The idea of mediation of elementary mental functions by “psychological tools” or “signs” was introduced and formulated by Vygotsky. The main purpose of this paper is to review some of the important aspects of Vygotsky’s mediational/semiotic psychology as they relate to the concepts of signalling, signification, and culture. It has been suggested that as a matrix reflecting many aspects of life, culture “creates special forms of behavior, modifies the activity of mental functions and adds new stories to the developing system of human behavior.” Culture regulates behavior through generating some “models” which may be reflected in different modes of representations as folk models and metaphors. (Habibollah Ghassemzadeh)