Common multi-day rhythms in smartphone behavior

The idea that abnormal human activities follow multi-day rhythms spans ancient beliefs centered on the moon to modern clinical observations in epilepsy and mood disorders. Multi-day rhythms remain obscure in normal human activities. To address multi-day rhythms in healthy human behavior we analyzed over 300 million smartphone touchscreen interactions logging up to 2 years of day-to-day activities (N = 401 subjects). By using non-negative matrix factorization and data-driven clustering of [~]1 million periodograms, we captured a range of multi-day rhythms spanning periods from 7 to 52 days - cutting across age and gender. Despite their common occurrence, any given multi-day rhythm was observed in different parts of the smartphone behavior from one person to the next. There was little support in the data for ubiquitous rhythm drivers like the moon. We propose that multiple multi-day rhythms are a common trait, but their consequences may be uniquely experienced in day-to-day behavior.