Human factors are widely defined as the application of psychological and physiological principles to the engineering and design of products, processes, and systems. In the last few decades, the consideration of these aspects has become very relevant to the design of human-interaction with AR/VR technologies. How the human mind respond to a simulated environment? How can the sense of presence be enhanced by understanding the principle of functioning of our brain? How can we effectively simulate beauty, luxury, sustainability, comfort, safety, and many other human perceptions, taking into account the technological limitations of the available device and techniques? How can we overcome the cognitive loads of users when presenting information in Augmented or Mixed Reality situations? How can we effectively mix information coming from our different ‘natural sensors’ distributed across our body in order to best simulate particular experiences? These are only a few of the questions that cognitive neuroscience has started to address in the last few years. In this presentation, a summary of what this approach can offer to the design of more efficient user experiences in AR/VR will be presented, together with some practical examples from applied research.