Young children demonstrate the derivation of equivalence relations after only a brief training history. Although a number of theories have proposed possible variables that give rise to these effects, the role of the child’s preverbal learning history has not been fully addressed. The present paper describes some perceptual skills that may be important for the later emergence of derived performances. Specifically, a distinction is offered between nonverbal and verbal perceptual discriminations. The relationship between these skills is discussed as is the role of receptive language in their development. This account suggests that explicit histories that establish generalized verbal perceptual skills are necessary for the emergence of equivalence. According to this account, equivalence is defined as a byproduct of practices within the verbal community, and not as a basic stimulus function.