Feature

The mismeasure of hands?

See allHide authors and affiliations

Science  07 Jun 2019:
Vol. 364, Issue 6444, pp. 923-925
DOI: 10.1126/science.364.6444.923

eLetters is an online forum for ongoing peer review. Submission of eLetters are open to all. eLetters are not edited, proofread, or indexed.  Please read our Terms of Service before submitting your own eLetter.

Compose eLetter

Plain text

  • Plain text
    No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Author Information
First or given name, e.g. 'Peter'.
Your last, or family, name, e.g. 'MacMoody'.
Your email address, e.g. higgs-boson@gmail.com
Your role and/or occupation, e.g. 'Orthopedic Surgeon'.
Your organization or institution (if applicable), e.g. 'Royal Free Hospital'.
Statement of Competing Interests
CAPTCHA

This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.

Image CAPTCHA
Enter the characters shown in the image.

Vertical Tabs

  • Some Questions About the Replicability and Practical Applications of Digit Ratio (2D:4D) Research
    • Gareth Richards, Teaching Fellow, School of Psychology, Newcastle University

    Leslie (1) makes clear that the 2D:4D literature is characterised by inconsistent findings and replication failures. The problem is arguably worse: questions concerning validity remain (2), and the field does not yet agree on what is the best measure of the ratio. As well as right hand and left hand 2D:4D, the average of these is sometimes used, as is directional asymmetry (i.e. the right-left difference) (3, 4). Studies typically use more than one predictor and report subgroup analyses, yet rarely correct for alpha inflation. To illustrate this problem: if right hand and left hand 2D:4D are examined in relation to just one outcome in males and females separately, there is a 20% chance of observing a spurious effect (i.e. Type 1 error) at p < 0.05. This issue is of course magnified when studies assess multiple outcome variables.

    Additionally, a fundamental question must be asked: what should be considered a successful replication in this field? For instance, if one study reports a correlation with right hand 2D:4D then another observes a similar correlation for the left hand, should the latter be considered a replication of the former? If yes, then an unrealistic picture of consistency may be painted. A related issue is how to interpret null-findings alongside significant effects. For example, a frequently cited study (5) reported a correlation between right hand 2D:4D and the testosterone/estradiol ratio in amniotic fluid; no such effect was observed fo...

    Show More
    Competing Interests: None declared.