Listening comprehension is a basic skill acquired in early childhood. As the years progress, learners are required to listen through longer periods of time in much more diverseand noisier conditions and process more complicated information. In the context of academic learning, students must focus their attentional resources on the auditory information conveyed by the lecturer or teacher in order to learn efficiently from listening: sustain their attention throughout the lesson and ignore distracting noises surrounding them- peers chatting, external noise etc. In my project, I plan to develop an online feedback system based on pupillometry to improve listening comprehension skills. Our eyes are an external window to internal processes such as cognitive load in general and more specific processes such as attentional fluctuations in time. I'm trying to implement the knowledge accumulated in the cognitive psychology labs regarding pupillometry and mental states and implement the knowledge in learning methods aimed to improve individual learning, by giving the learners online feedback on their cognitive state during the learning process.