President Obama's top White House economic adviser said Friday that consumer spending in the United States appears to have "stabilized," and he urged business leaders to show "more optimism and more confidence" in their investment decisions.

Lawrence H. Summers, director of the National Economic Council, said a $787 billion economic stimulus package that Obama signed into law last month is starting to have an impact, saving thousands of jobs, providing continued unemployment insurance and health benefits to several hundred thousand workers and initiating tens of billions of dollars worth of infrastructure projects.

In a speech at the Brookings Institution, a Washington, D.C., think tank, Summers also said the administration aims not only to start an economic recovery but to build a more sustainable foundation for future economic expansion. He suggested that people who are focusing solely on the recovery are setting their sights too low. And he urged Americans to take advantage of the bargains available now because of reduced prices brought on by recession in many sectors of the economy.

"Our single most important priority is bringing about economic recovery and ensuring that the next economic expansion, unlike its recent predecessors, is fundamentally sound and not driven by financial excess," he said. He said there was "one ineluctable lesson of the history of financial crises: They all end."

Obama made a similar point after a meeting at the White House today with Paul A. Volcker, chairman of his Economic Recovery Advisory Board, and other advisers.

"It is very important, even as we're focused on the financial system and the credit markets, that we are laying a foundation for what I'm calling a post-bubble economic growth model," Obama told reporters. "The days when we are going to be able to grow this economy just on an overheated housing market or people spending - maxing out on their credit cards - those days are over. What we need to do is go back to fundamentals."