In this paper we describe an embodied developmental model of the interactions between the neural representations of numbers and space in the humanoid robot iCub. We show how a simple developmental process that mimics real-world cultural biases leads to the emergence of certain properties of the number and space representation system that enable the robot to reproduce well-known experimental phenomena. We demonstrate the validity of the proposed approach by showing that it leads to the reproduction of three psychological phenomena connected with number processing, namely size and distance effects, the SNARC effect and the Posner-SNARC effect.