Tokens alone do not state what is the subject of discourse; and this can, in fact, not be described in general terms; it can only be indicated. The actual world cannot be distinguished from a world of imagination by any description. Hence the need of pronoun and indices, and the more complicated the subject the greater the need of them.
Classified measures of curiosity into two categories. First, curiosity is viewed as a motivational state and measured with behavioral indices. Second, he conceptualizes curiosity as a personality trait that is assessed by personality measures.