The first four business days of this year, which were also painful on Wall Street, are four of Fidelity's top six days of all-time contact volume.

At T. Rowe Price, which had nearly $300 billion in retirement assets under management as of September, phone volumes over the first week of January were 56 percent higher than a typical day and web traffic spiked by around 30 percent over normal.

Both Fidelity and T. Rowe Price reported a similar phenomenon when the markets had a dark moment back in August. "Nervous investors are calling or checking in with the web," said Judith Ward, a certified financial planner at T. Rowe Price.

But it's mostly just savers who want to gawk at an unfolding mess, a way to feel like you're taking action without actually making panicked moves.

"In terms of doing a transaction, the majority are doing nothing," said Ward. During the August downturn, for instance, 98.5 percent of T. Rowe Price's 2 million plan participants didn't touch their allocations.

Fidelity agreed that most investors haven't modified their plans during period of intense interest.

The rule of thumb for 401(k) plans during market volatility is to, in fact, do nothing.

As this best practices guide from T. Rowe Price explains, markets have enjoyed a 75-year stretch of increases.

People who keep their retirement money invested over the long haul do better than those who try to predict downturns. During the financial crisis, for example, Fidelity found that those who didn't take money out of their plans saw 88 percent growth over the next five years.

Savers who moved their assets out of equities in 2008 and remained that way for the next five years, a tiny minority of Fidelity clients, saw 15 percent growth over the period.

"It's really hard to time the market," said Chip Castille, BlackRock's chief retirement strategist. "And when you react to risky events what you're in effect doing is timing the market, that's a very hard thing to do for most individuals."

The good news is: Americans with 401(k) appear to have learned these lessons and tend to stick to the best practices.

Even during the financial crisis, only 1 percent of Fidelity's plan holders got completely out of equities. In any given year, on average, Fidelity's Thompson said only 10 percent of plan holders will move money between funds.

And yet, in seemingly dire times, we need something to assuage our financial anxieties.

Thompson believes that people compulsively check on their dwindling 401(k) plans to feel comforted that nothing needs to be done. "Most people are calling just for reassurance and confidence," she said, "and making sure that, in fact, they shouldn't do anything and stay the course."

Like with any tragedy, we want to take a clear look the damage—and then we want someone to tell us it's all going to be OK.

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