When confronted with ethical business dilemmas, people think and behave in a way that is not considered by business ethics theories. Our claim is that ethical theories overlook what, according to the distributed cognition approach, seems to be the standard operational way for our brain to work: the interplay between internal and external resources. We provide evidence in the literature that shows that advice taking is an external resource that is always available and fundamental in ethical judgement. We present a mathematical model of advice taking that allows one to express the probability of a decision as a function of the strengths of the judge and of the advisor in their relative positions and of the flexibility of the judge in receiving the advice of the advisor. Flexibility may depend on social proximity, advisor knowledge, power and authority. The model is then validated through the application to some empirical data.