Factors influencing visual comfort remain to a great extent unclear and in particular the impact of mobile devices with backlighting have been to date insufficiently studied. In this research project, artificial light is gradually dimmed while participants perform a normalized cognitive task. Participants' physiological parameters and psychological states are recorded through sensors for physiology and by asking participants about their comfort and their willingness to change current lighting conditions for psychology.

This testing is done in two screen luminance adaptation conditions (fixed or adaptive) to study the influence of backlighting. Preliminary results show that people react at different times - sometimes even close to complete darkness - and that the reaction to the decrease in light depends on screen adaptability: fixed screen backlighting makes participants react later than adaptive backlighting.