This study uses minimally invasive technology to monitor the emotional response of a subject during stress inducing psychological tasks. The goal of these tasks is to investigate the possibility of measuring and subsequently categorising the subject's level of stress using biosignal devices. If a consistent metric of stress can be determined it may be used for many forms of human-machine interaction in areas such as assessment and training. Two separate psychological tests were conducted, The Stroop Colour Word Interference Test (20 subjects), and The Towers of Hanoi (17 subjects). These tests examine directed attention, and sustained, consistent attention respectively. NeuroSky's Mindset device was used to record the stress and attention level of each subject. We examined the subject's attention while undertaking these tasks, and assessed any correlation between this and their level of stress during the task. This study shows that for most subjects, the less attent the subject is, the lower their stress level, and the higher the level of attention, the greater the level of stress (increased concentration etc.) As the difficulty of the task increased, some subjects appeared to 'lose interest' or reduce their level of attention, and consequently the level of stress measured decreased.