Editing Digit ratio (section)

==Criticism==
The credibility of research into the relationship between digit ratios and traits has been subject to criticism for various reasons.

# Weaknesses in the statistical significance of numerous findings.<ref name="Voracek_2019">{{cite journal | vauthors = Voracek M, Kossmeier M, Tran US | title=Which Data to Meta-Analyze, and How? | journal=Zeitschrift für Psychologie | publisher=Hogrefe Publishing Group | volume=227 | issue=1 | year=2019 | issn=2190-8370 | doi=10.1027/2151-2604/a000357 | pages=64–82| s2cid=86788835 }}</ref><ref name="Jones_2021">{{cite journal | vauthors = Jones AL, Jaeger B, Schild C | title = No credible evidence for links between 2D:4D and COVID-19 outcomes: A probabilistic perspective on digit ratio, ACE variants, and national case fatalities | journal = Early Human Development | volume = 152 | pages = 105272 | date = January 2021 | pmid = 33227636 | pmc = 7670914 | doi = 10.1016/j.earlhumdev.2020.105272 | publisher = Elsevier BV }}</ref><ref name="Voracek Pietschnig Nader Stieger 2011 pp. 417–422">{{cite journal | vauthors = Voracek M, Pietschnig J, Nader IW, Stieger S | title=Digit ratio (2D:4D) and sex-role orientation: Further evidence and meta-analysis | url = https://archive.org/details/sim_personality-and-individual-differences_2011-09_51_4/page/417 | journal=Personality and Individual Differences | publisher=Elsevier BV | volume=51 | issue=4 | date= September 2011 | issn=0191-8869 | doi=10.1016/j.paid.2010.06.009 | pages=417–422}}</ref>
# Irreproducibility of findings in many instances, with some studies reporting contradictory results.<ref name="Hilgard_2019">{{cite journal | vauthors = Hilgard J, Engelhardt CR, Rouder JN, Segert IL, Bartholow BD | title = Null Effects of Game Violence, Game Difficulty, and 2D:4D Digit Ratio on Aggressive Behavior | journal = Psychological Science | volume = 30 | issue = 4 | pages = 606–616 | date = April 2019 | pmid = 30843758 | doi = 10.1177/0956797619829688 | publisher = SAGE Publications | s2cid = 73496727 }}</ref><ref name="Leslie_2019">{{cite journal | url=https://www.science.org/news/2019/06/talk-hand-scientists-try-debunk-idea-finger-length-can-reveal-personality-and-health | vauthors=Leslie M | title=Talk to the hand. Scientists try to debunk idea that finger length can reveal personality and health | journal=Science | year=2019 | doi=10.1126/science.aay2735 | s2cid=241187298 | access-date=1 October 2021 | archive-date=10 October 2021 | archive-url=https://web.archive.org/web/20211010065849/https://www.science.org/news/2019/06/talk-hand-scientists-try-debunk-idea-finger-length-can-reveal-personality-and-health | url-status=live | url-access=subscription }}</ref><ref name="Medland_2010">{{cite journal | vauthors = Medland SE, Zayats T, Glaser B, Nyholt DR, Gordon SD, Wright MJ, Montgomery GW, Campbell MJ, Henders AK, Timpson NJ, Peltonen L, Wolke D, Ring SM, Deloukas P, Martin NG, Smith GD, Evans DM | display-authors = 6 | title = A variant in LIN28B is associated with 2D:4D finger-length ratio, a putative retrospective biomarker of prenatal testosterone exposure | journal = American Journal of Human Genetics | volume = 86 | issue = 4 | pages = 519–525 | date = April 2010 | pmid = 20303062 | pmc = 2850436 | doi = 10.1016/j.ajhg.2010.02.017 }}</ref><ref name="Wong_2016"/><ref name="Pratt_2016">{{cite journal | vauthors = Pratt TC, Turanovic JJ, Cullen FT | title=Revisiting the Criminological Consequences of Exposure to Fetal Testosterone: A Meta-Analysis of the 2D:4D Digit Ratio | journal=Criminology | publisher=Wiley | volume=54 | issue=4 | date=22 September 2016 | issn=0011-1384 | doi=10.1111/1745-9125.12115 | pages=587–620}}</ref>
# Lack of a clear [[Correlation does not imply causation|cause-and-effect]] relationship between digit ratio and traits.<ref name="McCormick_2020">{{cite journal | vauthors = McCormick CM, Carré JM | title = Facing off with the phalangeal phenomenon and editorial policies: A commentary on Swift-Gallant, Johnson, Di Rita and Breedlove (2020) | journal = Hormones and Behavior | volume = 120 | pages = 104710 | date = April 2020 | pmid = 32057822 | doi = 10.1016/j.yhbeh.2020.104710 | publisher = Elsevier BV | s2cid = 211112860 }}</ref><ref name="Jones_2021"/><ref name="Smoliga_2021" />

