Subjects then filled out the Verbal Aggression scale as well as the HEXACO Personality Inventory and the Argumentativeness scale.
The findings suggested that both men and women with smaller 2D:4D ratios self-reported themselves to be more verbally aggressive. Although a small degree of verbal aggression may be beneficial for a person (e.g., being able to stand up for yourself if attacked), higher degrees of verbal aggression have been shown to be detrimental to one's personal life (e.g., problems maintaining close personal relationships, loss of job).