1. A computer-implemented method of determining an object which causes an input to be sensed, the method comprising: receiving a first sensed input at a first plurality of time points; receiving a second sensed input at a second plurality of time points; determining a first temporal adjacency value, wherein the first temporal adjacency value represents a frequency that the first sensed input was received at a first time point within the first plurality of time points temporally adjacent to a second time point within the second plurality of time points; determining that the first sensed input and the second sensed input form a group of sensed inputs caused by the object based on the first temporal adjacency value; receiving a third sensed input; determining a first value that indicates a probability that the third sensed input is a member of the group; and storing the first value in a computer readable memory.