  This paper provides the foundations of a unified cognitive decision-making
framework (QulBIT) which is derived from quantum theory. The main advantage of
this framework is that it can cater for paradoxical and irrational human
decision making. Although quantum approaches for cognition have demonstrated
advantages over classical probabilistic approaches and bounded rationality
models, they still lack explanatory power. To address this, we introduce a
novel explanatory analysis of the decision-maker's belief space. This is
achieved by exploiting quantum interference effects as a way of both
quantifying and explaining the decision-maker's uncertainty. We detail the main
modules of the unified framework, the explanatory analysis method, and
illustrate their application in situations violating the Sure Thing Principle.
