The IS curve, by contrast, shifts whenever an autonomous (unrelated to Y or i) change occurs in C, I, G, T, or NX. Following the discussion of Keynesian cross diagrams in Chapter 21 "IS-LM", when C, I, G, or NX increases (decreases), the IS curve shifts right (left). When T increases (decreases), all else constant, the IS curve shifts left (right) because taxes effectively decrease consumption. Again, these are changes that are not related to output or interest rates, which merely indicate movements along the IS curve. The discovery of new caches of natural resources (which will increase I), changes in consumer preferences (at home or abroad, which will affect NX), and numerous other “shocks,” positive and negative, will change output at each interest rate, or in other words shift the entire IS curve.