(Adds today's rise in the S&P 500.)NEW YORK ( TheStreet) -- The stock market's erratic moves this year haven't been for the faint at heart. Still, investors shouldn't be so concerned. Jim Paulsen, chief investment strategist at Wells Capital Management in Minneapolis, says stock-price volatility for traders is different than it is for the average American. Traders take a short-term view because they live and breathe by daily moves in the market. Investors like us are in it for the long haul and are less affected.