This paper surveys psychological predicates cross-linguistically and observe some morpho-syntactic characteristics of a psych construction which takes a psychological one as its predicate. A psych construction usually involves two participants as the arguments: human experiencer and theme. They exhibit some correlative relationships between these semantic roles and surface grammatical relations cross-linguistically. In topic-prominent languages, the human experiencer of a psych construction is consistently marked as dative. These dative marked nominals are called as dative subjects, which exhibit properties otherwise limited to grammatical subjects. In many subject-prominent languages, the human experiencer is a nominative, or ergative marked subject and the theme appears as a superficial object. Some Sp languages, however, have dative subjects in psych constructions. A cross-linguistic sample tests that dative subjects are more freely recognized in psych constructions of topic prominent languages without any change of a case form. On the basis of this empirical evidence, this paper suggests that the dative subject in a psych construction is closely related to a topic of the structure and that if a language is topic-prominent, it has a dative subject as an implicational universal.