Friday, January 29, 2010

Digital Success: Finger Length and Athletic Prowess

Talent identification in youth sports is often more of an art than a science. Researchers and coaches continually debate what markers indicate natural talent for a particular sport. Factors such as genetics and anatomy are thought to determine potential ability. A newly published research review now argues that something as simple as finger lengths may predict athletic prowess. As it turns out, the relative lengths of the index and ring finger may be a marker of natural ability. Individuals with longer ring fingers may be more gifted athletes.

The relationship between the ring finger and index finger length is called the 2D:4D ratio. The 2D:4D ratio is calculated by dividing the length of the index finger (2nd digit) by the length of the ring finger (4th digit). Researchers often measure the palm side, taking the distance from the crease nearest to the palm to the tip of the finger (see Figure 1). For most, this ratio is 1.0 (they are the same length). However, this ratio can range from about 1.05 (longer index finger) to 0.85 (longer ring finger).

Researchers form England and Germany performed a meta-analysis of more than 20 studies that focused on the link between 2D:4D ratio and various sports and performances. For the most part, research shows that individuals with smaller the ratios tend to have greater athletic prowess. That is, those with longer ring fingers are more often the better athletes. The relationship seems to be stronger for endurance athletes and weaker for sprint, power and strength athletes. For example, the 2D:4D correlates better with 10k race performance than with 50m sprint time.

Three of the studies reviewed focused on the abilities of soccer players. Two studies showed that English professional players competing at the highest levels have lower 2D:4D ratio than lower division players and non-athletes (see Figure 2). Another study reported this ratio was linked to talent rated by the players and by others. Thus, there seems to be some relationship between the 2D:4D ratio and soccer ability.

The reasons for these relationships are not completely clear. Many feel that the 2D:4D ratio is a marker of pre-natal testosterone. That is, how much testosterone the fetus is exposed to in the womb may affect the finger length ratio. It may also influence a number of physical characteristics such as cardiovascular capacity. So, there may actually be a biological explanation for the relationship between the 2D:4D ratio and athletic prowess.

However, before coaches put the measuring tape to their players’ hands, there are some important considerations. While researchers have shown a correlation between finger length and physical performance, the relationship is not overly strong. On average, the 2D:4D ratio accounts for around 6% of the variation in athletic prowess. In soccer, it’s probably even less. Also, the ability to predict success using this ratio is debatable. In an interview article, a prominent researcher suggests that while 2D:4D ratio may be useful to identify natural talent, especially in sports that rely on endurance, there are some limitations. He is quick to point out that the finger ratio is a “probabilistic” indicator and that there are many other factors that determining success. Simply having a relatively long ring finger doesn’t necessarily guarantee either talent or success. Many, many other factors play very important roles in the development of these characteristics.

Hönekopp J, Schuster M (2010) A meta-analysis on 2D:4D and athletic prowess: Substantial relationships but neither hand out predicts the other. Personality and Individual Differences, 48:4-10.

Manning JT, Taylor RP (2001) Second and fourth digit ratio and male ability in sport: implications for sexual selection in humans.Evolution and Human Behavior, 22:61-69.