Daily rhythms in mobile telephone communication

TL;DR

This study analyzes 18 months of mobile phone data and questionnaires to reveal individual and social differences in daily communication rhythms, highlighting persistent personal patterns and gender-based call duration differences.

Contribution

It provides new insights into how circadian rhythms influence social communication patterns and demonstrates the social component of individual daily activity rhythms.

Findings

Clear individual differences in daily phone call patterns.

Persistence of personal rhythms despite social network turnover.

Women tend to make longer calls, especially in the evening and night.

Abstract

Circadian rhythms are known to be important drivers of human activity and the recent availability of electronic records of human behaviour has provided fine-grained data of temporal patterns of activity on a large scale. Further, questionnaire studies have identified important individual differences in circadian rhythms, with people broadly categorised into morning-like or evening-like individuals. However, little is known about the social aspects of these circadian rhythms, or how they vary across individuals. In this study we use a unique 18-month dataset that combines mobile phone calls and questionnaire data to examine individual differences in the daily rhythms of mobile phone activity. We demonstrate clear individual differences in daily patterns of phone calls, and show that these individual differences are persistent despite a high degree of turnover in the individuals' social networks. Further, women's calls were longer than men's calls, especially during the evening and at night, and these calls were typically focused on a small number of emotionally intense relationships. These results demonstrate that individual differences in circadian rhythms are not just related to broad patterns of morningness and eveningness, but have a strong social component, in directing phone calls to specific individuals at specific times of day.