We designed a mobile video game to test spatial ability & tested more than 2.5 million people from every country; spatial ability of the population is correlated with country economic wealth, & gender inequality of a country is predictive of gender differences in navigation ability

Global Determinants of Navigation Ability. Antoine Coutrot et al. Current Biology, https://doi.org/10.1016/j.cub.2018.06.009

Highlights
•    We designed a mobile video game to test spatial ability in humans
•    We tested more than 2.5 million people from every country in the world
•    Spatial ability of the population of a country is correlated with economic wealth
•    Gender inequality of a country is predictive of gender differences in navigation ability

Summary: Human spatial ability is modulated by a number of factors, including age [1, 2, 3] and gender [4, 5]. Although a few studies showed that culture influences cognitive strategies [6, 7, 8, 9, 10, 11, 12, 13], the interaction between these factors has never been globally assessed as this requires testing millions of people of all ages across many different countries in the world. Since countries vary in their geographical and cultural properties, we predicted that these variations give rise to an organized spatial distribution of cognition at a planetary-wide scale. To test this hypothesis, we developed a mobile-app-based cognitive task, measuring non-verbal spatial navigation ability in more than 2.5 million people and sampling populations in every nation state. We focused on spatial navigation due to its universal requirement across cultures. Using a clustering approach, we find that navigation ability is clustered into five distinct, yet geographically related, groups of countries. Specifically, the economic wealth of a nation was predictive of the average navigation ability of its inhabitants, and gender inequality was predictive of the size of performance difference between males and females. Thus, cognitive abilities, at least for spatial navigation, are clustered according to economic wealth and gender inequalities globally, which has significant implications for cross-cultural studies and multi-center clinical trials using cognitive testing.