Building on the brain’s functions to use information from the past and present to predict the future, Darkball by Che-Wei Wang is an iPhone application and a tool to understand how the nervous system makes such predictions.

This function is key to how animals, from dragonflies to humans, navigate a dynamic and uncertain world. To make predictions, the brain must have an “internal model” of the system it interacts with. A basic form of this function is at play when we move our body. For example, to reach for a cup, the brain must have a model to predict how the hand will respond to various motor commands. Internal models are also thought to play a crucial role when we mentally predict future states of the environment, for example when we track a ball as it moves behind another object. Here, we have designed a simple task to understand how the nervous system makes such predictions.