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.

There was good reason for the S&P 500 Index (SNPINDEX:^GSPC) to fall today, as Wall Street grew more concerned about increasing tensions arising from Syria's alleged use of chemical weapons on civilians last week. While the shift away from risky investments like stocks makes some sense intuitively in the short term, it has almost always been a losing position in the long run. Today's worst-performing S&P stocks, unfortunately, were the victims of Mr. Market's psychology of fear that ran rampant on the Street today. The S&P 500 shed 1.6%, or 26 points, ending at 1,630 Tuesday.

Chipmaker Advanced Micro Devices (NASDAQ:AMD), for instance, plunged 5.3% today, despite little company-specific news that could realistically be credited with such a decline. Think about it: Is AMD -- holistically, as a company -- really worth 5% less than it was just a day ago, merely because some suits on Wall Street got spooked about the Middle East? The Syrian conflict, I agree, is a massively important geopolitical issue. But how does Syria have such a colossal influence over the price of a semiconductor stock?

Western Digital (NASDAQ:WDC) appears to be another victim of illogical bearishness Tuesday. The stock, which lost 5.2% today, is already 50% more volatile than the broader market, and with the technology sector stumbling 2.2% today, the data storage company didn't stand a chance. To be fair to the market's mind-set for a moment, Western Digital's results are pretty darn volatile in their own right -- on an absolute basis, the company averages a 100% net change in yearly profits over the last four fiscal years. That's not exactly a pillar of consistency. 

Lastly Boston Scientific (NYSE:BSX) shed 5.2% today, as the $14 billion medical devices company took a big blow. Not surprisingly, the stock is also highly volatile, and unlike Western Digital Boston Scientific doesn't pay any dividend. Zilch. That didn't go over well with investors Tuesday, as money migrated to safer investments: companies, for instance, that haven't lost over $1 billion in four of the past five years, like Boston Scientific has..

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.