1. An information processing apparatus, comprising: a touch sensor configured to generate a sensor signal based on proximity and contact of a manipulation object on a display screen, wherein the display screen comprises a manipulatable region and a detection invalidity region that lies within the manipulatable region; and circuitry configured to: detect proximity of the manipulation object based on the sensor signal, wherein a first proximity detection of the manipulation object in the manipulatable region outside the detection invalidity region is invalid based on a second proximity detection of the manipulation object outside the detection invalidity region prior to the first proximity detection in the manipulatable region outside the detection invalidity region, and wherein the first proximity detection of the manipulation object in the manipulatable region outside the detection invalidity region is valid based on a third proximity detection of the manipulation object in the detection invalidity region prior to the first proximity detection in the manipulatable region outside the detection invalidity region; set a priority order among a plurality of manipulation objects based on the proximity detection of the plurality of manipulation objects; adopt a proximity detection result based on the set priority order; and set a display size of a first region corresponding to each manipulation object of the plurality of manipulation objects based on a signal strength of the sensor signal corresponding to the each manipulation object of the plurality of manipulation objects.