This paper proposes the study of 'phenomenon' described by the design actions in order to recognize the complex structure of decision-making processes to be faced by a designer. It is assumed that this process is composed of either the ‘designer act’ (or 'creative act'), and of the complex structure of information integration and the evaluation of decisions and alternatives. In this sense, design is not understood as a creative process that comes out of nowhere, but as 'the continuous process of evolutionary adaptation between the interpretative model of reality, and the intervention on that reality’.