Final answer:
Shifts in the aggregate supply curve result from changes in determinants such as productivity, input prices, technology, and policy decisions, which can cause shifts to the right or left with varying economic outcomes.
Step-by-step explanation:
Shifts in the aggregate supply curve are caused by changes in one or more of the determinants of aggregate supply. A shift in the aggregate supply curve can occur due to changes in factors like productivity, the price of key inputs, levels of technology, and policy decisions. For example, an increase in productivity or a decrease in the price of key inputs can cause the aggregate supply curve to shift out to the right, typically resulting in lower inflation, higher output, and lower unemployment. Conversely, factors that decrease productivity or increase the cost of key inputs may cause the aggregate supply curve to shift to the left, which can lead to higher inflation and unemployment, a situation known as stagflation.