This study follows the Radial Interactionism (RI) cognitive modeling paradigm introduced previously by Georgeon and Aha (2013). An RI cognitive model uses sensorimotor interactions as primitives-—instead of observations and actions-—to represent Piagetian (1955) sensorimotor schemes. Constructivist epistemology suggests that sensorimotor schemes precede perception and knowledge of the external world. Accordingly, this paper presents a learning algorithm for an RI agent to construct observations, actions, and knowledge of rudimentary entities, from spatio- sequential regularities observed in the stream of sensorimotor interactions. Results show that the agent learns to categorize entities on the basis of the interactions that they afford, and appropriately enact sequences of interactions adapted to categories of entities. This model explains rudimentary goal construction by the fact that entities that afford desirable interactions become desirable destinations to reach.