We often think of ourselves as individuals with steady capabilities. However, converging strands of research indicate that this is not the case: our biochemistry varies significantly over the course of a 24 hour period; and consequently our levels of alertness, productivity, physical activity, and even sensitivity to pain can vary according to the time of day. This project focuses on identifying novel measurements and interventions that can leverage these daily variations. Our findings demonstrate that phone usage patterns can be used to detect and predict individual daily variations indicative of temporal preference, sleep deprivation, and the effects of social jet lag.

Being able to unobtrusively measure biological misalignments means there is also an opportunity for technology to play to our biological strengths. Incorporating an awareness of individual biochemical variations could have a significant impact on a wide range of technologies and help support increased well-being, productivity, and higher quality of sleep.


  • Abdullah, S., Matthews, M., Murnane, E., Gay, G. & Choudhury, T. 2014. Circadian Computing: How “Early to Bed and Early to Rise” Makes Some of Us Unhealthy and Sleep Deprived. Ubicomp 2014.
  • Biological Rhythms and Technology.Matthews, M., Carroll, E., Abdullah, S., Snyder, J., Kay, M., Choudhury, T. & Keintz, J., CHI 2014 Workshop Abstract