Konferens: 2nd international conference on driver distraction and inattention, 2011, Gothenburg, Sweden

This study investigates how gender and testosterone (as measured by the 2D:4D ratio) affects driving performance under distracting conditions. The 2D:4D ratio is a widely accepted marker for masculinisation through prenatal androgen exposure, in particular testosterone, such that, on average males have a lower ratio than females. Documented effects of testosterone include; decreased susceptibility to distraction, increased ability to focus attention, faster cognitive processing speed and reaction times. Simulated driving performance of young male and female drivers was examined, whilst they were actively distracted by conversational tasks that were either cognitive or emotional in content. The cognitive task involved answering mathematical and spelling questions and the emotional task involved discussing moral dilemmas. Under emotionally distracting conditions it was the gender of the drivers that determined the number of errors that were made, with female drivers making more errors than the male drivers, particularly in regard to maintaining lane position. However, under cognitively distracting conditions it was the 2D:4D ratio that was significantly correlated with driving errors, such that, the lower the ratio (i.e. higher exposure to prenatal testosterone) the fewer driving errors were made – this was most noticeable in regard to situations requiring a fast response to potential hazards. Significantly, these results relating to digit ratio were independent of the gender of the driver.