A Correlational Study on the Relationship Between 2D:4D Ratio and Mood Change

ABSTRACT A CORRELATIONAL STUDY ON THE RELATIONSHIP BETWEEN 2D:4D RATIO AND MOOD CHANGE by Donald Robert Rickgauer Master of Arts in Psychology: Psychological Science Option California State University, Chico Spring 2010 The ratio of the length of the index finger and the ring finger has been found to be correlated with numerous behavioral phenotypes associated with prenatal testosterone exposure. In the present study, we examined the relationship between this ratio (2D:4D) and emotional arousal, as measured using the Positive and Negative Affect Scale (PANAS), in a competitive setting. For this study, 125 participants had their finger lengths measured and participated in a competitive video game, Soul Caliber 2. Their state affect was recorded by self-report inventory both before and after playing the game. Results showed a significant change in positive affect after playing the game. The valence of this change was found to be statistically correlated with the 2D:4D ratio of the right hand for both males and females. Those with neutral ratios (the middle third of the data) exhibited the greatest change, while those with masculine- and feminine- typical xi ratios (the bottom and top thirds of the data, respectively) exhibited less change in positive affect. It is proposed that higher levels of prenatal testosterone or estrogen exposure may act as a balancing factor in mood around competitive settings, while those whose 2D:4D ratio does not indicate this kind of exposure have higher reactivity to competition.