We Meet the Most Ticklish Girl Next Door’s Feet on Earth
They found that the subjects laughed just as much when they believed they were being tickled by a machine as when they thought they were being tickled by a person.
To understand how much of the tickle response is dependent on the interpersonal relationship of the parties involved, and Harris presented subjects with a "mechanical tickle machine".
We Meet the Most Ticklish Girl Next Door’s Feet on Earth
This suggests that when a person tries to tickle himself or herself, the sends to the precise information on the position of the tickling target and therefore what sensation to expect.