  The process of evolutionary emergence of purposeful adaptive behavior is
investigated by means of computer simulations. The model proposed implies that
there is an evolving population of simple agents, which have two natural needs:
energy and reproduction. Any need is characterized quantitatively by a
corresponding motivation. Motivations determine goal-directed behavior of
agents. The model demonstrates that purposeful behavior does emerge in the
simulated evolutionary processes. Emergence of purposefulness is accompanied by
origin of a simple hierarchy in the control system of agents.