Concerning the evidence for causal relationships, the reliability of digit ratio as a [[proxy variable]] has come under scrutiny.<ref name="Leslie_2019">{{cite journal | url=https://www.science.org/news/2019/06/talk-hand-scientists-try-debunk-idea-finger-length-can-reveal-personality-and-health | vauthors=Leslie M | title=Talk to the hand. Scientists try to debunk idea that finger length can reveal personality and health | journal=Science | year=2019 | doi=10.1126/science.aay2735 | s2cid=241187298 | access-date=1 October 2021 | archive-date=10 October 2021 | archive-url=https://web.archive.org/web/20211010065849/https://www.science.org/news/2019/06/talk-hand-scientists-try-debunk-idea-finger-length-can-reveal-personality-and-health | url-status=live | url-access=subscription }}</ref><ref name="McCormick_2020"/><ref name="Voracek_2019" /> Some studies that investigate the relationship between a trait and an unobservable variable fail to consider possible [[confounding variables]].<ref>{{cite journal | vauthors = Lolli L, Batterham AM, Kratochvíl L, Flegr J, Weston KL, Atkinson G | title = A comprehensive allometric analysis of 2nd digit length to 4th digit length in humans | journal = Proceedings. Biological Sciences | volume = 284 | issue = 1857 | pages = 20170356 | date = June 2017 | pmid = 28659446 | pmc = 5489719 | doi = 10.1098/rspb.2017.0356 }}</ref> This is especially problematic in cases where the relationship is likely to be weak, such as with prenatal testosterone.<ref name="Hollier_2015">{{cite journal | vauthors = Hollier LP, Keelan JA, Jamnadass ES, Maybery MT, Hickey M, Whitehouse AJ | title = Adult digit ratio (2D:4D) is not related to umbilical cord androgen or estrogen concentrations, their ratios or net bioactivity | journal = Early Human Development | volume = 91 | issue = 2 | pages = 111–117 | date = February 2015 | pmid = 25594498 | doi = 10.1016/j.earlhumdev.2014.12.011 | publisher = Elsevier BV | hdl = 20.500.11937/48405 | url = https://research-repository.uwa.edu.au/en/publications/b3d44281-0fcf-499c-9743-7daac128c486 }}</ref><ref name="Wong_2016">{{cite journal | vauthors = Wong WI, Hines M | title = Interpreting digit ratio (2D:4D)-behavior correlations: 2D:4D sex difference, stability, and behavioral correlates and their replicability in young children | journal = Hormones and Behavior | volume = 78 | pages = 86–94 | date = February 2016 | pmid = 26542674 | doi = 10.1016/j.yhbeh.2015.10.022 | publisher = Elsevier BV | s2cid = 26592548 }}</ref><ref name="Voracek_2019" />  Furthermore, critics have pointed out that controlling for confounding variables is an impossible task due to the expanding list of confounding variables, including ethnicity, sex,<ref name="Manning_2004" /><ref name="Lindová_2008">{{cite journal | vauthors = Lindová J, Hrušková M, Pivoňková V, Kuběna A, Flegr J | title=Digit ratio (2D:4D) and Cattell's personality traits | url = https://archive.org/details/sim_european-journal-of-personality_2008-06_22_4/page/347 | journal=European Journal of Personality | publisher=SAGE Publications | volume=22 | issue=4 | date = June 2008 | issn=0890-2070 | doi=10.1002/per.664 | pages=347–356| s2cid=18205251 }}</ref> and physical, medical or behavioral conditions.<ref name="McQuade_2011">{{cite journal | vauthors = McQuade DB | title = Does digit ratio (2D:4D) predict penile length? | journal = Asian Journal of Andrology | volume = 13 | issue = 5 | pages = 667–668 | date = September 2011 | pmid = 21725331 | pmc = 3739583 | doi = 10.1038/aja.2011.81 | publisher = Medknow }}</ref>

A 2021 paper by James Smoliga, titled "Giving science the finger—is the second-to-fourth digit ratio (2D:4D) a biomarker of good luck? A cross sectional study" followed similar research methodologies adopted by others in the field and came to conclude that low digit ratio is associated with good luck.<ref name="Smoliga_2021" /> This result is attributed to chance and presented as an illustration of the [[Replication crisis|reproducibility crisis]]. Smoliga would later go on to label the field as pseudoscience.<ref>{{Cite web |title=Faculty Spotlight: James M. Smoliga {{!}} Tufts University School of Medicine |url=https://medicine.tufts.edu/news-events/news/faculty-spotlight-james-m-smoliga |access-date=2023-12-25 |website=medicine.tufts.edu |archive-date=25 December 2023 |archive-url=https://web.archive.org/web/20231225091109/https://medicine.tufts.edu/news-events/news/faculty-spotlight-james-m-smoliga |url-status=live }}</ref> In a response, John T. Manning criticized the researchers for not controlling for ethnicity.<ref>{{Cite journal |last=Manning |first=John T. |date=11 June 2023 |title=The Big Finger Trumps the Lucky Jim Fallacy |url=https://www.bmj.com/content/375/bmj-2021-067849/rr |journal=The BMJ |language=en |access-date=11 June 2023 |archive-date=11 June 2023 |archive-url=https://web.archive.org/web/20230611013153/https://www.bmj.com/content/375/bmj-2021-067849/rr |url-status=live }}</ref>

Researcher Marta Kowal states: "One of the general limitations of studies on the digit ratios is the high number of degrees of freedom within the 2D:4D (the right, left, and right minus left 2D:4D). Running many analyses with different predictors [[Multiple comparisons problem|increases the chances of finding allegedly significant results.]]"<ref name="No relationship between the digit r"/>