Throughout the years a lively debate has flourished around niche construction theory. A source of contention has been the distinction between narrow and broad construction activities proposed by critics. Narrow construction is limited to the production of evolutionarily advantageous artifacts while broad construction refers to construction activities that have an impact on the ecosystem but offer little or negative adaptive feedback to the organisms. The first has been acknowledged as relevant to evolutionary studies in that it increases species’ fitness and (...) it is genetically inherited, while the second has been dismissed as accessory and irrelevant. I argue this distinction is unsatisfactory and leads to misinterpreting the achievements of niche construction theory. Instead I propose a three-tier categorization of constructionism (literal, analogical, and figurative) based on the analysis of the metaphor of construction itself. I show metaphors are not a mere rhetorical device but represent an instrument through which theories evolve and introduce new elements. In fact through this categorization I will be able to highlight two innovative features of constructionism: the introduction of reciprocal causation as a main causal framework and the expansion of studies about evolution to large frameworks involving multiple levels of biological organization. I will show their role in each of the three kinds of construction in order to offer a better understanding of the distinctive features of the niche construction approach. The innovations introduced encourage the revision of the concepts of adaptation and enlarge the range of phenomena to be considered relevant in biological studies. (shrink)