It may, a bit. If the 401k is in the stock market, and the stock market is down, their total visible money is down. That tends to decrease enthusiasm for spending.
It may also affect it a lot. Retirees I know have a retirement plan that involves their retirement accounts being at a specific level at the end of each year. If their accounts are over that level because the stock market had a good year, they consider it funny money that they're allowed to spend.
