When she saw what had happened, Mrs. Retallack began to wonder what other people had found out about sound and plants. She learned that in India scientists had tried to increase plant yield with music. In Canada sounds of a high pitch had seemed to help the growth of wheat. In the United States, when scientists had broadcast city noise to plants, their growth was cut almost in half. Another experimenter in the Unites States had found that plants seem to be able to show fear, worry, and even love.