A method authenticates a user in order to activate an access mechanism for a device. One or more processors detect a real-time initial emotional state of the user, where the real-time initial emotional state of the user dynamically changes over time. The processor(s) present content as a stimulus to the user, and predict a predicted post-stimulus emotional state of the user, where the predicted post-stimulus emotional state of the user is predicted to be caused by the content being presented to the user, and where the predicted post-stimulus emotional state is dependent upon the real-time initial emotional state of the user. The processor(s) detect a real-time post-stimulus emotional state of the user. The processor(s) match the predicted post-stimulus emotional state of the user to the real-time post-stimulus emotional state of the user, and then authenticate the user and activate an access mechanism for a device.