Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

Quiet days often follow big news events, and this morning investors seemed content to take their big gains from yesterday's session following Janet Yellen's first testimony before Congress as head of the Federal Reserve. As of 11 a.m. EST, the Dow Jones Industrials (DJINDICES:^DJI) were down 29 points, giving up modest gains from earlier in the session but still holding onto most of the ground gained in yesterday's nearly 200-point rise. Caterpillar (NYSE:CAT) led the Dow's gainers higher, while Procter & Gamble (NYSE:PG) was one of the poorer performers in the average early in the trading day.

Caterpillar's gain of more than 1% points to continued optimism that the global economy could finally be reaching firmer ground. In particular, Caterpillar's exposure to the mining industry has caused it substantial problems over the past year, as plunging prices for gold and other mined materials caused customers to spend less on heavy machinery and other capital equipment made by companies such as Caterpillar. Yet gold has surprised investors in 2014, as bullion prices have climbed by nearly $100 per ounce year to date. News of higher exports in China also led to greater enthusiasm about macroeconomic conditions worldwide. If those favorable trends continue, then Caterpillar could not only do better itself but also signal better times for other pure-industrial companies in the Dow Jones Industrials.

But things aren't all good in foreign markets. Procter & Gamble dropped almost 1.5% after reducing its guidance for 2014, blaming turmoil in several emerging-nation currency markets for a hit of between 2 and 3 percentage points to the company's all-in sales growth rate. The consumer goods giant also expects foreign exchange concerns to cause a 9 percentage point drop in earnings-per-share growth. Despite reaffirming currency-neutral expectations, P&G cited many different countries, including key emerging markets Brazil, Russia, and South Africa, as well as lower-profile markets such as Ukraine, Argentina, and Venezuela. Not all companies have as much emerging-market exposure as Procter & Gamble, but a strong dollar poses a threat to the entire Dow's earnings for 2014.

In assessing the sustainability of the Dow's recovery over the past week, it's important for investors to look closely at the stocks that have posted the strongest gains and see if they're able to build upward momentum. If recent gains give way to another corrective move, that would represent a shift in investor sentiment from the buy-the-dip mentality that has dominated the stock market for years.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.