The reason why the slowdown might not be long-term is because of other indicators such as jobs, inventories, wages, and investments don't seem to be doing too bad. If multiple data sets across varying industries show the same trend this could be indicative of a problem. At present it isn't.
Of course projections can always be wrong and I take some fun in seeing if I can find some accurate way of perceiving future trends based on present data. I see people being more cautious than anything else. Yes...I know what a few polls have said but.....there is no economic basis for it if other aspects of the economy have improved.
If unemployment actually is decreasing, wages are moving up, saving rates are stable, and manufacturing is making a turnaround despite the inflated dollar, than how does the average person come to a conclusion about the market? In many cases these are feelings based upon other aspects in their environment.
Lets look at an example. If politics is brutal, negative rhetoric about doomsday in the economy, international conflict brewing, and fears of personal safety related to terrorism talk impacts the thinking of a significant population of society there is bound to be some pessimism. People don't spend when they are not sure of the future. They covet and hold their money.
Animal spirits are wild and often uncontrollable. These phantoms of doom do have an impact on spending. Considering that over 3/4 of our economy is based on consumer spending pessimism can have an impact on consumer choices and the economy. Therefore, a dip in consumer spending may be more of our own making than any real issues in the market. Future information and data changes the assumptions.