Cell phones are making people walk differently. A study that tracked how 21 people negotiated an obstacle and a step, without a phone or while texting, reading the screen, or making a call, found that using a phone made people walk slower and in less of a straight path, particularly when texting (Timmis et al., 2017).
Timmis, M.A, Bijl, H., Turner, K., Basevitch, I., Taylor, M.J.D. & van Paridon, K.N. (2017) The Impact of Mobile Phone Use on Where We Look and How We Walk when Negotiating Floor Based Obstacles. PLoS One. https://doi.org/10.1371/journal.pone.0179802.