You may have seen graphs displaying the players’ excitement levels displayed periodically during The International tournament matches. This biofeedback data is collected using a wristband with custom hardware and works by measuring the electrical conductivity of the skin and sending signals to the player’s PC. The game collects this data continuously and plots the last two minutes of the player’s biofeedback history. Swings in a player’s emotional state, both positively and negatively, are represented by spikes in the graph.