Digit ratio: A Pointer to Fertility, Behavior and Health

Digit Ratio: A Pointer to Fertility, Behavior and Health

Book Review:

Digit Ratio: A Pointer to Fertility, Behavior and Health – author: John T. Manning

Publisher: Rutgers University Press 2002

Review by Michael Mills, Psychology Department, Los Angeles.

Michael Mills writes about John Manning’s book Digit Ratio:

“Take a look at your right-hand. Which of your fingers is longer: your ring finger, or your index finger? Surprisingly, a passing stranger who noticed a difference in length between these two fingers (and who had handy a copy of John Manning’s book Digit Ratio: A Pointer to Fertility, Behavior and Health) might infer some very personal characteristics about you. With no more data than that gleaned from a passing glance at your hands, a stranger might infer whether you are likely to have homosexual inclinations, are highly fertile, may eventually suffer from a heart attack or breast cancer, have musical aptitude or sporting prowess, and a surprisingly long list of other characteristics.

…Females typically have index and ring fingers of about the same length. The ratio of index finger length to ring finger length is called the “2D:4D digit ratio,” or more simply, the “digit ratio.” Manning reports that, for males, the index finger is generally about 96 percent of the length of the ring finger, which gives an average digit ratio for males of .96.

…Manning devotes separate chapters to explore the relationship between digit ratio and a variety of characteristics, including assertiveness and attractiveness (chapter 3), reproductive success (chapter 4), hand preference, verbal fluency, autism, and depression (chapter 5), health and disease (chapter 6), homosexuality (chapter 7), musical aptitude (chapter 8 ) and sports aptitude (chapter 9). A brief summary Manning’s findings (some of which he notes are quite preliminary) is presented in the table below.”

 

Low 2D:4D ratio

High 2D:4D ratio

Males

* More fertile
* Higher lifetime reproductive success
* More aggressive and assertive
* Greater proclivity toward homosexuality/bisexuality
* Higher musical and sports aptitude
* Lower SES (?)

* Higher risk of early heart disease

Females

* Greater proclivity toward homosexuality/bisexuality
* More aggressive and assertive

* More fertile
* Higher lifetime reproductive success
* Higher risk of breast cancer

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