People increasingly communicate with their mobile devices on the go. In the field, contexts vary and influence the users' internal state and behavior, which impacts the quality of interaction with mobile devices. In this work, we present results from a field study to assess typing behavior, stress and contextual characteristics. Our CoConUT toolkit tracks contextual and behavioral variables with apps and special hardware. We focus on the occurrence of typing errors, and confirm prior results in detail that people do not slow down for typing while walking, despite producing more typing slips. Furthermore, we show to which extent increased stress leads to an increase in typing errors.

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