Last month, the bank said it expects to raise interest rates twice to keep inflation below 3 percentage points by the end of the decade. Money sent home by migrants constitutes the second largest financial inflow to many people developing countries, exceeding international aid. Estimates of remittances to developing countries differ from International Fund for Agricultural Development's. Remittances contribute to economic growth also to the livelihoods of folks worldwide. After August 1987, for example, as the dollar fell, people rushed to buy sterling, the high-yielding currency, which rose from $1.65 to $1.90 in a very short time, up almost 20%. In order to limit the rise in the pound, the UK cut interest rates for several consecutive times between may and June 1988, falling from 10% to 7.5%, with the pound falling every time it cut interest rates. But the pound began to pick up again after the bank of England was forced to raise interest rates several times as the pound weakened too quickly and inflationary pressures increased. Most western interest-rate determinism focuses on the analysis of supply and demand comparisons, arguing that interest rates are a price. The difference lies in what supply and demand determines interest rates. For example, Marshall's real interest rate theory emphasizes the real factors of non-monetary factors - productivity and the role of economy in determining interest rate decisions. Productivity is expressed by marginal propensity to invest, and the marginal propensity to save is expressed. The response to variability is a resilient instinct. Elastic instinct (also called the conditioned reflex) is an organism formed in the process of life change with conditions and reflection, under certain conditions unrelated stimulus be signals caused by reflections of the unconditioned stimulus. It is not innate, but the reflection of the organism under certain conditions under certain conditions. Conditioned reflex can make animal learning and memory and non-conditional reflex related, but completely different new reflection activity. The formation of conditioned reflex is the formation or connection of the cerebral cortex, which is based on non-conditioned reflex. With conditioned reflex, animals not only reflect things that have direct physiological meaning, but also those that have indirect physiological significance. Elastic instinct can make animals for the changed things to adjust their instinctive behavior, make it easy to adapt to changes in the environment, thus than rigid instinct has more flexibility and purpose, and the body through the conditioning can not before the arrival of the stimulus itself accordingly reaction, make the body more proactive and initiative. Anyway, elastic instinct is higher biological value of variability of external things more advanced way of ordering reaction, is on the rigid instinct, extension, and the synthesis, make rigid instinct has more purposeful and flexibility