Final answer:
The concept consistent with the statement that a consumer can purchase a product on a higher indifference curve although it is outside their budget is the income effect. This effect describes the change in an individual's consumption resulting from changes in purchasing power. It is different from the substitution effect, which focuses on changes in consumption caused by relative price changes.
Step-by-step explanation:
The statement that a consumer can purchase a product on a higher indifference curve despite it being outside their budget constraint is consistent with the concept of the income effect. The income effect refers to the change in an individual's consumption patterns due to a change in their purchasing power, which can occur after a change in income or a change in the price of goods. When a consumer's income increases or the good becomes cheaper, they can afford to reach a higher indifference curve, wherein they can enjoy more utility or satisfaction even if the good was originally outside their budget.
Moreover, when looking at a scenario where a price change occurs, the substitution effect comes into play as consumers might opt for more of the good that has become relatively cheaper. However, the income effect takes into account the overall purchasing power and utility that a consumer gets from their budget. The present consumption patterns are affected by both the substitution and the income effects in intertemporal budget constraints, as illustrated in the given Figure B6 Indifference Curve.