What is the 2D:4D digit ratio theory?

The last few episodes have been pretty heavy. So here’s… well, here’s the 2D:4D ratio. Does the difference in length between your index finger and your ring finger reveal a huge amount about your personality (and much more besides)?

Perhaps you won’t be surprised by the answer. But we promise you’ll be surprised by just how much effort scientists have put into finding out…

The Science Fictions podcast is brought to you by Works in Progress magazine. And now, articles from Works in Progress magazine are read aloud to you by… Stuart from Science Fictions. Every week, a new audio version of a WiP article will be released for your listening enjoyment. Find out more at www.worksinprogress.news.

Show notes

* Anthropological paper from 1888 on hands

* A “preliminary investigation” of digit ratio and personality (2002)

* Meta-analysis on the topic of aggression from 2017

* PNAS study on the digit ratios of London City traders

* Vastly bigger, null study on 2D:4D and economic preferences

* Study of digit ratio in orchestral musicians

* Follow-up study with contradictory results on musical abilities

* 2D:4D and the wearing of wedding rings

* Original paper on sexuality and digit ratio

* 2025 meta-analysis

* Digit ratio and penis size

* Manning’s 2020 paper on COVID-19 and digit ratio

* Critical follow-up letter

* 2010 meta-analysis on athletic ability

* Using 2D:4D to understand prehistoric cave paintings

* 2021 BMJ Christmas Issue study on digit ratio and luck

* Comparing inter- and intra-observer reliability for digit ratios across different measures (and Manning’s concerns about similar)

* Debate over “allometric scaling”: concerned; less concerned

* 2024 meta-analysis on whether this even relates to other testosterone measures

* 2026 meta-analysis still using 2D:4D (among other measures)

Credits

The Science Fictions podcast is produced by Julian Mayers at Yada Yada Productions.

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