Example: Theory of Supply and Demand; this simplistic model of the supply and demand of goods in a market is always true no matter individual differences and biases. When the price increases, it can said that all consumers will be less willing to buy that product, considering the theory of rational choice (this can be contradictory). Hence, this example shows how the validity and evidence-based proof of the supply-demand model is so storng that it overshadows personal differences in spending patterns, culture, race, education, etc.