1. An information processing method comprising: storing sequential data relating to movements of a target object over a specified plane; generating a position hypothesis related to a candidate position of the target object at each sequential time point based on the stored sequential data; sequentially estimating a plurality of first likelihoods of a position of the target object in a direction of the specified plane based on the sequential data, each of the plurality of first likelihoods being associated with a generated position hypothesis; sequentially estimating a plurality of second likelihoods of touch of the target object on the specified plane based on the sequential data, each of the plurality of second likelihoods corresponding to one of the plurality of first likelihoods; updating the plurality of first likelihoods based on the plurality of second likelihoods; and determining a position of the target object in the direction of the specified plane based on the updated plurality of first likelihoods.