[show abstract][hide abstract] ABSTRACT: The goal of this paper is to investigate how to acquire useful action knowledge by observing the results of exploratory actions on objects. We focus on poking as a representative type of nonprehensile manipulation. Poking can be defined as a short term pushing action. Here we propose an explorative process that allows the robot to learn the relationship between the point of contact on the object boundary and the angle of poke and the actual response of an object. The robot acquires this knowledge without having any prior knowledge about the action. Initially, the robot was only able to move in random directions. Such self emergent processes are essential for the early cognition. The proposed process has been implemented and tested on the humanoid robot Hoap-3.