As Gulliver sails around the world, what he finds is that he may as well have stayed at home: everywhere he goes, familiar political problems emerge. In Lilliput, he encounters petty partisanship and resentment. In Brobdingnag, he is forced to account for the poor moral value of English government. And in Laputa, he witnesses the exploitation of lands and colonies for money. The Brobdingnagians may be a better kind of Yahoo, but the only real "Other" in this book is the Houyhnhnm Master Horse. Otherwise, it's always the same stuff, different day.
Gulliver's adaptation to Lilliput and, especially, Brobdingnag strongly foreshadows his conversion to Houyhnhnm-worship in the final portion of the book. His adaptation to the Houyhnhnms differs in degree, but not in quality, from his earlier travels abroad.
By emphasizing the curiosity and interest of foreign peoples towards Gulliver, Swift indicates the essential human nature that they all share, despite massive differences in appearance and culture.