Digit Ratio 4+

Digit Ratio (2D:4D‪)‬

Everyware Apps

Designed for iPhone

    • 1.5 • 2 Ratings
    • Free

iPhone Screenshots


A now widely studied putative marker for prenatal sex hormones exposure or, more precisely, for the relative exposure to testosterone compared to estrogens while in uterus, is the second-to-fourth digit ratio (2D:4D), that is the ratio between the index (2D) and the ring (4D) fingers.

Digit-ratio app is a tool to obtain anonymous measurements of digit ratios (2D:4D).

Earlier studies that have stood the test of replication have reported that 2D:4D varies by sex and ethnicity but that male 2D:4D tends to be lower than female 2D:4D in all ethnic groups and the effect is strongest in the right hand. These differences emerge prenatally and appear to be stable during the developing years.

While a number of failed replications have been reported, 2D:4D appears to be successfully associated with cognitive abilities, impulsivity, aggression and risk-taking, among other effects on personality and cognition.

The objective of the research project is to collect anonymous measurements from multiple individuals. The measurements and profile data may be sent to a server for research purposes. No image will be sent.

What’s New

Version 1.0.2

This app has been updated by Apple to display the Apple Watch app icon.

Updated detection algorithm and CSV export format.

Ratings and Reviews

1.5 out of 5
2 Ratings

2 Ratings

Autocheck111 ,

The Detection algorithm doesn’t work

I’ve tried it in different light and on different surface but the palm detection algorithm doesn’t work. And in the few cases it detects the palm it can’t figure out the correct length of the fingers. All you would need to detect a palm is some basic adaptive thresholding so I’m confused why this performs so poorly.

App Privacy

The developer, Everyware Apps, has not provided details about its privacy practices and handling of data to Apple.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.

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